I give up! CEL P0401 is BACK

[Ramblin Fever]

Ok, here's what all I've done as a recap.

Last October was the very 1st time I'd ever seen the CEL light come on, steadily. Not blinking.

Didn't think too much about it, had a run in with some very bad gas that caused the truck to idle weird (but not high), stall twice, and chug - got it down to half a tank and filled up with Shell gas. Problem instantly went away after about 6-10 miles.

But after 2 more tankfulls, CEL was still on.

Autozone code read "insufficient EGR flow"

Cleaned EGR; CEL stayed off for 2 months; came back on in December, same code. Cleaned EGR again, stayed off til January.

In January, I had a full-tune up, plugs, fluids/filters, belts, 4 new O2 sensors, waterpump, camshaft/crankshaft seals, timing belt/tensioner, idler pulley, and starter have all been replaced.

CEL code came back on in February, still the same EGR code - per Autozone.

Cleaned EGR again, CEL stayed off til sometime in April.

Since then, it comes on for 2 days, off for 2-3 days and back on again. CEL is not blinking, but steady, and truck runs great irregardless, idle does get a *tad* rough after it comes on, but idles at the same rpm's whether it's on or not.

2 weeks ago, I took off the whole air intake hose, cleaned it out, along with the Throttle body, MAF sensor, PCV valve and such. Air filter still looked fine.

CEL stayed off for the whole 2 weeks, then came back on yesterday!!! Again, same code, no symptoms for anything.

Two things of curiousity, what do I have to lose at this point - EGR gasket has been removed several times, but I haven't replaced it with new. Gas cap *looks* fine, and I always make sure it's on tight - BUT, you know how on most cars when you loosen the cap to fill up, you can hear air escape, like you know it's had a good seal. I haven't heard that sound in forever on the Rodeo, but I get that same sound on my other vehicles.

Any ideas are more then welcome?? My next two moves, are new gas cap and EGR gasket. Not gonna replace the EGR itself, yet.

I'm trying to narrow this down, as obviously it won't pass emissions and seems to be a problem I can't trace. I did get my tags for this year, but next February it has to have an emissions, and I don't want to wait til the very last few months trying to solve this stupid situation.

FWIW - was wondering if it was the cat convertor getting clogged, but the truck has too much power, doesn't act like it's congested.

[Gizmo42]

I'm thinking the internals of your EGR are getting questionable. Instead of spending all the money on a new one at the moment try pulling one from a salvage yard. If you cant find an isuzu one get one from a mid-late 90's GM 3800 v6. Its identicle and works. I dont know if the egr gasket would leak enough to cause enough of a problem to throw a code.

As far as the gas cap, I've never heard pressure release from mine. I've never had a CEL *knock on wood*.

[player11]

I'm no expert, but if cleaning the EGR works for a few weeks, then same code..wouldn't it make sense to replace the EGR?

[marcre]

go to the junkyard and get one. I got one for $15 and it works well so far.

[lifelongslacker]

Just a cheap fix is to run a can of seafoam through the pcv valve.

[rodeo02]

Ramblin, I don't recal if it's in your other threads in regards your EGR woes, but what type of EGR system do you have? Does the 1997 3.2L have an electronic EGR valve like the 1998+ or is it vacuum actuated like the 1993+ 3.2's? If it's electronic (solenoid type valve), just replace the valve. With all your cleanings, there no way its clogged. If you have a vacuum style EGR vlv, you have to look into the differential pressure switch on the EGR plumbing that measures flow. Some vacuum actuated EGR systems rely on a MAP sensor to sense flow as well, but your 3.2L uses a MAF sensor instead. Gas caps & PCV dont have anything to do with EGR.

Joel

[df2000]

It is an electronic EGR valve like the 1998+. GM part from 3800 v6 fit fine, through connector may be on other side.

[Muddskipper]

Like you, I was beside myself, and was told a number of different things from a number of different mechanics.

After I replaced my second EGR, I still had the CEL.

We ended up haveing to pull the top and lower manifolds to get to the clogged tube that ran from the EGR.

It was completly clogged......and there was no chemical that could clean it.

it had to be removed and we had to use tools to break up the carbon build up.

Ended up selling the other fairly new EGR on Ebay.....

Repair job cost me around $300 in labor

[rodeo02]

Originally Posted by Muddskipper

..We ended up haveing to pull the top and lower manifolds to get to the clogged tube that ran from the EGR.

It was completly clogged......and there was no chemical that could clean it.

it had to be removed and we had to use tools to break up the carbon build up.

If your rig is a 1998+, there was no need to touch the common chamber & this could have been fixed with a coat hanger and some basic tools. All you have to do is 'roto-root' out the EGR tube with a coat hanger or the likes, from the EGR valve base, to where it exits behind the throttle plate. Verify the coat hanger will go all the way thru and you are good to go. No need to pop the common chamber apart (upper intake) on the 1998+ for an EGR cleaning anyway.

Joel

[Ramblin Fever]

Ok, haven't had time to really look at the Rodeo, the Toyota's been stealing all the attention again - attention hog!!

Anyway, I'm pretty sure it's called a Linear EGR set-up, i.e. guessing vacume type set-up, in which the only thing left - I believe - that I haven't checked is the MAP sensor, but I don't have the tools to check it out.

I will look into it this weekend to see if there's anyway I can clean it, check for any broken wires/loose connection etc., other then that, I'm at a loss.

I need to do something though, as whenever the CEL is on, the truck drinks gas like it's going out of style, and it's been on all this week hasn't shot off yet. I'm also feeling a very slight loss in power going up the on-ramps.

Rodeo02 - you mentioned the MAF sensor as part of the EGR issue, I've already cleaned this twice; is it still possible to be part of the issue?

[rodeo02]

Originally Posted by Ramblin Fever

..you mentioned the MAF sensor as part of the EGR issue, I've already cleaned this twice; is it still possible to be part of the issue?

My thoughts are since your 1997 3.2L has a MAF sensor, it may not have a MAP sensor. You *usually* dont have both as a MAP is the predecessor to newer MAF based systems. MAF in itself is completely unrelated to EGR. Are you SURE you have a vacuum actuated EGR valve? It's real easy to verify this. Does the valve have a vacuum dome on w/ vac lines, or it or a cannister type electric solenoid with a harness/plugs?

Joel

[Ramblin Fever]

Will verify more when I pop the hood later, but I can readily tell you that it looks like an upside down canister with one electrical plug and two bolts holding it on - that's it. Real easy to take off.

Hoping that it's of the electrical and easy fix would be to just replace??

Per the Haynes manual, which I'm not totally confident in, shows a picture of a MAP sensor on a 3.2L engine, however it could be of an older model and not the '97 year.

I definitely have the MAF sensor, and I can always try cleaning it again. And like I noted above, I've reopened the EGR several times, but have never replaced the gasket - could this simply be the issue?

[Ramblin Fever]

Ok, truck definitely has a MAF and a MAP sensor. The MAP sensor is located on the passanger side of the truck just above the 2nd spark plug from the back of engine towards the front.

It looks like the clip from the MAP sensor wiring harness that clamps over the MAP sensor is broke; but the two definitely have a tight connection, from what I can tell.

I wiggled the connections a bit, and nothing appears loose; but after I did that, when I restarted the truck, it acted a little hesitant in momentum - only lasted about 2 blocks though.

Keep ideas coming please!

[rodeo02]

So is the EGR valve electric or vacuum? You have physically removed it before, correct? If the EGR valve is electric, the MAP sensor wont have anything to do with it.

Joel

[Ramblin Fever]

Ok, YES, finally got back to it; it is electrical as far as I can tell. If you were to remove it, it's 2 bolts, and a electrical harness - that's it. Looks like an upside down canister, and there is no vacuume lines attached to it, specifically.

Sorry for the delay, had to double check everything, as my 1st rodeo DID have a vacuume EGR system, and I had been looking up everything pertaining to that type.

So, is an EGR valve in need? Thinking back, I wonder if I didn't do something to it - I dropped it the 1st time I cleaned it, not hard, but wonder if that was enough.