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View Full Version : '84 Riviera T-type - Chip #5867DXP


sosuzguy
08-17-2006, 03:04 PM
Hello,

We have been working on the T-type this week. What we have found is that the PCM is reporting correct values from all the sensors. There was two fuel injectors that had slow pressure drips and we changed them out. We tried two different MAFs and it still runs way too lean. The car doesn't have a MAP sensor so what else could it be? It is around 140 to 140 fuel trim and should be between 126 to 130. My mechanic called someone at GM who said there was a chip update for this car Chip #5867DXP and I have the old one #2269DNP. I need to see if I can find the newer chip for testing or to buy. It's already been discontinued at GM. We have kind of been suspicious that the chip might be bad, it is very very slow communicating with any tools that hook up to it. Any ideas? For a brief flashback on the issues with this car read on below.

Thanks, Jayson Pruitt #3412 DFW/North Texas RC

I've always had a slightly rich exhaust, Code 45 that we could never work out. We finally replaced the Bosh 02 with a Denso 02 and cleaned the original MAF with electrical cleaner and it did run about 92% optimally. The day before I left for Flagstaff I washed the engine. I took every precaution. Shower caps, low pressure water. I used my air compressor to dry stuff off and then let it air dry. Well the car hasn't ran right since. When I started it didn't want to stay running. After messing with it I found some water had gotten down into the air filter container and probably in the MAF. Got that all dried out and it seemed to run somewhat better. I even tried another MAF from an 85 hot air GN and a new MAF from http://www.micro-tech-auto.com/maf.html The car did seem to run better initially with the used MAF From the 85 GN but as it kept running it seemed to get a little worse. I drove that car 1k miles one way to Flagstaff AZ. It now also keeps a code 44 lean exhaust and performed like the non turbo 4.1 V6 Buick engine. But the car did not use any oil, did not over heat, didn't smoke and got anywhere from 24 to 28 MPG on the highway. While trying to fix it sooner than later, I had to use a local shops snapon computer in Flagstaff. The BL was 140 INT 150, way too lean. TPS .58 @ 1900 MAF 9 grams @ 1800/1900. o2 191, no knock, EGR not holding vaccum.

sosuzguy
08-17-2006, 06:18 PM
no exhaust leaks and the o2 is fairly new with about 2k on it.

turbo2nr
08-17-2006, 09:29 PM
What do you mean EGR not holding a vacuum? Does the car die when you push up on the bottom of the EGR valve? You can reach a finger up under there and push up on the bottom of the diaphram with the car idling. The engine should die. If nothing happens, the EGR is clogged. I think the EGR is pretty important for idle and part throttle driving on a stock set-up.

turbo2nr
08-17-2006, 09:34 PM
So, you keep getting code 44 and code 45?

Hmmmm. MAF problems? Ahhh. ??? Maybe Bruce will think of something.

With a Check engine light and two codes, I don't know how important the BLM is. Maybe the ECU is just playing it safe and adding fuel?? (I gave up on the stock ECU)

sosuzguy
08-18-2006, 09:17 AM
Hey the last time I tried the finger on the EGR the car would start to run really bad but wouldn't completely die. We took the EGR off and it was not clogged up. I've owned this car for almost a year and half now. It aways kept a code 45 stored and would occassionally throw a SES light. Since the washing it has ran terrible (End of June) Now it's way too lean 140 and 150 and should only be between 126 ~ 130. When you say stock ECU are you talking about the PROM or ECM?

weeee_6
08-18-2006, 12:29 PM
Checked the fuel pressure?

turbo2nr
08-18-2006, 01:24 PM
My T-type got wrecked before I had a chance to play with it. I'm running a FAST in my GN. No More chips for me.

Sounds like you know what your doing. Keep poking around and maybe you'll find something. Good luck.

sosuzguy
08-18-2006, 01:32 PM
fuel pressure is awesome....

Here's an update so far:
I have a turbo mechanic that has himself an 87 GNX and a couple of 86, 87 GN's. He also works on high end sports cars. There are not any exhaust leaks at all. He has pinched off and then disconnected all the vaccum lines to see if it made any difference and nothing did. He even smoke tested the car and only found one really small leak in the charcole canister but after fixing that it still ran bad, and even then that would of made it rich not lean. He has tested and/or reset every sensor under the hood to do with the engine, checked all vaccum lines, checked all electrical connections, fuel pressure is great, o2 is ok, I had two injectors with a small drip, he put in 6 slightly used (300 miles) injectors to eliminate that problem, tried to different MAF's and nothing seems to be wrong or tested bad. He did put a performance chip in it from an 85 GN hot air and he said it ran differnet, the difference between night and day. Later today he is going to do a back flow test on it to check to see if the exhaust/cat is plugged up.

turbo2nr
08-18-2006, 06:23 PM
Sounds like you are in good hands, or at least, on the right track. Take care of that car. I never see any good ones left. Very rare. :beer:

sosuzguy
08-19-2006, 08:20 PM
Yeah and this one is CHERRY! Unmolested with only 36k original.

Roadrunner88
08-19-2006, 08:55 PM
That car looks awesome. :anbet:

turbo2nr
08-20-2006, 06:53 AM
That's the same interior I had, but on a white car. That material is tuff stuff. Those cars really hold up well with age.

I'd buy that car from you in a second.

Scott

turbo2nr
08-20-2006, 06:55 AM
Almost forgot.....