Carbon Buildup/EGR Probs

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


I read that Blazers and Jimmys are pretty much the same, so that's why I am posting this here.

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 to 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.

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 :(

some driving habit's promote more problem's, do you idle alot, in town
slow driving? do you ever use a fuel system cleaner, does it burn oil,
need more info

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

does it also use a little oil, i've also seen this start up at the begining
of a clogged convertor,

I'm pretty sure it's not an oil problem

if it uses oil it adds to the build up , it's in the ex. and the EGR is alowing
in into the intake, so if there is a high amount in there it will cause a problem sooner, i look at everything i know , cause if i rule out one thing
it will burn me most of the time, do you change you oil offten city/stop&
go driving is hard on cars

well thanks for that tidbit, it's in the dealer's hands now, and i won't be hearing from them until tomorrow.

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

All I can say is WOW...this reminds me never-never go to the dealer...with intake problems...
I HAVE A 1993 GMC Jimmy 4.3 V6 Wseries...
The carbon build-up on the injectors...can be treated with a GM Injector Cleaner...$21. bottle..
And, if the whole unit inside the plenium...(Under the colored Vortec label.) CPI Injector Unit...$321. and internal fuel lines...$40. I have had the CPI unit put in and am waiting for the Internal Lines...
A new intake? Let us know what the outcome is as this is a common problem with these...Search this thread and you will see... Sorry about your $$ loss...

never got answer if it use's any oil, :smokin:

never got answer if it use's any oil, :smokin:

what exactly do you mean?

All I can say is WOW...this reminds me never-never go to the dealer...with intake problems...
I HAVE A 1993 GMC Jimmy 4.3 V6 Wseries...
The carbon build-up on the injectors...can be treated with a GM Injector Cleaner...$21. bottle..
And, if the whole unit inside the plenium...(Under the colored Vortec label.) CPI Injector Unit...$321. and internal fuel lines...$40. I have had the CPI unit put in and am waiting for the Internal Lines...
A new intake? Let us know what the outcome is as this is a common problem with these...Search this thread and you will see... Sorry about your $$ loss...

so in other words, i'm being ripped off? the guy said the whole thing was bad and needed to be replaced. and that included oil, filter and some other stuff. also said its a 5-6 hour job. so i don't know, i'm not too intelligent when it comes to cars, but i'm learning

OK lets start over(don't know if you getting ripped,sounds a little funny
but ) i asked if it used any oil ,that means after the oil is changed ,do
you check it ? how long till it needs some? NOT a drop till next oil change
?? how long(time)and mile's between oil changes, do you know what oil is in it? :smokin:

OK lets start over(don't know if you getting ripped,sounds a little funny
but ) i asked if it used any oil ,that means after the oil is changed ,do
you check it ? how long till it needs some? NOT a drop till next oil change
?? how long(time)and mile's between oil changes, do you know what oil is in it? :smokin:

I check it every week or so. It really doesn't go through alot, and it doesn't leak any (that I know of). Um, couldn't tell ya how often I change it, I don't wait until 3,000 miles though to change it haha, I guess you could say I change it regularly

now i got something to work from :smokin: OK it's burning it ,oil will build-
up more carbon than normal ex. gas, it can be as simple as it's leaking
past valve seals ,burning and pump into egr valve, EGR will carbon up
faster from this problem, have you changed the PCV valve lately,it
helps lower crankcase pressure , maynot use as much oil, do some spark
plugs look oily or darker then the rest (lt. to a med. gray is good)
your intake can be cloged up but it will do it again if the problem isnt
found and fixed, what type & brand of oil do you use?

If cleaning the EGR valve makes the engine run ok, you need to replace it,…. not the complete intake manifold, (if the intake manifold needed to be replaced, the engine would never work ok not even after cleaning the EGR valve) by the symptoms you describe seems like the EGR is sticking open, that means it allows exhast gas to enter the intake manifold trough the whole RPM range, it should only open when the engine is at operating temperature and at medium to high RPM's, and should allways close at idle, as it seems it's sticking open and that's causing the rough idle, stalling, etc….. it's controlled by the computer that's why the check engine light comes on, so a computer verification should show the codes for the exact problem, if it reads a bad EGR valve, get a new one…

It's likely the intake manifold is not the problem….

R. is it possible part of the intake has corrodied and EGR can't seat close
????

If cleaning the EGR valve makes the engine run ok, you need to replace it,…. not the complete intake manifold, (if the intake manifold needed to be replaced, the engine would never work ok not even after cleaning the EGR valve) by the symptoms you describe seems like the EGR is sticking open, that means it allows exhast gas to enter the intake manifold trough the whole RPM range, it should only open when the engine is at operating temperature and at medium to high RPM's, and should allways close at idle, as it seems it's sticking open and that's causing the rough idle, stalling, etc….. it's controlled by the computer that's why the check engine light comes on, so a computer verification should show the codes for the exact problem, if it reads a bad EGR valve, get a new one…

It's likely the intake manifold is not the problem….

I've had the EGR Valve cleaned 2x before I took it to the dealer. When I first brought it to the local mechanic, he said that replacing the EGR Valve wouldn't make much of a difference. He said that the carbon would just keep breaking off from places.

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.

good info: back to the $$$$ the dealer wants 1100 bucks to pull and
clean (& reinstall) your intake, on a car that adds extra carbon into a
allready weak design...... am i in the right place on this???????

good info: back to the $$$$ the dealer wants 1100 bucks to pull and
clean (& reinstall) your intake, on a car that adds extra carbon into a
allready weak design...... am i in the right place on this???????


no :)

They had to order a brand spanking new intake manifold to replace the old one with. I said to him "now will this take care of the problem for good" and he said "it sure will" I'll know more tomorrow, that's when it should be done.

Dealearships have some sort of guarantee on repairs, right?

let us know if you can WALK tomorrow :lol2: :lol2:

let us know if you can WALK tomorrow :lol2: :lol2:

:( :(

kiddin' (i hope) :smokin:

This reminds me of a problem I had with a 95 Buick I used to have. Not being a very good mechanic I had taken the car to a mechanic I trust and he came up with the EGR valve needing to be replaced. After replacing it, the car still had the same problems so he got on the phone with some other mechanics. One told him that the hole where the valve mounts was big but got smaller as the hole traveled thru the manifold. He took a piece of wire and ran it thru the hole...cleaning it out. Put the old EGR valve back on and it worked great. Never had another problem with it. I'm not sure if this will help in other cases or not but it may be worth trying.

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.

call other GM dealers and price man. that seams :screwy: $700
also maybe to compare the online GM parts site don't have it :loser:

Whats done is done...I wish you well my friend...

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 :)

Here's a solution of the EGR carbon buiuldup problem.

A co-worker if mine has a 1994 GMC Jimmy and was continually removing the EGR solenoid to clean carbon particals which were jamming the EGR solenoid open. His vehicle has about 130k on it and doesn't seem to burn oil (That much). I found out after talking with a few auto parts suppliers that a gasket with an internal screen is available to prevent the carbon particals from getting into the solenoid. It is Standard part # VG57. This gasket is used on a Vortec V6 with Multipoint Fuel Injection.

This doesn't solve the carbon buildup problem, but restores the drivability of the vehicle until the engine can be replaced since the EGR will not get jammed anymore.

:smokin: the cheap way i've done it is to pull EGR use a coat hanger to rod out some of the build up, vac it,start it, vac again. use SS screen
to block carbon fron hanging valve open, used the spray copper gasket
sealer (let dry) and was able to reuse old gasket fix cost OH maybe
about :2cents:

Hate to burst your guys bubble but there was a recall for this sometime back. GM should have sent you a notice, oh btw if you have more than 80,000 miles this Recall is void for you folks ; (

Comp...what is this SS sreen you use to block the carbon from entering...?