1991 Mustang GT

Sorry for starting a new thread (I had one going below - for those that need the 'background' on my initial problems, I shared the info in that one)

But anyway, she starts right up on either but I can't get it to refire on its own. I was thinking an injector problem (when I couldn't get it to start when it was out in the road) I pulled some plugs and they were dry - but I did have spark). So now that its in the garage I checked at the injectors and I have 12 volts.

Before anyone asks, once its running you'd never guess there was a problem (no remote chance of stalling, etc).

mattdel

Make sure you can hear the tank buzzing for a second when you initially turn the key to ON. If yes to that, at the very least depress the schrader valve on the fuel rail and be sure that fuel is reaching it. If you can test pressure, that'd be cool.

After that use a test light on the injector circuit and if they're being commanded to fire, the light will blink quickly. The opposite wire of the one you found 12v at will be a rapidly switched ground from the ECM, use that as the ground for the light. Or go to autozone and rent a set of noid lights, they plug-in in-line on the injectors.


Edit: wait wait wait, are you saying the car will fire and stay running after a burst of ether, but won't fire or run without the initial shot?

1991 Mustang GT

-fuel pump kicks on/off
-i have 'good' pressure at the schrader valve (don't have a tester) but it filled a beer can up an inch in 5-6 seconds of cranking
-i have 12 volts at the injectors - haven't checked 'while cranking'

The car seems to have one problem - won't start without ether. Once running, youd NEVER guess there was an issue. I've read other 'similar' problems but typically others say theres idles rough then. Not mine, runs great.

It developed a high idle in the recent years which I'm almost positive is the Idle Air Control Valve. One reason I think the IAC is the problem for my high (about 1200) idle is when I 'loosen' it (I can manipulate the idle) the idle will come down. I cleaned it last night but it didn't improve the idle.

1991 Mustang GT

I am (and have been) following the Cranks OK, but No Start Checklist... having replaced the PIP-Ignition Coil yet because I'm doing checks still.

I just tested the TPS (tried my best like in this pic) >>>http://www.moddedmustangs.com/forums...djustment.html
Like I said, I tried my best (I say that because my reading seemed high)...

I came up with #'s between 4.74 and 4.96 when probing both green and orange.
I know my ground was good (I always check with probing the + on the battery)

1991 Mustang GT

Using this video as a guide I was able to get accurate and confident readings

Key Off - Black Wire... I get 0.4 ohms (maybe 0.5, can't get more accurate)
Key On - Orange... between 4.90 volts and 5.00
Key On - Green... Typically 4.24 volts

Now, that green reading is what should be 0.9 ish - 1.0 from what I understand. I don't bother checking the voltage while slowly sweeping the throttle. I'm pretty confident I got good, accurate readings. This time I did it was able to move that damn rubber proofing out of the way

mattdel

Well yeah thats no good

1991 Mustang GT

Does that mean, IYO, my problem is my TPS?

mattdel

I'd say you have a bad TPS, whether or not it's the root cause of your issues is up for debate. It doesn't explain the no-fuel aspect.

1991 Mustang GT

KOEO... via the Check Engine light flashing I got codes:
23
32
67
84

mattdel

32 is an EGR code. Produced when doing KOEO while engine is cold, or you actually have EGR problems.

23, 67, and 84 don't exist in KOEO.

23 in KOER is a TPS code.

67 and 84 don't exist in KOER either.