Datamaster Help 90 Vette

[billvh]

Does anyone have a cheat sheet for a 90 L98 so I know what range the values should be (O2 sensor , BLM, IAC etc.), and what they mean. I'm going to run Datamaster tommorrow, and would like to know what I'm looking at. Thanks

[Casethecorvetteman]

When you run it and you have you log files, send them to me and ill tell you if they are looking good or not. If you have not run it yet its not going to matter much what anyone tells you about it, youll probably understand that better when you see it all in action.


Also, it will all be written in the instruction file that comes with datamaster.

[billvh]

Thanks, I'll send them to you. The problem I'm having is when the car goes into closed loop, it starts to run bad and pop (kind of backfires) and miss. It's ok in closed loop, so I think it must be the O2 sensor or possibly the temp sensor. It uses all the other sensors in open loop doesn't it? I had a chip burned for my combo (HOT cam, headers, no cats, ported base), plus I have a chip that came with the car when it had a larger cam and LT1 intake, and stock chip. They all act the same way when in closed loop. I have a small exhaust leak where the pipes are clamped to the x pipe, could this be introducing air into the exhaust stream?

[Casethecorvetteman]

Where is the O2 sensor located in terms of both the leak and the header collector, and what type is it? (heated or non heated?)

[billvh]

The sensor is in the collector, is non heated, and the small leak is downstream of the sensor about 14". I am probably going to add a heated sensor, do you know what car to get one for, or will any GM do?

[Casethecorvetteman]

I dont know which heated sensor you need, but the leak is not going to be an issue as far as i can see. Run the data master and see what the log data tells you, then go from there.

[billvh]

I'm having trouble getating it to run, when I test com, it gets error 2, I checked and the version I have is the correct ver for 90 man trans. I have tried everything in the advanced column to no avail. Any ideas?

[Casethecorvetteman]

What sort of cable and what interface with the computer is it? If its a USB type setup, youre in for a tough time i think.

[billvh]

It's a serial cable I bought on Ebay, I can't get it to work with any scan program. I tried TunerproRT, but I read somewhere it doesn't support 90-91 Corvettes w/ digital dash. I did use a Snap On scanner t set TPS, so I know port works, might be cable though seller says cables are tested.

[Casethecorvetteman]

So it connects to the RS-232 connection on your computer, and then goes to the car where one part will connect to the ALDL (either pin E or M, try both cause im not sure which one it is for a 1990, only one of them should have a connection) and the other will plug into the cigar lighter socket?

[billvh]

It is port powered. My car doesn't have E, it uses M.

[Casethecorvetteman]

No worries, that solves that issue of which pin it goes into.

[billvh]

I replaced the O2 sensor with a heated one, and the car runs and drives without backfiring, although some tuning is going to be required. I sent the ALDL cable back, so we'll see where that leads.

[Trog]

TunerPro RT does work w/ 90. I use it myself. Currently using Moates USB cable but I've also used a serial cable I bought a few years ago w/ just the Moates software as well.