'98 LGT EGR problem

[fatkidLGT]

I have been trying to figure this out for a while. My '98 LGT has been spitting out an "egr flow malfuction" code (i forget the code #).

I currently have the EGR vacuum lines "looped" at the TB because if not it idles really rough and sometimes stalls the engine.

I have changed all vacuum lines, egr solenoid, egr valve, back pressure transducer, basicly everthing in the egr system aside from the wires.

I talked to a dealer about this and they said "Good luck, I'd like to meet the mechanic that figures this out." Then he said that it might be in the engine harness.


Any help would be AWESOME!!!

[fatkidLGT]

I also forgot to mention that I'm still getting cyl. 1,2,3,and 4 misfire even after I "looped" my EGR.

[joelwatts]

a guess would be that the wires are shorted to ground or rubbing somewhere or that your pcm is requesting egr meaning that a driver is shorted. i have the same car and havent had the pleasure of running into it yet. but the wires for the egr-pcm are pretty short. couldn't hurt to check them all. also, check to make sure you don't have any exhaust leaks or that the egr passages aren't gummed up. they can be annoying little biotches for the egr.

[legomaroon]

Whoops...

[fatkidLGT]

Ok, I guess I will have to get a wire diagram and start poking around there.

As for exhaust leaks, i have one at my axle back. However I don't see that being the issue. But that gives me an excuse to tell the wife why I need to get a new exhaust made for it lol.

Also when i changed my engine out I cleaned out the tube from the head to the EGR, and I also cleaned the intake manifold. Although it wouldnt hurt to do it agian.

Thanks for the input joelwatts, that atleast gives me new direction to go.

[broknindarkagain]

So you're getting code 420 (egr insufficent) and 301, 302, 303, and 304?

You likley have ECU or wiring problems. Have you checked the EGR wiring connection with a multi-meter to see if its getting signal?

[fatkidLGT]

So you're getting code 420 (egr insufficent) and 301, 302, 303, and 304?

You likley have ECU or wiring problems. Have you checked the EGR wiring connection with a multi-meter to see if its getting signal?


I have not had a chance to get my multi meter on it, and I beleive it is a p0400 if i remember correctly (egr flow malfunction) and then yes p0301-p0304. Im going to pull my codes agian and make sure.

I did tear my egr system apart and found a clog in the BPT line (the large one on the bottom of the BPT) But that didnt change anything after cleaning it out.

[fatkidLGT]

So, I went and pulled my codes agian.

These are the codes I have:

P0400- EGR flow malfunction
P0301- Cylinder #1 misfire
P0302- Cylinder #2 misfire

I know the misfire codes are most likely from the EGR, beings that the EGR valve is on that side of the intake manifold.

I pulled the entire EGR system out of my car agian the other day to see if I maybe missed a clog or something of that sort. I cleaned everything real good agian and I did find a clog in the BPT pressure tube (the metal line from the manifold to the bottom of the BPT).

That however did not change how my car runs what so ever. I was reading threw mitchell and I have done every step they say to diagnose this and the only other option on mitchell is that there is a clog in the intake manifold.

So i suppose it is either i need to clean/replace my intake manifold or there is a wire harness issue that I have not had time to look into yet.