1st start up, engine starts but won't idle. TPI is an 86 unit but modded to speed/density. Everything is new (plugs,wires, injectors gaskets.) 47 psi fuel pressure at the rail with the motor off. All vacuum ports on the plenum and manifold are plugged except map sensor and fuel pressure regulator #they are connected). It will occasionally surge once or twice before it shuts off. It will run if I bring it up off idle but I can't run it long cause I don't have coolant in it. I'm trying to set ignition timing and it won't idle long enough for me to shoot the blancer and timing tab with the timing light. It has a front runner system on it and once I install the radiator I won't be able to see the marks.

My past experience with fuel/air delivery has been with carbs so I don't know much about this system. Questions:
I don't have an oxygen sensor installed or plugged in to the harness yet, would that have any effect at idle?

Could the fuel pressure regulator be the culprit (new but sitting unused for 10 yrs.)?

Is there another way to check ignition timing on this system besides the balancer and timing tab?

Any other thoughts/suggestions would be appreciated.

Thanks
Bud

 

UPDATE
I can keep it running by blipping the throttle. diconnected the vacuum line to the fuel pressure regulator with no apparent change. Tempgun shows #8 cyl much cooler than the others, don't know yet if it is spark or fuel prob. Initial crank on cold engine takes several seconds (20?) to fire even after letting the fuel pump run for several seconds to build up pressure. Any thoughts from ya'll yet?

Thanks
Bud

 

Starting with the O² sensor disconnected should not affect the operation immediately following startup. Even on the SD systems there are cold start and hot restart timers programmed to ignore the sensor until the coolant temperature hits a threshold and/or the timer elapses. Not knowing how the program may have been altered for your application it may be turned down, but stock numbers are in the range of 30 seconds (86 AUM code).

I'm guessing you have issues other than the sensor affecting idle. The fuel pressure at 47 PSIG KOEO should be sufficient and that probably eliminated the FPR as a culprit. Are the injectors new or cleaned/tested?

I have seen some cars set up to check timing at the flywheel by removing the inspection cover. If you use a newer trans with no cover on the bellhousing this won't be an option. Your belt/sheave system shouldn't completely obscure the timing marks, although the fan shroud might.

 

Thanks for the reply Vader. The injectors are new accel units. They weren't tested prior to installation. I'll check to make sure the #8 plug is firing. Don't think I can check the injector plugs on the car because i have them rotated to the inside for a cleaner look. I just noticed. that when I installed the plenum I accidentally reinstalled the old gaskets but they had never been run so they should be ok. You are right about the timing marks.......kind of. The alternator/a/c compressor bracket is pretty beefy but I can just see the timing marks if I look straight down in front of the throttle body. If this was a carb I would say the accelerator pump was keeping it running but with this system.....? I'm still stuck but the answer has to be somewhere.

Thanks
Bud

 

I know this post is a year old but I'm having the same issue with my 1985 305 tpi. did you ever get it figured out 36fordcoupe?

 

In my case it turned out the wire to the ecu that controls spark advance was broken. Therefore ignition timing wasn't advancing beyond the initial 10 deg. base timing. Also, since I had been trying to fix the problem by enrichening the fuel schedule, once the timing issue was fixed I was running too rich. Problems all fixed now.

Bud

 

Similar issue recently...turns out it was a bad coolant temp sensor...which was reading negative degrees...so, it tries to send more fuel at startup than needed,therefore it was basically flooding my tpi...it can be intermittent too,so you end up chasing your tail awhile...i got lucky and had the SES light come on and give my mechanic the code....