My car is a NA with a EFI 5.0 Ford in it. The ECU is mounted in the stock location under the passenger side floor/firewall. I am having a problem with the car shutting off after it gets thoroughly hot (after about an hour or so of driving). I am thinking it may be the ECU getting hot, and I'd like move it to underneath the passenger seat.

Does anyone know of someone that makes an extension wiring harness that plugs into the ECU plug then into the ECU so I can move it without splicing wires?

 

Have you tried laying the ECU on top of the passenger footwell carpet & driving to see if that is the problem?

 

+1 on tbone's suggestion for sure.

Also, what about that TFI on the distributor thing. I've seen many cases were it creates intermittent problems.

My experience with ECUs has been they are either good or bad...

 

I am planning on pulling the ECU out of its hole out on to the floor and driving it some this weekend.

I am also pursuing moving the TFI module. I've seen MRM's kit to move it. Are those still available?

 

It could also be that your fuel line is to close to the header and the fuel boils and will not start until it cools down. Just a thought.

 

...or starter heat soak.

 

What you're talking about sounds like the TFI. I have one kit in stock currently but probably will not have any more made up until next week.

When I went with a plug-n-play MS2 I extended it's adapter harness to relocate it behind the passenger seat. You could do this using the female plug from an old ECU, a project box from RadioShack and a used male ecu plug. Unfortunately no one makes an extension harness for 60-pin Ford ecu's.

Starter heat soak and hot fuel will not shut the car down, only keep it from restarting until it cools.

-Jason

 

Right. I misread that, thinking it was a hot start issue.

 

I've been asked about making these before so I did a little research:

First I thought I could buy a MS2-Ford adapter harness from DIYAutoTune and modify the MS end to mate with a Ford processor. This would have been very easy and economical, unfortunately they do not make them any more.

Then I found a guy on eBay who makes them with a recycled ECU plug on one end and a 3d printed harness plug on the other. He wants $200 for a two foot long extension harness and $20 for each additional foot.

Using that as a guide I figure I can do the same using a recycled harness plug and only extending wires for the specific car to keep costs down. I think I can make a 5' one for about $150.

So...new a new MRM product is born. 5' Ford EEC-IV extension harnesses for $150 + S/H. Any takers? PM me if interested.

-Jason

 

Let's not forget the fuel is at 38-40 PSI. The boiling point gasoline at 40 psi - I don't know, but at that temperature I would be more concerned with it exploding than vapor locking. At 6-8 PSI in a carbureted application, vapor lock is a possibility, but not too likely in an EFI application.