Thread: 305 tpi questions

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hey all

I have a 87/88 305 tpui motor with the cpu that came with the car/motor. My first question is dose the vss senors have anything to do with the motor running( driving down the road)? Mine is not hooked up ,there is an cable speedo hook up now ,I have the senor that came out of it ,but it did not have any place to plug the vss into it .I thought it was just for a electric speedo ,it had a eletric speedo with the car not hooked up and having no info on it i chosse to do any with it .
Also I was reading alot of posts on different things here,so it brings up many questions. I have what I think is a timing issue, when step on it from a stop its spits spudders and back fires until I let up and ease into the gas but if im already up to speed in can step on it and she just gose!!! This is only a problem when im driving ,in the garage in park there is no problem,so thats what lead me to the vss not being hooked up ,but ive been told it sounds like timing
Where should the mark be ??? dead center of the scale ,advanced ,retarted???
Mine is about dead center of the scale
I guesss Ive rambled enough for now,and info ,advice will be great
thanks all
Jeff

I don't have an answer for you but from the TPI swappers guide book that I have the vss is said to control the torque converter lock up, controls the idle circuit, controls carbon canister purge, and the mph fuel shut off. Maybe the last one could explain your problem. Since fuel injection fuel systems are pressurized the moment you lose pressure to the system your engine should stall unlike a carb. Don't know if that scenario and the vss would be related in your case but it could be a start if it is not the timing.
I wish I could be more help but I have not messed with a tpi firsthand yet. Just waiting to get my hot rod built so that I can get started on my 72 Chevelle tpi twin turbo build. By that time I should know more but that is a long way off
Good luck and hopefully someone that knows firsthand what they are talking about will chime in.

If you have a OEM ecm(cpu) the vss hooks to the trans and the ecm needs to see a signal from it. You may need to have your ecm reprogramed. Timing should be 8-10 BTC(advanced). Be sure to set the timing with the brown wire disconnected from the dizzy. Good luck and keep us posted

Jeff also check a forum called Third generation. Its for Camero and Firebird. Look in the TPI section. There is a ton of info there. Keep us posted...

my earlier post got wiped out in the recent corruption....however, when you buy a VSS, beware that there are at least 4 pulse rates available for a GM ECM.....buy the one that matches your ECM

flame
With the car at a higher rpm I lose the timing mark ,I think its going 'up' the scale,,, The timing is set at idle with the brown wire disconnected on the first mark above the center mark going up the scale ,is that to high!! Is going up the scale advanceing the timing?

Is it normal for the timinmg mark to go off the scale at higher rpm???
Not very high rpm just alittle higher than idle.
thanks
jeff