EGR valve HELP

[OffRoadSonoma]

I have a '95 noma, v6 tbi. About two months after I bought it I noticed that the millege was horrible, it was hesitating and if I went on the freeway and shut my truck off right away it would not restart. It would backfire, and surge and smell like it was running very rich, then would die. I took it to a local high school and hooked it up to a code reader. Everthing looked ok, then we noticed that the EGR valve was reading at 50% open, when it shoulda been closed for starting. I replaced that, at about $120. I am now having the same problems, and my gas millege is even worse. If any one knows any tricks around it to keep it clean, or to take it off without getting a check engine code, I would really appreciate the help.

[cherokee_guy82]

with the egr, are you actually finding any carbon deposits? if so, what eng is it? if 4.3... could need a new thermostat to make it run a little hotter and prevent the carbon. You would not want to remove the egr because it is always controlling part of the emissions and removing it would probably make your mileage suck

[OffRoadSonoma]

Ya. I've taken this new one off twice now and cleaned it. It was filled with carbon. I ended up spraying carb cleaner inside the port and scraping alot of it out. Some one said that sometimes your computer goes bad. That sounds possible because it eats alot of gas, and runs bad, and a while ago I had to had the cat cut out because the cone inside broke. The muffler shop guy said it was because there was too much raw gas being dumped into the exhaust. So do u think the computer is the possible cause?? After 130,000 miles.

[johnsbackintown]

oxygen sensor more than likely

[rheaghen]

I recently ran into the same problem with my 98 s-10. the computer said I was running rich on bank 1, and that I had a problem with my egr valve... I replaced the EGR valve, and the Fuel Filter, checked the gas for water, and finally I found that the real problem was with my exhaust. I later found out that my (sorry if my spelling sux) Catalitic Converter was broken up inside, and I had to replace it. if you shake your cat. converter(about 1.5 feet up from your oxygen sensor) you will hear if anything is loose in there. if thats the case...it's probably clogging your exaust...
Note: you can remove the converter with out a cutting torch..all you need is a good set of wrences...save your self some money and do it yourself

[OffRoadSonoma]

I've had the catalytic converter cut off already, so I know that isn't the problem. Is there any one else that thinks it could possibly be the oxygen sensor, before I spend another $50 that won't fix the problem? Or is there anything else that could possibly be causing these sorts of problems. Can the oxygen sensor be cleaned, or is it best to just replace it? Thanks for the help.

[Jezzka]

First off, I already starting writing this someone, but I lost it, because it did not save the half I already wrote, so if you see it, please bare with me!

Anywho, I had to replace my fuel injector (FI), because that was causing a lot of things to go wrong. I also replaced that gasket and stuff with it, which does not cost much more, but is a good idea to do since you really don't want to mix in the old with the new. I also had to replace my EGR valve for the second time when I did this, because the "FI" was messing with that too (SOB) - btw, the injector, NOT cheap!!!! I also had to replace my O2 sensor because of it, and because some fuel had tracked into my plugs and was causing me starting issues, I had to replace one RECENTLY purchased, horribly old looking plug wire and its plug. Now my truck is running beautifully! (Well all except for the thermostat that I have to replace, because well that is going bad too, but what can you expect from a 10 year old truck!) Oh, and about the "Cat" (Catilytic Converter), that was not replaced, although it should have been (although they are not <i> really </i> needed (per my dad and bro's), a hole was just drilled into it.

My Rx is to take it to a mechanic and have them look at it - for FREE, like I did, as many do - and have them look at the fuel injector and stuff. This will save you A LOT of time, heartache, headaches, and, most of all, money-aches!!!! (P.S. I plan to soon write one about my wonderful world of brakes - I also had a/c issues, but that was MINOR, so ask if you want to know, I dont feel like writing about it.)

Dude, do I have bad luck with vehicles!

[j.patelia]

I'm not sure if GM uses a Cold Start sensor (I know Chrysler does)...But that's something I would look into! I'd also check the PCV valve, usually a bad EGR usually indicates a problem the vaccum system, so definately check out the vaccum system..It's not very common, as I've found on the ten different cars (so far!) that I've worked on.

[BKFT_HOTRODER]

Don't replace O2 sensor all it does is fine tune your air fuel ratio by controlling the pulse width (how long injectors are open) of your injectors, They only adjust like 10 milliseconds

[BlazerLT]

Check your CPI injector, it is probably blown and leaking causing the carbon, the poor gas milage.

Search for cpi injector in here or the blazer section.

[OffRoadSonoma]

I have throttle body injection. Two injectors spraying right into the intake. I've looked at them and don't see any leaks. When I'm driving and shut my truck off, if I start it back up within like 5 mins, it smells like it is running really rich, and it sputters a little. I don't know if that has to do with anything, but that happens also.

[BlazerLT]

Originally Posted by OffRoadSonoma

I have throttle body injection. Two injectors spraying right into the intake. I've looked at them and don't see any leaks. When I'm driving and shut my truck off, if I start it back up within like 5 mins, it smells like it is running really rich, and it sputters a little. I don't know if that has to do with anything, but that happens also.

Ah, ok, I would remove the EGR valve again and clean it.

EGR valve carbon problems are not a one time only thing, it can happenseveral times. What you have to do is stop what is causing it.

Set the timing with the timing wire unattached from the PCM and set to Zero with a timing gun.

Then do a full tuneup.

[OffRoadSonoma]

Ok. I'll try the timing and tune-up. I have been taking the EGR valve off about once a month, and cleaning it and all that, but it still sticks. So I'll do the tune and timing and post once thats done and let you know if it helped.

[BlazerLT]

Are you getting any chunks of carbon in the pintle at all?

[OffRoadSonoma]

There aren't really any chunks, its just really thick and tar-like.