Rough Running - Thinking it's something simple...

[Flapjack]

Rough Running - NOT something simple...

I'm posting here because my engine is closer to the 4.6L 3v than the GT500 engine...

I've been driving the Mustang pretty much daily now for the past few months. I've had no problems, other than the minor E85 tuning issues, which I've long since resolved.

I was driving the car home today after taking the kids out to eat when it inexplicably shut off. The CEL and battery lights were on (no code, just indicating the engine was off), so I put it back in gear and let the tranny start the car back up (was coasting downhill in neutral when it happened).

The first thing I noticed was how low vacuum was even in gear decelerating. It was -10. Normally, vacuum on decel is a reliable, set you watch by it, -18. When I got to the stop light, and put it in neutral, the engine was running really rough... loping and AFRs were in the 17s. Vacuum was a piddly -2. I quickly plugged in the tuner while the light was red, but there were no codes.

Luckily, I was less than a mile from home. As long as I kept the gas up, the car ran ok enough. Without gas pedal, the power brakes weren't working (incredible brake pressure to keep the car from driving into the garage door.

I let the car cool down for 10 minutes and checked the codes again. Nothing. I started it back up and let it idle.... same -2. It would rev fine if I gave it gas, but otherwise ran like shit.

The first thing I did was check all the connectors. At one point, I had a spark plug coil harness pop off, but the car ran rich, not lean, because of it. They were all on tight. Next, I checked each and every vacuum hose to see if one had popped off. They were all in place. I even checked inside the cab near the fuse box where I have my boost/vacuum gauge sender installed. That was fine too (I did not check the hole in the firewall behind the wheel guard and battery, but I did pull the hose both ways to make sure it was still connected. It was, and moved back and forth without issue.

Finally, I checked the temperature using an infrared heat gun with laser site. 2 out of 4 headers on each side of the engine (no pattern) were around 250-275F while the other two were around 400-450F. Again, no real pattern. Here are the temp numbers for the cylinders:

1: 265F
2: 400F
3: 275F
4: 260F
5: 400F
6: 400F
7: 265F
8: 255F

The firing order for this engine is: 1, 3, 7, 2, 6, 5, 4, 8. I don't see any pattern, as there shouldn't be, as each cylinder has it's own coil-on-plug.

So basically, 5 out of 8 cylinders aren't firing correctly and I can't figure out why. Even if they weren't, would this affect vacuum so significantly??

Here's a video of the engine running:
http://www.youtube.com/watch?v=n7hpdpjuYjQ (sorry about the wind... it's insane today)

Not sure what the knocking is. I've been told it's normal. VCT is not only disabled in the tune, but also physically locked out with a set of Livernois lockouts.

I'm certain one of the first ideas people would throw out would timing off due to bad tensioners causing the chain to jump a tooth, but I highly doubt that. One, the temperature (due to different AFR due to different compression) should be the same across that entire bank. 2) The tensioners were changed out when I rebuilt the engine.

Again, it's also running lean. AFR at idle is in the 17s (was ~14.6 with fuel trims +/- 5%). AFR at WOT is in the 13s where before it was at 11.5.

I'm out of ideas on this one. When the engine has cooled down completely, I might do a compression test... though I highly doubt 5 out of 8 cylinders detonated. Especially running E85 with no extra timing.

 

[BruceH]

You said you checked all the vacuum lines but how about the one for the brake booster? I had it come off once and my car ran like you describe. Took awhile to figure it out because it looked like it was hooked up and I only found it by feeling.

 

[1fast05]

Rough running

My 05 while cruising down the road just died the same as yours and ran bad also but it ended up being the alternator, It sure does sound like a vacuum leak though, but you checked already

 

[Flapjack]

My 05 while cruising down the road just died the same as yours and ran bad also but it ended up being the alternator, It sure does sound like a vacuum leak though, but you checked already

What kind of troubleshooting did you do? How could the alternator cause different AFRs in each cylinder? Not enough voltage for the spark plugs?? The three cylinders that run correctly are closest to the alternator (2, 5 and 6). Not sure if that means anything, as the alternator runs to the battery...

You'd think the alternator would throw a code, right? It's controlled by the PCM on newer Mustangs. I've had a miswired alternator throw a code before as well.

 

[1fast05]

Rough running

Not sure! I was just relaying an experience i had, and it actually didn't throw a code at all, It just died and wouldn't crank back up, so i got a jump and drove it home with it running like it had a blown head gasket, got up the next morning and the battery was dead, the alternator was shorting out, with out being there its hard for me to try and give even a half ass diagnosis, sorry about that, like you said" it's probably something really simple"

 

[Flapjack]

Not sure! I was just relaying an experience i had, and it actually didn't throw a code at all, It just died and wouldn't crank back up, so i got a jump and drove it home with it running like it had a blown head gasket, got up the next morning and the battery was dead, the alternator was shorting out, with out being there its hard for me to try and give even a half ass diagnosis, sorry about that, like you said" it's probably something really simple"

I'm actually hoping this is what the problem is. I can think of nothing else that would cause such sporadic issues. I mean, the cylinders are all acting differently...

I checked - to + on the battery and got +14v with the car running. I checked - on battery to the + terminal on alternator itself and also got +14v.

Not sure what else to check. I've definitely heard of these cars having alternator problems, though.

 

[Miracle]

Like you mentioned man, the only thing I would check out, is all your vacuum connections again, and do a compression and leak down check. If it's not in the tune, that would seem like the only 3 things it could be, based off of my knowledge. Pull your plugs too, see what they look like, it may help, it may not.

 

[Flapjack]

Like you mentioned man, the only thing I would check out, is all your vacuum connections again, and do a compression and leak down check. If it's not in the tune, that would seem like the only 3 things it could be, based off of my knowledge. Pull your plugs too, see what they look like, it may help, it may not.

Yeah, I'll check the plugs when I do a compression test, but I'm pretty sure this is something simpler. I just have no idea what.

(love your signature, btw)

 

[Miracle]

Yeah, I'll check the plugs when I do a compression test, but I'm pretty sure this is something simpler. I just have no idea what.

(love your signature, btw)

Which part? The quote? It's true, even today.

 

[Flapjack]

Which part? The quote? It's true, even today.

Yes, the quote. I'm so sick of the dismantling of the image of our Founding Fathers...

 

[bigray327]

I think it's your alternator, and the car is load shedding.

Is your A/C working? I noticed it shuts off when the engine is missing. At least mine did.

Just brainstorming, here are things that have caused that kind of thing on my car:

1. Bad coil on plugs, caused by water sitting in there (I have a vented hood).
2. Alternator, already discussed. Mine failed without throwing any codes, ever.
3. Vacuum leak, already discussed.
4. Stupid 2 step system wigging out.
5. Intermittent short (or lack thereof) to the upper radiator support.
6. Bad O2 sensors. Your AFR going wonky suggests this.
7. Bad wideband O2 sensor for your gauge. Your AFR going wonky suggests this.
8. Forgot to hook up that mystery hose going to the air intake... not the PCV system, that's deleted on my car. Boy, it runs like shit without that.

 

[Flapjack]

Excellent reply. Thanks. I'll do my replies inline:

I think it's your alternator, and the car is load shedding.

What in the world is "load shedding". A google search brought up all sorts of garbage. A focused google search on various stang forums (ie: site:modularfords.com) came up with a random PDF on ModFords. Nothing anywhere else.

Is your A/C working? I noticed it shuts off when the engine is missing. At least mine did.

I haven't checked, but I will tomorrow.
Side note: If the engine was missing, there are all sorts of codes for that. Why aren't I getting any of those?

Just brainstorming, here are things that have caused that kind of thing on my car:

1. Bad coil on plugs, caused by water sitting in there (I have a vented hood). I have a cowl hood, but I don't get a single drop of water in from the hood. Plus, it's been drier than a dog biscuit the past few days.
2. Alternator, already discussed. Mine failed without throwing any codes, ever. Is there any way to test this? The little roll-out cart AutoZone has only tests voltage and amperage at idle and with a load on the system. They also have a bench that tests alternators (if I remove it). My old 04 Crown Vic alternator didn't fit, but hopefully this newer Mustang one will.
3. Vacuum leak, already discussed. Unless more than 4-5 bolts simultaneously snapped on the intake flanges, I don't think it's a vacuum leak. :smile:
4. Stupid 2 step system wigging out. What is a step 2 system? I doubt I have this.
5. Intermittent short (or lack thereof) to the upper radiator support. Where exactly are you talking about? I can check this tomorrow. A pic would help greatly.
6. Bad O2 sensors. Your AFR going wonky suggests this. I don't think this is the case. I have two widebands and the AFRs match the fuel trims. When they come in line (~14.6), trims are minimal. When they're in the 17s, trims are outrageous.
7. Bad wideband O2 sensor for your gauge. Your AFR going wonky suggests this. I have two widebands, one for each bank of exhaust (I don't take chances with exhaust leaks and such). Both are reading exactly the same)
8. Forgot to hook up that mystery hose going to the air intake... not the PCV system, that's deleted on my car. Boy, it runs like shit without that. I'm running an aftermarket intake (custom made JPC intake for the 5.4L 3v. I have one tube in the front going for the fuel pressure sensor and the evap canister, then one 3/8" line going to the brake booster, and finally one 3/16" line going to my boost/vacuum gauge. All are intact. As for PCV lines, they're connected snug as a bug. Even tried to pull them off. Nothing.

 

[1fast05]

rough running

Yet again i have another experience to pass on, I bought some octane booster that was on sale at a local parts store at a DEEP discount because it was very old, I used it and it put some kind of coating on my plugs and made 4 out of 8 of my plugs have a miss,but only at under a load and yet no trouble code

 

[Flapjack]

Yet again i have another experience to pass on, I bought some octane booster that was on sale at a local parts store at a DEEP discount because it was very old, I used it and it put some kind of coating on my plugs and made 4 out of 8 of my plugs have a miss,but only at under a load and yet no trouble code

Thanks for the input, but that's not it. I figured out what's wrong... but I need to collect myself before I post.

 

[firestang70]

Crap Chris what has happened now??? Man you have had more patience with your car then I could ever muster.

 

[1fast05]

rough running

Is it a "DOH" or a "UGH" moment:furious

 

[Flapjack]

Is it a "DOH" or a "UGH" moment:furious

Bad as in FURIOUS bad. My guess is that the main cap and bearing came off of cylinder #8 and the rod is just hanging there. I'm getting ZERO compression in cylinder #8. The rest are fine. No engine noise... just runs rough. I could probably tell for sure by holding a screwdriver in the sparkplug hole and manually turning the crank, but to be honest... I'm too pissed to work on it anymore.

What pisses me off even more is that MMR told me the local engine builder I originally used overtorqued the main cap bolts and the entire crank was heated and warped as a result. They charged me for a new crank, polishing/balancing of said crank, new bearings, etc... they didn't charge me for the labor, though, since they already had to replace the two pistons their shitty heads blew up.

 

[Fallenauthority]

I doubt that the rod and rod cap seperated and its just dangling there. That would make for a hellacious scenario to which I would imagine would have thrown the piston into the head/valves, rod cap all up into the crank and other rods. You might want to do some further investigating.
Take a breather then go back with a screwdriver into the cylinder and hand rotate it like you said and see what happens. How did the plug look from that cylinder?

 

[bigray327]

What pisses me off even more is that MMR told me the local engine builder I originally used overtorqued the main cap bolts and the entire crank was heated and warped as a result. They charged me for a new crank, polishing/balancing of said crank, new bearings, etc... they didn't charge me for the labor, though, since they already had to replace the two pistons their shitty heads blew up.

Oh boy, this won't end well. This forum hates MMR.

 

[Flapjack]

A lot of people have been PM'ing me, emailing, even calling to see what's wrong. I appreciate everyone's concern.

It appears that the third time WAS NOT a charm and that my MMR-built engine has failed yet a third time. I suspect heads and that the lower half is for the most-part intact.

The engine will be going to JPC Racing for a complete breakdown, assembly check (per Ford Racing guidelines), diagnosis of failure, and a comparison of what MMR told me would be done (including parts used) with the engine vs what was actually done. Once I have that report, I will know what needs to be done.

MMR also accused my local engine builder (who has been building Ford motors for longer than I've been alive) of using incorrect torque specs and building the engine incorrectly. This is despite them admitting the engine failed due to faulty valves.

I am hesitant to discuss more, because I'm am strongly considering legal action. I have an incredible attorney here in Colorado who has associates who will work via proxy in the California area. I have a serious mountain of evidence via email, several ex-employees willing to testify against the company, as well the few phone conversations I got MMR to agree to allow me to record (California is a two-party consent state for recording).

I am even considering a class-action lawsuit, as MMR is a corporation, and since engine failure #1, I have received numerous support PMs, posts and emails. If you are interested in joining such a potential effort, please PM me so we can decide whether or not this is worth pursuing.

Regardless of what happens, I WILL NOT be sending the engine to MMR so they can snowball me again. JPC will be building an engine that will not be patchwork, haphazard, shortcutted, etc.... They will use new heads (definitely) and new block (if needed).

Thanks for everyone's support. I will know more later. I am not even going to touch the engine. It's going to come out and ship out to JPC on Tuesday. They should have the entire thing rebuilt in 3-4 weeks (vs 5-6 months at MMR).