1995 S10 2.2L - Code 32 But...

About 4 days ago, my 1995 S10 2.2L with manual trans wouldn't crank/start. I jumped it from another car and managed to get it running. Drove the truck hoping to charge the battery and it started fine again about an hour or two later. But next morning it wouldn't start and jumping didn't help.

I looked around for a possible battery drain. One at a time I pulled all the fuses. Finding nothing, I finally pulled the battery (from 2004, I think - before my time) and had it tested. Bought a new battery and and all was fine. I drove the vehicle in for a charging system test - which showed all was well too.

Since doing all this I have now seen the Service Engine light come on twice. This is not something I am used to seeing. So today I jumpered the proper connectors under the dash and read the error code. Only one of them: #32 - which I read to be something regarding the EGR valve.

I find it strange and very co-incidental that this should happen now just after the battery change. So I am wondering if they are related? Anyone have any insight on this?

One other thing to mention is that I have been hearing and ignoring rattling from the cat converter for some time. It seems worse at idle and until things warm up. But then not too bad. I am starting to look into that now. I can hit the thing and it sounds like something inside is loose and banging around in there. Since there are no bolt flanges on the thing, I think I will have to take it into a muffler shop for removal and replacement. Could that possibly be related? Just wondering.

Thanks for your time and input.

Well...You've had a fun couple days. To begin, the rattle you hear in the cat area is probably the guts breaking down. It's like a honeycomb looking stuff in there. This would be the 1st thing I'd address, because as the cat breaks down & the "honeycomb" breaks up, it sometimes starts clogging the exhaust. Pieces may also get caught in the baffles of the muffler.

In regards to the #32 EGR code, you may be able to do some bench tests and also clean out the exhaust port on the EGR valve. Sometimes the pintle becomes so caked up with carbon, it doesn't allow it to move or blocks the port. You may want to pick up a new gasket for it. Sometimes the old one will tear on you. The new one can be reused a couple times, like if you got a new EGR valve to install. Also check your vacuum hoses to it & all around. Not enough vacuum will also keep the EGR from working.

To check the diaphram on the EGR, use a vacuum hand pump and pressurize it (sucking) to no more than 6 psi. If it holds, then the diaphram portion is ok. I think you should also see the pintle move up & down when using the pump.

Are they all connected to you're battery issue? Probably not. Just all happened to come about or noticeable to you at the same time. Post an update with your findings, so that this tthread can help others in the future. Or if you have more questions... Good luck with everything!

Oh, you have no idea of all my "fun". Just barely finished diagnosing and fixing fuel injection issues on my 1983 Volvo when this all started. Cannot seem to finish one issue before the next rears its head anymore! I will follow your advice and put the cat converter at the top of the list. I have read about cleaning the EGR and that makes sense to me. I am concerned about actually getting it off/on since it looks hard to get at the fasteners. But it can be done so why not try? I will start looking for gastkets too. My truck was originally from California. It looks like their EGR and cat converters may be different than others. So I am thinking that I have look for those parts even though I now live in Washington state. I will report back. Thanks again.

Oh, you have no idea of all my "fun". Cannot seem to finish one issue before the next rears its head anymore!

Ohhh, I'm right there with ya buddy!!! lol... Everytime I turn around. :runaround: Can't seem to catch a break! It must be going around for sure!! :rolleyes:

I am concerned about actually getting it off/on since it looks hard to get at the fasteners.
If I can remember right, I think they were an 10mm or 3/8" nuts... Maybe use a ratcheting Gearwrench but 1st break it loose with a regular box end. 6 point if possible, whether it's a socket or a wrench, then chase it with a gearwrench, etc... If it helps, you may want to use an old blanket/towel or rags to wrap around your work area. Tuck it under the EGR area in order to prevent the bolts from dropping down or going through the fun of fishing them with a magnet, etc. There's a heater hose that runs by it, I think, which does flex & give a little leeway. Use a bunjee cord or rope to hold things out of the way. Just a few tips.

My truck was originally from California. It looks like their EGR and cat converters may be different than others. So I am thinking that I have look for those parts even though I now live in Washington state.
Yes in some cases, especially emissions, there are variances in parts. Check the white Emission label under the hood. It usually says federal (regular) or cali emissions.

Thanks again. Funny you should reply today as the "fun" got more intense. My wife took the truck off on a painting job yesterday and was headed back there again this morning. Part of the way there she called and said the truck was not running right! Of course, I am far away with my own pile of stuff to do today.

She described the truck as having VERY low power and not wanting to get above 2K on the tach. It could be slowly gotten up to speed but under acceleration load it was totally wimpy. And hills were awful.

I had called a known, good muffler shop yesterday to start arranging the cat converter replacement. They said they would order the part. It was not all that far from where my wife was when she called. So I had her call AAA to tow here there. I called the shop to warn them of her arrival. They didn't yet have the part but expected it this afternoon. They were not sure they would get it or if they could work the job into today's schedule.

The long and short is that they did get the part and were able to squeeze it in. At first the mechanic doubted the cat converter was a problem since it didn't rattle at all when he put the truck on the rack. But I assured him it did rattle when cold and sometimes quite loudly. So he cut it off and welded a new Calif. generic cat converter into place. He later told me that 1/2 the insert was disintegrated while the other 1/2 was intact. Sadly I did not get to converse with him until after my wife drove away and later called to say the problem persists.

When I finally did chat with the guy, I asked if he thought the insert debris could have blown downstream and clogged the exhaust elsewhere. He said he did not perform a back pressure test but while he thought it possible, he did not think it likely. Darn it, I really wanted to have that checked as I knew it was possible so why not confirm? My fault for not being totally explicit with the wife or mechanic. I was just trying to not overload everyone and go one step at a time.

Anyhow, the wife crawled home at 30 mph max and had to climb hills in first and slowly. She also told me that near the end she was so frustrated and mad that she really pounded on the throttle. When she did she smelled alot of gasoline from the cab.

Once I got my hands on the truck, I checked for new codes and found only the 32 EGR reported earlier. I also thought the engine compartment was VERY hot - maybe I am wrong but that was my first impression and I am sticking with it. Then with the engine idling (which it does just fine), I put my hand up to the tail pipe. I don't recall doing this with the truck before but have with our Volvos and the amount of exhaust gas and pressure seemed strangely small. I had a buddy rev the engine and while more exhaust came out of the pipe, it still felt weak and limited to me.

So now I have to figure this out along with fooling with the EGR - which could be related I guess. But I rather doubt it since it has been several days since getting this code 32 and the truck has had no problems since then beyond the occasional flash of the check engine light.

Any input is appreciated. Thanks and sorry for the long post.

To me, from your description & how it's acting, it certainly can be blocked.

I have a peeve with repair people (no matter the service, no matter the field), the lack of checking work. I know the mechanic didn't know the whole story, but as you stated, check the back pressure. It's very possible that there is a blockage. Have you compared with another vehicle? The way the exhaust pressure feels? Are you using a rag to cover the tailpipe, or just using your hand? Use a rag instead... it should almost want to bog in idle if the "rag" blockage is making a difference.
Are there any bolted on sections between the muffler & cat? Think there is a chance of unbolting & checking backpressure then.... or going back the exhaust repairman tmrw. grrr... I just hate to waste the trip.
The gasoline smell was solely from the engine compartment?

See a blockage will have similar symptoms....

You know what? Contine with the EGR.... come to think of it...it will cause running rich & lack of power when stuck

Thanks.

I did compare it with my buddy;s Mazda 4 cylinder small truck and his exhaust, as well as my Volvo's, seem stronger at both idle and higher RPM.

I also wondered if this was a symptom of insufficient fuel delivery. But I really don't think so because it did create a smell (not sure if from the engine compartment or out the tail pipe) of gas when the wife really stomped on the gas pedal.

I figure a blockage could cause all the symptoms due to inability to intake adequate air because adequate exhaust isn't moving. So heat from exhaust which normally gets discharged, stays around the engine (causing who knows what hell?). And if tramping on the gas pedal causes the throttle position to move and this is sensed by the control mechanism, it might respond by injecting more gas even though there is not enough air flowing to properly mix and burn it. Of course there would be less exhaust and the amount would not climb with RPM as expected.

The whole EGR thing is new to me so it could easily come into play as well.

I guess my plan is to first tap all around the exhaust system downstream of the cat converter with a rubber hammer to try and listen for any rattling that would indicate cat converter material in that region.

Then some form of back pressure test. I have read that one could check vacuum pressure as an analog to exhaust pressure. I have no such tools either way. And no experience. So that might require a shop.

Then if all else fails to make things more clear, dive into the EGR.

Thanks

Yes...since that darn code keeps popping up...it actually is worth looking at.

I kept editing so reread the last post. I may have edited while you were typing. I can't help but analyzing & reanalyzing... trying to recall past experiences correctly as well. So I apologize for that too. I usually write & reread my post a few times before publishing... so I don't drive people crazy with my edits. Lol. GM in itself act differently... so I'm trying to throw out irrelevant data while I'm going through things in my head. I have notes from all my prior jobs, but I keep them with my work. I'll go over them tmrw. Hoping not to overlook anything in the meantime.

PS. Tmrw, while truck is idling... pull off vacuum from the EGR. Be sure there is ample vacuum/sucking. You may even encounter change on the idle (after disconnecting the vacuum hose but plug it with your finger, so the vacuum loss is not the change). which means there is something at least partially working

Remember , if you have a hand vacuum pump, use it. That can help you determine the issue, if it's the Valve before having to fumble with it. Use the vacuum port on the EGR...pump it up (sucking) 6 to no more than 8 psi. It should hold for at least 20 seconds. If no change, than EGR is bad or pintle is blocked up. If it holds, then recheck with engine idling... when you start sucking engine will start bogging. That is if the pintle and EGR is working.

So now there's 3 tests you can do without having to remove it 1st. The other test is the last paragragh on last msge.

If you find the EGR bad, then go with a Delphi or AC Delco. otherwise you may not get a good fit. Remember to check the emission label for Cali or "except Cali"/Federal.

Having a hard time going to sleep. I'll check in tmrw. ;)

Thanks again for all your time and help here. Sadly, no vacuum test tools in my boxes. Never really needed them before. Will have to look into that after doing my low-tech tests first. So that line coming off the EGR is a vacuum line and not an electric lead? It appears to run along the top of the engine to a box which I thought was a relay or solenoid of some sort. If that were true, I would have thought it electrical. But in the photos I have seen online, it does look like a vacuum connector. With a little luck I can get enough time to do something today. Will report back what I find.

Being a 95, it should be the vacuum operated "flying saucer top" looking one. That port going to it should be vacuum. In some vehicles, instead of using a rubber vacuum hose, they'll use a plastic hose with rubber ends (which I don't like becasue they tend to crack & become brittle over time or when you are trying to work with them. Rubber vacuum hose & the plastic stuff is completely interchangeable.

Because it's a 95, if you trace the vacuum hose, it should go to the EGR controller. It's a little black motor with 2 or 3 ports on it and an electrical connector. This is the EGR Solenoid. I have not mentioned this part, for it is so rare for this component to go bad (so rare, all the Chevys I've ever worked on back to 86, never needed a replacement yet). It's job is to route the vacuum when the ECM commands it.

I think some part stores allow you to rent the tool (acuum pump) for free, with only having to pay for the pump upfront (maybe$20) but giving you a full refund when it's returned.

You are, of course, correct about the EGR valve. I found it easily and it looks just as you said. And it is a molded plastic hose with rubber on at least the EGR end. It does run along the top of the engine and goes into a black box which appears to be on the intake route just downstream of what I am sure is the throttle mechanism.

No test of things yet. Just been looking around. Since we have had field mice around this year getting into cars I though I ought to look at the air filter, etc. No problems I can see there.

I also rapped all along the exhaust system downstream from the cat converter. It is interesting but I see absolutely NO bolts on the exhaust line save those holding it all to the manifold. I knew there were none on the cat converter and was very surprised by that. But to see none anywhere seems really odd. Anyhow, it is hard to tell exactly what I am hearing but when I rap on the muffler I do think I hear some rattling from inside. Hard for me to be sure though. And even if I do, it could just be a loose baffle.

I rapped down by the tailpipe and definitely heard rattling as a small pile of chips came out (see photo). This looked like rusted out exhaust pipe material to me and I checked it for magnetic attraction and it sticks to a magnet. I presume the converter liner would not be magnetic. Is that right? Anyhow, I can clearly see that the tailpipe has some holes (see photo). My wife actually told me she saw this with the car on the rack and asked specifically if it was an issue. She was told no. It may not be contributing to the current problem but it definitely seems an issue in the future. Maybe some of the exhaust is coming out there instead of the main pipe opening? I will have to check that further too.

I haven't yet tried to clear the error 32 and see if it shows up again. I have seen the service light come on for sure. But I am not sure if that indicates that the error has JUST HAPPENED or if it is just reminding me that an error has been previously detected. I think I have to remove the negative battery terminal to clear this. Is that correct?

Now that I have had a good look at the EGR I think I should be able to remove and install again.

Thanks

It does run along the top of the engine and goes into a black box which appears to be on the intake route just downstream of what I am sure is the throttle mechanism.

The throttle mechanism being the Throttle Body? Carb looking thing... to one of the ports on it, you mean? Just curious.

I knew there were none on the cat converter and was very surprised by that. But to see none anywhere seems really odd.

It's not uncommon, but it does make it harder for the DIYer to repair or replace... on the positive end, they tend to leak less this way.


Anyhow, it is hard to tell exactly what I am hearing but when I rap on the muffler I do think I hear some rattling from inside. Hard for me to be sure though. And even if I do, it could just be a loose baffle.

Very plausible here too.

I presume the converter liner would not be magnetic. Is that right?

You are correct there too. It's more of a ceramic type material lined with platinum... not magnetic

Anyhow, I can clearly see that the tailpipe has some holes (see photo). My wife actually told me she saw this with the car on the rack and asked specifically if it was an issue. She was told no.

I agree.

It may not be contributing to the current problem but it definitely seems an issue in the future. Maybe some of the exhaust is coming out there instead of the main pipe opening?

Yes, you may have to look into that when it comes time for inspection. There aren't supposed to be any leaks throughout the exhaust, per state regulations. (check online for your state under emissions if applicable). After a search, this is in fact a requirement to pass on your vehicle, in your state.

This will also keep the projected backpressure weak, obviously, since it's escaping before it reaches the end.


I am not sure if that indicates that the error has JUST HAPPENED or if it is just reminding me that an error has been previously detected.

Could be either on these. If this is a test done by the PCM on startup, then it will set almost immediately after start.
I can't remember off hand if hard codes are stored the same way as the OBDII systems, "Light will stay on until the problem is corrected" scenario. Not a big deal there.

I think I have to remove the negative battery terminal to clear this. Is that correct?


100% correct. Keep it disconnected for up to 5 mns to be sure any capacitors in the system are completely drained.

Fantastic job on the uploads too. For some ppl it's not the easiest task to do. :)

The uploads were not that easy for me either. Had to reduce the images sizes to meet requirements. But thanks.

I was reading elsewhere that a quick and dirty test for back pressure would be to remove the O2 sensor (I guess "real" back pressure tests can be done from there too), run the engine, and see if anything changes/improves. Obviously gotta be careful due to the fumes and maybe not a good idea at all.

But I have never replaced or even inspected the O2 sensor in this thing so I thought I would at least remove it and take a look. Another failure (so far). Not easy but I got my 22mm O2 sensor socket on the thing. But try as I might, I could not budge it. Even with a pipe over the 3/8 and 1/2 socket wrenches. Nada, nothing, nowhere. I have put some liquid wrench on it and will apply more before even bothering to try again. No idea why this is so hard. On my 2 Volvos, it is not anywhere this hard to remove (and way easier to get at).

More later. Thanks for your time and patience with this newbie.

I suggest using trans fluid for the rust inhibiter. Either used or clean, not fussy, and this is some of the best stuff I've ever used. A couple drops, fully covering threads, then every half hr for 2 hrs reapply... reapply right before reattemtping removal too.

Cheap & highly effective. & you are right about the check being done there, but usually with the aid of a backpressure gauge/tool. Just more input is all

Didn't have any tranny fluid around so stuck it out with Liquid Wrench. Followed your instructions and, after a long time and a crazy amount of effort, the O2 sensor is out at last. Doesn't even have that many threads! Later I will try to fire it up and see what happens. Hopefully nothing bad. I presume I will get an O2 sensor error of some sort. When I put the thing back in there, what should go on the threads?On my Volvos I use wheel bearing grease - careful not to get any on the sensor. But maybe anti seize is better? Never had any of that stuff. Thanks

Yes, when I install them, I typically use copper anti-seize. I don't like the gray stuff and it doesn't work on the high temp things anyway. If you can't get a hold of copper anti-seize, then go with the grease. That's fine.

Well I am just in from taking a short test drive with the O2 sensor out. All windows open, fire extinguisher at the ready, etc. I did a short loop that included a small hill.

The other day, the engine would simply not rev high enough to be able to climb that hill with any power at all. Today, without the O2 sensor in place, it climbed it just as normal. Obviously more noisy but in terms of power and engine RPM response, it was normal.

From this I feel I must conclude that there is a very high probability that the exhaust system downstream of the cat converter is plugged. I see no other explanation - especially knowing that the original cat converter was said to be 50% disintegrated.

I sure feel that when a muffler shop finds such a condition they should test for such a condition (if they can) or even try to blow out any debris (if they can) as standard procedure. But this one didn't. Oh well.

Now I have to review the theory of operation on the EGR valve. Since this basically sits atop the exhaust system I cannot help but wonder if it can possibly operate properly when there is a high level of back pressure. After all, it seems to be powered by nothing but intake vacuum. I know nothing about this but it seems like there may well be a connection.

Now to find a shop that can install a cat-back exhaust system here on the island where I live. I don't want to drive the car very far so it will likely have to be towed.

Thanks

I see no other explanation - especially knowing that the original cat converter was said to be 50% disintegrated.

I sure feel that when a muffler shop finds such a condition they should test for such a condition (if they can) or even try to blow out any debris (if they can) as standard procedure. But this one didn't. Oh well.
I totally agree with your statement. We, as repair techs, should ALWAYS check the work done afterwards anyway. In this particular case, I also agree, the mechanic knew how bad the cat was after removal. In his place I would've gone a step further and check the exhaust for restriction. Even if needed to charge extra (and the "go ahead" from the customer), I would have attempted to have it done right the 1st time. This is what separates good shops from the ones out to make the fastest buck. No care about the quality, just do it to get paid. Grrr. More & more common.
Now I have to review the theory of operation on the EGR valve. Since this basically sits atop the exhaust system I cannot help but wonder if it can possibly operate properly when there is a high level of back pressure. After all, it seems to be powered by nothing but intake vacuum. I know nothing about this but it seems like there may well be a connection.

I'm quite sure there is a motor/solenoid to operate the vacuum to the EGR. As far back to the mid 80s, all the S10s have a similar motor/setup. I'll post an image to help guide you. But on the EGR Solenoid, there are ports for the vacuum hose hookups. From the Solenoid, one hose goes to the Throttle body, the other goes to the EGR Valve. The Solenoid is operated by the ECM...

In idle the valve is closed, even on light acceleration it may stay closed. The valve recirculates the exhaust gases into the intake manifold... this is why the manifold can't control the EGR. These valves also need a certain amount of exhaust backpressure to work..

I know I've seen a few videos on their function... there are different types & they work differently. I'm sure a quick search on Youtube will do it.


Great job in testing and very logical way about it. :thumbsup: :thumbsup:

Thanks again for your help and encouragement! I have read about different EGR valve designs and my Chilton's talks about 3 different ones but I cannot find out if my system is "ported", "negative back pressure", or "linear". My guess at this point is the latter. Either way, even though I got an EGR gasket today I am going to refrain from doing anything with the EGR until I get the exhaust system dealt with. Then I can clear the code and see if it comes back again.

In partial defense of the muffler shop, I have to say that this was all done ad-hoc. My wife just showed up at their door. No appointment, etc. There were folks with appointments standing around waiting while they did the truck. And they did well to force the truck into their schedule. Still, after seeing the condition of the cat converter it seems like it would have made good sense to check and do it all at once. Of course, no warranty that they'd have a cat-back system for the truck in stock anyhow.

I would wonder if there is any way to "save" the existing muffler and pipes? Could the pipe be cut and the cat converter side plugged temporarily and somehow blow out the debris with high pressure air through the cut? The tailpipe is known to be shot so maybe it is best to just replace all. But I do wonder if, once cat converter debris goes downstream, there is anyway to get it out again.

Cheers!

PS, I just remembered that I have a lighted inspection camera that records video on my phone. I bought it on a whim. Maybe I can send it up the tail pipe for a look around?

I was posting these images for another thread, but some may be relevant here too... just for future reference.

image 1, Typical Chevy EGR Solenoid
https://www.dropbox.com/s/rx49erkvfouwait/2016-08-14%2019.26.46.jpg?dl=0

image 2 I'm pointing to the vacuum hose that goes to the EGR Valve
https://www.dropbox.com/s/awda6843anliqo5/2016-08-14%2019.27.02.jpg?dl=0

image 3 I'm pointing to the vacuum hose that goes to the TBI, to feed the vacuum...
https://www.dropbox.com/s/5ij6hbxhuwaaevn/2016-08-14%2019.27.13.jpg?dl=0

As far as your last post and possibly using the scope camera, I doubt you'll be able to see much up the tailpipe end because of how the baffles are setup in the muffler... However, maybe using it in the downstream O2 sensor port towards the muffler, you just may find something. As long as the blockage is not in the muffler. *shrugs*

Thanks. You are correct that I did not get very far with the scope camera this morning. Oh well!

I tried to look at those photo links but got 404 errors on all of them.

Cheers

Ahh yes, I just copy & pasted. I verified on the other post but the mere copy/paste method must've screwed it up.. I'll fix it now. Ty

Update, they're fixed

Same has happened to me many times. Thanks for the updates. That engine looks pretty different than mine. But I think I have similar components/mechanisms. Cheers and thanks for all the help.

Oh yeah, mine is a 4.3 s10 blazer, but like you said, many of the components are similar. The s10 series all are quite similarly set up.

got the truck back yesterday from having new muffler and tail pipe installed. runs normally now as I expected. Thanks for all your time and help.

I am still getting the code 32 even after clearing the code the other day. So I guess the EGR system is next on my list. It is always something!

Cheers