Specifics:
Just installed a completely rebuilt Long block (87 305) in my 87 5sp GTA. 30 over with a later 89 stock GM cam. New GM ecm and Napa MAF. new GM egr. new GM plug wires and ing. module cap and rotor. Currently I have 150 mile on the new motor
Problem:
Car starts in a heartbeat when cold and idles fine. But when driving it until it is fully warmed up she will stall evertime I put the clutch in to come to a stop. This problem goes away when she is full warmed up but then it will develope a hard starting problem after parked. It will always start but it cranks over 3 or four seconds before it will run. Then when running she will idle rough at stoplights.

I just checked the fuel presure and it is at 30-35 lbs at idle and I backed the timing off from 10 BTC to 6. No effect.

Any suggestions.

Thanks

 

Did you reset the base idle and the TPS?

 

When I set the idle I disconnected the brown wire on the pass side of the firewall coming out of the dist. is that the throttle Positioning sensor?

 

Not even close. That is the advance for the distributor. When you disconnect that, it leaves the timing at base which should be 6 deg. You did set it to 6 deg, right?

This is assuming the engine is in good working order and is warmed up. Take scantool and hook it up to the car and from there you can see what your IAC counts are. They should be around 20-30. If you see it is less than 20 I would close the throttle blades by turing the TPS stop screw out. If it is more than 30, turn the screw in. The higher the count, the more air is needed to maintain an idle. If it needs more air there are 2 ways to get it. You open the throttle or it opens a valve. More counts means you screw the adjuster in which opens the throttle blades. Less counts means you screw it out thus closing the throttle blades. When it is finally set it should be around 20-30 counts. After that you can adjust your TPS

 

I just checked the fuel presure and it is at 30-35 lbs at idle

That sounds too low to me. I don't recall exactly, but shouldn't the fuel pressure be up around 43 psi? The Ford 5.0 HO Mustang runs less fuel pressure than our cars, and they run 38 psi at idle.

Too low a fuel pressure will cause your engine to run like crap.

 

aklim

Thanks. You made me realise i need profession help. That is way above my skill level.

 

Check the fuel pressure and make sure it is around 43-45 psi, Timing 6 deg, IAC 20-30 counts, TPS 0.54-0.56V. Also the fule pressure regulator must be able to hold pressure after shutdown for a couple of hours at least or your FPR is bad. If this is a stock unit, you need either a new FPR or a fuel pump.

 

thank you for that info. I will attempt to take those steps before I take it to the shop.

PS: hope it is the fuel reg and not the intank pump.