Carbon in EGR Valve

I just replaced my EGR Valve last week in my 95 Blazer. Just yesterday it started sputtering again like it was before the replacement. I took it in and they said carbon is getting into the EGR valve and it will continue to get in it until it is all cleaned out. Has anyone else had this problem? They said take off the upper intake and clean the passage out and for them to do it they want $180 - "ya right". Do they mean the air intake? Anyway any help is greatly appreciated.

I just replaced my EGR Valve last week in my 95 Blazer. Just yesterday it started sputtering again like it was before the replacement. I took it in and they said carbon is getting into the EGR valve and it will continue to get in it until it is all cleaned out. Has anyone else had this problem? They said take off the upper intake and clean the passage out and for them to do it they want $180 - "ya right". Do they mean the air intake? Anyway any help is greatly appreciated.

Find a egr valve gasket with the screen made in it.
Tomco and other aftermarket parts co make them.
All of the engines around that year go threw the old carbon ball making deal.
No big deal just screen the egr valve gasket and live with it.
And when you have the egr valve off start the engine up and let some of it blow out of there.
Most engine will quite that bad habit in time or later on.
Good luck
MT

I just replaced my EGR valve in my ’95 Blazer too. I’ve been using a Tomco gasket with the screen for about the last 20k or so, but I think the EGR was due to be replaced anyway. It was original and had 119k on it. I had cleaned it several times, but it still seemed to stick, so I got a new one from Advance Auto Parts for like $125.

Anyway, it runs pretty good now, but still idles rough and the exhaust smells sort of rich and a bit like rotten eggs. I am wondering if I have messed up the CAT or possibly need to replace something to do with the fuel injection?

I should also note that it has been hard to start for the last six months and the new EGR hasn’t helped this noticeably. You have to crank on it a while before it will finally fire. Also, there is a good amount of black carbon in the tail pipe – looks like the same carbon that was building up in the EGR valve.

There was a code set about a month ago too. It related to the EGR valve, so that’s another reason why I replaced it. I have already done a tune up prior to all of this. If anyone has other suggestions, please post them.

Thanks.

I just replaced my EGR valve in my ’95 Blazer too. I’ve been using a Tomco gasket with the screen for about the last 20k or so, but I think the EGR was due to be replaced anyway. It was original and had 119k on it. I had cleaned it several times, but it still seemed to stick, so I got a new one from Advance Auto Parts for like $125.

Anyway, it runs pretty good now, but still idles rough and the exhaust smells sort of rich and a bit like rotten eggs. I am wondering if I have messed up the CAT or possibly need to replace something to do with the fuel injection?

I should also note that it has been hard to start for the last six months and the new EGR hasn’t helped this noticeably. You have to crank on it a while before it will finally fire. Also, there is a good amount of black carbon in the tail pipe – looks like the same carbon that was building up in the EGR valve.

There was a code set about a month ago too. It related to the EGR valve, so that’s another reason why I replaced it. I have already done a tune up prior to all of this. If anyone has other suggestions, please post them.

Thanks.


Welcome to your first post on AF
Sounds like you may have more problems.
But it would be better to start a new tread or post on it and post the year and all info you have and some one will help you.
MT

Anyway, it runs pretty good now, but still idles rough and the exhaust smells sort of rich and a bit like rotten eggs. I am wondering if I have messed up the CAT or possibly need to replace something to do with the fuel injection?

I should also note that it has been hard to start for the last six months and the new EGR hasn’t helped this noticeably. You have to crank on it a while before it will finally fire. Also, there is a good amount of black carbon in the tail pipe – looks like the same carbon that was building up in the EGR valve.

There was a code set about a month ago too. It related to the EGR valve, so that’s another reason why I replaced it. I have already done a tune up prior to all of this. If anyone has other suggestions, please post them.

Thanks.

Your problems seem a lot like the ones I had with my 93 S-10 Blazer several months ago. Replacing the "spider" and "nut kit" fixed the black carbon coming out of the tail pipe (also had an EGR code set but I only cleaned the EGR valve). This did not fix my no start/hard start problem. To fix that problem, I had to drop the tank and replace the fuel pump.

if the cpi is bad, excess fuel in the exhaust will mess up the cat (mine started to rattle after cpi/nut kit replacement).

THANKS FOR THE HELP MT-2500. I am on the Tomco site know and that looks like it might work or it is at least my best shot. Even the mechanic that looked at my truck didn't know about this. You guys rock.

THANKS FOR THE HELP MT-2500. I am on the Tomco site know and that looks like it might work or it is at least my best shot. Even the mechanic that looked at my truck didn't know about this. You guys rock.

You are welcome.
The screen in there is a life saver on that problem.
Get the gasket no and check your local parts places.
Most of them now have them.
Good luck MT

if the cpi is bad, excess fuel in the exhaust will mess up the cat (mine started to rattle after cpi/nut kit replacement).

I was lucky in that I did not put on too many miles with soot coming out of the tailpipe. Probably not more than 20 miles. After replacing the fuel injection and fuel pump I passed the California smog test without replacing the CAT or the EGR valve (or the O2 sensor but that's another thread).

One thing I replaced that didn't need to be done was the starter switch. I was sure that the hard starting was due to the switch. On my 93, replacing the switch was a super PITA because it was very difficult to get both tools and hands together into the limited access space.

cpi and nut kit will need replacing.

I also don't like using the screened gaskets seeing it just keep the carbon in the plenum where it doesn't belong, you want the carbon out of there.

The carbon is there because of the cpi and nut kit leaking. You should fix that to stop the cause.

The screened gasket is just a bandaid.

Since my cpi and nut kit replacement I no longer have any carbon and I don't have a screened gasket.

With the screened gasket, the carbon pieces will collect which will hinder the EGR flow over time which will cause pinging due to the inappropriate amount of EGR gas being able to get into the combustion chamber where it is needed.

cpi and nut kit will need replacing.

I also don't like using the screened gaskets seeing it just keep the carbon in the plenum where it doesn't belong, you want the carbon out of there.

The carbon is there because of the cpi and nut kit leaking. You should fix that to stop the cause.

The screened gasket is just a bandaid.

Since my cpi and nut kit replacement I no longer have any carbon and I don't have a screened gasket.

With the screened gasket, the carbon pieces will collect which will hinder the EGR flow over time which will cause pinging due to the inappropriate amount of EGR gas being able to get into the combustion chamber where it is needed.


BlazerLT
That might be hard to do on the ones that do not have a nut kit.
MT

BlazerLT
That might be hard to do on the ones that do not have a nut kit.
MT

We are talking about a 1995 right?

Only 95's that have problems with carbon in the EGR is the CPI motor with a nut kit.

We are talking about a 1995 right?

Only 95's that have problems with carbon in the EGR is the CPI motor with a nut kit.

BlazerLT
The poster did not say what engine he had.
3 different 4.3 V6 that year.
You may be right if it is a CPI.
But 95 had both PCM and VCM W engine codes and also the Z computer systems.
In 1996 they went to he fuel lines going into the top of intake.
MT

Yip and both VCM and PCM engines were CPI engines and from what I have heard and seen, almost no 1995 Blazers came with the Z motor, most if not all had the W CPI motor which had carbon and EGR problems due to a defective nut kit or CPI injector regulator.

Yip and both VCM and PCM engines were CPI engines and from what I have heard and seen, almost no 1995 Blazers came with the Z motor, most if not all had the W CPI motor which had carbon and EGR problems due to a defective nut kit or CPI injector regulator.

BlazerLT looks like you have been doing a little home work. On the 95 4.3 V6.
Carbon ball codes in the old EGR valve are Kinda like a 02 sensor codes.
Do not throw parts at it untill you check it out.
Proper testing would be in order. Could be the nut kit or cpi injector unit or one of many other things.
I thing for sure the screen in the egr valve gasket will save a lot of removing and reinstalling the erg valve untill the problem is found.
MT

BlazerLT looks like you have been doing a little home work. On the 95 4.3 V6.
Carbon ball codes in the old EGR valve are Kinda like a 02 sensor codes.
Do not throw parts at it untill you check it out.
Proper testing would be in order. Could be the nut kit or cpi injector unit or one of many other things.
I thing for sure the screen in the egr valve gasket will save a lot of removing and reinstalling the erg valve untill the problem is found.
MT

:D

But with all due respect intended, wouldn't it be better to get the carbon out of the engine instead of being trapped in the screen which will hinder EGR flow over time and potentially increase combustion temperatures and pinging when the inert EGR gases is restricted?

:D

But with all due respect intended, wouldn't it be better to get the carbon out of the engine instead of being trapped in the screen which will hinder EGR flow over time and potentially increase combustion temperatures and pinging when the inert EGR gases is restricted?

Well I have never had one make that many carbon balls to stop up the port and shut off the egr flow.
The screen is more to keep them from getting under the egr valve.
But it could be possiable restrict flow if it make hole lot of them.
A person shoould pull the egr valve and check it from time to time is there is any flow problems.
MT

Hi Gang, hope it's OK for me to sit with you at the "grown folks table".
My experience with a screened EGR passage has been good for many years on my '92. I'm not sure if it was my leaky lines or 2 leaky regulators or even just accumilated carbon like my old carbed Chevys, loosened carbon was/is still the result. The possibility of a clogged EGR passage interests me. The lack of inert gasses to cool the combustion process and resulting knock activates the knock sensors which quickly retard the ignition timing so no damage occurs but at what cost?
Would there be a detected power loss?
What about fuel milage?
What besides an EGR removal and check would indicate a clogged passage?

Hi Gang, hope it's OK for me to sit with you at the "grown folks table".
My experience with a screened EGR passage has been good for many years on my '92. I'm not sure if it was my leaky lines or 2 leaky regulators or even just accumilated carbon like my old carbed Chevys, loosened carbon was/is still the result. The possibility of a clogged EGR passage interests me. The lack of inert gasses to cool the combustion process and resulting knock activates the knock sensors which quickly retard the ignition timing so no damage occurs but at what cost?
Would there be a detected power loss?
What about fuel milage?
What besides an EGR removal and check would indicate a clogged passage?

You are welcome to jump in any where and give us your ideas and experiance on it.
Actually if EGR valve is blocked or not working you will have a little more power but it will cut fuel mileage a little and may cause some spark knock.
But newer VCM /PVM computers will detect no egr valve flow and should set a code if it has no or restricted egr valve flow.
I always like the screen in the gasket to keep the spit balls out of the egr valve but a blazerLT pointed out it could led to restricted EGR valve flow.
You can not win for losing. Just do the best with what you have.
It seemes to me like all of the 4.3 v6 go threw the old spit ball in the egr valve making at some time in there life.
And some get over it after a while.
The cause could be one of many things. Gas additives,fuel mixture not right or engine not running right and as BlazerLT said the nut kit or internal fuel leakage inside the plantuim or even needing a good tune up..
MT

I had the same problem with my 95 s10. Black smoke coming out of the exhast and a clogged EGR valve. Dealer put it on the computer and found that the coolant temp sensor was bad. Changed the sensor and never had the problem again.

That makes sense. Bet the mpg's improved too.
The stem on the '92 plug valve gets a "coating" that causes it to stick open every now and then...been about a year ago. I remove the EGR and work the plug valve in and out until it frees up then reinstall for another years service.

I've used the tomco gasket on the 95 I had, put it in as soon as I got the truck, about 100,000kms on it before I sold it, never had a problem with it. I understand LT what your saying, but I would rather have the carbon only go as far as the screen, then give me intermittent idle problems and stuff.

I've used the tomco gasket on the 95 I had, put it in as soon as I got the truck, about 100,000kms on it before I sold it, never had a problem with it. I understand LT what your saying, but I would rather have the carbon only go as far as the screen, then give me intermittent idle problems and stuff.

True, I understand your point.

But after the actual cause (CPI / nutkit) is fixed, you won't ever have a carbon problem again. You might have a couple chunk but after that, smooth sailing, I haven't had one single chunk of carbon since I fixed everything.

But to each there own, just wanted to let people know what MIGHT occur with the screen. :D