Engine Replacing relays?

91GTstroked · Oct 3, 2020

Hey guys,

I'm wondering if anyone has replaced the ECU and fuel pump relays? Just because of age or because they went bad?

Also if the ECU relay is faulty, what are the symptoms? Will it throw a code?

I have replacement relays for both. I did have my ECU repaired this summer because of some bad capacitors.

Thanks for the help.

Potomus Pete · Oct 3, 2020

I read that if they are good , then they are good. What do you think guys should we bother replacing these thing with cheap Advanced Auto relays , or leave them alone.

7991LXnSHO · Oct 4, 2020

Leave it alone or replace with Borg Warner or Echlin if NOS Motorcraft is out of stock.

Mustang5L5 · Oct 5, 2020

Relays either work, or they don't. And when they don't work, you'll know it.

Honestly, I have more faith in a 30 year old motorcraft relay than a modern replacement. I would track down a NOS relay from the 90's over a new one.

If you really want some reassurance, put together a little roadside repair kit with the various relays you think you would need, as well as a TFI module and the screwdriver to replace it. I have such a kit in my car, but I also have roadside assistance so i'll likely never use it

91GTstroked · Oct 6, 2020

Mustang5L5 said:
Relays either work, or they don't. And when they don't work, you'll know it.

Honestly, I have more faith in a 30 year old motorcraft relay than a modern replacement. I would track down a NOS relay from the 90's over a new one.

If you really want some reassurance, put together a little roadside repair kit with the various relays you think you would need, as well as a TFI module and the screwdriver to replace it. I have such a kit in my car, but I also have roadside assistance so i'll likely never use it

Some solid advice. I have a tfi relocation kit, probably be easier to get to. I actually have a new tfi module, I need to install it to make sure it actually works.

Blown88GT · Oct 6, 2020

91GTstroked said:
Some solid advice. I have a tfi relocation kit, probably be easier to get to. I actually have a new tfi module, I need to install it to make sure it actually works.

I tried relocating it, but it didn't work. Something to do with the harness shielding. I attempted to figure it out, but with the newer TFI's, relocation is not necessary. Newer TFI's have an extended temperature range. The originals were pushed right to their limit.

91GTstroked · Oct 6, 2020

Blown88GT said:
I tried relocating it, but it didn't work. Something to do with the harness shielding. I attempted to figure it out, but with the newer TFI's, relocation is not necessary. Newer TFI's have an extended temperature range. The originals were pushed right to their limit.

My relocation kit works fine. Interesting you mentioned newer tfi modules being better. This is the first I've heard this. The Ford ones are now made in China. And I had a Ford one last year bad right out of the box. The one on my relocation kit looks ancient.

Blown88GT · Oct 7, 2020

TFI history is here.

Ford TFI Module National Class Settlement

%

www.autosafety.org

"When its temperature goes above 257 degrees Fahrenheit, the module is likely to cut out and cause the vehicle to die on the road."
257 degF = 125 degC

Mustang5L5 · Oct 7, 2020

Is there any documentation that states newer TFIs have a higher temperature tolerance? That’s the first I’ve heard of it

91GTstroked · Oct 7, 2020

Blown88GT said:
TFI history is here.

Ford TFI Module National Class Settlement

%

www.autosafety.org

"When its temperature goes above 257 degrees Fahrenheit, the module is likely to cut out and cause the vehicle to die on the road."
257 degF = 125 degC

Yes I'm familiar with all that. I put a heat gun on my tfi module while it's on the heat sink. It's mounted on passenger side fender. It stays plenty cool.

But like I mentioned before, I've never heard todays tfi modules being better. I actually think they are worse. See people posting about failed ones all the time. Even new out of the box duds.

Ford knows it was a bad design and later put tfi relocation setups on other models.

WhiteCobra95 · Oct 8, 2020

Have you guys had any experience with the Dyna Mod TFI modules from Performance Distributors? I remember reading about these in the mid 90's and how they pair up with their high energy coils. I always thought about going with their stuff if I ever need replacement ignition parts, but I haven't found much real-world feedback on the reliability of their parts. (I also like their distributors as potential replacements for when the Motorcraft supplies dry up.)

https://performancedistributors.com/product/5-0-dyna-module-86-93/

91GTstroked · Oct 8, 2020

WhiteCobra95 said:
Have you guys had any experience with the Dyna Mod TFI modules from Performance Distributors? I remember reading about these in the mid 90's and how they pair up with their high energy coils. I always thought about going with their stuff if I ever need replacement ignition parts, but I haven't found much real-world feedback on the reliability of their parts. (I also like their distributors as potential replacements for when the Motorcraft supplies dry up.)

https://performancedistributors.com/product/5-0-dyna-module-86-93/

I had one probably 20 years ago, worked then. I've heard recently some have had luck and others not.

I did buy there livewires and screaming demon coil.

Blown88GT · Oct 11, 2020

91GTstroked said:
Yes I'm familiar with all that. I put a heat gun on my tfi module while it's on the heat sink. It's mounted on passenger side fender. It stays plenty cool.

But like I mentioned before, I've never heard todays tfi modules being better. I actually think they are worse. See people posting about failed ones all the time. Even new out of the box duds.

Ford knows it was a bad design and later put tfi relocation setups on other models.

I didn't say "better". I said extended temperature range. How much is unknown but anything will help. 257 degF (125degC) is right at the limit of possible temps of the electronics. They also put almost no silicone grease on the back of the TFI. An even layer of silicone grease is likely all that is needed for efficient heat transfer.

Foxslider · Oct 11, 2020

My PCM relay went out couple weeks ago. Was running fine, i was beating the out of my car just prior, drifting. Then i bet it heat soaked for its final time, and cut out as inwas heading home driving normal..

But this is what i found... Lol.

I lost all fuel, no prime and spark. I bought mine from LMR. Its been good so far.

Also, if your blinkers are slow, a new flasher relay will speed them right up. It did for mine.

Blown88GT · Oct 12, 2020

Water got into that relay. Fix the leak.

Engine Replacing relays?

91GTstroked

Potomus Pete

I'm still waiting for the fully nude shots

7991LXnSHO

wanna catch the space herp

Mustang5L5

That is…until I whipped out my Bissell

91GTstroked

Blown88GT

91GTstroked

Blown88GT

Ford TFI Module National Class Settlement

Mustang5L5

That is…until I whipped out my Bissell

91GTstroked

Ford TFI Module National Class Settlement

WhiteCobra95

91GTstroked

Blown88GT

Foxslider

im not that much of a idiot

Blown88GT

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Engine Replacing relays?

I'm still waiting for the fully nude shots

wanna catch the space herp

That is…until I whipped out my Bissell

That is…until I whipped out my Bissell

im not that much of a idiot

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