S197 BackInBlack Build Thread Profile - S197 Mustangs

[BackInBlack]

Loaded canned tune and datalogged to see if maybe something is wrong with what is supposed to be a stock tune on my car. No change. At least my tune is OK. Time to make an appointment with my mechanic. I'll replace the throttle body gasket this weekend but I don't expect any improvements...

 

[BackInBlack]

Replaced throttle body gasket over the weekend. No change in fuel trims. Car goes into the shop on Wednesday. If they can't figure it out I'll start throwing parts at the issue. Here's my suspects list:

1. Fuel pump? I have been hearing a whining noise back there while driving. I thought it was just the differential, but you can also hear/feel sputtering when you release the gas pedal while driving. Also, the fuel pump is one of the carryover parts from the V6 (same part as on the Boss), so at this point it has around 175k miles on it...
2. Dirty Fuel Injectors. Could ignition coils cause this issue?
3. Mode 6 data from my car reveals a rare misfire on cylinder 3. New Motorcraft spark plugs were put in when we built the car.
4. Forward O2 Sensors. I have noticed while logging that the O2 sensor readings cut out from time to time (once every 10 minutes or so and only for a fraction of a second). I see in the wiring manual that both sensors return data through the same wire. Could wiring be an issue?
5. Unmetered air coming in from the intake manifold gasket, or exhaust manifold gasket, etc.
6. I think it unlikely as MAF logs appear within normal parameters, but maybe the MAF sensor?

 

[BackInBlack]

Update: I was right! (Dammit I shoulda done the install myself!) Replacing the old fuel pump lowered my fuel trims by about 10%. Bank 2 is still running about 3 points higher than bank 1. Replacing bank 2 O2 sensor next.

Meanwhile... having my mechanic check the condition of my Trac-Lok clutch plates. If they're bad, it's Torsen time.

 

[BackInBlack]

Bad clutch pack confirmed. Boss 302 Torsen is going IN!

Gonna follow the recipe outlined in this thread:

Torsen Differential Install

Got my hands on New M-4204-MB Torsen Differential and was wondering if you guys have any suggestions for replacing anything else, for maintenance or otherwise, while I'm under there? I do have an Allstar differential breather I plan on installing as well.Yeah, I didn't get that option on my...

trackmustangsonline.com

 

[BackInBlack]

Really looking forward to trying out the new diff. I know it's not a huge change but ... apparently my salvage Boss came with worn out Trac-Lok clutch plates so I've been running an open diff this whole time. I thought my traction was bad in the rain! But I've never had tires this wide before so I thought maybe I had wet traction loss from that!

 

[302BOB]

It's hard to miss what you never had, but when you DO get it back you realize how much you WERE missing.................

 

[BackInBlack]

Wellp ... good news/bad news. I got the car back. Torsen feels great. Rear feels much more planted and my wheels didn't spin after washing my car Mechanic said that the clutch plates had been removed from the original diff! It was just a straight open diff! Why would someone do that other than as a super lazy way to not have to do it properly? Maybe some sleazy dealership did it at some point...

On the fuel trims... apparently my mechanic just isn't that good with computerized stuff. I had the feeling before but, he just wasn't reading things right. He thought the fuel pump fixed the issue when in fact it didn't. I think he was reading the short terms or something... giving him the benefit of the doubt that he wasn't blowing smoke. This is the guy that built most of my car so I trust him. Anyway, new fuel pump + bank 2 O2 sensor didn't make a dent in the trims.

1. Fuel pump? I have been hearing a whining noise back there while driving. I thought it was just the differential, but you can also hear/feel sputtering when you release the gas pedal while driving. Also, the fuel pump is one of the carryover parts from the V6 (same part as on the Boss), so at this point it has around 175k miles on it...
2. Dirty Fuel Injectors. Could ignition coils cause this issue?
3. Mode 6 data from my car reveals a rare misfire on cylinder 3. New Motorcraft spark plugs were put in when we built the car.
4. Forward O2 Sensors. I have noticed while logging that the O2 sensor readings cut out from time to time (once every 10 minutes or so and only for a fraction of a second). I see in the wiring manual that both sensors return data through the same wire. Could wiring be an issue?
5. Unmetered air coming in from the intake manifold gasket, or exhaust manifold gasket, etc.
6. I think it unlikely as MAF logs appear within normal parameters, but maybe the MAF sensor?

On the plus side, the car drives much better. But I've gotta break in the new diff so it'll be a while until I can really experience it fully...

Fuel injectors/ignition coils ho... sigh. Unless anyone has any better ideas!

 

[BackInBlack]

Interesting note: FRPP coil packs have part number BR3E12A375AA whereas Ford sells their coil packs under part number BR3Z12029A.

I could find no references to part number BR3E12A375AA other than that it is often listed as a part number that aftermarket coil packs are compatible with. Searching for BR3E12A375AA at parts.ford.com returns BR3Z12029A.

@mwjscn says that the, 'E' in 'BR3E' stands for, "Engine Engineering"...

 

[mwjscn]

The engineering part number printed or molded onto the parts is never exactly the same as the 'replacement part' number (sometimes even beyond the department code change). It can be frustrating to deal with, but like you found out at least parts.ford.com can recognize the engineering part number and point you to the replacement part number.

 

[BackInBlack]

Gonna try to do injectors and coils this weekend, weather permitting. Never done it before. Hope I don't fack it up! It's gotta be injectors... I'd have to have horrendously bad luck to find that this issue continues and I've gotta start looking at things like fuel lines...

Happy 4th guys.

 

[BackInBlack]

I'm in Texas, and as I'm sure you all know, it's been raining like hell. Spent my 3 day weekend working on the car and sitting in the garage waiting for breaks in the rain (tiny garage, no room for the car). Finally got it done at the last minute. Removed everything down to the engine. Found a couple loose bolts sitting on the engine block. I was actually able to find where they belonged -- they belong to the Boss fuel rail dress-up cover. Was dirty as hell down there. Found a bit of oil outside of the intake manifold gasket. Pretty sure my high fuel trims were causing my engine to eat a significant amount of oil before I installed my catch can as there were more oil stains near the top of the head where it meets the manifold. Cleaned it up best I could. Found camber plates hadn't been torqued properly, so fixed that since I had to remove the strut tower brace. Replaced the intake manifold gaskets... had an, "oh shiz" moment when while cleaning up the manifold gasket area; a wooden q-tip I was using to clean the channels broke in half and fell inside one of the runners. Flipped it over and it didn't come out. Looked inside and couldn't see it. For a minute I wondered whether it had fallen on the wet floor instead and got washed away by the rain. Hadn't planned on removing the throttle body, but when I did, I was able to find the piece inside, way at the back stuck to oil inside of the manifold. Got it out with a coat hanger. Whew! Replaced the fuel injectors, don't know how bad they were, but they were dirty as hell. Replaced the ignition coils, they looked ok but some of the boots were messed up. I tested trims after installing the coils and they made no difference. I'll keep em for spares. Buttoned everything back up, after doing the idle relearn process, and after letting the car get back up to temp, all of my trims stayed at 0.0. Thought I finally got it, but then I turned on the A/C and went for a drive and when I got back, the trims were sitting at about .08. So -- trims down several points, apparently the injectors were causing a problem, but my trims are still too high. Shaun at AED wanted me to get them at .05 or below before he'd tune my car.

So, going after the fuel trims so far I've replaced the fuel pump, one of the O2 sensors, the intake tube, cleaned the throttle body, replaced throttle body gasket, cleaned MAF sensor, replaced intake manifold gaskets, replaced injectors, replaced ignition coils, and my trims are still running high. Trying a new MAF sensor next. If that isn't it, there isn't much left for me to try! All that's left after that is bank 1 O2 sensor (which looks like it reads fine) and the fuel lines themselves... which seems pretty unlikely. Can the passenger side fuel siphon thing go bad? That seems even less likely.

I've been trying to find some MAF graphs for comparison, but the few I've been able to find have varying numbers. At idle my MAF reads an average of about 0.55 lb/min. From what I've been able to gather, this does seem like it is a little high. Could the real problem have been the MAF sensor this whole time? The salvage car had a paper filter in it when we got it, that was way over due to be changed out. Filled with dirt and leaves. I run a K&N drop-in filter. Been using them for a long time. Ran one in my V6 that was still running strong when I sold the engine at 170k miles... I might try a paper filter just to see if less airflow helps.

 

[BackInBlack]

New MAF yielded no change. In fact, yesterday trims were up to 9%. I've taken the car to two different mechanics who said they were sure I didn't have an exhaust leak... They MUST have been wrong. I've come full circle back to exhaust. Will make a plan for it and get it done.

 

[steveespo]

If it is adding fuel you have a vacuum leak. I had a Boss 302 manifold that was new but came with a crack on the runner. Chase down every where there can be an air leak between the MAF and O2 sensors. Smoke machine is helpful.

 

[BackInBlack]

If it is adding fuel you have a vacuum leak. I had a Boss 302 manifold that was new but came with a crack on the runner. Chase down every where there can be an air leak between the MAF and O2 sensors. Smoke machine is helpful.

That makes sense... if it was an exhaust manifold leak it'd be reducing fuel, right?

Intake hose is new... MAF sensor is new. That just leaves the Boss manifold?

Was your crack visible from the outside? I actually had the manifold out last weekend and while I did not do a thorough inspection, I didn't see anything...

Thanks for the assistance. This issue is becoming a money pit.

 

[BackInBlack]

The internet says an exhaust leak before the O2 sensor sucks in air and creates a rich condition.

Maybe I'll get it smoked again. That's how we found the crack in the intake tube.

 

[BackInBlack]

If it is indeed the intake manifold (I don't think it is but who knows) I'll just get a replacement.
I know everyone has a thread like this but... If I have to remove the exhaust manifold, should I install:
A. New old stock OEM exhaust manifold ($500)
Will last longer, and will work right.
B. BBK ceramic coated shorties ($650)
Maybe a little extra performance while I'm in there. Not top quality but should be good enough.
C. New old stock Hooker Blackheart shorties ($550)
They look really nice, but no coating, and I don't want to spend a bunch more to get them coated...

 

[mwjscn]

If you're asking what to do if you found a crack in your exhaust header and have concerns about it becoming a money pit, I'd either weld up what you got or get a replacement set for $100 off Facebook Marketplace. Bunch of people have the stock headers lying around from their own header swap projects.
I personally wouldn't spent money on BBK headers. The construction seems questionable and the 'ceramic' coat appears more like tin foil that flakes off.

 

[stevbd]

@BackInBlack What is your basic drivability problem? Your report of so much oil in and around the intake manifold seems like a clue. I'm not understanding your theory that your fuel trims caused your engine to eat oil? I think I would go back to some basics. Have you done a compression or leak down test? I would also carefully inspect the engine wiring harness, it gets old and worn and can start shorting out causing all sorts of weird problems ask me how I know....

Good luck I'm sorry for your troubles, these kinds of problems are annoying.

 

[BackInBlack]

@BackInBlack What is your basic drivability problem? Your report of so much oil in and around the intake manifold seems like a clue. I'm not understanding your theory that your fuel trims caused your engine to eat oil? I think I would go back to some basics. Have you done a compression or leak down test? I would also carefully inspect the engine wiring harness, it gets old and worn and can start shorting out causing all sorts of weird problems ask me how I know....

Good luck I'm sorry for your troubles, these kinds of problems are annoying.

Hmm -- well to be honest I didn't really think that one through. Fuel trims a bit high and having higher than what I'd expect for oil consumption also (I'm averaging about 3/4 quart every 2500 miles or so). I just figured they would be connected...

 

[BackInBlack]

Made another log today. No, not that kinda log. A data log. Fuel trims back to +12%. Everything I did barely made a dent.

Starting to wonder if this engine is cammed... if not -- it's gotta be an exhaust leak, right?

Found a source for an OEM exhaust manifold removed from crate engines:

Mustang Coyote Exhaust Manifold Set

Where to buy factory 5.0 Coyote Shorty Exhaust manifold set for Mustang and Truck restoration Project. Coyote Engine Swap setup.

tdmotion.com

Not sure if this is a trustworthy site or not...

Anyway I did some thinking and some research and it turns out the stock exhaust manifold is steel. Probably thick steel but that means that underhood temps probably wouldn't change THAT much with a set of steel shorty headers like Hookers or Kooks?

Gotta think on what to do next. Will try another smoke test soon, but my next steps are either, A. Replace exhaust manifold with new gaskets. B. Take the car to a performance shop and spend a wad of cash to see if they can figure it out.

The engine isn't misfiring. The only misfire I've seen was 1 misfire when I did the WOT pull for Shaun. Would a compression test be something I should do? I initially asked my mechanic who built the car to run a compression test on the engine while we built it, but he said it'd be a waste of time as he said the engine runs fine...