Hey guys,

Strange problem here. '95 F150, 4.9, 5-speed w/110k miles.

Seems ONLY when I am in a hurry it acts up, figures huh? And I can't find a pattern on when it happens (hot/cold, how long it sits, etc..). But it seems to be happening more frequently.

When it isn't going to startup I'll know right away, the check engine light will stay on while cranking. Just turn the key completely off, and many times it will crank right up the second try (check engine light goes off right before it fires up). Thought maybe fuel, replaced the fuel filter (been about 30k since done). I noticed when I cranked it up that even though it DID take about 5-7 seconds of cranking before it fired up, the check engine light did NOT stay on, went out as normal before it started up.

Example of tonight. about 75 degrees temp here: Fired right up from the house, and ran one mile to the gas station to fill up, and had it shut down for about 10 minutes while pumping. Tried to start it up and check engine light stayed on solid and no joy. It will crank fine, the fuel pumps hum like a baby when I first turn the key to on. I probably took about 20-30 tries of cranking (with moments of swearing and other such things during each break) and when it finally did fire up for me it ran horrible for the first 20-30 seconds and did die on me once. I was just figuring that was from un-burnt fuel from my 20-30 failed attempts to get it going. Ran like a champ after sitting there and revving it a few times.

The strange part to me, the check engine light stays on solid when it doesn't fire up, but yet it's not storing any fault codes. One time I used a jumper wire and the code came back 'all OK' even while it wouldn't start, and ran through the full test with a neighbors code scanner and it came back 'A OK' also.

One thing making it kind of hard to really test is that whenever I've had a mechanic look it over it's running like a champ, only acts up while alone, or at an odd hour when no one is around. Whenever it's thrown a big fit and I have to go through the whole procedure more than 4-5 times it does run like it's flooded as a river when it first fire up, and any time it does not start it's acting as if there's no spark at all, not even a sputter it leads me to something ignition related (coil/ICM, etc..), but it's been years since I've been under the hood except for minor things and only worked on Japanese imports when I used to do this all the time.

Is this a wild goose chase on where to really start, or does the check engine light staying on whenever it doesn't want to to fire lead anywhere? It started out doing it about once a month, then moved to once a week, now about half the time it seems.

Open to any ideas :-)

Larry

 

Sounds like the "PIP" pulse is not always there. Check your Distributor or the Ingition Module.

 

Figures I'd get time to test it out a bit today and it started like a champ everytime!

I picked up a Haynes manual from A-Zone and went through most of the ignition tests just to see what was going on, but of course everything looked fine since it would fire up. One thing I was concentrating on were the resistance tests, and everything was within specs, ignition coil fine, and between coil and ICM.

And one quick way of testing for spark when it acts up again, I dug my timing light out and when it does it again I'll be able to test for spark at the coil and also at the cap. At least to know for sure if it's ignition or fuel related. Oh yes, dug out my test light and volt/ohm meter and have em handy :-).

Still intrigued though, that whenever it's failing to start the check engine light stays on, but when it's happy and is gonna fire up it goes out within half a second after I turn it over.

I hate intermittent problems, lol, would be so much easier if it just wouldn't startup at all!

Larry

 

When was the last time plugs, wires, cap, and rotar were changed? Pull the cap and see whats goin on in there. Once found one full of water! Pull a plug to see how they look. Heck, just make sure all the wires are tight.

Adrianspeeder

 

Check the wiring harness that goes from the distributor to the module on the fender, and make sure it's not rubbing on the steering.

 

Woo hoo! I think I have it fixed up now.

The daily routine the last few days has been to try to fire the truck up when I get home (drive company car during the day), and it finally started acting up again. A bit worse than normal, I backed it in the garage to put my new '06 sticker on my license plate, and let it run while I took off the plate and went inside to clean it. Truck died after about 5 minutes. Tried to restart and no go, check engine light stuck on.

Got out my test light and timing light to check for spark, and also check the ground on the coil to see if it was getting a 'pulse' when cranking. No spark and no pulse, the test light is on solid while cranking (should be blinking off/on). Looked up to see that it SHOULD be either a wiring fault between coil and ICM or a bad ICM. Tested with Volt/Ohm meter and wiring checked out fine. Picked up a new ICM from AutoZone and figured I'd get cap/rotor too since they both looked kinda 'close' to retirement.

Popped in the new ICM, and of course, STILL not firing. Double checked wiring, everything still good there, and the harness is not rubbing anywhere. While saying some bad words and etc..... I figured I'd go ahead and pop on the new cap & rotor before I started digging for something to get to the PIP sensor wires on the distributor, and for giggles I tried to start it up once more. And of course it fired RIGHT up. First thing was to put the old rotor back in, and it went back to the CEL light stuck on and no starting. Replaced with new, fired right up. (Tried this about 3-4 times just to make sure I could replicate).

Still gonna give it funny looks the first few times I take the truck out, but looks like it's running like a champ now. And also idles a bit smoother than before too. Wish I'd thrown on the cap & rotor sooner now, but this last week I wanted to wait until it acted up before I threw anything on it so I could try to replicate the problem on command.

Thanks for the tips on things to look for guys, now I just need to find some extra money laying around so I can put some more power in it :-)

Larry

 

Who hoo, finally right for once

Adrianspeeder

 

Spoke too soon about being solved, well poo...

I did one extra check today that I haven't done before (on the PIP sensor). Checked between pin 8 and the ICM and it was about .2 ohms (gotta be under 5) and also checked pin 8 to ground, shows over limit of my ohm meter which i think pegs out at 10kohms (supposed to be at least 10kohms). so good there. Also checked for voltage going through pin 8 in either run or start position, and showing battery voltage there. All looks well as far as wiring.

Here's the strange part, it only wouldn't fire up for me about the first 3 tries, but then it's acting 'normal' again, but I figure I'll check the PIP sensor anyway, so I run through all the checks for voltage coming back out through pin1 (had to pierce the insulator with a pin to get at it of course, should be between 3-8.5 volts), and am getting basically no voltage coming back out while cranking), and when I have either a volt meter or a test light hooked up to the lead and have it grounded it also will not startup (fire). As soon as I take the meter off of ground and crank it, fires up. Oh yes, I DID try testing for voltage with the PCM disconnected and also with the ICM disconnected to make sure they weren't shorting out the PIP, and same results.

Also...... before I checked the PIP sensor, I tested with test light from the ground on the coil, and ALSO, when I have the lead hooked up to the tach terminal and crank it over I am getting a bright light on teh test light, but NO flickering and it will not crank. As soon as I disconnect the ground on the test light it fires right up. The other day when I was testing (when it WOULD start) it was doing fine and would flicker when I turned it over but was HARDER to start with it in place.

Oh yes, I did get an ignition control module, and popped it in yesterday when it would not fire, and had same results, no fire.

Wondering..... does this point to the PIP sensor being at fault or still a wild goose chase? Seems strange that if I start poking around with a test light it's enough to cause not to fire when it would still fire up the other day when I started testing things. Just for grins, I have checked everything I could get my hands on under the hood to make sure everythings all tight and clean.

What's everyone think?

Larry

 

Sounds like the "PIP" pulse is not always there. Change the pip sensor, I know it's a lot of work to change. If there is any wobble at all in the Distributor, change the Distributor, it will come with a new pip sensor.

 

I think you were right on the money subford... Hopefully . A neighbor luckily DID have his scanner with him yesterday when he got home, and he hooked it up while I had the 'no fire' symptom. No failure codes but also did NOT show a pulse either while I was cranking it over.


Turns out I spent only about $25 for a reman'd distributor than I would have just the PIP sensor by itself, so I went with the distributor. Also hurt that I don't really have something to hold the distro in place to have gotten the gear off and back on without it being a severe pain, so otherwise I would have ended up buying a vise and a small puller to get the gear off without killing it, so would've cost the same, lol. Got a new cap/rotor on it, and the plugs/wires have have about 20k on them (will change plugs soon probably).

It already SEEMS to have fixed the problem, the last four days or so it had gotten a 'no fire' sympton during the heat of the day, and today I've tried it a couple of times and it's fired right up. Learned one thing last night too, NO fun putting a distributor in the inline6 in the dark. And I'm 6'4" so it SHOULD have been a much easier reach for me over someone shorter but oh my, NO fun!.

Thanks for the tips guys, and hope to be cruising around in my ole' truck now instead of sneaking trips in my company car.

Larry