On my '87 Limited, I'm seeing a boost problem that may be a partially plugged catalytic converter.
Symptoms:
1.) Low boost (7 lb or less, as indicated on the dash gage) (I know it's inaccurate, but read on for other symptoms)
2.) Delayed boost - can feel added torque after the car's gotten moving
3.) Cannot break back end loose from a standing start
Contrary signs:
1.) Builds 3-4 lb boost easily in 3rd and 4th
2.) Gets 18-20 mpg around town (with the A/C on)
3.) Car runs very smooth, even under heavy load (i.e. WOT acceleration)
4.) No odor
I searched the archives, and the common denominators of a plugged cat are: low boost, sluggish response, rotten egg smell, lousy mileage, rich exhaust.
BTW, the cat seems to be original (114k miles). Also, I'm running at 5400 ft above sea level.
Am I on the right track, or is something else amiss?
It could be other things. Perhaps an exhaust leak, damaged turbo, or a torque converter problem. However, it would be easy enough to pull the cat and see if its the root of the problem.
After reading several posts on the mailing list (I posted this same thing there, as well), I concluded that changing the cat wouldn't be a bad idea, just on general principles. I ordered a Random Tech low-restriction unit that should arrive later this week. I'll post what ever results I get from that.
Hmm, yes a bad catalytic converter is a possibility. From experience, it is better to be safe than sorry as I blew my turbocharger when my cat got badly contaminated with gasoline. Once that is done, have another look at the problem. You may have pre-turbo exhaust leaks as Scott says, or the altitude may be richening your fuel mixture too much.
Well, the new cat went in Sunday. WOW!!!! I guess I've spent the last 2 1/2 years trying to get this race horse to exhale through an essentially non-porous box! Before Sunday, the best I could muster was the aforementioned 7 psi. Now, I find that there are red bars at the far right end of the boost gauge. And before, it was a slow process to build that boost. Now the gauge goes off like a neon sign. Also, the 1-2 shift has smoothed out dramatically, although that funny fish-tail thing during the shift is new! I think I'm ready for a whole new set of issues to rear their ugly heads, since I think I'm finally near "stock trim".
Great! now are you monitoring retard/detonation in case of over boost? Those red lights could be trouble unless you are set up to handle the extra boost.
As I said, a whole new set of issues...
Yes, I am watching things. The last thing I need is for my NOT (new old toy) to go SPLAT (or maybe THUNK?) due to driver stupidity. After nearly 3 years of struggling to get this far, I have finally gotten to the base that I was looking for. Now the fun begins!