ROTICKA

Here's the deal. I bought an 84 t/a with an 88 350 tpi in it. The previous owners bought the car and got it running but gave up on the "issues" and sold it. Now it's my headache. I've done alot of things to it since I've had it; Swapped the dist, new dist cap, rotor. New MAF, MAF relay, New TPS, New coolant temp sensor. New thermostat. After alot of reading and working and deducing I have a theory. THE SYMPTOMS The car is running rich, (recently replaced one of my CATS due to this) and will not go into closed loop very often. When it does it is only for a few seconds then it goes into open loop again. Once in a while I get a check engine light TPS volts low code (22). But the check engine light goes off within a 30 seconds. there's an intermittent miss at idle (idles around 800, sometimes up to 1200). Shifts around 2300 to 2400 rpm from 1st to 2nd (way too soon in my opinion) but with any other TV cable setting the tranny slips pretty bad. THE DIAGNOSIS Since this is an 84 T/A (H.O. 305 carb) and the motor is an 88 TPI, maybe the VSS is missing from the tranny? If it's the tranny from the 84 t/a there would not be VSS right? How do I check this?

sofakingdom

iTrader: (1)

Look at it.

It is a small yellow box mounted on the back of the speedo IIRC. At least, that's what it is in Camaros of that vintage, and I think the Birds worked the same in that year. Firebirds went to a trans-mounted VSS starting in 85, Camaro a couple of years later. How you would hook up that little yellow box to the later-model harness, I'm not too sure. That would depend to some extent on how hacked-up the harness already is, and what kind of car it came out of. A Camaro from 88 would have used the same little yellow box, so the harness from one of those would already have that provision, IF that's what the harness is.

Best thing for you to do is probably to visit the DIY PROM forum on this site, and learn about how to obtain run-time data from the ECM and interpret it, and how to re-program the ECM should it become necessary.

The runnning rich and all that, won't have anything to do with the VSS, regardless. Neither will the transmission shifting, because that's entirely hydraulically controlled. The only electronic thing about it is the TCC.

I think as far as blaming all of that on the VSS, that's not a good "theory". While the ECM may in fact not be seeing VSS pulses, and might be confused as a result (not know how fast the vehicle is moving), pursuing that won't lead to a solution for all those other things, that's for sure.