Help, no warm start...still

[mplspug]

My 92 X won't start when the engine is warm, as a matter of fact, the problem has grown to include warm ambient temperature, even if the engine is cold. After reading posts, I banked on it being the Fuel Pump Relay so I replaced it. After putting everything back and attaching the battery and tried starting it right away. No FP prime. I am hearing a lot of relays clicking every time I turn the key, but if I don't hear the fuel pump hum and prime, I know it won't start. So the FP relay doesn't appear to be the culprit.

Any ideas?

I haven't read any posts where people have had to replace something along with the relay. Because it is temp related and it happens now with air temps +80 or so, I am guessing it is still electrical.

Some of my thoughts are the EEC relay, wiring to and from FP relay and computer chip. Maybe someone else has thoughts on a fuel pump not priming when it is warm out or the engine is hot. Also, can I swap my old FP relay that apparently wasn't the problem with the EEC relay. And is the EEC relay located on the far right as you look down on the fuse box.

Anyone with thoughts on how to troubleshoot the problem from here would be greatly appreciated.

 

[fordracing89]

Troubleshooting

Tried the Temperature control unit ? as in the ECT can not remember the part number off hand, can you start it as in a hard start by holding the pedal to the floor or pumping or no start at all? If no start got spark ? If no spark you check all the fuses ? Could always take off the fuel rail cap and see if you have fuel or air in it

My X didn't want to start for about 6 months I would trouble shoot and get no codes no problems nothing took out the mulitmeter started testing for voltages etc everything came up normal ended up being the ECT sensor Good luck

 

[mplspug]

Pumping and holding the pedal down does nothing. I have checked all the fuses and it does start and run fine when the air temp is cool. What is the ECT and where is it located (I am a novice, but like fixing my own problems when I can)? What does the temperature control unit do?

Here's what happened today. I tried starting it during the day when it was warm 80-85 and no luck. No fuel pump hum. It just turned over without firing like no fuel was being fed. Now I just tried starting it and it is 70 out. First try I heard no Fuel pump hum and it cranked without starting, no firing. Tried it a second time and heard no hum, but after turning over for a few seconds it fired and started up. Turned it off and turned the key. Wouldn't you know it, there is now a hum from the fuel pump priming.

I hope someone recognizes these symptoms. Any thoughts?

 

[MrShorty]

It sounds to me like a fault in the fuel pump circuit. I would inspect that circuit carefully to look for a loose wire/bad connection. Check the inertia switch, too. Do you know how to manually run the fuel pump? One of the leads on the self-test connector energizes the fuel pump relay (and, as a result, the fuel pump if everything is working correctly you may need to have the key on to do it, too, I'm not sure) when grounded.

 

[mplspug]

Inertia switch is in place. The truck will start when the temp is cool. Turns over like there's no problem.

What is the circuit you are refering to? Is that what plugs into the relay? I think tonight I will inspect the entire length of the wires to and from the relay.

 

[MrShorty]

I'm referring to the entire fuel pump circuit. From battery positive through the PCM relay through the ignition switch through the fuel pump relay through the inertia switch through the fuel pump to ground (not necessarily in that order). You'll want a wiring diagram so you know which wires to trace.