Help me kill a grimlin

[Mr.smith38637]

Hello everyone!

Ive been reading this forum a while and im greatful for the useful info I have gotten from here, Here is my story.
I was given a 1992 explorer with 70k miles on it. It is a 4door 4wd automatic. it sat dead in someones backyard for 3 years with a dead fuel pump. i took an interest in it and started working on it. I replaced the fuel pump and it started running. i called myself cleaning out the gas tank as it had a few gallons of rotten gas in it. hah hah. I have a 91 2wd im using for a donor truck i ended up getting the tank from it as i know it is clean. i have replaced the fuel pump twice i have replaced the fuel filter, fuel pressure regulator, new plugs,wires, coil pack.
It is not wanting to start you can crank many times and it will eventually start it will act like its flooded and even pop like its backfiring when its hard to start will run rough like its chugging then it will smooth out and run fine. It didnt do this as soon as i repaired it by the way. ive been using it for my daily driver it just started this suddenly. What is annoying is it wont do it all the time but it is becoming more frequent. when i changed the fuel pressure regulator the problem seemed to go away for a few days then it was back. I cleaned out the IAC and it seemed to help for a few starts then its back to being hard to start.
I am not getting a check engine light. when it does start it runs...ok at an idle it seems to miss or stumble a bit and at an idle the rpm fluctuate between 600 to 850?. Im guessing there
Any ideas you folks can provide would be great ive done a lot of work to this thing and want to get around to do other stuff tot his truck but im not going to worry about radios,lights until this problem is put to rest. ive also replaces the front wheel bearings and radius arm bushings but im sure that isnt rer.lated

 

[Albino 94LTD]

Try replacing the fuel pump relay in the power distribution box under the hood.

I hate to say it but that could have been the problem all along. Replace with a genuine Ford relay, not an aftermarket one (even though they are more expensive).

 

[Mr.smith38637]

ill go to the dealership tomorrow and pick one up. from what ive been reading here ill definitely get the motorcraft one.

 

[tweakedlogic]

Albino said it all. that's exactly what I was going to reply with.

 

[Mr.smith38637]

We shall find out tomarrow. I was looking at that thread about the relay earlier. When i first started on this explorer i looled for the relay never found it asssumed the manual meant that big fuse in the distribution box. Face palm. Now that i know where it is.....

 

[FIND]

one bit of advice before you buy a new relay. Swap the fuel pump relay around with one of the relays next to it. If your problem is not solved, a new relay will not solve it.

 

[Mr.smith38637]

Well i changed it. It started good about 5 times then it went back to not wanting to start. It will backfire a bit and and idle rough. I wish i knew more about these systems id say its flooding

 

[Albino 94LTD]

Vacume leak? Check the bottom of the ducting between the air box and the Throttle body.

Did you change the relay with a new one or just move around the ones in the distribution box?

If there is an issue with the MAS/MAF, you'd probably get a check engine light but it wouldn't hurt to clean it anyway

 

[Mr.smith38637]

i replaced the relay with a new relay. its really frustrating when you do something to the truck and seems tio improve than goes back to what it was doing.
Tuesday im going to go buy a fuel pressure test kit. ill get a propane bottle out tomorrow and look for vacuum leaks. could my IAC be bad? at this point id urinate on a spark plug if i thought it would help.Again thanks for the input guys im grasping at straws.

 

[Albino 94LTD]

Maybe it's time to start over from the beginning.

Check for stored trouble codes and clear any that may be stored
Disconnect the battery for at least 10 minutes
Pull the plugs and check for wet ones (what kind of plugs did you use? Motorcraft all the way, definitely NOT Bosch!)
Check the oil for coolant
Check the coolant for oil (there's a kit for this)
Compression test?
Clean the MAS/MAF
Check fuel pressure on the rail

Then let's see how it goes

 

[Mr.smith38637]

Thanks again albino. Im pretty much coasting till tuesday. I pass near a harbor frieght on the way home from work. Ill get a security torx bit kit and fuel pressure test kit. I am assuming a wet plug is symptom of leaking fuel injectors? And yes i used all motorcraft plugs i bought them from advance autoparts. Got whateveer thier brand wire set is to. What gets me is mostly after it gets started it will run the idle is a little rough. Whould changing the O2 sensor hurt? I suspect im running rich i dont see black smoke but i do smell something. Anyway i agree starting over is in order.

 

[Mr.smith38637]

new symptoms

Ive done some of the things requested. there is no water in the oil. now its...backfiring? when it tries to start it will make a loud puffing sound under the hood started last night it tried to crank it did it about 4 times in rapid succession. There was a smell a bitter half burned gas smell cant think of another way to describe it. i was worried it was on fire. i looked under the hood and saw nothing. i cranked it today and it spit a few times and cranked.im worried but also kind glad its doing something differnt as it may help isolate what the problem is.

 

[thisfords4u]

I see you say you replaced the fuel pres. reg. but was it a new one? mine went out and it washed the plugs, I changed everything and it still had symptoms like your describing. I replaced the o2 sensor cleared codes just in case and its been running fine ever since. If you replaced the fpr with a used one, pull the vacuum line off it and see if its leaking.

 

[Mr.smith38637]

It is a new fpr. Ill check it tomarrow going to try to get any codes if i have any. Im going to try to determine if my mass air flow sensor or pcm are bad. I still dont have a check engine light also plan to test the fuel pressure.

 

[Mr.smith38637]

update

i havent checked fuel pressure yet. now that it has warmed up a little here it seems easier to start. i got out my compression gauge and on the driver side of the engine im getting about 185 psi if the gauge it right. in cyl 4,5,6. i cant get to cyl 1,2,3 there isnt enough room on the passenger side to screw the hose in to the adapter.
i took it to a shop and they cant get a code out of it. they checked for vacuum leaks and found none. im am now occasionally getting a check engine light it comes on for about five seconds and goes out again no codes to be gotten. I am getting suspicious that i could have badly fouled fuel injectors to the point dumping seafoam in the gas tank wont help.

 

[Mr.smith38637]

Grimlin Found

its the freaking fuel pump! according to pressure test its only doing 14 pounds or less. no more airtex pumps for me. does anyone know if the delphi branded stuff that car quest sell is any good?

 

[thisfords4u]

did you ever recheck the fpr? and the delphi pump should do ya.

 

[damnford]

to killa gremlin get it wet and don't feed it after midnight.

 

[410Fortune]

Well thanks to Damnford this 7 year old thread is back to the top.

To anyone looking to see what happened the old 92 was fixed by a better fuel pump.


Looks like Airtex sucked 7 years ago as they still do today.
FYI anyone going down this road here is a clue:
Backfiring through the intake is almost always a lean condition

Knowing he had a lean condition may have saved some headaches...........

 

[damnford]

your welcome i bought an airtex pump for my 95 f-150 and it worked great for about three times now it is crapping out again just before i traded the truck for my 91 explorer that also doesn't run not sure who got the better of the deal.