Help! Engine misfire 2000 Mustang 4.6

headers burning through the plug wires?

Check application of injectors/COP

Help me understand the problem. There is absolutely no fire at all on the right side? However, a compression test of all of the right side cylinders is OK. Further, a noid light on the fuel injectors indicate the fuel injectors are firing. Followed by a noid light on the COP indicates the PCM is signaling the COP’s to fire.

If all of the above is true, this is what is left.

1) All of the right side fuel injectors are defective.
2) The right side fuel injectors are the wrong type. Some Ford applications have the polarity reversed (same plug).
3) The right side COP are the wrong type. I seam to recall that some applications have use the same plug but reversed polarity. This would give a good indication on the noid light but would not actually fire.
4) All of the right side COP’s are defective. Check High voltage side for actual spark. The boot is fragile and rough handling can damage.
5) wiring modification has reversed polarity of fuel injectors or COP (not likely).
6) PCM totally mess up timing wise. The tests done check for a signal. However, how do you know it is correctly timed? How does the engine run? Smell fuel?

Anything else changed during the install? Any problems? Where did the parts come from?

The fact the compression tests OK would indicate the motor is basically good mechanically. Unreasonable to think a CAM/valve problem.

If you do not smell fuel, then look at the fuel system. If you smell fuel, look at the ignition.

The lean/rich limit is 25%. After that, the PCM will throw a code. Even at 25% lean, the headers would still be hot.

Regarding the compression test. Was it a leak down test or the kind where the motor is turned over? What were the results?

I have got to believe that if the fuel injectors were working, you would smell fuel.

Can you monitor operational data with your scanner? If so, log the O2 values and compare the two sides.

The PCM has to be throwing codes. What are they?

Check the crossover on the fuel rails. I don't know how/if they come apart but they are rubber but maybe something got stuck in there ... Isn't the test valve on the passenger side? Check your fuel pressure.

be sure you put some dielectric grease in there when you get it clean or it will just corrode again.

Check CAM timing

I have done some additional study of the wiring diagrams. Personally am perplexed by your symptoms. Since you have asked for an educated guess, here goes my attempt to knock this one out of the park.

Refresh and go back over the details. No fire at all from the Right side. Some kick back during starting. Back to the basics. Fuel, Air, Spark, Timing (FAST).

A dynamic compression tests is OK. This would rule out valve and cam issues.

Previous posts state that you do smell fuel. This would indicate the fuel injectors are working.

Cylinders 5-8 are working. In addition, the PCM is communicating with the scanner. IMO, this would rule out anything but a one in a million PCM problem.

We believe that the COP’s are firing. What we don’t know is if they are firing at the correct time.

This gets back to timing. Let’s look at the things that could cause timing to be off on a complete bank. One thing that comes to mind is CAM timing. Since a dynamic compression test is good, we can assume the mechanical timing of the CAM is good.

But what about electrically? What if the CAMs themselves are timed correctly but the CAM gear is not? There is a raised piece on the CAM gear that is used to tell the PCM the position of the CAM (CAM sensor). If this is not in the correct position in relationship to the crank position sensor, it seams like this could cause some real problems.

Who timed this engine after the re-build? Were the recommended procedures followed? Were the correct tools used to hold the CAM and crank shaft when the chains were installed?

If it is NOT the CAM timing, let’s concentrate on the things common to the 1-4 COP’s. Splice S171 (engine, top, Right) supplies power to the Right side COP’s. However, unless something happened to damage the harness, a splice failing is a long shot. However, it is worth investigating.

The next thing common is connector C133. It is a large square connector located engine compartment, right side, rear. Your previous posts stated corrosion in this connector. CLEAN, CLEAN, CLEAN and CLEAN some more. Use electrical cleaner (brake cleaner not recommended). Another option is to use MAF cleaner. Afterwards put some dielectric grease on it.

I have some diagrams that may be of help.

<cutesy quote for the day>
Remember, there is no elevator to success. You have to take the steps.

The cam sensor is on the drivers side bank, cy 5-8 so if 1-4 are cold then the cam can be out of time but the computer won't have a clue. There is a good chance that if the cam is indeed out of time only on the pass side (bank 1) that the valves and pistons have meet.

Op, you need to pull the front cover off and verify visually that the cams are timed. The easiest way to do that is to set the marks at wmburns described above at 10 o'clock and 2 o'clock. (raised bumps on the outside of the cam gears) Once they are at 10 and 2, visually count how many links are on each side of the chain down to the crank sprocket, There should be an equal amount on each side. The crank sprocket has a mark on it to tell you where the middle is. The link that is on the markers on both the cam and crank sprockets don't count when your counting... does that make sense. Someone help me explain this here.... I can do it much easier than explain it.

Sounds like you did ok. Did you reinstall the cam gears or were they factory pre assembled?

Then thats likely not your issue. I'd say you need to do a leak down test.

Could someone help me understand how it is possible for a 4.6 modular motor to have good dynamic compression but fail a leak down test? And further, to have a problem that is so profound that ALL 4 cylinders do not work?

Squeak93 stated in a way that I thought about but did not put on paper. The Right bank is out of time. It is not so much out of time to have PTV contact. But since the cam sensor is on the LEFT side, the PCM is able to adjust enough to allow the left side to function. The PCM ASSUMES that the right is in time.

Further, is 180 degrees hot enough for a set of working headers? IMO the left side is not working as it should. The headers should be hotter.

What if the cam gear has slipped on the cam itself? The OP stated that was not removed during the rebuild. However, this then ASSUMES it was correct in the first place.

Doesn’t the timing procedure start with #1 being TDC and then backing up by 90 degrees?

Does this engine have removable cam gears? If you say “yes”, consider that the 2000 Mustang originally came with a Windsor engine. The Windsor had pressed on cam gears (not removable). This adds credence to the possibility of cam gear slippage.

I also recall reading an article in Engine builder about mixing matching parts from different model year modular engines. The jest of the article stated there were subtitle changes in the crank shaft timing trigger, timing adjusters, and various other parts. The article advised against mixing parts from different model years.

I really feel that something is wrong in the cam timing or how it is put together. Otherwise, there HAS to be an error in one of the other base assumptions (working COP, working fuel injectors, good dynamic compression).

That's it! cam 180 degrees out of sync

Right cam 180 degrees out of sync. Now that makes sense! Mechanical dynamic compression would be ok. Fuel injectors work. COP's work. I was honestly thinking about 1 or 2 notches out of sync. But 180 degrees would explain everything. No PTV contact. But the injectors would fire while the intake valve is closed.

Ok, I didn't hit that one out of the park. If it turns out to be true, do I get credit for a triple? Double?