ignition/fuel issues??

[89OctaneStang]

I was on my way home last night and the car was running fine. Then all the sudden it got sluggish and choked itself out while sitting at a light. After a few minutes it would fire back up and ran fine but then after a minute or so, it got sluggish again and choked out. Like it was out of fuel but it has a full tank.

I pulled into a parking lot and did a quick visual on things but everything looked normal. Went to fire it back up to see if it would run ok after sitting for about ten minutes and it ran just fine, for another few minutes then got sluggish and died again. Finally just had it towed home.

Fuel pump primes like normal and fires up first crank after sitting for a few minutes with no issues. Runs normal even with reving and all. But only last for a few minutes.

Any ideas?

One suggestion from a buddy is the TFI module. Which ones have worked best for anyone that has had this issue?

 

[HISSIN50]

Pull codes.

When it won't run, check for spark, injector pulsing and fuel pressure.

If everything looks ok, consider an exhaust restriction.

 

[89OctaneStang]

OK. I'm confused now. I was told that when they go bad they will overheat and stop working at high or normal temps. I pulled it out of the garage and let it run for a while and got it up to the normal operating temp (which is where it was when it died on me Friday) and it ran fine the whole time. So my next test that I'm going to do will be to take it out around the neighborhood and just keep driving it till it acts that way again (if it even will). On Friday it had been running for about 1 1/2 hours before it did what it did. So after driving it around for 15 minutes or so and it doesn't do it, I will give up...

I'll keep you all posted.

 

[89OctaneStang]

Well, took it out and ran it for a while. Runs like normal. Maybe this is why they say its hard to diagnose the TFI module cause after you get it to the shop it runs fine cause it isn't hot enough to kill the module.?.???

I will be putting a new one in later this week and I will just keep the old one just in case. I'll keep posting as to if the problem persists or if a new module has seemed to fix the problem. But like I said, if I were a mechanic I would be looking at me like I am an idiot cause the car runs great now...

 

[ID89GT]

My guess is a fuel pump going out

 

[jrichker]

Dump the codes and see what the computer says is wrong…Codes may be present in the computer even if the Check Engine light isn’t on.

Here's the link to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great. You watch the flashing test lamp or Check Engine Light and count the flashes.

See Troublcodes.net Trouble Codes OBD & OBD2 Trouble Codes and Technical info & Tool Store. By BAT Auto Technical

If your car is an 86-88 stang, you'll have to use the test lamp or voltmeter method. There is no functional check engine light on the 86-88's except possibly the Cali Mass Air cars.

The STI has a gray connector shell and a white/red wire. It comes from the same bundle of wires as the self test connector.

89 through 95 cars have a working Check Engine light. Watch it instead of using a test lamp.

The STI has a gray connector shell and a white/red wire. It comes from the same bundle of wires as the self test connector.


There is a single dark brown connector with a black/orange wire. It is the 12 volt power to the under the hood light. Do not jumper it to the computer test connector. If you do, you will damage the computer.

What to expect:
You should get a code 11 (two single flashes in succession). This says that the computer's internal workings are OK, and that the wiring to put the computer into diagnostic mode is good. No code 11 and you have some wiring problems.

Codes have different answers if the engine is running from the answers that it has when the engine isn't running. It helps a lot to know if you had the engine running when you ran the test.

Trouble codes are either 2 digit or 3 digit, there are no cars that use both 2 digit codes and 3 digit codes.

Alternate methods:
For those who are intimidated by all the wires & connections, see Actron® for what a typical hand scanner looks like. Normal retail price is about $30 or so at AutoZone or Wal-Mart.

Or for a nicer scanner see EQUUS DIGITAL FORD CODE READER (3145) – It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $30.

 

[HISSIN50]

To give a relative idea, the TFI's critical temp is ~257*F. That generally takes getting on the car and/or a bit of heat-saturation per time.