Intermittent starting problem

[rp]

94 Explorer. On warm days, if car is driven for a while and then left in the heat for 45 min or more, when you go to start it, it will crank, turn over and start, but goes into a "sub-idle" funk for a few seconds and then dies. Once it has done this, it will only "crank", but won't turn over. If car is left sitting for 1-3 hours, it will then start as if nothing were ever amiss. I am assuming that there is something wrong in a heat-related sensor, but can't find a mechanic who can figure this out - help!

 

[Bwana Bob]

My 92 does something similar. Fires right up in the morning or after sitting all day, but let it sit for just an hour on a warm day and it will take a few seconds of cranking to make it start. When it starts, I smell a little gas, as if its running rich. I find that it will start up right away if I give it a little throttle when cranking.

Otherwise, it runs fine. I almost acts like vapor lock, but I don't thnk that can happen on a fuel-injected engine.

It certainly seems to be temperature related, but what could it be? MAF is OK, maybe a leaking injector or stuck IAC making it start with too rich a mixture. TPS? Coolant temp sensor? I just don't know, and its not putting out any codes.

I see that Wal-mart has an OBD I code scanner for $30. Will this give a readout of the sensors, or does it only display codes? I might have to set up some probes and monitor the sensors with a voltmeter.

I reset the computer this past weekend after I drilled the airbox and cleaned the MAF. I'll see if that makes any difference.

Let me know if you find anything.

Bob

 

[HF with a 94 EB]

I have the same exact problem with my 94 Explorer. It will start with no problem, but when I come out of the store, it will turn over, light off, run fine for a split second, go rough on the idle, than stall. Then it will not start (still turns over, but not light off). When I turn the key on to power, I can hear the fuel pump energize. I let the car cool off (open the hood) and 20 to 30 mins later, it starts up fine - as if there was never a problem. I've had it towed to the shop and they can't find anything wrong - no computer codes, fuel pressure is fine, and tell me to bring it back when it not working.

I've noticed that when I roll my windows up and keep the button down after the window has closed, that the electric meter gauge swings wildly to the negative side and then back to normal when I let go of the button.

Any Ideas?

 

[ma96782]

Try reading this...........perhaps it will help:

I have a '94 XLT that had intermittent starting problems last year. On an infrequent and random basis the engine would crank fine but doesn't catch. After wiggling the wires and tapping on the fuel tank it would start, but eventually I was told the fuel pump was failing. I knew it was 12 years old so I had it replaced and everything's OK for eight months, but now the same problem is occuring. When it's working, you can hear the whine of the fuel pump when the key is turned. When it's not, no whine so I don't think the fuel pump is getting power. Once the engine is running I've never had any problems, so I'm not sure it ever was a fuel pump problem. Sometimes it won't start, then after sitting for an hour it will. Any suggestions?

______________________________________________________________________



Did you change the fule pump relay? My 94 XLT (with 180K) had a problem to start right after the engin was off for 10 to 20 minutes, when the engin was cool, it can start again and runs fine. I traced to the fule pump relay and bought one from AutoZoe for $6.00 and have not have any problems since.


____________________________________



My 95 Explorer would occasionally crank but not start. Occurred ONLY when engine was warm -- never on the first start of the day. After waiting anywhere from a few minutes to 2 hours, the engine would then start normally. Happened between once every few months and 2 - 3 times a week, and VERY intermittently. When I drove it to work and then it sat for several hours, it would always start. When I monitored the EEC-IV codes, it would always start, of course. Finally took it to a dealer I trust and left it for 2 days so they could try to repeat the problem. They finally got it to happen and determined that there was no fuel pump pressure when the engine was in this state. They replaced both the Fuel Pump Relay and the EEC Power Relay. After these replacements, they could no longer duplicate the problem. This was almost 4 weeks ago, and I have not experienced the problem. It could just be the odds, or the relays may have been intermittent. Since it is a cheap repair you can easily do yourself, replacing these two relays would be my recommendation as a starting point.

Aloha, Mark

 

[HF with a 94 EB]

Did you ever find out what was wrong with your Explorer? I'm having the same exact problem...thanks...