Well.... Done! With your help Steve83, telling me that all the R wires are on the same circuit from the PCM and that was the info I needed. Pulled everything out of the way and toar into the harness. Found the harness pouched deep in the cluster at the turn for the dist. box. Had to be a factory Friday thing as the harness was still factory rapped. Glad I did too, turned out that there was three wires damaged. The R for the MAF was rotted right through. While the MAF return and one wire to the IAT had the insulation missing as well. I would load the pics if I had time. Now just to swap out the injectors this week. I'll finnish the thread with how I make out with the P0302 code. Thanks again eveyone.

 

Read these before you wrap it all up.

.

After finding/fixing such an obvious & widespread problem, I'd just clear the codes & drive it before diagnosing any old code. P0302 could have been a symptom of the wiring faults. If it comes back, then diagnose it.

 

Hey thanks for the imput. The P0302 was there before the P0102 showed up. And it's still there now. I looked at the attachments and will follow up checking the ignition system wires soon as the sky closes up again. They don't call it rainforest for nothin. Took the truck to town and the computer set itself to OK mode on the scanner. But soon as I fired it up in town it threw the P0302 code. Reset the PCM and drove home. Scanner read OK again before I got back. Only codes at low RPM's. Will update.

 

The code may appear when the RPM is low, but that's not necessarily when the fault is occurring. The EEC doesn't instantly set KOER codes; it monitors the fault condition over a period of time (which varies by calibration & fault) and only stores the DTC after a particular threshhold has been crossed. So the misfire might have occurred intermittently from the first time it ran after you cleared it, but it could have been too sporadic for the EEC to identify it or recognize it as a real problem. Maybe the miss is slighty worse during open loop after a short heat soak, and it's just enough to meet the criteria for the DTC at that point.

So I'd be looking for things that don't work quite as well during a warm startup, like maybe thin oil coming out of the lifters a little too quickly, or a small gap between the Aluminum intake & iron head at the #2 intake journal being just a little wider when their temperatures are at that crossover point.

 

So I took your suggestion glc and threw in a set of Autolites. After replacing the connectors on the injectors due to some of the plastic retaining clips breaking off, I started to inspect my ignition system again. So I pull my cap & rotor to find my rotor unually burnt on the striker. The cap is OK as far as wear. But the rotor tip looks like slag. So I pull my cap out and find micro filings in a film. Must of mixed with a little moisture to create this very thin paste like coating in the top of the cap. And I can see these micro filings down in the distributor housing. So I fire up the compressor to plow them out but first remove the armature (if thats what it's called) from atop of the distributor shaft. And what I find is that one of the six contacts is bent and has been striking the back side of the PIP as it rotates. Fixed it. So I now have new cap and rotor. But still have my P0302 code.

So If I go back to when I first had a misfire code, What can cause a P0305 and a P0302? With one replacing the other. I did a qhick compression check on #2 and have satisfractory compression. And it's not behaving like a bad valve or colasped lifter. Either of those two issues should remain problem constant and get steadily worse. (been there) So I'm left with electrical, yes? PIP, ICM, or crank sensor? If the crank sensor was faulty wouldn't that mean the EEC wouldn't see the misfire? After reading some threads about misfires inharent to the 4.9, could it be just bad grounding? The PIP doesn't look like it was damaged from the wheel making contact and still has good magnet draw. The issue I'm stuck on is that the code keeps coming up P0302. If the PIP is failing, what are the chances it only misfires on #2? As for the ICM, same question. The constant is cylinder #2. Which keeps me thinking about that darn intake valve. But I had the head off only 10K ago and pulled every valve, cleaned, checked and re-lapped all of them when I replaced the burnt intake on #5. Did a full leak down on all the cylinders and all showed good. One thing I noticed when I peeked into #2 spark plug hole today was a small amount of what looked like a paint run of shalack on the piston. But if I had good spark and an open intake valve I would of had some sort of sign on the injector pintle cap, which looked just fine. So will I need a press to R&R the PIP on this model distributor? And wouldn't it be better to drop the extra $100 and replace the whole distributor? So could an ICM fail for just one cylinder? Does it not send a signal in the same way for all cylinders? Meaning I should have a P0300 rather than a
P0302? Appreciate any input, Thanks.
PS: intake gasket is OK, as is all vacuum lines, tested. And P0305 appeared well after the intake valve was replaced.

 

Semi update,

So I talked with an friend whose a 25+ year mechanic. (doesn't live close) He confirmed what I thought regarding the intake valve. So I noticed that the cap screws looked a bit too close to 8 & 2 oclock. Pulled #1 and checked TDC and rotor. Was a tooth out. Fixed that. Cleared code, but it came back immediately. Will disconnect batt. but don't think it should make any diff. with OBDII system. So again I'm back to "what would throw a P0302 code when everything has been replaced in the circuit but the PIP & the ICM?
plugs
cap
rotor
leads
injector
power to the injector
timing set
Mechanic friend can't see either PIP or ICM throwing P0302 and never any other misfire.
Could the KS be responsible without throwing its own code? I don't know what's worse..... spending money to eliminate the possibilities and not solving the problem? Or not having anything to check and change, yet still coding? PIP.....ICM? hhmmm????? Guess we'll move on to testing these two in depth.

 

How?Yes. A reman dist. has a 90-day or more warranty; a PIP usually has none. My dist came from CarQuest several years ago.

If the vane is damaged, that alone could cause an irregular PIP signal for the cylinders associated with the damaged tab.

 

It had a twist on one corner at its furthest edge from the main plate. So first I grabbed one of my carbide die grinder bits and cleaned up the bur from the inside face. Then holding the vane looking down on it, same as you would if mounted I "carefully" reshaped the tab to match the other five.
Never thought about warranty... Good point!! I was just thinking easy!! and fresh bushings etc. No hassle.
Ya know I was ranting at the neighbours after watching Boston kick butt tonight thinking "P0302... P0302!!!" It has to be related to that darn bent tab! But I never counted the tab position after re-dailing in my distributor. #1 is the skinny tab, right? I just read on one of your attach. that the rotor is a two to one rotation with the crank. But I'm pretty sure it's the opposite. That's what I got out of checking for TDC and re-aligning the distrbutor today. What are the chances that you have a copy of the injector wiring? I took the whole section from the gang connector on, out when I replaced all the injector connectors. And found no problems with it. Thinking I should do a resistance check on #2 from gang connector to main harness. So 5 ohms pretty standard for threshold? So am I on the right track thinking the PIP (rotory vane aside) and ICM are working properly if there is no other misfire codes?

 

You lost me in there...

I think your PIP/vane is FUBAR, and you should begin by replacing the dist. Most injectors are bank-fired, so if the 2&5 injectors are opening at all, the wiring is good. Put your truck's details in a signature so I don't have to go digging back through your posts to find out what year/engine/trans... you're working on.

 

Signature? Do mean garage? I filled in the garage section. 96 F250 XL 4.9L automatic 3 speed. I tryed to upload pics, but it seems as hard as finding a misfire. Do you have to create a photo album first? Tryed following the FAQ section but I just get the URL link box. Distributor... Guess we all can't be in the frieght business. Somebody's gettin rich out there. All this so I can pay $1.35 a litre. OK I feel better now.
Distributor will get off the plane tomorrow so I'll let you all know how I made out.

 

Scroll ~1/2way down this page to "Thread Display Options" and check "Show Signatures" (I check all 3):
https://www.f150online.com/forums/pr...do=editoptions

Edit your sig here:
https://www.f150online.com/forums/pr...=editsignature

 

I have all three checked as well. Guess there was nothing to display. Filled in the sig. box. Can you see me now?

 

Go into your User CP, then Edit Your Details. Go down to Additional Information and fill in the blocks that pertain to your truck that will identify the pertinent details.

 

Update.

Well new distributor is in. Does run smoother, but that peskie P0302 is still with me. Only things left are the ICM and the PCM as far as electronics. I can't see it being the ICM as it doesn't know the difference from one cylinder to the next. I sprayed the intake with electrical cleaner when I vacuum tested all the hoses and checked the bolts. Everything is good on that side of the motor. So the only part that decides what code to throw is the PCM. Has anyone ever had the ICM be the reason the PCM continually throws just one misfire code before? Was just reading the attachment Steve83 included. My ICM is a CCD. Which means it (ICM) requires the spout signal in order the activate the secondary coil signal. So the PCM Doesn't actually tell the engine when to fire? I'm off to find a niod tester and a piece of hose to fit over my propane torch. Reset the PCM by pulling the batt. connection, so far no code again. Talked with a shop that R&R's PCM's. He figures I should double check the intake and injector circuit. So I will. He also said it doesn't sound electronic because it only codes at low RPM. We differ in the opinion that the misfire code is only electrical/electronical. This tech says a low RPM P0302 could be caused by a mechanical issue. Ford service manager says I should save my money rather than pay them to do a scan diagnosis given the year of the OBDll system. Long weekend up here in Canukville so I guess I have time. Not like I have any beer money left anyways. Looking forward to more input. Thank everyone for the help you've offerd till now.

 

The ignition system is independent of the PCM - it'll throw sparks if it has power & the engine is turning, even if the PCM is removed. The SPOUT circuit only adjusts the timing (same as the vacuum & mechanical advance on older systems). '96 injectors are SEFI, so the PCM opens them individually. Check the wiring for #2: R should be hot any time the key is in RUN; W should show hot if the engine is NOT turning, but pulse to ground when the engine spins.

It doesn't take anything special to R&R the EEC - a 10mm & a deep 11mm socket.

I hope you aren't going to put something flammable on the running engine. Use a mechanic's stethoscope or a 3' piece of garden hose to find vacuum leaks.

Yes, there are a LOT of things that can cause a misfire, and the electronics are the least-likely. Have you done a compression test yet? Leakdown? Vacuum? Have you inspected the misfire sensor & the teeth behind the harmonic balancer that it reads?