Carbon Buildup/EGR Probs

[Fixxxer]

Hey everybody, I'm new here and sorry to have to make my first post a complaint

I have a 1995 GMC Jimmy V6 Vortec.

In December I had the rough idle/stalling/loss of power/engine light on and all that good garbage. So I took it to a local mechanic and he said it was carbon buildup. So he cleaned the EGR valve and it ran fine.

The very next day I took it to go run some errands out of town and it started acting up again. So I took it right back to him and he did the same thing. Got it back the next day and it's worked fine up until yesterday, it started acting up once again.

So I took it to the GMC Dealer this morning and they're going to look at it first thing tomorrow morning. I've read all over the internet that this is a common problem for Jimmy's and Blazers. Something about the EGR Valve staying open.

My question is, does anyone know what the Dealer could possibly do it? Carbon cleanings don't seem to be working. The local mechanic said that replacing the EGR valve wouldn't make much of a differance. And I had to replace the Oxygen Sensor back in September because the engine light came on and I had it checked out and that was the problem. But it was running fine.

I live in a small town, and work right in town, so there's alot of slow and short distance drives. After I got it cleaned the 2nd time I started making alot more longer trips out of town. I've tried using fuel system cleaners and I've even switched gas stations


So if anyone has any advice at all about all this I would love to hear it, I'm getting very nervous over all of this

[XtremeXP]

I'm also having the same problem. I have taken the EGR off twice in the past week and cleaned chunks of carbon out of it. I've read where Tomco makes a gasket with a screen on it to not let the carbon get in. Don't know how good it is but I'm thinking of ordering one or making my own with a screen from a faucet. Please let me know what the dealer tells you. Maybe theres another solution than this. But here is the link if tou want to check it out.

http://www.northernautoparts.com/Pro...ctModelId=7514

another link

http://www.tomco-inc.com/Catalog/m1667t.pdf Open with Adobe Acrobat Reader

[Fixxxer]

I talked to the dealer. It's going to cost me $1,100. Said it needs a whole new intake manifold or something.

[XtremeXP]

Originally Posted by Fixxxer

I talked to the dealer. It's going to cost me $1,100. Said it needs a whole new intake manifold or something.

WOW! Must be the cpi or spider I've seen other people on here talk about. I may have the same problem. I've heard they're not hard to replace so maybe I can save a few bucks and do it myself. Thanks for the info though and sorry to hear it's $1100. If you get it fixed let me know how it runs after the repair.

[Fixxxer]

Originally Posted by XtremeXP

WOW! Must be the cpi or spider I've seen other people on here talk about. I may have the same problem. I've heard they're not hard to replace so maybe I can save a few bucks and do it myself. Thanks for the info though and sorry to hear it's $1100. If you get it fixed let me know how it runs after the repair.

I'll let you know. But he also said it's a 5-6 hour job. I guess you have to change the oil and antifreeze and and all that too.

[mjohn]

Just got my Jimmy back...the 4.3 Wseries...
Runs great...Starts perfect...idles...not Rich...
It was worth the $500. + for Parts...labor... :o)

[Fixxxer]

Originally Posted by mjohn

Just got my Jimmy back...the 4.3 Wseries...
Runs great...Starts perfect...idles...not Rich...
It was worth the $500. + for Parts...labor... :o)

What'd you have done to yours?

[Fixxxer]

I also made a copy of this article I found and gave one to the dealer

http://www.alldata.tsb.com/techtips/1999/19990809c.html

Jim Grant's Tech Tips

95 GMC Jimmy, EGR Carbon Problems
Q: I recently bought a used '95 GMC Jimmy at a dealer with 78,000 miles with a 30 day warranty. The very next day after the warranty expired the fuel pump also expired. After replacing the fuel pump a code for the EGR pintle out of position occurred. Upon inspection of the EGR it appeared that it had been recently replaced. I personally pulled the unit and found pieces of carbon stuck in it keeping the pintle from closing all the way. I removed the carbon and reinstalled the EGR. The problem caused a serious idling effect. The very next day the same thing happened. I cleared the EGR again and the Jimmy ran fine. My question is where does the carbon come from and will this continue to happen? Is this a problem unique to Central Multi-Port Fuel Injection systems or is there some special maintenance that I need to perform to prevent it from happening again. Any info would be appreciated...........Don


A: The valve that you are referring to is GM's Linear Exhaust Gas Recirculation (LEGR) valve which is common to GM vehicles equipped with a 4.3 liter engine. The LEGR valve has been prone to carbon problems that cause the valve to stick open. When carbon deposits get caught in the valve it can turn the Check Engine Light on and the driver of the vehicle may experience problems such as engine surge, stalling, rough idle, and/or hard starting. Where does the carbon come from? The exhaust system. The LEGR valve introduces metered amounts of exhaust gases back to the engine. As the hot exhaust gases travel through the cooler passage, leading to the LEGR valve, the gases will cool and form deposits. Over time the deposits can build up and break off. If the deposits get caught in the valve, it will stick open and cause driveability problems. ALLDATA Information Systems shows GM Technical Service Bulletin # 96067 addressing problems caused by deposits of foreign material affecting the LEGR valve. The fix was a revised program for the computer that would increase the movement of the valve, reducing the chance of debris being caught in the valve.

[XtremeXP]

Originally Posted by Fixxxer

I also made a copy of this article I found and gave one to the dealer

http://www.alldata.tsb.com/techtips/1999/19990809c.html

Jim Grant's Tech Tips

95 GMC Jimmy, EGR Carbon Problems
Q: I recently bought a used '95 GMC Jimmy at a dealer with 78,000 miles with a 30 day warranty. The very next day after the warranty expired the fuel pump also expired. After replacing the fuel pump a code for the EGR pintle out of position occurred. Upon inspection of the EGR it appeared that it had been recently replaced. I personally pulled the unit and found pieces of carbon stuck in it keeping the pintle from closing all the way. I removed the carbon and reinstalled the EGR. The problem caused a serious idling effect. The very next day the same thing happened. I cleared the EGR again and the Jimmy ran fine. My question is where does the carbon come from and will this continue to happen? Is this a problem unique to Central Multi-Port Fuel Injection systems or is there some special maintenance that I need to perform to prevent it from happening again. Any info would be appreciated...........Don


A: The valve that you are referring to is GM's Linear Exhaust Gas Recirculation (LEGR) valve which is common to GM vehicles equipped with a 4.3 liter engine. The LEGR valve has been prone to carbon problems that cause the valve to stick open. When carbon deposits get caught in the valve it can turn the Check Engine Light on and the driver of the vehicle may experience problems such as engine surge, stalling, rough idle, and/or hard starting. Where does the carbon come from? The exhaust system. The LEGR valve introduces metered amounts of exhaust gases back to the engine. As the hot exhaust gases travel through the cooler passage, leading to the LEGR valve, the gases will cool and form deposits. Over time the deposits can build up and break off. If the deposits get caught in the valve, it will stick open and cause driveability problems. ALLDATA Information Systems shows GM Technical Service Bulletin # 96067 addressing problems caused by deposits of foreign material affecting the LEGR valve. The fix was a revised program for the computer that would increase the movement of the valve, reducing the chance of debris being caught in the valve.

Just made me one of those gaskets with a screen to keep the chunks of carbon out. I bought an exhuast repair kit from the parts store just for the screen inside its heat resistant and I think it will do good. Cut it out and used a little rtv and gonna put it on tomorrow I'll let yall know how it works. Looks like i'm gonna have to replace the cpi also. Appears to be leaking. Thanks to all for the help.

[mjohn]

I got mine back and idles fine now...and runs not rich at all...therefore...I hope no carbon to clog the erg...But, let us know if the gasket...keeps the erg valve clean and eliminates your problem...
rockauto.com has the new CPI for about $300.
A great AC Delco unit...2 day delivery is like $13.

[Fixxxer]

Just got my Jimmy back tonight. Ended up costing about 1,200(including labor. They gave me back the old manifold and holy shit, that thing was friggin BAD! It was so gunky and just down right nasty looking. They said it had to be replaced otherwise the carbon would have just kept on building up and breaking off. They also had to change the oil and antifreeze. So far it seems to be running excellent. Alot smoother and quieter.

[Fixxxer]

Manifold - $742.96
Gasket KI - $20.47
Gasket - $6.36
Adhesive - $11.25
Dex-Cool Coolant - $15
Oil and Filter Change - $12.90
Thermostat - $9.58

Total Parts - $833.52
Total Labor - $357.50
Tax - $86.35
Total - $1277.37

What they did (Straight from the Receipt)

Technician found code for EGR Valve System. Checked Bullitin and removed and cleaned ran ok for 1 min. found that carbon buildup in lower intake manifold was plugging EGR System. Replaced withnew manifold installed new thermostat and gasket replaced. Replaced oil and filter which may have been contaminated. Also replaced all coolant with Dex-Cool set for winter driving.


All and all I think it was definitely worth it. It's running GREAT. Sounds better too. And it heats up much faster due to the new thermostat. Even though it was the Dealership, my dad thinks everything adds up right. I'm just happy to have it back

[XtremeXP]

Well my cpi (regulator side) was leaking. Bought a new cpi and installed. Also doing a major tune up and changing the thermostat and fuel filter. Hope to have it all put back together tomorrow. Should run a lot better I hope.

[XtremeXP]

Praise the lord. The cpi was the problem. Installed the new one and idles perfect. Coming to a stop and everything. Cpi was 270.00 at advance auto parts. Now I can work on the other little things. Thnks everyone the info here helped me out a whole lot.

[BTC]

Originally Posted by XtremeXP

Well my cpi (regulator side) was leaking. Bought a new cpi and installed. Also doing a major tune up and changing the thermostat and fuel filter. Hope to have it all put back together tomorrow. Should run a lot better I hope.

What year is your jimmy?