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Old 04-27-2008, 10:48 PM   #26
ChevyTech
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Re: HELP, Broke down Again !!!

Youíre welcome

Itís a good idea to save information you run across.

I save links / favorites, but I also copy and save useful information to a word file and save it on my computer. Links may not work in the future. My challenge is organizing what I save so I can find it easily. When I write a good reply to a post I also save it and improve it a little each time I reply to a similar thread about the same topic.
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Old 02-26-2017, 09:19 PM   #27
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Re: HELP, Broke down Again !!!

Well, lets see if I can get this old thread to work again.

Ran into some hard times and had to park my truck. Almost lost it in the divorce so she has been setting since May of 2015. I had started it every once in a while but the last time, I can't remember how long ago its been maybe a year.
Now she would not start up.

Can I just post what she is doing, not doing here?
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Old 02-26-2017, 09:26 PM   #28
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Re: HELP, Broke down Again !!!

drain fuel gas goes bad
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Old 02-26-2017, 10:12 PM   #29
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Re: HELP, Broke down Again !!!

You can try a shot glass or 2 worth of gas down the throttle body and if no start it's not fuel system.
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Old 02-27-2017, 12:20 AM   #30
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Re: HELP, Broke down Again !!!

Ok.
Looks as I can post on this thread even if it is old.

As far as the fuel, it has a half tank of non ethanol fuel with the marine stabilizer in it. No drain on that tank for one.

I took the car hauler over to get it and winch it up but tried one last time.
Nothing, no fuel pump sound.
I then jumped the fuel pump and could here it running.
I then tried to start it and just rolled over. Tried it again, seen the oil pressure go up and she started.
I let it run for about 30 minutes as I loaded her up on her own power.
Brought it home, pressure washed the whole outside to clean her up.

I tried to start her back up, no fuel pump sound, jumped the fuel pump again, watched the oil pressure come up and this time, did not start, just rolled over.

I pulled the jumper form the orange wire to the center wire on the plug on the fuel pump relay. The notes that I had written down and in the Chilton book says it it was supposed to be a Gray wire to the pump, Mine is Pink going to the pump.
I then had my friend work the ignition switch and I tested the Green/white wire which is supposed to be the prime I think its called.
Anyway, No other wire in that plug was hot so the next step is go get to the ECU and test I that same color wire, Green/white to see if it comes hot (A1 in my notes). My hopes are its got 12 volts with the key on.

This chilton book is really not that helpful.
So, my thinking right now, with no special tools is to pull the fuel line from the throttle body, stick it in a quart bottle with a rag over the end, then make a LONG jumper wire (NO Sparks) plugged into the fuel pump relay plug. Its a 5 foot jump starter setup that I will just cut the alligator clips off and make sure its plugged in so No sparks, have my friend just tap that starter cable button to energize the fuel pump.
I won't be able to measure the fuel but will now if its pumping.

This book does not show the wiring so if anyone knows if that is A1 on the ECU I should be testing and where does it go, right to the fuel pump relay ?

If I remember right the oil pressure switch is what tells the ECU to keep the fuel pump working, that green/white wire just primes and runs the pump until the oil pressure is up.
I can't seem to find that information so hoping someone knows or has a real book to look at.

There is also a module in the distributor that I think runs that fuel pump relay too but can't remember what it does.

I can put a shot glass of fuel down in the throttle body and see if she will run on that.
I will do that tomorrow in between snow showers ;-)

Oh yeah. I have been plagued with a phantom draw on the electrical system which I will get into after I get her running again and off the trailer.
Long story short, pulled the Alt wire, pulled fuses trying to find it. If she sits three days, it would pull a new fresh battery down to were it would need jumped. So, several issues to chase down. Right now, its got a marine power switch that disconnects the battery which means the ECU has not recorded any error codes.
Real mess huh...
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Old 02-27-2017, 01:17 AM   #31
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Re: HELP, Broke down Again !!!

My 92 K2500 had an few issues when we bought it like yours. 1st was the every 4-5 day dead battery that was caused by an aftermarket stereo the PO installed that had a constant draw even though wired correctly, Second was the no start without a cup of fuel in the tbi every now and then that turned out to be a fuel pump with a dead spot, but as soon as it started on that cup of gas it (vibration?) worked.
The ignition module is not connected to the fuel pump circuit so don't waste time there unless no spark. This sounds stupid but did you check all fuses?
You should be able to see fuel spraying from the injectors when cranking also. It seems strange to me after sitting 2 yrs to have these problems, it must be something simple.
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Old 02-27-2017, 10:43 AM   #32
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Re: HELP, Broke down Again !!!

Quote:
Originally Posted by rickpilgrim View Post
My 92 K2500 had an few issues when we bought it like yours. 1st was the every 4-5 day dead battery that was caused by an aftermarket stereo the PO installed that had a constant draw even though wired correctly, Second was the no start without a cup of fuel in the tbi every now and then that turned out to be a fuel pump with a dead spot, but as soon as it started on that cup of gas it (vibration?) worked.
The ignition module is not connected to the fuel pump circuit so don't waste time there unless no spark. This sounds stupid but did you check all fuses?
You should be able to see fuel spraying from the injectors when cranking also. It seems strange to me after sitting 2 yrs to have these problems, it must be something simple.
Working on the fuel issue first so once I get my first cup coffee in, will go out and do the shot glass of fuel to see if she fires right up..

When I had this issue before, I replaced that module in the distributor plus the fuel pump relay only to find out the fuel pump was on its way to failing. Once it failed and stayed that way, found it and replaced it.

One thing I do know, is while trying to start it, that one wire that is supposed to prime, does not come hot.

Here is one I don't know for sure. It Does have some in line fuse looking things right up close to the fuel pump relay but they don't come apart, or if they do, I don't know how. I can take the light probe thingy and stab the wire before and after the barrel that looks like a fuse.
All the other fuses under the dash I checked.
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Old 02-27-2017, 01:04 PM   #33
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Re: HELP, Broke down Again !!!

Ok, she Failed the Shot Glass test.
I put in a half of shot glass of gas, no start, dumped in the rest of the shot glass, no start.
The Relay was plugged in just in case too.

I also heard the fuel pump running after I quit trying, Pretty sure she is fueling.
I didn't have help so I was not able to turn her over and watch to see if the EFI was spraying fuel in but never the less, heard the pump working.

Not sure what to test next. Distributor module or maybe I had better dig out the ECU, make sure its got a good ground and the contacts do not have any corrosion on it from setting with mildew in the cab.
Going to test A1 for 12 volts and hope the ol gray matter is correct. I think that is the primer signal wire to the relay...

I also left the battery hooked up and will put the float charger on her. Maybe I can get a code once I figure out what the paper clip needs to be plugged into. This is first generation computer.
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Old 02-27-2017, 01:54 PM   #34
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Re: HELP, Broke down Again !!!

Ok-first I would take a good spark plug and hook up to #1 plug wire and ground it to the engine. Crank it over and see if you have spark. A shot glass of fuel should have got you a good pop or attempt to start.
Also- there are grounds on the back pass side of the engine for the ecm that need a good clean ground.
If still no spark cap/rotor plus ign module are the main problem areas.
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Old 02-27-2017, 02:16 PM   #35
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Re: HELP, Broke down Again !!!

Quote:
Originally Posted by rickpilgrim View Post
Ok-first I would take a good spark plug and hook up to #1 plug wire and ground it to the engine. Crank it over and see if you have spark. A shot glass of fuel should have got you a good pop or attempt to start.
Also- there are grounds on the back pass side of the engine for the ecm that need a good clean ground.
If still no spark cap/rotor plus ign module are the main problem areas.
As soon as my helper is back from town, Will check to see if spark it to the plugs. I even have one of those little gizmos that you put on the plug and plug the wire onto it, I am old school, jam a screwdriver into the spark plug in and hold it close to ground works too :-)
As soon as I test that, I will report back in :-)
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Old 02-27-2017, 05:22 PM   #36
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Re: HELP, Broke down Again !!!

Ok, no spark to the plugs.
So, that is possibly the coil (which was replaced about a year ago) or the module in the distributor.
I will look to see how to test the coil and go from there.
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Old 02-27-2017, 06:14 PM   #37
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Re: HELP, Broke down Again !!!

Coils don't normally fall but an old school cheater test was to hook a live wire to the + side and to the - side a wire with a bare end. Hook your spark testing screwdriver to the coil output wire and have your assistant tap the bare end on a grounded part of the engine like . . . . . . . and watch for spark.
O Reilly's and other parts houses have module testors but if your module failed DO NOT buy the cheap replacements as I've had those fail with alarming regularity on our daily drivers
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Old 03-01-2017, 05:57 PM   #38
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Re: HELP, Broke down Again !!!

Quote:
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Coils don't normally fall but an old school cheater test was to hook a live wire to the + side and to the - side a wire with a bare end. Hook your spark testing screwdriver to the coil output wire and have your assistant tap the bare end on a grounded part of the engine like . . . . . . . and watch for spark.
O Reilly's and other parts houses have module testors but if your module failed DO NOT buy the cheap replacements as I've had those fail with alarming regularity on our daily drivers
Was trying to kill myself yesterday getting Firewood into the wood shed.

So, went back out, pulled the module out and noticed the pickup coil inside looked rusty. I just slid a piece of sand paper down inside that and kind of wiped it around and notice the rust on the sand paper when I pulled it up and out.
I did that several times, but this worthless chilton book does not give a clue on how to test it, pretty much says replace the distributor at $140 bucks.
Yeah maybe if had it to spare but I don't. The pickup coil does not come with it either.

So, I have been looking for how to test that thinking its be ohms open, ohms closed so turning that engine over, it should be pulsing the ohm meter.
Mine is a Fluke DMM and pretty fast reading anyway.
I took the distributor module over to NAPA and my friend tested it and said No problems with it. New one (good one was 51 bucks) but didn't need it he said.

So, what you said to test the coil, its a transformer so power to the plus, take the minus and ground it for a spit second and if the coil is working, spark will come out of the spark plug wire hole. I always get mixed up with primary and secondary circuits.

Anyway, this does not have that and without a schematic, I have no idea once I pull the plug off that coil on which pin is which.

I will get a picture of it as I think I remember a red and white wire coming from the distributor to the coil, then the other two go into the wiring loom.

Kind of lost on what procedure to go after next.
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Old 03-01-2017, 11:54 PM   #39
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Re: HELP, Broke down Again !!!

This truck has just a tad over 300K.
I am going to pull the distributor and if the bushings are still ok, will pull it apart and just rebuild it with a new pickup coil. She is in dire need of a tune up anyway so might as well throw that in too.
I pretty sure that pickup coil is what triggers the pulse to the distributor module and tells the coil when to fire.

I can't find a description or diagram on what wire does what on that coil to really test it but will keep looking.
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Old 03-02-2017, 08:26 PM   #40
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Re: HELP, Broke down Again !!!

Got it. She fired right up. She rolled over maybe twice and lit right up.
Over the years there had been enough condensation in that distributor that it was rusty, so out and apart it came. Polished up things and added a new pickup coil. Use the old cap, old everything else and she is running so not its time to unload her off the car hauler.
I was concerned about that distributor with 300k on it but the shaft is still snug fitting so it was a easy rebuild.
Lots of other things to do to her now, tune up, serpentine belt, check all the hoses, license and title change back to Oregon.

Next thing is to try and chase down that phantom draw.
New battery, new alternator plus pulled the wires off to test for draw. I think I was pulling a bank of fuses at a time but now she is not required to be running every day so now I hope to chase that down and hook my alarm system back up.

I am sure I can come up with a little device that can trigger a relay for a horn or whatever that once the current drawn is over what is normal, she will warn me.
Then I can start pulling fuses and disconnecting things until I find it.
The radio started acting up but its on a fuse that I think I had pulled but will start over finding that phantom draw she has.

Does a 60 or 85 milliamp draw sound about right, don't exceed that ?

Last edited by 88lowrider; 03-02-2017 at 08:37 PM. Reason: Forgot something.
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Old 03-02-2017, 11:01 PM   #41
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Re: HELP, Broke down Again !!!

Congrats on finding the pickup coil was the problem! We normally test those on our Snap on Verus lab scope while cranking it over, no wave form equals bad pickup.
On your GM dual coil the while wire is effectively ground or - and the red is + or so the Snap On test program says in testing instructions.
My 92 has 21 milliamperes draw at rest or about 6 weeks until battery is to depleted to start it.
300K mi is a lot but cared for properly you could go 100k more. Don't replace anything because of miles verify failure or problem first.
Glad your back on the road in more ways than one!
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Old 03-03-2017, 12:31 AM   #42
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Re: HELP, Broke down Again !!!

Quote:
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Congrats on finding the pickup coil was the problem! We normally test those on our Snap on Verus lab scope while cranking it over, no wave form equals bad pickup.
On your GM dual coil the while wire is effectively ground or - and the red is + or so the Snap On test program says in testing instructions.
My 92 has 21 milliamperes draw at rest or about 6 weeks until battery is to depleted to start it.
300K mi is a lot but cared for properly you could go 100k more. Don't replace anything because of miles verify failure or problem first.
Glad your back on the road in more ways than one!
Thanks for your help too !!
That was pretty rusty so didn't think it was able to make much pulsing and got lucky.

I thought I had found my phantom draw as one time I went back up to the shop were I parked it and noticed a red glow. Brake lights were on. Adjusted that but, nope, not it.
Got to find the connection that went bad for the electric windows once I get her off the car hauler too.
On to the next issue :-)
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Old 03-06-2017, 02:01 PM   #43
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Re: HELP, Broke down Again !!!

My being able to search for specific topics is not very good.
I am looking for the Wiper motor section or threads and well, got Thousands of not what i am looking for so I could sure use the help with that.

For instance. I have a 1988 GMC Sierra 1500. From my understanding for the trucks, it was the first year for the body stile change.
I went to get the Wiper module as my wipers have been acting screwy. What is shown for 1988 is Not what I have.
I will add a picture of mine And, I was just searching the Internet looking for the one that the parts stores show it Should have, and found a picture of the one on my truck. Its showing 1967 to 1972?? Whats with that ?? Why in the hell would they choose the older ones like that and not like 80's?
Anyway, what I am looking for or trying to search for is a wiper motor interchange. Will the the one they say should be on the truck, fit my truck ?
Anyway, the second picture is the that Should be on my truck.
Mine has all the symptoms of the control module board being bad.
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Old 03-06-2017, 06:12 PM   #44
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Re: HELP, Broke down Again !!!

Quote:
Originally Posted by 88lowrider View Post
My being able to search for specific topics is not very good.
I am looking for the Wiper motor section or threads and well, got Thousands of not what i am looking for so I could sure use the help with that.

For instance. I have a 1988 GMC Sierra 1500. From my understanding for the trucks, it was the first year for the body stile change.
I went to get the Wiper module as my wipers have been acting screwy. What is shown for 1988 is Not what I have.
I will add a picture of mine And, I was just searching the Internet looking for the one that the parts stores show it Should have, and found a picture of the one on my truck. Its showing 1967 to 1972?? Whats with that ?? Why in the hell would they choose the older ones like that and not like 80's?
Anyway, what I am looking for or trying to search for is a wiper motor interchange. Will the the one they say should be on the truck, fit my truck ?
Anyway, the second picture is the that Should be on my truck.
Mine has all the symptoms of the control module board being bad.
That first pic you posted is the 88-90 style.

The next pic you posted is the 91-98(00) style.

They interchange, but you have to replace the entire motor. The plug is even the same.


A few threads down on the 88-98 board page is this:

http://67-72chevytrucks.com/vboard/s...d.php?t=492998
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Old 03-07-2017, 12:31 AM   #45
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Re: HELP, Broke down Again !!!

Quote:
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That first pic you posted is the 88-90 style.

The next pic you posted is the 91-98(00) style.

They interchange, but you have to replace the entire motor. The plug is even the same.


A few threads down on the 88-98 board page is this:

http://67-72chevytrucks.com/vboard/s...d.php?t=492998
This is Great !!!. Can't thank you enough.
My thing is still, How do I search for for something like the thread link you just gave me ? (cut me some slack, I am older than dirt ;-)
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Old 03-07-2017, 04:44 AM   #46
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Re: HELP, Broke down Again !!!

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This is Great !!!. Can't thank you enough.
My thing is still, How do I search for for something like the thread link you just gave me ? (cut me some slack, I am older than dirt ;-)
This is DIRT speaking. Many of the 1988+ trucks had defective windshield wiper circuit boards that were recalled and fixed free by GM. I wouldn't be shocked if someone swapped an older motor assembly to replace a failed one.
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Old 03-07-2017, 11:54 AM   #47
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Re: HELP, Broke down Again !!!

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This is DIRT speaking. Many of the 1988+ trucks had defective windshield wiper circuit boards that were recalled and fixed free by GM. I wouldn't be shocked if someone swapped an older motor assembly to replace a failed one.
I was looking at the costs to replace those circuit boards and it seems that the older ones like that fit the wiper motor in mine, are quite expensive in comparison to the newer style wiper motor.

I was told by a friend (owns a toyota) that if there is a recall and its not a class action law suit, that they still honer those recalls.
So, I might just go to a bone yard and get my the later model wiper motor from a California truck (less rain down south so the concept would be, less use on the wiper motor) and then go to a dealership and see if they will give me a new controller board for it.
A Not OEM board for the newer stile is less than 25 bucks so maybe the stealerships will use a Delco replacement board. No harm in trying :-)

I am the second owner on my truck and it came from a company called Overhead Door out of Portland. The truck had 65K on it and it was used by one of the owners to transfer small parts between Portland Oregon and Bend Oregon so most was highway miles.
When it came into my friends Chevrolet Dealership (Suburban Auto Group, home of the famed Trunk Monkey commercials) it was just in and Full of service records. The truck looked new other than scratches in the pickup bed. First thing I did was drop her.

Sorry for the blathering on but I think my next step is to get a used one from a bone yard.

Oh, speaking of bone yards, this is the wrong place to post this but I grew up in my Dads wrecking yard and I have all the old Hollendar Interchange books from the 50's and 60's and offering to look up things for folks.
More blathering :-)

Any idea on the interchange, what all years fit the 1988 GMC ?
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Old 03-14-2017, 07:24 PM   #48
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Re: HELP, Broke down Again !!!

Does anyone know how to test the door lock switches, wiring diagram maybe?
If I knew what wire went where, I would try to jump the electric solenoids to make sure they are working.
My after market book shows Nothing.

Thanks guys.
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Old 03-14-2017, 09:52 PM   #49
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Re: HELP, Broke down Again !!!

Chevy Tech is the man! I'm going to be printing all this good information myself. Good ideas.
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