I'm losing my mind with my trusted 300. As I stated in the title, it will crank over but won't start.... This has never happened in all 10 years I have owned it.

Recently this year, I found a major culprit with it running like crap, as if it was only running on 3 cylinders, violent shaking until it reached around 2000+ RPMS, was due to the notorious leaking capacitors that plague the 4.9's. Replaced with a Remaned PCM, same calibration, ran like a top for 3 weeks. This was from 9/10/13 till first of October. Then back to only a miss after warming up. All new plugs, cleaned cap and rotor, checked fuel PSI.

Checked for codes and noticed there were some anomalies with like having IAC and Spout disconnected and the KOER test couldn't find fault with that even though, they were.

Took that PCM back and got another. Ran a bit better, but miss was there after warming up, Fuel PSI fine, ran Self-check, no problems, even though it was slightly missing. Ahhh, well, I didn't have time to check further into it.

Now, it has sat for about 3 weeks, as of today, and I go to start it. Nothing, just cranks over. I can hear fuel pump, though it was kinda dull...Oh great, fuel pump must be going out. that would explain driveability problems after warming up. Got the rubber mallet out, knocked on gas tank, got back in, much better cycle sound when ready to start and crank over...Nothing..Ok I said. Get the Fuel PSI gauge, check it, I have 48 lbs, ok, try again, Nothing. Swap out coil for known good coil. Cranks, but no start. Finally, I think, Pull SPOUT out, get in, FIRES RIGHT OVER. This tells me something, that either the ICM or Stator is bad. Now, after it ran for about 15 minutes, I reconnected the SPOUT, and I could hear the engine rev up a bit higher and it never died. I limped it over to the gas station and put a few gallons of fresh fuel in and came home. I shut it, let it sit for a few minutes and tried to start it and it did. Going to try one more time tomorrow morning and see if it does start again with the SPOUT in and post back results.Can anyone verify my assumption?

I happen to remember another member GreaseManicure having similar starting problem with his 1993, 4.9, 300. Checked his 4 Page thread and his solution was replacing the distributor and ICM module.

Anyone with ideas, suggestions, opinions, I would appreciate any feedback, as I need this truck back on the road. Thanks again for taking a moment to read.

 

Hey timbersteel you think maybe the ignition control module is going to crap maybe or did you say that already? My memory stinks man LOL. of course if you did replace the distributor you would get a new one any way right? is yours on the front of distibutor like mine? or how about maybe, the pickup coil inside the distributor? but of course that is inside the distributor to so I guess if you replaced the distributor you would get a new one of them to. Don't know for sure what it is just throwing around some stuff Brother, talk to you soon. Scrobbie (Rob)

 

Earlier this year you mentioned testing the resistance in the wiring harness. I've got the 91 4.9 and I think that is where my issue is at.

 

I have been having the same problem, found that my TPS was bad also my throttle my be an issue

 

Looks like I may be on to another problem. Checking this site pointed to the EEC relay. I will check tomorrow when it warms up.

No spark [Archive] - The Ranger Station Forums

 

Ok, so replacing the Stator made things only worse...I can't understand why it won't even fire now with the SPOUT plug out. I have no spark, with SPOUT in or out.

I replaced the Stator with BWD ME58, they tried to sell me the other stator that the ICM module was on the dizzy, but told him my module is on the Fenderwell. Had the ICM checked while I was there. It passed. Checked the EEC fuse's and all good. What could be next, another bad ECM/PCM? Can I just unplug that one and plug my old 302 PCM in and check to see if I have spark?

I spent all day in 20 degree weather, and there's no chance it's gonna get another look until next week. I'll be working all weekend.

 

Sounds like possibly two problems are going on. If thr spark return with the computer unplugged that usually indicates the PCM is bad. If you have no spark plugged or unplugged then you need to trace it back to the stator or ICM.

I have pointed others to that Ignition Diagnosis you posted earlier, it is a good write-up. If you have power to the stator and no output when you crank the truck then the stator you purchased could be bad or have you verified the distributor rotor is turning? It is somewhat rare for a 4.9L to have a bad timing gear, but it can happen.

 

Ok, just so I didnt missread your post...if I disconnect the PCM, and spark returns, then I can verify that its bad. Is that the same as pulling the SPOUT? Just bear with me RLA. It was a bitter, bitter, cold day.

I will verify the rotor is turning tomorrow. I even thought I left the rotor out, and can't believe I didn't check to see if it had moved. Darn it was cold and dark. Verified plug wires coil connection, TFI plug connected. I know the timing was 8 BTDC before because it was at least running and there wasn't any variation in the timing.

Can you post that link for Ignition diagnostics? I didn't see it in my thread.

Thanks everyone for the suggestions.

 

I never clicked on your link, but it looked like the one I have posted before........Ford Ranger/Bronco II TFI Ignition Diagnostics

Disconnecting the SPOUT is not the same as disconnecting the PCM. There are more connections between the two. You stated you have replaced the PCM before but you may have another bad PCM if unplugging it nets you some spark.

 

Ok RLA, will.check hopefully today. 16 was the high here, and today, maybe 24. Will try to look at it and post back results.

Thanks again.

 

Ok, had another chance to check things again. I checked for battery voltage with key in Run/Start position for PIP IN. 11.5 vlt.
Checked coil for battery voltage, good.
Checked to see if rotor was turning, Good.
No Spark. Bad.

I then unplugged PCM, no Spark. I checked for PIP OUT for AC voltage, getting .30-.10. I unplugged ICM, only get .10 volts AC. It's worst when unplugging ICM. Only other thought I have is that the new Stator is bad.

Pulled distributor out, got gear off, gonna have to wait till tomorrow to swap it out for another new one.