no start when engine warm

[roswell sun]

when my engine is warm my 94 navajo wont re-start. the engine cranks but it wont fire. i noticed that the fuel pump doesnt make a sound...so obviosly its a fuel pump problem...my question is do i need to replace it (ugh!) or is there another problem to look at, like a relay or something. the engine runs fine once its started..the problem is only re-starting after its run for awhile. also if it is definately the fuel pump..how hard of a job is it to change? and do i have to buy a pump with a strainer kit?
thanks for any advice in advance

 

[TPLYNCH]

If it was your FP, I don't think it would happen only when warm. Should happen when cold too. You can try replacing the relay. Is in the box under the hood. To test, try tapping on the box next time it happens. If its a loose connection, you should hear the FP kick in. Other possible causes... bad battery cables - they rot on the inside; bad coil pack or connection to it; faulty crankcase position sensor.

For info on how to change FP, run a search - been covered alot lately. Also, see the Singleton maintenance site - Dead Link Removed

Welcome and good luck!

 

[roswell sun]

well....i replaced the relay...actually i replaced the eec, fuel pump and ac relays...figured while i was in there. it seems to be ok now...thank god for this post because id be yanking the fuel pump out right now (its cold here in ct right now brrrrrrrr)..it was hard for me to find relays, i had to go to the ford dealer. after arguing with idiots from pep boys,strauss auto and auto zone that a navajo is the same as an explorer...they insisted its not a ford. ive decided its worth the extra cash and time and right advice to either go to the dealer or a "real" auto parts store (one that doesnt have 3 aisles of air freshners and window tint and no damn auto parts). anyways...so far so good!
thanks for the advice

 

[jimEMT]

I actually have/had a similar problem with my '95 Explorer...still unresolved to a degree. If the truck is warm, if I park it and leave it for 30-45 minutes, it cranks but won't start. We (the mechanic and I) both were thinking it to be the fuel pump, because I didn't hear it whine when I keyed the ignition during the no-start periods. Eventually I had it no-start and stay that way...so they replaced the fuel pump and relay. It was working fine for the past few weeks, and two nights ago it did it again. It ended up starting after a few minutes. Anyone have any ideas at all? I was curious if it might be bad wiring somewhere. As a side note, in the times when this is most frequent, the engine idles funny (fluctuating RPM's...500-750) when started while hot, then is fine after you give it a little fuel. I am at kind of a loss here. I just noticed this board and figured I would post to see if anyone may have had this problem before. Thanks.

 

[TPLYNCH]

Bad FP relay, Crank Position Sensor, or coil have been known to cause problems similar to yours....

 

[PROTEUS]

It is not the battery, pump, and any relays !

Hello, , the problem "no start when warm, but it is when cold" is very frecuently as frecuently it doesn't have the right answer !...

Well, This problem is normal on very used vehicles, it is because there is carbon accumulated inside the motor, so, the compression ratio is increased, so far of its normal limits.
This situation apply an extra load to the start system, and it can't be driven. So, if the motor goes cool, it would start good again.

Your problem sounds to be this problem.

You might do a compression ratio test with the operation temperature of the motor! and verify its value. So , there is to remove the carbon and rectify the valvles if this necessary.

If the test results in a excess of the compression ratio, you'll have found the problem of no start when warm.


PROTEUS