Guess At My Problem

Mentat

Mentat

Member
Sep 12, 2007
25
7
13
Sugar Land, TX
#1
Hey guys.

93 GT 5 speed, 173k miles.

Coming home from work today, my car died on me as I was coasting to a light. I was able to jumpstart it in 4th, fired right up and continued driving. This has never happened before.

It happened twice more on the way home, once while coasting, and once while actually driving (45mph in 5th gear).

My fuel pump is running, everything under the hood looks ok, but I don't have any access to get the codes pulled until the weekend.

I'm sure ignition/fuel issues would be the culprit, but is this common enough for someone to be able to diagnose it just by the symptoms?

Thanks!
 
#6
Mentat said:
Is there a test for it?
Click to expand...

You can take it off and have it tested at autozone, if you can, have them run the test like 20 or 30 times so the module will get nice a hot so it will fail.

Even that test isnt 100%, I personally tested mine like I said above and it didnt fail, I still suspected it, so I went to the junkyard and got one for a buck and the car finally ran like a Mustang, then I bought a new one right away. (btw my bad TFI wouldnt let me go over 3k rpm, which was unusual.)


If you get a new one make sure it comes with a packet of white paste to put on the backside of the module to keep it cooler and less likely to fail while driving.
 
#9
^ meh I'm leaning toward TFI because he said he was actually driving 45mph in 5th, but I wonder how low the rpm would be on his car, would the IAC be functioning? My car would die at that speed in 5th. (I have 273's.)

BTW the best tool to get to take off a TFI is the Duralast brand 1/4 drive 7/32 deepwell socket that they sell at Autozone. Being a regular socket, it's more useful than the weirdo TFI wrench thing. Its cheaper too.
 
#10
My car has done the same thing, mine would sometimes do it at an idle, sometimes while running around 50mph or so, while slowing to a stop light, basically mine would do it throughout the entire rpm range, so one day I was going to oreilly's to get something, don't remember what but, when I pulled in to the parking lot mine died one last time while coasting to my parking spot, it would not start back at all, I tried for about 30 minutes and finally went in and bought a new tfi and borrowed their tool to remove my old one, and while I was installing the new one my buddy was testing mine inside and it failed all of the tests they run it through, anyways now with my new one my car hasn't died again, well actually it has but it was due to the msd coil going bad, so I bought a stock replacement coil and it now runs like a champ.
 
#11
Mentat said:
Hey guys.

93 GT 5 speed, 173k miles.

Coming home from work today, my car died on me as I was coasting to a light. I was able to jumpstart it in 4th, fired right up and continued driving. This has never happened before.

It happened twice more on the way home, once while coasting, and once while actually driving (45mph in 5th gear).

My fuel pump is running, everything under the hood looks ok, but I don't have any access to get the codes pulled until the weekend.

I'm sure ignition/fuel issues would be the culprit, but is this common enough for someone to be able to diagnose it just by the symptoms?

Thanks!
Click to expand...

Sounds a lot similar to the problem I'm having. It died a couple times when I was driving on the highway and a few more times in a parking lot.
 
#12
89LXhelp said:
Sounds a lot similar to the problem I'm having. It died a couple times when I was driving on the highway and a few more times in a parking lot.
Click to expand...

You should replace your TFI module then and tell me if it solves your problem. :)

Has anyone used the cheapo TFI module at 50resto? I know the Accel one is a couple bucks more, but just for the sake of the argument I'd like to know if someone has used the cheaper one.
 
#13
LiquidGT said:
^ meh I'm leaning toward TFI because he said he was actually driving 45mph in 5th, but I wonder how low the rpm would be on his car, would the IAC be functioning? My car would die at that speed in 5th. (I have 273's.)

BTW the best tool to get to take off a TFI is the Duralast brand 1/4 drive 7/32 deepwell socket that they sell at Autozone. Being a regular socket, it's more useful than the weirdo TFI wrench thing. Its cheaper too.
Click to expand...

I believe that I'm doing anywhere from 1600-1800rpms at that speed.

Would the IAC have any effect in that range?
 
#14
Mentat said:
I believe that I'm doing anywhere from 1600-1800rpms at that speed.

Would the IAC have any effect in that range?
Click to expand...

The IAC should definately be closed in that range.

The Accel TFI is the one that crapped out on me and put my newly built engine in "limp mode". It only had about 12k miles on it.

You could get a Motorcraft, but I tried one from Autozone and it hasnt missed a beat. Its made by Wells and I was told by someone knowledgable that Wells makes the OEM sensors.

On a side note I heard the PIP (pick up coil) inside the dist can to go bad sometimes and mess up the TFI. (or vice versa) I replaced it before, just for newness, but I dont recomend it unless you're a cheap bastard like me. You have to take the dist apart and its very hard to do, just get a whole new dist.
 
#15
Mentat said:
You should replace your TFI module then and tell me if it solves your problem. :)

Has anyone used the cheapo TFI module at 50resto? I know the Accel one is a couple bucks more, but just for the sake of the argument I'd like to know if someone has used the cheaper one.
Click to expand...

I just purchased the stock one from checker. What do I need to remove the old one? I can't find the right tool for it.
 
#17
also, if you look in the OEM section on the the tool isle at autozone, there is a tool that is made SPECIFICALLY to remove the tfi module on our cars. one side is a torx bit, the other is a little socket. it's like $6.
 
#18
cenok is family said:
also, if you look in the OEM section on the the tool isle at autozone, there is a tool that is made SPECIFICALLY to remove the tfi module on our cars. one side is a torx bit, the other is a little socket. it's like $6.
Click to expand...

I just replaced the TFI. I was driving back to base and still having the same problem. Do I have to wait for like the gel to do anything or should it work instantly?
 
#19
I was gonna say fuel pump going out but thats out of the question?

If it was the IAC it would still start once you hit the gas which will let some air in the intake and let it start which is what the iac does. Happened to me many times cuz the clip that holds the connector onto my iac is missing so it disconnects after I hit some bumps and then it will idle wherever I set the base idle and wont start unless I open up the throttle a little.
 
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