91 X problems NEED MECHANICS HELP BAD WITH ENGINE!!

[PHAT91XLT]

Ok..here is the deal. Have a 91 Ford Explorer XLT 4x4 4dr. About 2 months ago we were going to Indy so I did a tune up on the engine. As part of it I used a special fuel injector cleaner that is sucked as a foam/mist through the vacume line. Well we picked up power and the fuel usage was MUCH better (a trip that last year took 3 tanks took 2). About 2 weeks after the trip we started having problems with the engine..little harder to start (after the treatment it poped right off). It slowly got worse so we pulled the fuel filter and it was dirty. It ran better for a bit then started acting up again. Well it got to the point where we would pull to a light and it would die. It was rough to start but it would get going. If we turned it off for a bit it wouldnt restart untill it had sat for about 45 minutes. Got worse and worse so I yanked the tank and pulled the intank filter off (we replaced the feul pump with a factory new part a year ago) disconnected the battery and did the work. When I was done bolted it back together and started it. It ran like a champ, when I mashed the gas peddle it would push you back in the seat. We drove around for about 30 minutes, letting it sit and idle..slow drive..ect. Then we go to a store for 5 minutes..come out..it goes 10 feet and dies. Restart..10 feet and dies. It is backfiring a bit as it dies..and the engine sounds like it isnt getting gas. I am at wits end..went out and bought another car today as it wont run. I dont want to take it to ford if I can help it as they want $160 just to hook it up to the freekin comp..THEN more to fix it. So PLEASE someone help me!!

 

[jimbo74]

Try MAF, IAC, FPR, O2 sensors

 

[PHAT91XLT]

and those would be???? Can they be tested or do you just replace them? Also why would it do that and would the battery beind disconnected reset it thats why it ran good? Any extra info you can give would be GREAT! I have the manual for it so let me know!

 

[88vert]

Check the vacume line in the fuel pressure regulator for gas if there is gas then it is bad.Do you have check engine lights going off and on.Brad in Iowa

 

[88vert]

Nice to see somebody from Iowa on the board.

 

[88vert]

idle air control valve,mass air flow sensor,and oxegen sensors,fuel pressure regulator.Hope that helps

 

[CADDYBILL]

Look for the simple things also. Lose wires, vacum hose. You would be surpriced what a bad wire, vacum hose will do.

 

[UTexplorer51]

look at replacing the fuel pump relay, its cheap and it will help emiminate your problem. if it is not allowing current through to the fuel pump, it isnt going to run. its located in the relay block on the passenger side of the engine bay.

other options are the IAC, pressure regulater, vacum leak, computer (very unlikely), or MAF.

my 94' pulled the same crap until i replaced that relay. now its fine. a quick way to check and see if that is the problem, switch the ABS relay with the fuel pump relay. if it starts and runs fine then your have found your problem. and yes you can drive the car fine without the ABS relay, just now cowboy stuff.

brian

 

[Msupertek]

Ford Certified Technician

Well the good news is I work for ford and fix cars for a living, the bad news is I live in Texas. In your your story you said you ran injector cleaner that ran through a vacuum hose (did this hose connect to the fuel reail or do you mean a cleaner that connected to the intake manifold vacuum port). If it connected to a vacuum port it didn't clean the injectors just the carbon on the inside of the intake. Go buy you a sunpro fuel guage from sunpro be sure it is from 0psi to 100 psi. They are pretty cheap, screw it on to the schrader valve fitting on your fuel rail (on your explorer it has a little black cap on it and looks like part of the intake). Your fuel pressure should be between 30 to 34 psi. if it is way less either the fuel press regulator is stuck or your pump is bad or restricted. Also inspect your maf sensor at your air breather box and be sure no debris can be seen on those two little wires inside of it (they are called hot wires), if so clean them with a cleaner that is safe for 02 sensors. That is probably most likely the problem. Post if you need more help.

 

[sgt.spawn]

Need picture or diagram of fuel relay

My 1991 explorer runs great, however after turnning off the engine, the fuel pump continues to run? I assume the fuel relay is the problem? It first started randomly continuing to run for a few seconds after the engine was stoped. Then noticed it ran longer and longer, sometimes turning the ignition on and off a couple times would stop it. As time goes on the thing runs longer and now seems to stay on untill the battery is drained...I know it is supposed to be mounted over passenger side firewall under the fuse block. I have removed the upper part of the fuse panel to reveal the lower half, I can see 3 connector plugs that plug into 3 different (relays)? They just do not look like relays i am used to dealing with and they are attached to the plastic cover with what seems to be metal prongs or tabs that are bent to hold the in place? I do not have a repair manual for this truck and just want to be sure of what i am looking at. The local parts supplier says there are 2 relays listed for this model and does not know how to tell them apart or which one i require.

 

[UTexplorer51]

take both relays in and have the parts store cross reference the number. it will come up which one is which, if there is a difference. they should be marked on the bottom of the cover on which one is which.

bt

 

[88vert]

Any updates?

 

[PHAT91XLT]

update: took off the mass air sensor and cheched it and the idle arm controll and checked it. Friend told me about a small shop that had the tester..they only wanted $35 to run a diagnosis on it. Took it down and everything tested fine. What the mechanic said is that he see's it alot where the connector on the mass air sensor on these year Xs that come loose..sends a funny signal. It runs fine now it seems, I dont take it far anymore as I am scared it will do it again. I am going to look for a spare motor..they only want $650 to pull my old one and put a new one in..seems fair I recon. Wish someone made a refreshen kit for these motors like they do for every other dern motor..grrrr. Who knows! Thanks to everyones help!