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Old 04-21-2010, 08:14 PM   #1
JetForceF22
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Throttle Mashing hesitation? (Help!)

Hello everyone.

I have a 1995 Silverado Z71 4x4 with the 5.7L 350 engine. (Need any more specs please ask)

I've done a lot of work to this truck, Engine mods include

-The ULTIMATE TBI mod (most of it)
-Adjustable Fuel Pressure Regulator (running 15-20psi, depending on outside temp)
-TBI "Swirl torque" 1in spacer plate
-Flowtech Shorty headers (3in collectors)
-Y pipe with 3 inch outlet, going to 3 inch high flow walker cat converter
-Single offset factory style exhaust outlet, also 3 inches
-Highflow Edelbrock 255lph (Roughly 66gph) fuel pump and new sending unit
-In cab fuel pressure guage
-New fuel filter about 6,000 miles ago

(aside from that regular maintenance oil changes pcv valve air cleaner ect ect.)



Okay my issue (which I was having BEFORE I changed the fuel pump and did the ultimate tbi mod and fuel filter and pressure guage) was I would mash the pedal, but it would sputter and almost die, then the transmission would down shift and then I had all the power back (but I wouldn't have any high rpm power, and would have to let off the gas to get the power) but the initial loss of power would almost kill the engine.

When I changed the fuel filter, the problem went away, shortly after that the transmission died, and I had it rebuilt a year later.

So now the problem has returned. Its not as bad as before (The sputtering before I changed the fuel filter- it would sound like the truck would go down to one or 2 cylinders before the downshift, and now its not quite that bad) But I'm experiencing the large drop in power when I mash the pedal, which should not be the case. I'm wondering if its the fuel filter again, because when I knocked the old sending unit, the sealing ring was completely covered with rust, and a small amount of dust/debris fell into the gas tank. There was really no way to get it out since there was still gas in the tank and at the time draining the tank completely was not a option.

*Edit* Also I have tested to see if the "hesitation" would also happen in 1st gear. Its like when I put the pedal to the floor, the truck doesn't respond right away, I get a large drop in the RPMs, then the truck comes back alive. Also I noticed that it does it when the truck is warm. The truck seems to run stronger when its cold, odd I thought it was supposed to be the opposite. Any help is appreciated.

Hope I explained everything clearly,
Thank you all in advanced for reading this and any suggestions is very much appreciated.
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1972 3/4 Ton Cheyenne Super, 350ci 650 cfm Edelbrock 4bbl Performer AVS, Edelbrock Torquer intake manifold, Headman Longtube Headers to 2 1/2in cutouts to 3 inch flowmaster super 40's true dual. 4.10? Rear SM-465/205 transfer case. Now this one is busted!! http://s59.photobucket.com/albums/g2...k/1972 Pickup/
1995 K1500 Silverado 5.7L 350 TBI with 1in swirl torque spacer, Flowtech shorty headers, 3 inch collectors to y pipe going to 3in highlfow cat converter, single offset passenger side outlet, full 3 inch setup from collectors. Edelbrock High Flow 255LPH/67GPH Fuel pump, adjustable fuel pressure regulator and gauge, running at about 18psi. 3.73 Rear 4L60-E 4 speed auto (Rebuilt)http://s59.photobucket.com/albums/g2...1995%20Pickup/

Last edited by JetForceF22; 04-21-2010 at 10:44 PM.
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Old 04-21-2010, 10:48 PM   #2
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Re: Throttle Mashing hesitation?

I'm an old-school carburetor and ignition guy in an HEI world. Clearly, there's a lot lacking in my knowledge base.

BUT, you 've come to the right place. There's someone on here who will know what you need to check to help decipher your problems. Stay with us and it'll come.
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Old 04-21-2010, 10:52 PM   #3
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Re: Throttle Mashing hesitation?

Yes its wonderful having a knowledge base to tap into when I need assistance. Honestly if I could go Carb I would, but since I still have to pass emissions for 5 more years I'll have to put up with it. The throttle body is not a bad unit, its really just a electronic carburetor, and for that I actually do like it a lot, its a very reliable unit. But with anything electronic the issues can easily expand to multiple different things and since I'm really just a back yard mechanic and by no means a electrician I turn to you guys for assistance

Joining this messaging board was prob one of the best moves I have made being a Chevy Truck owner.
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1972 3/4 Ton Cheyenne Super, 350ci 650 cfm Edelbrock 4bbl Performer AVS, Edelbrock Torquer intake manifold, Headman Longtube Headers to 2 1/2in cutouts to 3 inch flowmaster super 40's true dual. 4.10? Rear SM-465/205 transfer case. Now this one is busted!! http://s59.photobucket.com/albums/g2...k/1972 Pickup/
1995 K1500 Silverado 5.7L 350 TBI with 1in swirl torque spacer, Flowtech shorty headers, 3 inch collectors to y pipe going to 3in highlfow cat converter, single offset passenger side outlet, full 3 inch setup from collectors. Edelbrock High Flow 255LPH/67GPH Fuel pump, adjustable fuel pressure regulator and gauge, running at about 18psi. 3.73 Rear 4L60-E 4 speed auto (Rebuilt)http://s59.photobucket.com/albums/g2...1995%20Pickup/

Last edited by JetForceF22; 04-21-2010 at 10:53 PM.
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Old 04-21-2010, 11:11 PM   #4
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Re: Throttle Mashing hesitation?

A few things come to mind:

-Is the timing correct?
-Conditions of timing components (cap, rotor, gear, chain/gears)
-Is fuel pressure staying up when the pedal hits the floor
-I wonder if the MAP sensor is responding quick enough when the vacuum drops and telling the ECM what going on to compensate with fuel/timing
-Same for the TPS voltage
-Possible flow issue, kinked/deteriorated/dented fuel line
-If it only happens in gear, I wonder if it might be the adjustment of the TV cable
-Again, happens in gear only, is the TCC engaging too soon or not disengaging correctly


How long has this been happening? If it has been since you can remember, I wonder if the Torque converter has been changed to a very low stall and the engine can't get the revs up to get into the power range?
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Old 04-21-2010, 11:32 PM   #5
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Re: Throttle Mashing hesitation?

Okay,

To first answer your question, this has been doing this about a year before the Transmission broke down, and was extremely bad the winter before it broke down. When I changed the Fuel Filter, the truck felt like it was running new, but before I could really get a feel for it the transmission quit about 2 weeks later.

Well just thinking back, I did adjust (loosen) the throttle cable screw to put more tension on the throttle cable for immediate response when I push the pedal, I don't think that would be causing this issue.

Yes its only doing it when I'm in gear, (I'm 99% sure) I'll double check that tomorrow too.

The TV Cable.. is that related to the transmission? I'm not to familiar with that

Fuel pressure as far as I can remember stays the same when I mash the pedal. The TBI has a sensor that actually raises fuel pressure when idling. As far as I know that shouldn't be a issue either, I'll double check it tomorrow when I drive.

I have no idea how good of condition the timing chain is, I don't think its ever been replaced, so that very well could be the issue, but would that explain why the truck seems to only hesitate when its warmed up? As opposed to running stronger when its cold? Either way I prob need a new timing chain (or go to a gear drive haha)

I'm pretty sure its not the fuel lines, I checked all the lines after I did the ULTIMATE TBI mod (that's when I installed the new fuel pump ect.) and have no leaks on the lines. The lines however are pretty close to the transmission.

I'm unfamiliar with the MAP sensor (Except the basic understanding of what it does) and just doing a little research says these can go bad and cause fuel delivery problems.

And I know little about the Throttle Positioning Sensor.

Thanks for your quick response, I'll get back to you after I drive her some tomorrow to give you more definitive answers on what I can answer haha Thank you!
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1972 3/4 Ton Cheyenne Super, 350ci 650 cfm Edelbrock 4bbl Performer AVS, Edelbrock Torquer intake manifold, Headman Longtube Headers to 2 1/2in cutouts to 3 inch flowmaster super 40's true dual. 4.10? Rear SM-465/205 transfer case. Now this one is busted!! http://s59.photobucket.com/albums/g2...k/1972 Pickup/
1995 K1500 Silverado 5.7L 350 TBI with 1in swirl torque spacer, Flowtech shorty headers, 3 inch collectors to y pipe going to 3in highlfow cat converter, single offset passenger side outlet, full 3 inch setup from collectors. Edelbrock High Flow 255LPH/67GPH Fuel pump, adjustable fuel pressure regulator and gauge, running at about 18psi. 3.73 Rear 4L60-E 4 speed auto (Rebuilt)http://s59.photobucket.com/albums/g2...1995%20Pickup/
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Old 04-21-2010, 11:38 PM   #6
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Re: Throttle Mashing hesitation?

And about the torque converter, I don't think the torque converter has ever been changed, my father bought the truck in 96' with I think 30,000 miles, original everything. The transmission went up at 280,000 miles, and I'm pretty sure the torque converter was the issue, as I was told when you have singular gear loss its usually because the torque converter took a crap. So I MAY Have a new torque converter now, but to confirm that I would have to ask the shop that did the repair for me (I lost OD, then shortly after 3rd gear, then a week after that 2nd gear, and I had 1st gear and reverse, and drove it to the transmission shop with one gear lol)
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1972 3/4 Ton Cheyenne Super, 350ci 650 cfm Edelbrock 4bbl Performer AVS, Edelbrock Torquer intake manifold, Headman Longtube Headers to 2 1/2in cutouts to 3 inch flowmaster super 40's true dual. 4.10? Rear SM-465/205 transfer case. Now this one is busted!! http://s59.photobucket.com/albums/g2...k/1972 Pickup/
1995 K1500 Silverado 5.7L 350 TBI with 1in swirl torque spacer, Flowtech shorty headers, 3 inch collectors to y pipe going to 3in highlfow cat converter, single offset passenger side outlet, full 3 inch setup from collectors. Edelbrock High Flow 255LPH/67GPH Fuel pump, adjustable fuel pressure regulator and gauge, running at about 18psi. 3.73 Rear 4L60-E 4 speed auto (Rebuilt)http://s59.photobucket.com/albums/g2...1995%20Pickup/
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Old 04-22-2010, 12:29 AM   #7
TennesseeZ
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Re: Throttle Mashing hesitation? (Help!)

Quote:
Originally Posted by JetForceF22 View Post
Hello everyone.

I have a 1995 Silverado Z71 4x4 with the 5.7L 350 engine. (Need any more specs please ask)

I've done a lot of work to this truck, Engine mods include

-The ULTIMATE TBI mod (most of it)
-Adjustable Fuel Pressure Regulator (running 15-20psi, depending on outside temp)
-TBI "Swirl torque" 1in spacer plate
-Flowtech Shorty headers (3in collectors)
-Y pipe with 3 inch outlet, going to 3 inch high flow walker cat converter
-Single offset factory style exhaust outlet, also 3 inches
-Highflow Edelbrock 255lph (Roughly 66gph) fuel pump and new sending unit
-In cab fuel pressure guage
-New fuel filter about 6,000 miles ago

(aside from that regular maintenance oil changes pcv valve air cleaner ect ect.)



Okay my issue (which I was having BEFORE I changed the fuel pump and did the ultimate tbi mod and fuel filter and pressure guage) was I would mash the pedal, but it would sputter and almost die, then the transmission would down shift and then I had all the power back (but I wouldn't have any high rpm power, and would have to let off the gas to get the power) but the initial loss of power would almost kill the engine.

When I changed the fuel filter, the problem went away, shortly after that the transmission died, and I had it rebuilt a year later.

So now the problem has returned. Its not as bad as before (The sputtering before I changed the fuel filter- it would sound like the truck would go down to one or 2 cylinders before the downshift, and now its not quite that bad) But I'm experiencing the large drop in power when I mash the pedal, which should not be the case. I'm wondering if its the fuel filter again, because when I knocked the old sending unit, the sealing ring was completely covered with rust, and a small amount of dust/debris fell into the gas tank. There was really no way to get it out since there was still gas in the tank and at the time draining the tank completely was not a option.
*Edit* Also I have tested to see if the "hesitation" would also happen in 1st gear. Its like when I put the pedal to the floor, the truck doesn't respond right away, I get a large drop in the RPMs, then the truck comes back alive. Also I noticed that it does it when the truck is warm. The truck seems to run stronger when its cold, odd I thought it was supposed to be the opposite. Any help is appreciated.

Hope I explained everything clearly,
Thank you all in advanced for reading this and any suggestions is very much appreciated.
Flat spot in the TPS maybe. Do the voltage test on it, I've had new ones go bad in a matter of months.

Also watch the fuel pressure when the "bog" happens, could be a dirty filter from debris left in the tank from before. And check the spark at the plugs to make sure it's got the basics.
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Last edited by TennesseeZ; 04-22-2010 at 12:32 AM.
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Old 04-22-2010, 12:44 AM   #8
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Re: Throttle Mashing hesitation?

You describe the same thing that seems to be wrong with my truck, except mine does this and I get check engine light sometimes. Only codes i have is 12 and 43, (no signal from knock sensor) I've posted about the knock sensor a month or so ago, and truck runs much better, but still have what you describe, same thing.

Sometimes truck works like it should though, but very rarely, I'd say 8 out of 10 times I give it gas, truck bogs down and then like yours takes off. Mine is a 88 5.7, know a little different model, but sound oddly the same.

Curious about TPS, I had to replace mine, because even in park (doesn't do it in park now) truck would almost die if you gunned it suddenly. Found TPS was corroded inside and wouldn't allow you to plug connector all the way on.
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Old 04-22-2010, 04:17 PM   #9
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Re: Throttle Mashing hesitation?

There's quite a few threads concerning this with our trucks,and it seems there can be more than one cause. IIRC, ChevyTech just recently helped a member trace his problem back to a faulty EGR. And I was having problems where the truck (93 Yukon) would crank and run after a shot of starting fluid but not without it, and the transmission was acting stupid also. A new TPS fixed both problems. 68C15 finally figured that out for me. TPS can also have a "flat spot" that will cause part throttle hesitation. And a clogged fuel filter can starve the engine where it makes no power. And before trying to diagnose any of this, it's imperitave that the engine be in good tune.
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Old 04-22-2010, 06:12 PM   #10
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Re: Throttle Mashing hesitation?

Interesting, Sounds like the majority of the responses are cycling back to the TPS (which I have never changed in mine) Also for safekeeping I might as well change the fuel filter, as by now most of the debris have prob been sucked up through the fuel line and partially clogging the filter. (Would anyone recommend changing the MAP sensor too while I'm at it?)

And to Tony, the truck is giving a "Service Engine Soon" light after it has been running for about 10 minutes, I haven't had it checked but I'm presuming its lean codes from all the engine mods I'm running, the fuel pressure usually goes up once the engine is at normal operating temp.

To Tennes. I double checked the fuel pressure today when I mash on it, no sudden changes in pressure, the gauge holds steady.

Sounds like a new TPS is in order...

Thanks everyone for their help on this topic, any other suggestions are more then welcome!!
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1972 3/4 Ton Cheyenne Super, 350ci 650 cfm Edelbrock 4bbl Performer AVS, Edelbrock Torquer intake manifold, Headman Longtube Headers to 2 1/2in cutouts to 3 inch flowmaster super 40's true dual. 4.10? Rear SM-465/205 transfer case. Now this one is busted!! http://s59.photobucket.com/albums/g2...k/1972 Pickup/
1995 K1500 Silverado 5.7L 350 TBI with 1in swirl torque spacer, Flowtech shorty headers, 3 inch collectors to y pipe going to 3in highlfow cat converter, single offset passenger side outlet, full 3 inch setup from collectors. Edelbrock High Flow 255LPH/67GPH Fuel pump, adjustable fuel pressure regulator and gauge, running at about 18psi. 3.73 Rear 4L60-E 4 speed auto (Rebuilt)http://s59.photobucket.com/albums/g2...1995%20Pickup/
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Old 04-22-2010, 07:37 PM   #11
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Re: Throttle Mashing hesitation?

so if the pressure holds steady then i would rule out the filter.
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Old 04-22-2010, 07:42 PM   #12
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Re: Throttle Mashing hesitation?

Quote:
Originally Posted by JetForceF22 View Post
Sounds like a new TPS is in order...
Test it before you replace it. ChevyTech tells how here.
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Old 04-22-2010, 09:14 PM   #13
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Re: Throttle Mashing hesitation?

Very helpful Tenn., thanks for that. I prob won't be able to get around to checking it anytime soon but I will when I get the chance. Do you even think its worth testing tho? I mean it has never been changed since we've owned the truck, and the truck has 283,000 miles lol
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1972 3/4 Ton Cheyenne Super, 350ci 650 cfm Edelbrock 4bbl Performer AVS, Edelbrock Torquer intake manifold, Headman Longtube Headers to 2 1/2in cutouts to 3 inch flowmaster super 40's true dual. 4.10? Rear SM-465/205 transfer case. Now this one is busted!! http://s59.photobucket.com/albums/g2...k/1972 Pickup/
1995 K1500 Silverado 5.7L 350 TBI with 1in swirl torque spacer, Flowtech shorty headers, 3 inch collectors to y pipe going to 3in highlfow cat converter, single offset passenger side outlet, full 3 inch setup from collectors. Edelbrock High Flow 255LPH/67GPH Fuel pump, adjustable fuel pressure regulator and gauge, running at about 18psi. 3.73 Rear 4L60-E 4 speed auto (Rebuilt)http://s59.photobucket.com/albums/g2...1995%20Pickup/
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Old 04-22-2010, 10:21 PM   #14
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Re: Throttle Mashing hesitation?

I would test the MAP and the TPS both. The proceedure should be very similar. I totally forgot about the EGR also. You said that it runs better when the engine is cold and develops this issue when warm, is that correct? When the engine is cold, the ECM is running the engine a little more rich during warmup. The Coolant Temp SENSOR (not sender for the gauge) is what controls this "warm up period". Once the CTS hits something like 130 or somewhere in that range, the ECM goes into closed emissions loop. At this point the ECM is now modulating the EGR and adjusting fuel and timing from all the sensor inputs.

Does this bog exist at idle?
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Old 04-22-2010, 10:41 PM   #15
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Re: Throttle Mashing hesitation?

The truck idles strong, even maybe a 100 rpms or so higher then normal (when in neutral) but the idle settles down as the truck warms up.
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1972 3/4 Ton Cheyenne Super, 350ci 650 cfm Edelbrock 4bbl Performer AVS, Edelbrock Torquer intake manifold, Headman Longtube Headers to 2 1/2in cutouts to 3 inch flowmaster super 40's true dual. 4.10? Rear SM-465/205 transfer case. Now this one is busted!! http://s59.photobucket.com/albums/g2...k/1972 Pickup/
1995 K1500 Silverado 5.7L 350 TBI with 1in swirl torque spacer, Flowtech shorty headers, 3 inch collectors to y pipe going to 3in highlfow cat converter, single offset passenger side outlet, full 3 inch setup from collectors. Edelbrock High Flow 255LPH/67GPH Fuel pump, adjustable fuel pressure regulator and gauge, running at about 18psi. 3.73 Rear 4L60-E 4 speed auto (Rebuilt)http://s59.photobucket.com/albums/g2...1995%20Pickup/
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Old 04-24-2010, 06:43 PM   #16
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Re: Throttle Mashing hesitation?

Okay Update for everyone. I had my buddy do a code scan through my OBD port and this is what we found.

|Code#|System| (Indicating)

|13|Oxygen Sensor Circuit| (No signal to computer)

|22|TPS| (Low Signal Voltage)

|32|EGR| (EGR system failure)

|35|IAC - Idle Air Control Motor| (Idle speed above/below desired idle speed)
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1972 3/4 Ton Cheyenne Super, 350ci 650 cfm Edelbrock 4bbl Performer AVS, Edelbrock Torquer intake manifold, Headman Longtube Headers to 2 1/2in cutouts to 3 inch flowmaster super 40's true dual. 4.10? Rear SM-465/205 transfer case. Now this one is busted!! http://s59.photobucket.com/albums/g2...k/1972 Pickup/
1995 K1500 Silverado 5.7L 350 TBI with 1in swirl torque spacer, Flowtech shorty headers, 3 inch collectors to y pipe going to 3in highlfow cat converter, single offset passenger side outlet, full 3 inch setup from collectors. Edelbrock High Flow 255LPH/67GPH Fuel pump, adjustable fuel pressure regulator and gauge, running at about 18psi. 3.73 Rear 4L60-E 4 speed auto (Rebuilt)http://s59.photobucket.com/albums/g2...1995%20Pickup/
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Old 04-24-2010, 07:04 PM   #17
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Re: Throttle Mashing hesitation?

Quote:
Originally Posted by JetForceF22 View Post
Do you even think its worth testing tho?
Proper diagnostic procedure is to test to find the fault, before throwing parts (and $) at it in hopes you get lucky.

Quote:
Originally Posted by JetForceF22 View Post
I mean it has never been changed since we've owned the truck, and the truck has 283,000 miles lol
Doesn't nessesarly (sp?) mean it's bad. On the other hand, just because you just put it on 6 months ago, or just put it on today, does not mean it can't be bad now. Sometimes they don't last, sometimes they're bad right out of the box. Test, test, test.
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Old 04-24-2010, 07:31 PM   #18
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Re: Throttle Mashing hesitation?

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Doesn't nessesarly (sp?) mean it's bad. On the other hand, just because you just put it on 6 months ago, or just put it on today, does not mean it can't be bad now. Sometimes they don't last, sometimes they're bad right out of the box. Test, test, test.
I should have been more specific. These parts have NEVER been changed since we've owned the truck (since 96) So IMO its worth it to buy a new part, check it and replace it then to go through the trouble of testing these old units that are known to go bad on these trucks, since these pieces are now 14 years old with heavy use and abuse. However I completely understand what you're saying and appreciate your advice, (I will definitely test my new parts, that something that I don't normally do) and I thank you for all your help so far!!

Either way, in about 3 weeks I'll have all the time in the world to do this when the 72 is running and I'm out of school for the semester, so I'll prob tear apart the truck then and check my parts/test my possible new parts then.

As of right now, the codes are telling me that my IAC, O2 Sensor, TPS and EGR are possibly faulty. That narrows down the list. We changed the 02 sensor a few years ago when we put the new headers and Y pipe, but I remember something being sketchy when we did it. I'll have to check and make sure its hooked up since the computer apparently is getting no response from it.
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1972 3/4 Ton Cheyenne Super, 350ci 650 cfm Edelbrock 4bbl Performer AVS, Edelbrock Torquer intake manifold, Headman Longtube Headers to 2 1/2in cutouts to 3 inch flowmaster super 40's true dual. 4.10? Rear SM-465/205 transfer case. Now this one is busted!! http://s59.photobucket.com/albums/g2...k/1972 Pickup/
1995 K1500 Silverado 5.7L 350 TBI with 1in swirl torque spacer, Flowtech shorty headers, 3 inch collectors to y pipe going to 3in highlfow cat converter, single offset passenger side outlet, full 3 inch setup from collectors. Edelbrock High Flow 255LPH/67GPH Fuel pump, adjustable fuel pressure regulator and gauge, running at about 18psi. 3.73 Rear 4L60-E 4 speed auto (Rebuilt)http://s59.photobucket.com/albums/g2...1995%20Pickup/
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Old 04-24-2010, 07:55 PM   #19
franks72
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Re: Throttle Mashing hesitation?

my 93 blazer was doing the same , thought it was the tps, but it was the egr valve on mine.The egr is easy to test if you have a vac tool .
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72 cheyenne super BB402 TH400 Air Tack Tilt Posi P/S P/B AM/FM 12.96 @ 101.82 mph 60ft 1.82
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Old 04-24-2010, 08:17 PM   #20
JetForceF22
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Re: Throttle Mashing hesitation?

Hmm okay I don't have one but my buddy who has a code reader does. How do you go about testing the EGR valve??
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1972 3/4 Ton Cheyenne Super, 350ci 650 cfm Edelbrock 4bbl Performer AVS, Edelbrock Torquer intake manifold, Headman Longtube Headers to 2 1/2in cutouts to 3 inch flowmaster super 40's true dual. 4.10? Rear SM-465/205 transfer case. Now this one is busted!! http://s59.photobucket.com/albums/g2...k/1972 Pickup/
1995 K1500 Silverado 5.7L 350 TBI with 1in swirl torque spacer, Flowtech shorty headers, 3 inch collectors to y pipe going to 3in highlfow cat converter, single offset passenger side outlet, full 3 inch setup from collectors. Edelbrock High Flow 255LPH/67GPH Fuel pump, adjustable fuel pressure regulator and gauge, running at about 18psi. 3.73 Rear 4L60-E 4 speed auto (Rebuilt)http://s59.photobucket.com/albums/g2...1995%20Pickup/
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Old 04-24-2010, 08:36 PM   #21
franks72
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Re: Throttle Mashing hesitation?

The valve has a spring in it to keep it closed ,when you pull vacume it will open ,if the valve is good it will stay at that point, if it is bad it will not stay at that point it will drift back closed..
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72 cheyenne super BB402 TH400 Air Tack Tilt Posi P/S P/B AM/FM 12.96 @ 101.82 mph 60ft 1.82
12.39 @111.33 With a 180 shot nos

69 Camaro RS http://s94.photobucket.com/albums/l117/fdelcoglin/

email fdelcoglin@hotmail.com
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Old 04-24-2010, 08:38 PM   #22
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Re: Throttle Mashing hesitation?

Interesting... that's something I'll have to look into then.
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1972 3/4 Ton Cheyenne Super, 350ci 650 cfm Edelbrock 4bbl Performer AVS, Edelbrock Torquer intake manifold, Headman Longtube Headers to 2 1/2in cutouts to 3 inch flowmaster super 40's true dual. 4.10? Rear SM-465/205 transfer case. Now this one is busted!! http://s59.photobucket.com/albums/g2...k/1972 Pickup/
1995 K1500 Silverado 5.7L 350 TBI with 1in swirl torque spacer, Flowtech shorty headers, 3 inch collectors to y pipe going to 3in highlfow cat converter, single offset passenger side outlet, full 3 inch setup from collectors. Edelbrock High Flow 255LPH/67GPH Fuel pump, adjustable fuel pressure regulator and gauge, running at about 18psi. 3.73 Rear 4L60-E 4 speed auto (Rebuilt)http://s59.photobucket.com/albums/g2...1995%20Pickup/
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Old 04-25-2010, 11:30 AM   #23
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Re: Throttle Mashing hesitation?

OK first thing first. The codes you have can definately cause your issues. You need to trace the wires from the oxygen sensor and make sure they arent burnt or broken. Chances are the o2 is bad at that age but you always need to check the wiring and connector. The egr system is probably clogged up. unbolt the egr and look in the ports i would imagine they are gummed up pretty bad. You will need to test the egr and clean the ports out in the intake. The Iac is another thing thats likely gummed up and clogged. That could cause your high idle as well. The iac is nothing more than a poppet valve. unscrew it out of the side of the throttle body and check those ports as well. DO NOT pull the plunger out manually on the iac you will ruin it. It has a very short stroke and you will pull it out beyond its normal movement. Im sure its filthy inside as well. You will need a good foaming cleaner to get all the crud out. I would also say if it hasnt been done recently do a complete tune up. cap rotor plugs wires and even a coil just because of the high mileage its worn out. Make sure you buy decent ignition parts or you will be doing it again. I prefer to run the factory stuff bc the parts store junk never lasts especially the wires.
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Old 04-25-2010, 11:07 PM   #24
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Re: Throttle Mashing hesitation?

Quote:
Originally Posted by cableguy0 View Post
OK first thing first. The codes you have can definately cause your issues. You need to trace the wires from the oxygen sensor and make sure they arent burnt or broken. Chances are the o2 is bad at that age but you always need to check the wiring and connector. The egr system is probably clogged up. unbolt the egr and look in the ports i would imagine they are gummed up pretty bad. You will need to test the egr and clean the ports out in the intake. The Iac is another thing thats likely gummed up and clogged. That could cause your high idle as well. The iac is nothing more than a poppet valve. unscrew it out of the side of the throttle body and check those ports as well. DO NOT pull the plunger out manually on the iac you will ruin it. It has a very short stroke and you will pull it out beyond its normal movement. Im sure its filthy inside as well. You will need a good foaming cleaner to get all the crud out. I would also say if it hasnt been done recently do a complete tune up. cap rotor plugs wires and even a coil just because of the high mileage its worn out. Make sure you buy decent ignition parts or you will be doing it again. I prefer to run the factory stuff bc the parts store junk never lasts especially the wires.
Thanks, yeah we've done a recent tune up not to many miles ago I would prob say no more then 20,000 miles old if that, but I'll have to run through and check everything since the truck was sitting for almost a year. (Driven bi-weekly though) We replaced the 02 sensor at prob 250,000 miles but I've heard they're not reliable so yes I will def check that. My thoughts were just to replace the EGR and clean up the IAC valve and prob replace the TPS while I'm at it.
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1972 3/4 Ton Cheyenne Super, 350ci 650 cfm Edelbrock 4bbl Performer AVS, Edelbrock Torquer intake manifold, Headman Longtube Headers to 2 1/2in cutouts to 3 inch flowmaster super 40's true dual. 4.10? Rear SM-465/205 transfer case. Now this one is busted!! http://s59.photobucket.com/albums/g2...k/1972 Pickup/
1995 K1500 Silverado 5.7L 350 TBI with 1in swirl torque spacer, Flowtech shorty headers, 3 inch collectors to y pipe going to 3in highlfow cat converter, single offset passenger side outlet, full 3 inch setup from collectors. Edelbrock High Flow 255LPH/67GPH Fuel pump, adjustable fuel pressure regulator and gauge, running at about 18psi. 3.73 Rear 4L60-E 4 speed auto (Rebuilt)http://s59.photobucket.com/albums/g2...1995%20Pickup/
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Old 12-28-2017, 10:44 PM   #25
Supahsteve69c10
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Sputters

Hey guys I have a little trouble on my 1969 Chevy C10 pickup okay I have an issue with my truck sputtering on first gear it hesitate when I drive so the first thing that came to my mind I have a ignition problem so I switch the spark plugs I switch the wires I switch the ignition module switch the coil switch the cab and it still sputters on me I'm kind of lost at the moment right now don't know what else we could be I really appreciate it for you guys is help thanks
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