Help, Won't Start

[mplspug]

My 92 Explorer sport won't start if the engine has been running for a while and it is hot. It does fine on a cold start and there are no issues when I am driving it.

The temp guage reads the normal readings, but the engine block and everything atthached like the alternator seem to be hotter than normal. This may have something to do with the issue, since it starts fine cold. The fuel pump/filter were just replaced last year (along with the common pressure regulator problem) and like I said, it runs fine, so I don't think the pump or filter has any thing to do with the problem. However, the fuel pump doesn't start when I turn the key when it is hot, it does when it's cold. So I think there is check some where ios not letting the fuel pump on a start when it is hot. Something very unusual I found when it won't start and I turn it over a bunch of times is the brakes have a lot of pressure built up and it is hard to press the pedal. I think this may be a big clue. Someone said I may have a pressure hose issue somewhere.

I hope that someone recognises this issue and can steer me in the right direction. I used this last year and was able to find troubleshoot a Fuel Pressure Regulator problem that I was able to fix without bringing it to a shop.

Thanks

 

[Alec]

If the fuel pump doesn't start up then it's most likely the fuel pump relay that's getting fried. Very easy to replace.

 

[mplspug]

Would the relay be affected by a engine that's warm and been running? Becase it wouldn't start yesterday and I tried starting it for 3 hours periodically. Every time I couldn't hear the fuel pump kick on when I turned the key. It never fired, even though it was turning over just fine, just like it wasn't getting any gas.

After letting it sit all night, it started right up on the first try like normal and I had a feeling it would because I heard the fuel pump when I turned the key.

Thanks for your help

 

[Alec]

Yes, relays that are failing can be affected by heat.

 

[mplspug]

Not the Relay

I replaced the relay and had no luck. The truck won't even start now after it's been sitting. It might if the air temp gets cool enough???

Anyway, are there any other relays involved in the ignition process? I investigated where all the relays were clicking and here's what I came up with. The FP relay clicks. I get at least 2 relays clicking under the fuse box, but I can't tell if the third one is too. I read somewhere else that if you replce the FP relay, there was another that should be replaced at the same time. Could this be one under the fuse box? Also, there is a relay clicking under the car on the drivers side. It appears to be connected to wires running back to the fuel pump. Mounted right next to the fuel line and connected to something I don't recognize. Any ideas what this is? It just appears to use the same current as the fuel pump.

If there is another relay involved in ignition, I am guessing my FP relay was fine and the other one needs to be replaced instead. If you know which it is, is it the same part as the FP relay so I can just swap my old one in there?

Thanks in advance; Ireally thought I had this one fixed.

 

[mplspug]

Well, I replaced the EEC and Fuel pump relays and it hasn't solved the problem. I am begining to think it is the ECA.