Hello Listers, I'm new to this forum and this is my first post. What I have is a '94 Sonoma, 4.3L Vortec, VIN "W" auto trans, about 126,000 miles plus on the engine. I've been getting a solid "Service Engine Soon" light on the instrument cluster, I have a handheld diagnostic scanner, (AUTOXRAY CodeScout 2500), ran a scan and code 32 came up, EGR failure, so I replaced the EGR. Now the light is intermittent. So I took it to a ASE mechanic and asked them if they could do a diagnostic check. They came back with the same code. They did mention something to the effect to cleaning out the EGR ports. My question is: Is there anyway this can be done? I do realize I'll need to pull the EGR back off, but can anyone explain any procedures on how I should go about doing this and are there any cutaway engine views showing the exhaust ports leading up to the EGR.

Thank You for your knowledge.

'94sonoma

 

First, remove the EGR pipe from the exhaust manifold to the fitting on the intake. Inspect and clean that. If it's completely clogged, you've found at least part of the problem.

For the manifold passages, take off at least the throttle body, see if you can get a hose on the EGR pipe into the plenum through that hole. If your fingers (and hose) aren't flexible enough to work through the throttle opening, remove the upper plenum. You can pump water or cleaning solution or blow air out from the plenum to the EGR valve opening.

For the exhaust passage in the intake manifold from the pipe fitting to the EGR valve, pump water or cleaning solution or blow air in from the fitting where the pipe to the exhaust manifold attaches. The dirt and solution or air will come out where the EGR valve mounts. Keep the hose on the pipe inside the manifold plenum when you do this, and be careful not to wash/blow gritty dirt into the intake manifold plenum. You don't want to run the crud through the engine.

 

Racer_X,

Thanks for the knowledge, I will proceed with your procedures as soon as possible. I tried to get to it this past weekend, (6/9/16), but another task took priority. I hope this will cure my ills with the service engine soon light. I went to get a smog test, (I'm in Calif. with the smog ****'s), and it failed as my vehicle registration has passed its due date. This gave me insight with another possible problem, the test guy said it appeared the catalytic converter was on its last leg. So I have a few days before I'll need to return for the smog test again. So along with your instructions and this, I should be on my way to clean motoring again.

Again, Thanks for the reply. I'll report back after the above is taken care of.

'94sonoma