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Discussion Starter #1
Help. I posted before that on Saturday the car died close to home requiring that I rely on the kindness of others to push it back to the garage. That one was an easy fix as the positive battery cable end had broken. Got that fixed Sunday morning.
So we grease up with the sun block and drive 30 miles to a car show. No problem. Drive almost all the way back and stop at a store to buy something then she would not start. Turned over but did not catch. Only coughed a few times. I noticed there was no sound of the fuel pump. We happened to be at a Canadian Tire and a couple of mechanics came to look but did not want to roll it into the shop as they said they wouldn't be able to get it on their lifts (whatever). CAA came but he didn't want to load it because he was afraid of doing damage with his winch cable to the front end. Anyway, nice CT guys helped push it onto the flatbed and we got home. This morning, on a hunch, I tried it and the fuel pump ran and it started. What is going on? Vapor lock? Before you say it we all had a go at banging the gas tank to jar the pump into life. That did not work.
It is a 1988 5.0 with Cobra intake, converted to MAF with 24# injectors, cobra computer, 95mm MAF, 65mm Edelbrock intake. It has always been hard to start when cold.
The walk of shame twice in one weekend was a tough one to swallow. Fixed that with a couple of beers.

All input welcomed as usual.

Thanks
 

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On my fox body 'stang, the fuel pump relay failed a time or two. I always carried a spare as it was easily accessible under the drivers seat. If you just hold it in your hand when you turn the key you can feel it click if it is working.If you are sure the pump isn't coming on, I would start there, but if the pump itself may be starting to fail it might still be intermittent. Otherwise, the inertia switch could be suspect although it is unlikely it reset it self, but who knows - I have seen stranger things.
 

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Discussion Starter #3
On my fox body 'stang, the fuel pump relay failed a time or two. I always carried a spare as it was easily accessible under the drivers seat. If you just hold it in your hand when you turn the key you can feel it click if it is working.If you are sure the pump isn't coming on, I would start there, but if the pump itself may be starting to fail it might still be intermittent. Otherwise, the inertia switch could be suspect although it is unlikely it reset it self, but who knows - I have seen stranger things.
OK thanks. The relay wouldn't fix itself overnight would it? I do wonder about the fuel pump. I think it is original. How would I test that? The inertia switch was new with the build. I did check that at the time and it hadn't been tripped.
 

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Lets start with the basics. Yes, check the relay. If it over heats, it will not click on. So it could fix its self over night. My money is on the fuel filter.

My MKII with pretty much the same engine has the hot air intake issue. It starts fine, and while moving, there are no issues. Once in traffic or stopped, the idle jumps till it dies. Then it will not start unless you give it some gas. Moving the air filter forward is my next project.
 

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OK thanks. The relay wouldn't fix itself overnight would it? I do wonder about the fuel pump. I think it is original. How would I test that? The inertia switch was new with the build. I did check that at the time and it hadn't been tripped.
If the relay cools down it can work. Run the car & see if the relay gets excessive hot.
 

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With the EEC-IV when you turn the ignition to on the pump will run for a couple of seconds to charge the lines then shut off until the ECU sees a signal from the TFI module indicating that the engine is cranking. The usual failure mode for the TFI modules is to occur when hot---sometimes "healing" themselves when they cool. I'd be suspicious of the TFI module...

Good luck,
Jeff
 

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That's true also, and a good possibility. The problem with intermittent faults is you can't fix it until it quits. It is easy and cheap enough to throw a new relay and tfi module on it. and see what happens. I hate "shot-gunning" stuff like that but when you weigh it against the inconvenience of getting stranded on the side of the road , sometimes it makes sense.
 

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Discussion Starter #8
Lets start with the basics. Yes, check the relay. If it over heats, it will not click on. So it could fix its self over night. My money is on the fuel filter.

My MKII with pretty much the same engine has the hot air intake issue. It starts fine, and while moving, there are no issues. Once in traffic or stopped, the idle jumps till it dies. Then it will not start unless you give it some gas. Moving the air filter forward is my next project.
Thanks. I will check the relay and maybe just replace.
Not so sure about the fuel filter. Although not impossible it has only had one tank of gas through it.
Didn't know about the hot air intake issue. How would this stop the fuel pump from running?
 

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Discussion Starter #9
With the EEC-IV when you turn the ignition to on the pump will run for a couple of seconds to charge the lines then shut off until the ECU sees a signal from the TFI module indicating that the engine is cranking. The usual failure mode for the TFI modules is to occur when hot---sometimes "healing" themselves when they cool. I'd be suspicious of the TFI module...

Good luck,
Jeff
Thanks Jeff. Always value your advice. Is there any way to test the module?
 

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Discussion Starter #10
That's true also, and a good possibility. The problem with intermittent faults is you can't fix it until it quits. It is easy and cheap enough to throw a new relay and tfi module on it. and see what happens. I hate "shot-gunning" stuff like that but when you weigh it against the inconvenience of getting stranded on the side of the road , sometimes it makes sense.
So true
 

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TFI issues

As always, I 100% agree with Jeff . . . the TFI could be your culprit here.

They are known to [sorta] fail in the way you describe - go ahead, ask me how I know this). Ford lost a law suit because of heat related failures with the TFI module.

There is a way to test it but not conclusive because it doesn't take in to account the heat soak issue.

So, that being said, there is a way to [maybe] recover it if you get out there on the road and it quits on you - carry a water bottle that you have frozen over night, pour it over the TFI module and it probably will recover.
Another fact about the TFI: IF you are running the "grey" colored module, even if it won't "crank" start, you should be able to push start the car.

This method won't work with the "black" module.

There are a few solutions to this issue with the factory placed TFI module, the best is to relocate it to an off-engine place - that is what I did to mine after two episodes exactly like yours . . .
Here's mine, relocated to the PS footbox



And the block off plate to cover its old mounting location:



HTH

Doc
 

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Thanks. I will check the relay and maybe just replace.
Not so sure about the fuel filter. Although not impossible it has only had one tank of gas through it.
Didn't know about the hot air intake issue. How would this stop the fuel pump from running?
I am not fully convince that the fuel is the problem. With my car the pump only turns on till there is pressure and then it turns off. I have a fuel pressure gauge in the engine bay that has helped me with similar issues before. After you crank over the car for a couple of tries, smell the exhaust for fuel smells. That would be a good low tech way of checking if you are getting fuel to the engine. I assume that you have checked the ignition also. I was stuck on the side of the road for a while because the coil to distributor wire came loose. It looked good, and then when I pushed down, it went click.

Also, there is no shame being here. I have been on the side of the road way too many times. Now days, I take the kids out and we go over everything in the engine to make it a learning experience. Then they talk back to me with funny sayings like, "didn't you replace the spark plugs yesterday" and even, "You know they make a click sound when you push them in." Kids these days...
 

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On my old GT, I had issues at different times with both the TFI module as Jeff pointed out as well as with the relay as sread pointed out. When my relay went bad, with it being under the seat, I could usually bang on it a few times and get it to run.
 

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TFI Testing

IF you really want to test it . . .




Doc :beerchug:
 

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Discussion Starter #15
As always, I 100% agree with Jeff . . . the TFI could be your culprit here.

They are known to [sorta] fail in the way you describe - go ahead, ask me how I know this). Ford lost a law suit because of heat related failures with the TFI module.

There is a way to test it but not conclusive because it doesn't take in to account the heat soak issue.

So, that being said, there is a way to [maybe] recover it if you get out there on the road and it quits on you - carry a water bottle that you have frozen over night, pour it over the TFI module and it probably will recover.
Another fact about the TFI: IF you are running the "grey" colored module, even if it won't "crank" start, you should be able to push start the car.

This method won't work with the "black" module.

There are a few solutions to this issue with the factory placed TFI module, the best is to relocate it to an off-engine place - that is what I did to mine after two episodes exactly like yours . . .
Here's mine, relocated to the PS footbox



And the block off plate to cover its old mounting location:



HTH

Doc
Thanks Doc it does help. Have ordered the module. It is good to know there is a temp fix for the grey module if it happens again. Did you buy a relocation kit or fab that yourself? If a kit can you suggest a supplier?

Steve
 

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Steve,
I'm using the McCully Racing relocation kit but a search for them wasn't any good. LMR has a kit. Also Summit Racing and more. Just search for TFI relocation kit.
George
 

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Discussion Starter #17
Steve,
I'm using the McCully Racing relocation kit but a search for them wasn't any good. LMR has a kit. Also Summit Racing and more. Just search for TFI relocation kit.
George
Thanks George. Hope all is well there. Are you on the road now?

Steve
 

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TFI Relocation

Here's the link to the vendor mentioned (I don't believe a FFCars vendor):

McCully Racing Motors- We have exactly what your over-heated TFI Module Needs!

( - probably going to get myself in trouble for posting non-participating vendor links - )

OR

Scour the bone yards / pick-a-part lots for the one FORD made for this issue. (Bronco's and Rangers - early 90's) don't forget to get the "extended" harness.



Built my own block-off plate from 1-1/2" aluminum 90° angle

Doc
 

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Discussion Starter #19
Here's the link to the vendor mentioned (I don't believe a FFCars vendor):

McCully Racing Motors- We have exactly what your over-heated TFI Module Needs!

( - probably going to get myself in trouble for posting non-participating vendor links - )

OR

Scour the bone yards / pick-a-part lots for the one FORD made for this issue. (Bronco's and Rangers - early 90's) don't forget to get the "extended" harness.



Built my own block-off plate from 1-1/2" aluminum 90° angle

Doc
Thanks. Module and kit ordered. Special tool to make removal easy only 4 bucks. Lets hope this fixes thee problem. Not fun getting stranded.
 

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if you did not do it yet I would also change the fuel pump relay, they do fail intermittent sometimes.
David W
 
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