fuel issue? HELP!!

[1991explorerEB]

i have a 1991 explorer eb 180,00 miles. ive had it for a year and it has always started alittle hard but ALWAYS started on the first try. recently i went to start it and it just turned over and turned over for about 10 or 15 seconds, then would start. so i kept driving it like that, then yesterday it did its normal "hard start" but then would die off imediatly,turn the key to start it again and it will start like it was brand new. and just to add, when im driving it, it runs perfect, its just the starting. im HOPING its not the fuel pump. but if anyone knows let me know! thanks

 

[R&T Babich]

I know if I try to start ours right after turning the key to ON it is sometimes hard to start. If I turn the key to ON and let the fuel pump pressurize the system (2 or 3 sec) it will start right up every time.

Check the voltage when you're starting, it should be around 9.7-10v. If it gets below 9.5v I don't think the ignition will fire. The battery cables may be adding resistance and might be corroded inside where you can't see it.

Your timing chain maybe stretched to the point it is affecting timing while starting. Does it ever diesel when shutting down or backfire when starting? Ours would sometimes backfire when starting and blow vacuum lines off the tree at the rear of the engine.

 

[Maniak]

Your early symptoms sounded like the fuel pump check valve. If you have to turn in on/off/on/off and then start it to get it to start first try then your loosing fuel pressure.

Normally its the check valve on the fuel pump BUT it can also be a fuel leak too, including a leaking injector.

I have yet to see a timing chain on a 4.0 OHV stretch bad enough to causing starting/driving issues. Its possible but its not something that has been reported here and there are many explorers with 200k-300k or higher miles. Ours had 355k miles on it when I replaced the motor (cracked the heads) and I only replaced it so I could drive it until I had the new motor ready and could just drop it in.

Now, for the start and then dies... If that is only when it is cold it could be the IAC. If you can keep it running for a minute or so using the throttle and then have it idle (although, a lower than normal idle) then the IAC isn't working. Its job is to give you the no touch start and raise the idle when needed (cold, a/c etc)..

~Mark

 

[1991explorerEB]

yeah to get it to start better ive always run the pump twice, and when i did it would start better. how about the pressure regulater?

 

[1991explorerEB]

but my battery cables are very corroded, and they need to be replaced

 

[Maniak]

If the FPR diaphram is broken you will have fuel in the vacuum line and the other symptom people get is fuel in the oil plus running like crap.

Fitting could be leaking too but that is just a fuel leak and unless things are disturbed the FPR fittings and injector connections don't leak.

A dirty injector can seep into the engine though.

~Mark

 

[1991explorerEB]

now it wont even start, it trys to and pops off but dies immediatly.? i CAN hear the fuel pump though?

 

[MrShorty]

Have you put a fuel pressure gauge on it to see how much pressure the pump is generating?

 

[TheGaginator]

you can get a fuel pressure testing kit for about $20 at harbor freight. if you need a new pump, here is a thread i posted pics on how to replace it the easiest way.

http://www.explorerforum.com/forums/showthread.php?t=367012

 

[kdspapa]

Key on/off/on/off pressure builds

I just put my new Actron fuel pressure gauge on my 99 Mountaineer 5.0 and the first key on only showed around 20lbs. Second key on the gauge jumped up to 50lbs. Third key on gauge jumped up to 64lbs and that is where it stayed during engine idle (900 rpm). Reved the engine up to 3000 rpm with no change in fuel pressure. Stomped on the gas with just a little fluctuation in pressure but settled back to 64 lbs. Turned the key off and watched gauge for over 5 minutes and no drop in pressure.

I repeated the key on test. This time on the first try the pressure jumped up to 50 lbs. Second key on 64 lbs.

Redid key on test. First key on pressure jumped to 60 lbs.

I'm thinking my gauge needs to be broke in or I had junk in the fuel. I'm going to redo the test tomorrow to see what happens.

UPDATE

Next Day: Same results as before! Pressure starts low at first "key on" but after running this "key on" test several times the pressure will eventually jump right up to 60 psi on first "key on" test.

Is this a sign of a faulty fuel regulator or pump or both?