HawaiianRS

What's up,
New to the board and really apreciate all the great info here. The search has really kept me from posting up until now. but I need some help.
I have an 89 RS (305/auto) 91k miles that is giving me some trouble. Only had the car a couple weeks but I've performed all the basics; cap, rotor, plugs(ngk@ 0.035), wires, set timing at 0* with brown/black wire disconected, can of fuel injection cleaner, changed 02 sensor, checked all vaccum hoses. So far nothing has made the car run any better....at all.

Car starts, idles, and cruises good (not great), but gets rough and noisy under acceleration. Not bad enough to be undrivable, but it's not right and I don't feel comfortable pushing the car in this state.
It sounded like it was pinging. I found that the EGR was not opening, but vaccum was present so I replaced it, pinging is gone (or lessended) but it still sounds like there is a slight exhaust leak under load. Revs a little cleaner sitting in park than it does out on the road.
Retrieved some codes. These breakdowns are from http://www.troublecodes.net/GM/86-89_50F.shtml

23-Manifold air temperature sensor signal showed an air temperature below -22? F after the engine has been running for 5 minutes.

32-EGR open command did not change the fuel mixture when the command was given during off idle operation. EGR opening should cause the mixture to be slightly richer because of the low oxygen content of exhaust gas.

42-The EST signal did not change when the ECM applied bypass voltage to the ignition module

44-Oxygen sensor voltage was under 0.2 volts for 50 seconds of closed loop operation

53-ECM sees a battery voltage of more than 17.1 volts for 2 seconds.
I'm pretty sure 32, 44 will go away now that those part have been replaced, I still need to reset the computer. I think 23 is probably just a stored code from running the car with the air cleaner off while trouble shooting (sensor was disconected).
I could use some help with 42, and 53. I'm not sure what they mean as far as touble shooting goes.
Any help would be greatly appreciated.

Benm109

I would suggest reseting the computer first, and then driving the car around a while, and then see what codes come up. Some of those codes are probably stored codes, and not necessarily current codes. You are right, code 23 most likely came from when you started the car with it disconnected, and the code 42 is from when you set the timing (when you disconnect the tan/black wire, usually code 42 shows up).

As for you code 32, you replaced the EGR valve, but don't forget to check the vacuum lines to and from the EGR valve, and check out the condition of the EGR vacuum solenoid and wiring with it. When you had the EGR valve off, did you check or clean out the EGR port at all? They get clogged up with carbon over time.

As for the code 44, either the O2 sensor was going bad or you engine is running extremely lean. A lean condition is usually caused by a vacuum leak or a fuel system problem. If you get this code again, I would highly suggest checking fuel pressure. It should be 9-13 PSI. Did you happen to replace the fuel filter when you did your tune-up?

And lastly, code 53 sounds like the engine is overcharging, but honestly, I'm not familiar with what causes overcharging, so hopefully someone else can help you out with that one.

Good luck.

HawaiianRS

Alright, I reset the computer and took it on a 10 mile or so loop in traffic and on the freeway. Still runs the same but the check engine light did not come on. Decided to check for codes anyway and found that I'm still showing 53. My gauge shows barely over 13 volts so I don't think I'm overcharging. However I did find the trouble code guide on this website that lists code 53 as

53. High voltage at battery OR High voltage at exhaust gas recirculation valve OR Voltage reference error OR Problem at vehicle anti-theft system

The column on my car was broken by the P.O. and the ignition has been converted into a toggle switch to turn the ign on and a button for the starter. However the VATS is still fully functional. (did I mention I got this car cheap?)

I did not change the fuel filter yet, but the original unit has been replaced in the past. I don't think it's starving for fuel because it seems to run fine at WOT.
I'l try to be a little more accurate

At idle it runs O.K. but with a slight intermitent miss. When you dip into the throttle while driving down the road there is a moderate bog at about 1/4 to 1/3 throttle. If I give it just enough gas to accelerate without down shifting there is increased vibrations and the motor sounds like it laboring, but it does accelerate pretty well. If I floor it (quickly, but not slamming it), the motor bogs/downshifts and then seems quite smooth in comparison at higher RPM's during WOT.

I plan to check the fuel pressure, and charging voltage but assuming my charging system is good and the code 53 is VAT'S related what else should I be looking for? I'm not a Chevy guy so I'm hoping someone will say something like " Oh, gee, that's the thermo-matic-fuel-spark control sensor. They go bad all the time, just pop down to Napa."

bolinger89z

i have the exact same problem right now. It's driving me crazy. The only difference is my is a 350 tpi. I've replaced everything just like you. The only thing i haven't done is put injector cleaner in it, but I Just picked some up from Auto Zone today. It revs just fine and idles normal in park but put it in R or D, it starts shaking really bad. IT's like an on off thing. Last year when i bought the car it ran fine, then a while later it started doing this. The radio would always cut out like there was a short or something when i went over a bump. So i tried fixing the radio and messed w/ some wires and i started it up and it ran fine. Then it started acting up again a week later and I did the same thing and it ran fine. Then it jsut happened recently again. It's driving me crazy. I think, not for sure one bit, but i think there is a short in a relay somewhere close to where my short for my radio was. In the last 2 days, i've spent about 10 hours trying to take my dash off to get to the wires underneath. I could see them but didn't have any way of checking them. I can't really take it to a shop cause all they would do is trouble shoot till they find something, and that could take hours up on hours. I donno what else to do... hope someone helps us out soon. lol good luck w/ everything and if you find somethign out please post back

HawaiianRS

Just to clarify a little more, the cars starts runs and drives OK. It's just that it runs like a crappy old car in need of a tune-up, which I've done and re-checked. I'm sure everyone knew that guy in High School who thought his car was awesome, but everyone else laughed at him because it never ran quite right.
Our guy drove a 69 mustang that might muster a 16.5sec 1/4 mile and was called Ducky. But ask him and he would've beat that vette except he's got too many tickets and can't race, or whatever other excuse he has that day.
I feel like I'm driving that guys car right now. The 3" edelbrock exhaust (only mod) is loud enough to attract attention, but I know it sounds as out of tune as it feels.

So barring some Chevy secret that someone wants to share with me, I guess I'll just go on ahead with fuel pressure, and compression tests, followed by double checking the "custom wiring".

pvt num 11

Are you on Oahu, or another island? Go see if anyone at the Pacific Region forum can steer you in the right direction, we've got some pretty good tinkerers over there (not me, though, I don't belong within ten feet of tools). If you like, maybe someone could hook up with you and help out.