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post #1 of 60 Old 05-02-2013, 06:31 AM Thread Starter
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5.0L Engine Swap PCM/Injection question

I am putting a '00 5.0L Explorer engine/trans into an old Volvo and have one more problem . . . the #1 cylinder is not firing. The engine/trans/wiring harness/PCM/etc. are all the original assembly with only 11k miles on it. Good compression, blue spark, replaced plug. Gotta be the injection (?).

Have B+ at the hot side of the injector. See ground operation from the PCM but at very high resistance, 20k ohms. Replaced the injector . . . no change. Tested continuity from the injector connector to the PCM connector pin at 1.7 ohms. Cleaned M/F connectors at PCM.

All this is telling me that the PCM is not working, on this cylinder alone. Is that a reasonable diagnosis?

Any other tests or changes anyone can think of?

Now this gets more complicated. The PCM has a custom tune to disable PATS.

Discussions with several PCM repair/tune folks seems to lead to a replacement and/or reflash. Does that seem like the correct solution?

How do I get from here to there?


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post #2 of 60 Old 05-02-2013, 09:31 AM
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I would swap the injector plugs between cylinders 1 and 2 and see if the problem moves to cylinder 2.

Your harness tests sounds legit so I think your conclusion that it may be the injector driver in the computer is reasonable. However I'd like to see that problem follow the injector plug over to a different cylinder as a sanity check.


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post #3 of 60 Old 05-02-2013, 09:35 AM Thread Starter
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Discussed with the yard that sold me the engine et.al. and they have a similar PCM that they will provide under their 90 day warranty. Its part code extension is PC rather than my PD. My other code is EQE3 and the potential replacement is EQE2 from a '99 Explorer.

Their look-up charts say they will swap. Anyone have an opinion?

By 'injector plug' I assume that you mean the physical connector (?) or put the injector connector #1 on injector #2. Thought the injectors were timed to stroke but maybe they are just timed to RPM.

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post #4 of 60 Old 05-03-2013, 09:06 AM
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Quote:
Originally Posted by TestPoint View Post
Discussed with the yard that sold me the engine et.al. and they have a similar PCM that they will provide under their 90 day warranty. Its part code extension is PC rather than my PD. My other code is EQE3 and the potential replacement is EQE2 from a '99 Explorer.

Their look-up charts say they will swap. Anyone have an opinion?
Worth a shot, won't hurt anything.

Quote:
Originally Posted by TestPoint View Post

By 'injector plug' I assume that you mean the physical connector (?) or put the injector connector #1 on injector #2. Thought the injectors were timed to stroke but maybe they are just timed to RPM.
Yeah literally just unplug the connectors from injectors #1 and #2 and then swap them. See if the issue moves to cylinder #2 or stays with cylinder #1.

I'm assuming the injectors are timed to stroke (sequential) on the explorers but I don't know that for sure. If it is sequential you'd have 8 injector drivers in the computer so maybe the driver for #1 is bad. If it's batch/bank fire I'd think you'd only have 2 drivers in the computer which would kill 4 cylinders if one of them went bad. But you never know, perhaps even on the batch fire computers Ford still used 8 injector drivers and just ran them in sets of 4.

Anyway, even if it is sequential you can 'mess up' the firing order of the injectors and it will still run. You probably won't even be able to tell any difference. It doesn't cause problems like when you screw up the order of the spark.

So the theory here is you have an ecu with 8 injector drivers, and the driver for cylinder #1 is bad. If that's true, you plug the #1 connector to injector #2 (and vice-versa) and the problem will move to cylinder #2. Real easy test to sanity-check the theory.
If the problem stays with the #1 cylinder, something else is wrong. Perhaps the injector itself is bad, in which case physically swapping the injectors would verify or nullify that theory.

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post #5 of 60 Old 05-03-2013, 09:21 AM Thread Starter
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Thanks for the comment!

I picked up a replacement PCM yesterday and will try that first since it doesn't involve taking the TB et.al. off . . . again. If I remember correctly they may well be enough slack to swap the harness connectors. Already replaced the injector with a rebuilt and tested one.
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post #6 of 60 Old 05-03-2013, 07:52 PM Thread Starter
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I installed the new (used) PCM and updated it with a custom tune to disable PATS. The same problem exists.

Going to swap the harness connections between #1 and #2 tomorrow.

Glad this is a hobby. I cannot imagine working on this problem for a living.
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post #7 of 60 Old 05-04-2013, 02:05 AM
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You sure the problem is not the tune? Is your transmission the 4R70W or the 5 speed auto? Is it a returnless style fuel system? Coil packs or on plug? Reason why I ask is that the earlier (1996) explorers with the 5.0L from what I recall did not have the P.A.T.s system, but still has EEC-V with early 4.6 style coil packs and 4R70W transmission. For simplicity's sake I would have chosen that to start with and I would consider using a processor from that as well to test (providing the interface is the same and should be). That said it does sound like you have more of a hardware problem (but an EEC is also that).


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post #8 of 60 Old 05-04-2013, 03:31 AM Thread Starter
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The set up does have the 4R70W and the returnless fuel system with the wasted spark double coils and PATS. The only thing done so far with the tune is to disable PATS. Had I known the difficulty that PATS brought to the party I would have avoided it but to find a 11k mile fully assembled everything was too attractive to pass up.

Converting to the earlier PCM is not practically possible due to the many fuel system differences. It would require replacing the engine and trans harness, them modifying the old harness to the new trans, replacing the fuel rail and the injectors and rewiring and changing the CPS. Other than that, no problem.

The PCM injector driver ground is clearly different from the others. The problem symptom is exactly what you would expect from an ignition problem but a blue spark is clearly there.
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post #9 of 60 Old 05-04-2013, 10:50 AM Thread Starter
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While I could cut the harness open and move #1 back to #2, #2 is never going to move to #1.

Took the C202 (PCM) connector apart and nothing looks out of place. Inspected the injector connector closely and nothing seems wrong. Resistance between the injector connector and the PCM connector is really only about 1.0 ohms since my VOM measures 0.7 ohms on just the test leads.

I am befuddled.

Maybe I will have a flash of adequacy by this afternoon.
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post #10 of 60 Old 05-04-2013, 05:58 PM
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If the problem remained with the other computer it shouldn't be the computer.

Your tests of the harness show it shouldn't be the harness.

If you have a known good injector it shoudln't the injector either.

That leaves air and spark.

You said compression on that cylinder is good so the air should be good.

Spark is fat and blue so it shouldn't be spark.

That covers pretty much everything, you shouldn't have any problems but clearly you do, so one of the items above actually is an issue.

Do you have or can you get ahold of a noid light so that you can verify that the #1 injector is really receiving a signal to fire?

11 Piece Noid Light and IAC Tester Set

Or you can do this with a test light.




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post #11 of 60 Old 05-04-2013, 06:38 PM Thread Starter
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I know it is not getting an 'operate' signal because by comparing the PCM side of the injector connector reading on a VOM to the others. I tested two other injector harness connectors that I can get to with out removing the intake manifold. In 'RUN' all have B+ standing on the 'red' lead. In operation the two others, with the PCM operating the respective injectors, on the PCM side and because of the VOM sample rate reads in the 4-6v range. That is a lot easier to measure than the ground from PCM.

No noid lights.

On cylinder #1 the PCM side simply reads B+ fluctuating a few tenths because of the alternator charge rate.

Further tests this afternoon: the PCM connector pin #75 to the injector measures about 1 ohm . . . absolutely, positively. Hooked a spare spark plug, actually the matching one to the set installed to the spark plug wire and grounded. Hot, blue spark . . . no question.

Cylinder #6, the mate to the wasted spark design coil #1 is firing normally as defined by the temp of the exhaust header.

This issue has taken on mystical characteristics.

Speculation welcome!
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post #12 of 60 Old 05-04-2013, 06:50 PM
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Quote:
Originally Posted by TestPoint View Post
I know it is not getting an 'operate' signal because by comparing the PCM side of the injector connector reading on a VOM to the others. I tested two other injector harness connectors that I can get to with out removing the intake manifold. In 'RUN' all have B+ standing on the 'red' lead. In operation the two others, with the PCM operating the respective injectors, on the PCM side and because of the VOM sample rate reads in the 4-6v range. That is a lot easier to measure than the ground from PCM.

No noid lights.

On cylinder #1 the PCM side simply reads B+ fluctuating a few tenths because of the alternator charge rate.

Further tests this afternoon: the PCM connector pin #75 to the injector measures about 1 ohm . . . absolutely, positively. Hooked a spare spark plug, actually the matching one to the set installed to the spark plug wire and grounded. Hot, blue spark . . . no question.

Cylinder #6, the mate to the wasted spark design coil #1 is firing normally as defined by the temp of the exhaust header.

This issue has taken on mystical characteristics.

Speculation welcome!
Right with a digital meter it's hard to "watch" a pulsewidth. No noid light... how about a lightbulb pigtail and some spare wire?

I'm not 100% sure I'm tracking how you know #1 isn't operating. I think you're saying that you watch for voltage on the injector's ground wire at the PCM side and you're getting a 4-5v read on other known working injectors (normal on a digital meter b/c of the pulse thing) but you aren't seeing that on the #1 injector's ground wire? However you are getting battery voltage on the #1 injectors power wire (red).

Have you looked at the pinout for the computer that you have, and can you confirm that the #1 injector's ground wire is in the correct position in the 60 pin harness for whichever ecu you have?

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post #13 of 60 Old 05-04-2013, 07:00 PM Thread Starter
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#1 is not firing because the header pipe is stone cold while all others are HOT.

All ground for the PCM have been verified.



Appreciate your responses!
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post #14 of 60 Old 05-04-2013, 07:02 PM
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Oh I meant specifically the #1 injector. I thought you were saying you knew for sure the #1 injector wasn't operating.

Another way is with a stethoscope, you can hear it clicking.

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post #15 of 60 Old 05-04-2013, 07:03 PM
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Quote:
Originally Posted by TestPoint View Post
All ground for the PCM have been verified.
I specifically mean the ground for the injector. All the injectors get power from the main relay, the same way the computer does.

The computer provides ground to the injector on it's other wire (not the red wires) to turn the injector on.

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post #16 of 60 Old 05-04-2013, 07:06 PM Thread Starter
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I assume that the injector is not operating because the cylinder is not firing as witnessed by the header temp, because it obviously has spark and the compression has been measured more than once and the cam/valve operation has been observed with the cover off.

As originally noted, I am seeing ground operation from the PCM but at such a high ohm value as to not operate the injector.

I have not tried to manually operate the injector from the PCM connector but can easily.

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post #17 of 60 Old 05-04-2013, 07:13 PM
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I think that's a fair assumption.

For the injector to actually work, all it needs is power and ground. You've verified power, if you give it ground it should click. IMO it doesn't matter but to be extra prudent disconnect the PCM first as it's the only other thing connected to that injector's ground wire, which also makes it every easy to give that injector ground. Turn the key to on and then just jump it's wire at the PCM's connector to ground listen or feel for it to click.

Assuming it works, either you aren't getting fuel through it b/c the injector or the fuel rail right there is somehow clogged, or the computer isn't providing the ground, or the computer's ground signal isn't getting to the injector.

I think clogging is least likely, not providing ground should have been covered by 2 computers but it is possible you have 2 bad computers, that leaves the signal not getting there. You verified the harness and you only have 1 ohm. What's left is that the injector's ground pin isn't lining up with the computers. Maybe the pin is damaged, or it's in the wrong "spot". You'd need to verify which pin on the ECU is the #1 injector pin, and then make sure that the #1 injector wire is actually in the correct place.

Hope that makes sense.

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post #18 of 60 Old 05-04-2013, 07:19 PM
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according to your previous posts it's pin 75 on the harness. Are you 100% sure your ecu model has injector #1 on pin 75 also?

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post #19 of 60 Old 05-04-2013, 07:25 PM Thread Starter
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It does but I think I have done all that except for the manual application of a ground on the 'TAN' lead, circuit 555, PCM connector (C202) pin #75.

The injector has been changed 3 times so I would hope any blockage would have been evident or resolved.

I keep coming back to the fact that the PCM side of the #1 injector connector measures differently from two others.

All this is so strange that I think I need to put it down for a day and wish for divine inspiration or at least a flash of adequacy.

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post #20 of 60 Old 05-04-2013, 07:37 PM
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Quote:
Originally Posted by TestPoint View Post
It does but I think I have done all that except for the manual application of a ground on the 'TAN' lead, circuit 555, PCM connector (C202) pin #75.

The injector has been changed 3 times so I would hope any blockage would have been evident or resolved.

I keep coming back to the fact that the PCM side of the #1 injector connector measures differently from two others.

All this is so strange that I think I need to put it down for a day and wish for divine inspiration or at least a flash of adequacy.
I know this may sound a bit crude, but how about spray some starter fluid (or gasoline, explorer intakes have a Teflon coating on the inside that starter fluid may damage) into the T-body and do a "flood start", see if the tube heats up? It sounds like you have a fuel delivery problem more than anything else. I'm 60% sure that your tune is the problem. I've never had or diagnosed a no-fire or wrong fire injector problem with an EEC car that wasn't PCM related.


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post #21 of 60 Old 05-04-2013, 07:42 PM
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Quote:
Originally Posted by TestPoint View Post
It does but I think I have done all that except for the manual application of a ground on the 'TAN' lead, circuit 555, PCM connector (C202) pin #75.

The injector has been changed 3 times so I would hope any blockage would have been evident or resolved.

I keep coming back to the fact that the PCM side of the #1 injector connector measures differently from two others.

All this is so strange that I think I need to put it down for a day and wish for divine inspiration or at least a flash of adequacy.
Okay cool. Not a crossed wire, nothing blocked.

Can you elaborate on the different measurements? I'm sorry if I missed it already.

I'd really be interested in firing the injector manually from the PCM harness. I understand if you need a break.

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post #22 of 60 Old 05-04-2013, 08:10 PM Thread Starter
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Sorta sure about the pin number:



Measurements taken with a straight pin pushed through the harness wire.

Red lead has B+ on RUN

Harbor Fright VOM measures very high resistance, above 20k ohms, on the pulsating ground from the PCM with the connector off the injector. Measures no change in the B+ voltage against the pulsating ground ie: too much resistance. Two other injectors measure the B+ being dragged down to 4-6v on the PCM side by operation.

The tune was done by a long time Explorer tuner, James Henson, who only disabled PATS so I could get the thing started. He did copy the original 'tune' with the 'strategy' number of the new PCM so both are operating on the same basic software. We discussed this issue and he has never seen a failure affecting only one injector and, as I said, he has been doing this for a long time. Since both PCM's are producing the same result I would think it is not a hardware problem and the software is the same as used for many Explorer tunes.
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post #23 of 60 Old 05-04-2013, 08:14 PM
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How comfortable are you with popping the case off of the computer and ohming out that wire from the PCM to the injector plug, but testing from the motherboard's pad for pin 75 so that we're testing through the PCM/Harness plug?

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post #24 of 60 Old 05-04-2013, 08:22 PM Thread Starter
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Had the cover off but the PCM connector for pin 75 is buried back at the third level of connectors so it would be VERY difficult to get a valid test without great fear of letting the smoke out. These things only work when the smoke is kept under constant internal pressure.

With all power off that could probably be done. That would verify connectivity from the mother board to the injector connector.

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post #25 of 60 Old 05-05-2013, 07:51 AM
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Tom am I correct in understanding that this problem has morphed from too much fuel being injected (#1 rich and backfires from excess fuel in the exhaust system) to not getting any fuel at all into #1? If that summary is correct, just wondering where that might lead in terms of diagnosis....

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post #26 of 60 Old 05-05-2013, 08:11 AM
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Quote:
Originally Posted by TestPoint View Post
Had the cover off but the PCM connector for pin 75 is buried back at the third level of connectors so it would be VERY difficult to get a valid test without great fear of letting the smoke out. These things only work when the smoke is kept under constant internal pressure.

With all power off that could probably be done. That would verify connectivity from the mother board to the injector connector.
Yeah definitely do it with power off. Disconnecting the battery is generally a good idea. A continuity test won't hurt anything even if you do end up bridging 6 pints to reach 75.

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post #27 of 60 Old 05-05-2013, 08:17 AM
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Originally Posted by Michael Yount View Post
Tom am I correct in understanding that this problem has morphed from too much fuel being injected (#1 rich and backfires from excess fuel in the exhaust system) to not getting any fuel at all into #1? If that summary is correct, just wondering where that might lead in terms of diagnosis....
Oh, where'd that info come from?

Single cylinder rich with excessive fuel a lot of times means the injector's ground wire rubbed through the insulation somewhere and is grounding out, leaving the injector wide open. In that instance continuity from the injector plug to PCM plug will still check out fine, but if you test from the wire to ground you'll find continuity that you shouldn't have.

I'd just been assuming in this thread we have no fuel but too much fuel will cause no fire too, and the smell should make it obvious.

Is the spark plug for #1 coming out wet or dry?

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post #28 of 60 Old 05-05-2013, 08:47 AM Thread Starter
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Yeah, earlier trouble shooting and posting off forum indicated that the plug was wet and black and was getting little explosions in the exhaust system. That is why the first thing I did was change out the injector with the thought that it was stuck open. New, freshly bench tested injector did not change the problem.

I am still getting the little backfires. That tells me that the injector is holding open or the cylinder is not firing. BUT . . . I am not getting ground pulses at all like two other cylinders . . . and . . . I am getting blue spark at a plug grounded on the block . . . and . . . the compression is over 200 psi. Cylinder #6, the coil wasted spark twin of #1 is running perfectly. Pulled the valve cover and observed valve operation.

I'll go measure from injector control lead to ground but I think that is going to be 0.0.
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post #29 of 60 Old 05-05-2013, 08:57 AM Thread Starter
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No ground of any resistance on the control lead.

Does this tester operate like a noid light? Buy Equus Innova Test Light / Circuit Tester EPI3410 at Advance Auto Parts

Last edited by TestPoint; 05-05-2013 at 09:00 AM.
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post #30 of 60 Old 05-05-2013, 09:37 AM
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I think you should cut #2 injector harness and 'extend/jumper' it to #1, and plug #1 onto #2 and see if the problem moves. Can't believe the problem is with the PCM software or hardware given that you've tried 2.

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post #31 of 60 Old 05-05-2013, 10:50 AM Thread Starter
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I guess I agree since I can't think of anything else to do or test. That means I get to do another speed test of removing the throttle body and related parts. Guess I should be thankful that the bad cylinder is not under the other side requiring complete removal of the intake manifold.

To summarize:

Swapped plugs - no change - I'll put another one in.
Swapped injectors - no change - I have another fresh bench tested one.
Swapped PCM's - no change - no more spares
Injector control lead - about to change that
Plug wire - no spare but see hot spark
Coil - no spare but wasted spark paired cylinder works fine.
Compression - tested twice but will do it again

Any other suggestions?
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post #32 of 60 Old 05-05-2013, 12:32 PM
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Are you certain you have full fuel flow to that part of the rail -- behind the injector?

Michael Yount - Charlotte, NC - 82 Volvo 242 - 6.2L; '17 Mazda3; '16 CrossTrek
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post #33 of 60 Old 05-05-2013, 01:09 PM Thread Starter
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No, but I will use air to blow out that side from the quick connect connector.

Too much fuel, too little fuel?
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post #34 of 60 Old 05-05-2013, 02:37 PM
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I think I'd also swap a coil pack position with the one that fires this cylinder and see if that changes anything.

Fuel, air, spark at the right time and a bit of compression are required as you clearly know. You've nailed down air and compression. I think you've eliminated the PCM/connection between wiring harness at the PCM and injectors. So, to me, it's got to be wiring harness, connector at the injector or something wrong with the spark/spark timing.

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post #35 of 60 Old 05-05-2013, 03:35 PM Thread Starter
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Afternoon report:

Still has not quit raining. About 6 inches so far.

Pulled the TB off . . . again . . . 8 minutes, 50 seconds. Getting better.

Pulled fuel rail off and removed Schrader valve. Blew air into rail at that point and all injector ports are open with no junk coming out.

Moved the injector harness back so that #1 connector would reach #2. Added about 6" of wire to extend #2 harness connector to the #1 position.

Installed the last of my bench tested and certified injectors into #1.

Did a compression test. With only one plug out with the throttle plate open measures 195 psi, down from 200+ with all plugs out.

Verified blue spark at plug with plug sitting on engine.

Installed a new plug.

Started engine . . . drum roll please . . .

Number 1 cylinder is still not firing. Number 2 cylinder runs fine. Number 1 Exhaust header pipe is still cold while all others are very hot in only a few seconds.

That leaves:

Plug wire - but have blue spark

Coil - but the wasted spark twin runs fine.

I will swap the coil connections but I think I am through for the day.
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