EGR Mystery

[91Reatta798]

I'm still trying to narrow down my problem. However, I absolutely can not find the location of the EGR valve. I've got through and through the shop manual, searched on-line, and stuck my head in the engine compartment. I called a buick dealership and they said the '91's have an EGR on the parts list, but no diagram or location was listed for that year. Does anyone have experience locating and/or removing the EGR on a '91? Any help is much appreciated.

[Guest Greg Ross]

What problem are you trying to address?

On your front exhaust Manifold (immediately behind the rad.) you should have a fitting on the collector before it turns and runs up over the transmission. From that fitting should be stainless steel corrugated/ bendable tube that runs to the EGR. From there it runs to the intake manifold immediately behind the Throttle Body. Das It.

EGR on the '91 is a proportioning Valve and is entirely different compared to the triple valve affair found on the '88 thru '90 3.8L

[Guest jcc3inc]

Greg,

I have looked over my '91 and CANNOT find the EGR as you recommended. Earlier I remember reading that '91's did not have an EGR! Could that be the case? Nothing is said about EGR in the shop manual.

Regards,

Jack C.

[Guest Greg Ross]

Jack,

Padgett has a couple of other 3800 equipped vehicles and he's commented that I believe it's his Van wasn't fitted with an EGR.

Any possibility the engine has been swapped out before you got this Reatta?

Attached is a PIC of my engine/ tranny when I was starting to build up my conversion to a 5-Spd. Note where the front exhaust manifold turns up to arch over the bellhousing. The bright spot is the fitting where the EGR would be fed from, I reused the nut fitting with a US Quarter as a plug and it's still there.

Anyone else with a '91 able to shoot a low resolution photo or two of the EGR on their '91 Reatta.

What sort of problem are you having?

[Reatta45]

This is a picture of my ?91? No EGR? KennyV.

[91Reatta798]

Thank you for the feedback on the EGR. Greg- I was addressing a stalling issue I have at idle and low RPM's. I was fairly sure I didn't have one after talking to as many people as I did, but the conflicting information kept me searching. After talking w/ a co-worker well verse in electrical systems, I'm going to check the cam sensor timing. Hopefully that will yeild some results. It seems that every time I rule out 1 potential cause, several other possibilities arise. I'll keep everyone updated as I go. Thanks again.

[Guest Greg Ross]

Very first this that comes to mind is the IAC, and you definitely have one of those!

If the IAC pintle/ passageways are carboned up your exact complaint is going to occur. Have you addressed servicing or replacing the IAC previously?

[2seater]

From my boneyard searches it appears the early L27 engine with the aluminum tuned port manifolds did not use EGR but the General brought it back on the later plastic manifold types, along with some melting problems. The engines without EGR must be tuned differently. From the limited testing I have done, the EGR actually helps fuel economy while cruising. I wonder if that has anything to do with the generally poorer fuel economy for the '91's. Yes they run a lower differential ratio, but a slightly taller tire, so the ratio difference isn't as great as it would first appear (about 9%).

[91Reatta798]

I've changed the IAC twice and pulled out and scrubed the throttle body, including the area for the pintle. This has not helped. The other suggestions people have had include the coil pack, the ECM driving for the IAC, fuel pump, and cam sensor. At least now I can rule out an EGR since the '91 doesn't have one. I hope it's something as easy as the coil pack, but we'll see. Thanks.