Hard Starting

[Spartan]

Hey all,


The first time I crank my explorer over in the morning (or after it has sat for more than an hour after running) It cranks, but doesn't want to catch. If let go of the key, and try it right away again, it catches and runs fine.

If I keep on the key the first time, it takes almost 20-30 seconds for it to catch and run. No smell of fuel when this happens, and I pulled the vac line for the FPR and there is no gas/smell that I noticed. All the vac lines on the drivers side are tight and sealed properly. I also noticed that in neutral I will get a wavering tach (wavers along with an exhaust tone change). It varies by about 1-200 RPMS as I sit and watch it. Every once in a while after starting it will idle a little bit rough. There is no CEL on at all. Battery and Alternator are about 1 month old, cables are in good shape.

The only thing that I've done to the truck to try and solve this was to change the air filter (it was yellowish, and dusty as hell..... the markings say it was replaced in 09 of 2007.... so definitely time) and to clean the MAF real good. After that, the truck started on the first try, with only having to actually turn over 3 times before it caught. That only lasted a couple of days however, and it went right back to doing the same thing. I pulled the MAF again, dn cleaned it again (both times, it appeared to be clean, but I did it anyways) and it improved my starting for about a day.

Any Ideas here? i know the IAC can become flakey if carboned up, and the ACT sensor can get a bit covered in oil...... where is the ACT???

The fuel filter has NOT been changed yet.....Thats in the works for this weekend. Also, i don't have a fuel pressure guage handy to test the startup pressure. I DO hear the pump run when the key is initially turned however. I do have a vac gauge, but I'm not sure how many HG this engine should pull at warm idle. Also, cycling the key multiple times before the initial start doesn't do a thing to help it start.


Any help would be great!


PS, its a 92 XLT 4X4 automatic trans.

 

[MrShorty]

Is there a pressure switch on the fuel rail or at the pump that shuts off the pump when primed?

My first thought with this kind of no start is that the pressure is bleeding off too quickly. Only real good way to check it, though, is with a fuel pressure gauge. IMO, it will be difficult to diagnose without a fuel pressure gauge, so I would strongly recommend you get one or borrow one.

 

[Spartan]

Either that, or i have a clogged fuel filter, and its not getting enough pressure to the injectors on startup. I DO have a pinging problem under heavy load or accel up a hill on the highway. I seafoamed the truck and it still does it.

 

[shaggymane]

what happens if you just cycle the key. on - off- on - start. A friend had a spin no start issue unless the key was cycled 3 times. After replacing the fuel pump and the pump relay no luck. Then it became 6 cycles to get it to start. then finally it'd run for a mile then die. it came down to a computer replacement.

it's that yours starts right away the second cycle that makes me wonder. How to test for a faulty computer I don't know. Mr Shorty would, ........right?