EGR.....another adventure

Home  \  Repairs & Maintenance  \  EGR.....another adventure

89 Chevy Silverado 1500 series 1/2 Ton Truck w/ a 5.7L engine & a 700r4 auto transmission...it is not a 4x4. Recent engine rebuild.

After replacing the Service Engine Soon bulb and learning to read codes I took the truck out for a long spin...about 50 miles of hwy driving 55-65mph while making a few stops in between. While riding @ about 50 my SES light came on. when I stopped for lunch and restarted the engine it was gone....then after I was up to speed once more (around 45-55mph) it came back on. I pulled the codes immediately when I got home. It was Code 32-EGR System. At the begining of the testing procedures portion for the EGR in my chiltons manual it says "assumes no code 24 or 32 is stored" so I did not complete the testing procedure since code 32 was stored. what I did do however was push the EGR Valve back and forth while the engine was at idle....this resulted in the engine "wanting to die" until I no longer depressed it. I have checked for vacuum leaks as well and found none. Ignition timing is right on...plugs, wires, cap and rotor, 02 sensor are all new.

Does this mean that there are no carbon deposits blocking passage in the intake itself because the engine was flooded w/recirculated exhaust gasses when the valve was actuated? I did not remove anything (EGR, Throttle Body...etc.)from the intake during the rebuild.

Other symptoms that may be related:
1. Engine wants to run warm when cruising @ hwy speeds 190-210 degrees.
Thermostat is a 160 degree, normally runs @ approx 175. (I am mentioning this because the chiltons says the EGR helps lower combustion temperatures.)

2. At idle, I feel what I can only describe as...the engine seems to want to hesitate. I know thats vague, but it doesnt miss and it seems to run smooth except for that small feeling I have...maybe this symptom is all in my head :screwy:

This forum has been a big help, your insight is always appreciated. Thanx

posted by  Cantesoleares

the egr valve only work's when the computer wants it at certain conditions load/speed throttle position it will not come on at idle
as for the test you did opening the egr at idle will allow exhaust gas into the intake and stuble/stall the engine
may want to check the egr solinoid/vacuum actuator for the egr this is the computer signal to open valve and allow vacuum to egr(this maybe the cause of code 32 egr failure)
the place to check on the egr is the center pin is it seated and sealing it may leak exhaust into the intake at idle if not sealing

as for crusing temp is the rad or a/c condenser built up with dirt/dust plugging fins use a garden hose flush it throught the backside to grille
how old is the thermostat maybe starting to stick they recommend a thermstat rated for 195 in my manual 98-2000 models

posted by  osborste

update....after some searching on the net I decided to remove the EGR and check for carbon deposits, I cleaned the ports w/carb cleaner. I shook the EGR Valve and could hear particles inside of it moving around. The center pin also seemed to be loose....so I replaced it.

Drove it for a while (30min on hwy) and all seemed fine, then parked the truck for the night....when I began to drive home from work this morning the SES Light appeared once again....the engine surged a few times then ran w/almost no power until I made it home (about 3 miles). Now if I crank it, it will not idle at all and it only stays running if I keep my foot on the accelerator.

I checked the codes and a code 45 (o2 sensor indicates rich exhaust). I pulled the spark plugs and they looked ok, I also checked for air restriction to the Throttle Body...It seems fine.

When I replaced the EGR I used a lot of carb cleaner to clean the passages. There was not any carbon buildup. I hope I am doing a good job explaining everything I did....

posted by  Cantesoleares

by you telling me that you have to use the accelerator to keep it running mean 1 of 2 items to check
1 faulty injecter (dumping to much fuel)check the injecter's spray one or both are allowing to much fuel if fuel spray looks ok then check the fuel pressure regulator may not be opening allowing higher psi(more fuel)
2 egr is stuck open (bad egr solenoid allowing vacuum at idle to the egr)check vacuum hose at egr for vacuum at idle(if none good) if there is follow hose back to the soleniod

posted by  osborste

did you ever get your odometer fixed?

run a compression test, that's all i can say. good luck.

posted by  carls47807

osborste....Thank you so much, whenever I inspected the injectors one of them was not on all the way (what I mean by this is the connector that clips to the top of the injector).....this must have happened while I was cleaning the throttle body after I replaced the EGR Valve. Now it runs exactly as it did before I replaced the EGR Valve.

I took it for a test drive and it threw a 32 Code for EGR once again. So, now I am back to square 1. When I parked from the test drive I did let it idle and I checked for vacuum at the egr valve (as you suggested) and found none.

"did you ever get your odometer fixed"

Hey carls4, not yet...still scouring on ebay to find one. I will give a heads up when it is repaired though.....I search alot on here and find alot of solutions. It really pains me to see people never answer as to what the actual fix was. I'll try not to be like that.

posted by  Cantesoleares

ok now we are back to code 32 egr failure
the egr is new good
now the solenoid may not be operating/opening vacuum to egr during crusing speeds as i posted earlier and by what you said about the ses light being off till you got up to crusing speed your o2 sensor is picking this up as a no change in the exhaust telling the computer turning on the light giving you code 32
my book tells to check connection at solenoid for broken wire(s) there's only two on the solenoid valve grey and pink or black/pink stripe the gray is ground and pink is 12v in run position you could run power and ground here to see if it clicks/opens then you know it works from there it shows a vacuum regulator with 3 wires grey(ground from egr solenoid pink= 12v from computer (signal wire during crusing speed)and black/white stripe=ground
looks like you have a bit of testing to do
if you want the diagram i have(haynes manual)send me a private message with your email i'll scan and send

posted by  osborste

ok...I see the grey and pink wires for the solenoid....now the part about running power and ground here to see if it clicks open....does this mean I am to disconnect the solenoid here.....connect a 12v wire from battery to a pin on the solenoid while grounding the other pin? Please forgive my inexperience.

Edit: Maybe while the engine is at idle I could ground the grey wire and listen for the click since the pink wire will already be providing the 12v. Or is this a really bad idea?

posted by  Cantesoleares

[QUOTE=Cantesoleares]ok...I see the grey and pink wires for the solenoid....now the part about running power and ground here to see if it clicks open....does this mean I am to disconnect the solenoid here.....connect a 12v wire from battery to a pin on the solenoid while grounding the other pin? Please forgive my inexperience.

Edit: Maybe while the engine is at idle I could ground the grey wire and listen for the click since the pink wire will already be providing the 12v. Or is this a really bad idea?[/QUOTE
engine running you would stall it(open vacuum to egr valve)
match the power to the pink pin dont wont to reverse it if it stalls/stumbles it works move on to the egr vacuum regulator if equipt

posted by  osborste

ok...I grounded the grey wire while the engine was at idle, the solenoid opened and the engine stumbled....I then searched for a egr vacuum regulator but didnt find one. checked the chiltons component location chart and it doesnt list this component for my year model even though they put it in the wiring diagram :screwy:.......

so....I then went back to the chiltons and went down the line for the egr system testing procedures...I disconnected the solenoid from the manifold and egr valve. I left the connector in place. I then applied vacuum to the manifold side of the solenoid. Very slowly the solenoid lost vacuum pressure. I checked the connection and hoses to see if the held vacuum and they were fine, then I rechecked the solenoid again just to be sure....exact same results. The chilton says if it does not hold vacuum then the solenoid is faulty.

....bingo, thanks osborste...will replace it today

.....the radiator looks great, although the a/c condenser fins are flat on over a third of the condenser, and the rest of it is plugged with dirt/dust. my a/c is not charged so I will be replacing the condenser today (do not know how I could have overlooked this :laughing: )....thanks again

posted by  Cantesoleares

Replaced solenoid, cleared codes, test drove on hwy for 30min at operating temperature (this is more than it usually took to trigger the SES light).....The SES light did not come on. No codes are stored in the ECM. :thumbs:

posted by  Cantesoleares

problem solved great come back anytime :laughing:

posted by  osborste

Your Message