egr valve problem

[salrod00]

im new to this so let me tell you my situation. i have a 95 tbi 350. i unhooked the vacuum line to the egr and no suction comes out., the egr soleniod has two vacuum lines to it. one is plugged and the other runs to the egr. truck seems to loose power so i was wondering could this be the problem. thanks

[ChevLoRay]

Do a search on here for EGR and/or EGR solenoid. There should be a few (!!) to say the least. This also seems to affect more of the 88-95's, that the 96-up.

[bwood]

The line between the EGR and EGR solenoid will not always have vacuum on it. The other line on the EGR solenoid goes to the base of the throttle body. The solenoid is controlled by the ECM and only opens when required.

Here is a pic from a recent post that shows some of the vacuum lines:
http://67-72chevytrucks.com/vboard/s...d.php?t=414861

[ChevyTech]

If you can post a photo of the EGR solenoid it would help.

TBI trucks are generally Negative pressure EGR or Port EGR systems.

On negative backpressure EGR solenoid the is one port which is the vent and should be left open but people find a spot they think should have a vacuum hose, so they plug the vent port. The vent port does not have barbs on it like the one that is supposed to go to the EGR valve.

This is a site that has a photo and an illustration about EGR vale numbers which should help you determine which type of valve your vehicle has.

http://shbox.com/1/EGR_ID.jpg

Negative pressure EGR valves - Should have an “N” after the last numbers on the valve. The pressure in the exhaust system effects (modulates) how much the valve opens.

Port EGR Valves – The EGR solenoid pulses like a mixture control solenoid/fuel injector to control vacuum supply. Port valves have no “P” or “N” and it is blank after the last numbers on the valve.

[salrod00]

i put a scanner on it and it said code xxx (forgot the number) but it said egr. it pops up while im driving after 15 minutes but when i get some where and turn off the truck and back on the check engine light disapears. seems to reset itself

[Bus Ted Knuckle]

Originally Posted by salrod00

i put a scanner on it and it said code xxx (forgot the number) but it said egr. it pops up while im driving after 15 minutes but when i get some where and turn off the truck and back on the check engine light disapears. seems to reset itself

the code will still be stored. have it read again, it will be there.

[Boog]

My old 88 did the exact same thing. I think I finally replaced the egr valve before I sold it. It's been a while.
If you do end up replacing the egr valve buy a good one. Don't skrimp on it with a cheapy, universal valve. You will be happier.

[salrod00]

i unplugged the vacuum going to the egr valve and it ran about the same. i found two spark plug wires that were making contact with the header and it was causing it to ground itself . so i replaced the whole set of wires .

[ChevLoRay]

So, is that the answer to the problem, or just another one?

[bwood]

Originally Posted by salrod00

i put a scanner on it and it said code xxx (forgot the number) but it said egr. it pops up while im driving after 15 minutes but when i get some where and turn off the truck and back on the check engine light disapears. seems to reset itself

My Dad's 95 was doing the exact same thing. He's 350 miles away, but we narrowed it down to the EGR over the phone. The code that came up was 32. He took it to the shop where he lives in Austin and they came up with the same thing. New EGR and a tune up, he said all was great. He said they told him that when they put a vacuum on the EGR, it wouldn't hold at all.

[salrod00]

i think that im going to put a egr valve for the heck of it . im assuming it could be it. runs better with new wires but still hestitates on take off and after 30 mph it runs like a champ.

[bwood]

Disconnect and cap the line feeding the EGR and see if it improves. If so, sign point to a ruptured diaphram in the EGR. As far a a new one, do what you have to to get a OEM unit. Stay away from the "universal" ones that you have to select and install your own oriface. Use the part # from yours to get your new one to make sure you get the correct one.

[Bigg G]

Check all your vac lines for cracks & breaks. They're made of plastic and do get brittle as they age & will make your truck run like a hog if leaking or not seated at it's connection. If you go with a new EGR be sure to buy the GM AC Delco EGR. I replaced my EGR and vac lines and it woke my TBI 350 up giving it new life.


Oh...and BTW I have a 95 Silverado with the TBI 350 like yours

[ChevyTech]

i unplugged the vacuum going to the egr valve and it ran about the same.

i think that im going to put a egr valve for the heck of it . im assuming it could be it.

If it runs the same with the EGR disconnected, you should look for another problem.

I suggest trying a new fuel filter and checking the fuel pressure with the engine running.

[ChevLoRay]

Is it just me, or do I perceive that the majority of EGR/EGR solenoid problems are in the OBDI (88-95) vehicles? Or, could it be due to the age of the vehicle? I just don't see posts that ask about EGR problems for the 96-up vehicles.

[salrod00]

i put a new fuel filter two days ago. i also checked under the cap and it had carbon or build up on the prongs . so i just scraped and sanded it clean . the truck was sitting for about three years in my dad driveway. i bought it off him last month and trying to get it back to original condition. it was perfect before the long 3 years of neglect.

[Bigg G]

Sitting for 3 years could be your problem .

How many miles have you put on it since you started driving it ?
How many full tanks of gas have you used w/ injector cleaner since you started driving it ?
Did you replace the wires, plugs and fluids and check all your vac lines
& connections before you started driving it ?


Reason I'm asking.....is the worst thing you can do to a TBI 350 is park it and let it set for long periods of time. Seems like you just open up a whole can of mechanical worms when you do.

What trouble light (CEL) code/s did it throw ?

[salrod00]

code was 32 stating egr. i swapped it out today with a oem and it cured the problem. so the whole time it was running slow and the rpm's would shoot up to 3xxx and shift hard from 1 gear to D over drive. i changed the burnt spark plug wires, plugs, rotor cap and egr cap. thanks for the advice and help people

[Bigg G]

Good hear that you got her fixed.....now drive it because 350 TBI's love to be in the wind man--yunnnn !!!

[ChevLoRay]

Thanx for letting us know that you got it fixed. It is helpful to us and others to get the feedback so we know how we did.

Another satisfied customer!!

[Boog]