Need Help

[rdmaster]

Hi i have 92 explorer i have changed the fuel filter the fuel pressure regulator cleanned the maf anf the iac and checked for vacum leaks and still my truck stumbles and then dies when i step on the gas and then is hard too start again and blows black smoke does anyone out there have any ideas what is my problem now ...thanks

 

[MrShorty]

Up to now, it appears that you have assumed it is a fuel system issue. I'd probably next put a fuel pressure gauge on it and see what the fuel system is doing. If the fuel pressure is too high, then figure out why it is too high. If normal, be sure to check if the system holds pressure (if the pressure drops off quickly when the pump shuts off, that could indicate something like a stuck open injector).

I might also pull codes from the computer to see if there is any useful information from the computer.

 

[rdmaster]

codes

i did get the codes from the computer using the the old method of using a jumper wire on it and as far as i can tell it has two codes with key on and not running they are 116 and 539 and running codes of 136 and 116 and i dont know if the obd2 codes are the same as the obd1 codes and i cant find them only obd2 if you can help would be a great help ...thanks:exp:

 

[Mettler]

Bad O2 sensor.

 

[MrShorty]

BrooklynBay put together a nice EEC-IV code list for us in the EEC-IV forum http://www.explorerforum.com/forums/forumdisplay.php?f=114

KOEO and KOER 116 are usually operator error -- namely, running the tests on a cold engine. If the engine will run long enough to warm up, then warm up the engine and repeat the tests to see if these go away. If the engine won't warm up, then test the ECT with a volt/ohmmeter to see if it is working reasonably (Chiltons has a table of voltage/resistance vs temperature, and I thought I posted a similar table here somewhere)

KOEO 539 is also usually operator error -- namely running the test with the AC on (or DEF on since the DEF sometimes automatically turns the AC on).

KOER 136 in the absence of a CM O2 sensor code (can I assume it gave you a 111 for CM, since you didn't list an CM codes?) could also be operator error -- namely, running the KOER test without preheating the O2 sensor. If the engine will run long enough, run the engine for a few minutes to preheat the o2 sensor and then repeat the test.

 

[marragtop]

Check again for vaccum leaks, particularly at the vacuum tree located on the drivers side by the fire wall. Make sure all lines are connected tightly.

 

[RustySJohnson]

Vacuum line to regulator boots

Replaced the little rubber boots making the connections. They need to be a tight seal. If they are hard/brittle or soft/expanded that'll cause this issue. I just went through the same problems. I didn't realize this was my problem till I heard the boot connecting the FP regulator leaking after it warmed up. I've never seen one expand that much from being warm, it was fine when I connected it cold, but after a warm up, it grew larger and quit sealing. They're cheap and if it's not the problem, you saved yourself some headaches down the road.

You're #4 post I've read today with similar issues, it's still fresh in my mind.