S197 BackInBlack Build Thread Profile - S197 Mustangs

[steveespo]

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.

The crack on the manifold looked like a cobweb, that is how fine it was, visible on the rear driver side runner. I patched it with superglue, and then overcoated it with RTV. Next log I sent Shaun the fuel trims were 0%. An exhaust leak ahead of the O2 would allow oxygen from the outside air to fool the sensor into detecting a lean condition and add fuel. I would bet on the intake side at 12%.

 

[BackInBlack]

The crack on the manifold looked like a cobweb, that is how fine it was, visible on the rear driver side runner. I patched it with superglue, and then overcoated it with RTV. Next log I sent Shaun the fuel trims were 0%. An exhaust leak ahead of the O2 would allow oxygen from the outside air to fool the sensor into detecting a lean condition and add fuel. I would bet on the intake side at 12%.

Thanks. I'll make sure we smoke the manifold!

 

[steveespo]

Thanks. I'll make sure we smoke the manifold!

The reason I believe it is on the intake side is because of the 12% fuel add. Exhaust unless the leak is close to the O2 sensor or is a large crack would not be that high. The vacuum draw is much higher on the intake side and would pull in more unmetered oxygen.

 

[BackInBlack]

Was doing some reading and some thinking. If it's a vacuum leak, I'll have high trims at idle but it won't matter much when the throttle body is open, right? If I had an exhaust leak, what would the behavior be? More pulses would be happening and more gasses would be flowing at open throttle and so the leak would get bigger at higher rpms, yes? But then again, the heat may cause expansion that would make the leak smaller...

I only have high trims at idle. It levels out at open throttle. So it seems maybe you're right about the intake manifold?

Gonna think about this a little more. Thankfully Boss manifolds are cheap. It might be easiest to just throw a new one on there. Hopefully I can transfer the original Boss numbering plate over...

The thing is, occasionally I could swear I see the tiniest puffs of smoke coming out from the exhaust manifold area. It doesn't happen often. If I put my face down there I can breathe just fine, but there's definitely an odor. Course, that doesn't seem too unusual.

 

[steveespo]

Was doing some reading and some thinking. If it's a vacuum leak, I'll have high trims at idle but it won't matter much when the throttle body is open, right? If I had an exhaust leak, what would the behavior be? More pulses would be happening and more gasses would be flowing at open throttle and so the leak would get bigger at higher rpms, yes? But then again, the heat may cause expansion that would make the leak smaller...

I only have high trims at idle. It levels out at open throttle. So it seems maybe you're right about the intake manifold?

Gonna think about this a little more. Thankfully Boss manifolds are cheap. It might be easiest to just throw a new one on there. Hopefully I can transfer the original Boss numbering plate over...

The thing is, occasionally I could swear I see the tiniest puffs of smoke coming out from the exhaust manifold area. It doesn't happen often. If I put my face down there I can breathe just fine, but there's definitely an odor. Course, that doesn't seem too unusual.

Well here is the real potential problem with vacuum leak. As you note the trims chase at idle and part throttle. At wide open throttle the car ignores the O2 sensors and goes off of the MAF and torque source data. So if extra air is bleeding in, then the car will adjust to the torque but the MAF info is wrong, and the car will go lean exactly when you don't want it to. High load/high RPM. Try and get smoke in there. Just take the CAI hose off, block the throttle blade open, tape off the TB opening and pump some smoke in with a barb fitting on the hose. You will see it wherever it is coming from. Good luck, gremlins are a pain.

 

[BackInBlack]

The pain continues. So I thought if I need to smoke the manifold, my options are A. take it to the mechanic and pay another $200. B. Buy my own smoke machine and hope the results are good. C. Take off the manifold again and smoke it with cigarette smoke and/or fill it with water. I decided to do C. But I figured if I've gotta take it off again I'd rather just replace the damn thing and be sure. Replacing costs about the same as the other options anyway. So, I got a new Boss intake manifold. Swapped it out with the old one. In the process I smoked the old one with cigarette smoke. I also filled it with water and held it up at an angle upside down so I could really fill it up. It does hold quite a bit of water. No leaks from what I could tell. The water did wash a lot of the oil out of there so that's good. Said, fudge it and installed the new one anyway just to be sure. End result trims are +9 bank 1, +11 bank 2. Pretty much the same.

FYI, a new FRPP Boss intake manifold comes with new gaskets. So that's nice.

It's gotta be the exhaust manifold, right? I could take it to a local speed shop to be sure. They said they'd diagnose. But it'll be expensive... Or I could just do it. About the only thing else it could be is fuel lines or the engine itself?

Anyone know what is the best type of adhesive to use to transfer over the original Boss manifold plate? I got this: https://www.amazon.com/dp/B0BWYLBF7F but the adhesive under the plate looks like something different. Almost looks like 3M spray glue. It's got foamy bubbles in it. Really sticky stuff. Tried WD-40 and alcohol but nothing is removing it better than my fingernail.

Also. Used Boss 302 intake manifold for sale

 

[mwjscn]

Almost looks like 3M spray glue. It's got foamy bubbles in it. Really sticky stuff. Tried WD-40 and alcohol but nothing is removing it better than my fingernail.

Try GooGone, usually is good at taking off old adhesive if you let it sit for a bit.

 

[BackInBlack]

Try GooGone, usually is good at taking off old adhesive if you let it sit for a bit.

Funny, this stuff usually doesn't work well for me. After trying WD-40, alcohol and some good scrubbing, I tried the GooGone as you suggested and let it sit. It is helping!

I'll go ahead and try that adhesive I bought. I found a guy that was selling custom Boss manifold plates and that's what he was using to stick them on so it should work... Hopefully it doesn't fall out onto the road while I'm driving!

BTW - if anyone needs a replacement for their airbox mounting grommet, this worked well for me: 5S4Z17C431AB

 

[BackInBlack]

I think I might try the local stealership. The car is kinda stock after all. At least if they can't diagnose it, it'll be interesting seeing their reaction to it. If they can't do it I'll go to my local speed shop. Also haven't tried them yet...

 

[BackInBlack]

Slight progress today. Was able to rule out a vacuum leak entirely... I think. The last possibility left on the intake side would have been a leak somewhere in the brake booster vacuum system. Today I took off the brake booster vacuum tube and blocked the port that it connects to (thanks for the tip @JDmustang82). I did a nice long idle data log and trims increased a couple of points. So brake booster and friends are fine. That leaves one realistic possibility I think. The thing I thought it was from the very beginning, but my mechanics said was fine. Exhaust manifold. Still, I've wasted so much effort on this... I might go ahead and see if Ford can diagnose it anyway. Who knows, maybe they'll say everything's fine like everybody else.

So I'm back to what to put on. Will probably go stock or shorty headers. I think I'd rather stay stock at this point, but I'd like to get a hold of a new exhaust manifold set if I can... If I can't, maybe I'll do the Hooker Blackheart shorties.

 

[stevbd]

If I recall you cleaned the throttle body, but did you ever replace it? If the throttle body isn’t opening or closing exactly as called for, wouldn’t that cause problems with the AFR and resulting fuel trim?

 

[BackInBlack]

If I recall you cleaned the throttle body, but did you ever replace it? If the throttle body isn’t opening or closing exactly as called for, wouldn’t that cause problems with the AFR and resulting fuel trim?

Yeah, it does seem like a possibility but it seems strange that it'd function somewhat properly but be misaligned somehow... I'll put it back on my hitlist, thanks.

• Cracked intake tube (replaced, trims improved slightly)
• Dirty throttle body (cleaned. wasn't that bad)
• Bad throttle body gasket (replaced, but the old one was fine)
• Old fuel pump (had 175k miles on it, but it wasn't the issue)
• Bank 2 forward O2 sensor (replaced, resulted in no change)
• Dirty injectors (replaced, trims improved slightly)
• Old ignition coils (replaced, resulted in no change)
• Malfunctioning MAF sensor (replaced, resulted in no change)
• Crack in the intake manifold (replaced, resulted in no change)
• Bad intake manifold gasket (replaced, resulted in no change)
• Vacuum leak in the brake booster system (tested. no issue found)
• Leak at the exhaust manifold sucking in air creating a false lean condition (2 mechanics say not the issue after visual inspection, but I'm not so sure)
• Something wrong with the throttle body?
• Bank 1 forward O2 sensor
• The ECU was not programmed correctly (unlikely, SCT canned Boss tune has same fuel trim problems)
• Wiring/electrical problem
• Obstruction in the fuel lines
• Something weird is going on in the engine

I'm taking it in to a stealership on Monday. I've never taken this car there - as a Boss 302 anyway, so we'll see if they have any luck with it.

 

[BackInBlack]

Just for poops I'll put the stock intake tube I bought recently on there along with a Motorcraft air filter. Just in case anyone at the stealership decides to blame my trims on aftermarket stuff. Will re-datalog, but I don't expect anything except a slight drop in air flow. Might remove the foam Boss coil covers too. When I pulled the manifold I found a pair of nuts (yep) sitting on top of the cylinder head. Fortunately I was able to figure out that they were the nylon lock nuts that hold down the foam coil covers. They're pretty easy to lose to the void if you're not careful removing them. I found that using a magnet-on-a-stick to spin them off of the last thread works well. One of the nuts is still missing. Working on finding a replacement. Been test fitting on the old manifold. So far, I can only say that they're bigger than 1/4".

 

[EF1]

Just for poops I'll put the stock intake tube I bought recently on there along with a Motorcraft air filter. Just in case anyone at the stealership decides to blame my trims on aftermarket stuff. Will re-datalog, but I don't expect anything except a slight drop in air flow. Might remove the foam Boss coil covers too. When I pulled the manifold I found a pair of nuts (yep) sitting on top of the cylinder head. Fortunately I was able to figure out that they were the nylon lock nuts that hold down the foam coil covers. They're pretty easy to lose to the void if you're not careful removing them. I found that using a magnet-on-a-stick to spin them off of the last thread works well. One of the nuts is still missing. Working on finding a replacement. Been test fitting on the old manifold. So far, I can only say that they're bigger than 1/4".

Try m8

 

[BackInBlack]

Try m8

Haha thanks! Will do.

 

[BackInBlack]

Stupid nuts! I bought every nylon lock nut at the hardware store and none of them fit. Since this part only comes from FRPP I figured Ford wouldn't have the nuts. I thought I could check the catalog for the nuts that hold down the hoses underneath which are a different type but fit the same stud... and what the f do ya know, they do have the nylon lock nut. Part number W520201S440. Apparently it's used for other stuff too. Figures. The catalog says that the stud is an M6. But the M6 nut I bought at the hardware store doesn't fit. Must be a weird thread pitch I guess? Also, the Ford one takes a 10mm socket whereas the hardware store one was smaller.

Now what am I gonna do with all these nuts!

 

[BackInBlack]

Got the Boss manifold plate transferred. I was able to get the old glue off mostly with 3M adhesive remover. Goo Gone and a nylon brush helped. I used 3M 300LSE double-sided tape plus 3M adhesive promoter to attach the plate to the new manifold. Stuff was pretty sticky and with the adhesive promoter it seems to be holding well. The original tape had some kind of foam in it b/c the plate is not entirely flat. When I removed the plate it separated the foam from the adhesive. It was pretty easy to remove b/c the foam was old and dried out so, in some ways using a foamless tape is probably a fair compromise as long as it holds. The adhesive on the 300LSE has a rubber cement consistency so it does have a little give.

When I removed the Airaid intake tube and put the stock tube I bought back on, I didn't expect any performance difference but I thought maybe things would sound different. I didn't notice any difference at all. I did a data log before and after and all I can say is the MAF sensor flowed an average of 2 lb/min higher with the stock tube... who knows though, could be environmental factors. The Airaid does look nicer. I threw a paper filter in there while I was at it. JIK the dealership is looking for excuses. Also, I noticed a bit of Texas dust in the old tube. Maybe it's best to run cleaner for the time being while I get everything in order.

Car is at the stealership right now. They said they gave it to their ASE master tech to diagnose so... hopefully they can figure it out. In the meantime, my wife who does like the car, says she is annoyed by the vibration of the shifter which I know is caused by the Blowfish bracket. So... I'll be removing that soon and we'll see how the MGW gen 1 shifter does without the Blowfish bracket. Will probably end up selling the Blowfish bracket on here if anyone is interested, but will want to do some testing first. Shifting with this setup is perfect, but the downside is that the shifter rattles. Not long ago I put some Dynamat on the shifter bracket. Before I did, the vibration came from the center console area b/c the shifter bracket would vibrate against the studs under the car.

 

[BackInBlack]

Just got the car back. It took the Ford stealership 2 weeks to decide that they didn't want to touch the car b/c of the VIN on the chassis. I talked to them in detail about this in advance before I even took the car there to make sure that they wouldn't do this and they assured me that they were okay with it. Service advisor said they didn't touch the car, but I can tell that they checked the coolant and filled the wiper fluid. I was told that they did not perform the standard multipoint inspection either. They ran the car down half a tank of gas idling. Either way, my guess is they couldn't figure it out anyway. I inspected the car afterwards and didn't see any screwups. Fuel trims haven't changed so it seems I'm at least no worse for wear. That will be the first and the last time I go to a Ford dealership.

To the local speed shop I go. They have a long queue so it'll take me over a month to get in. Meanwhile, I'll do some other stuff. Will try removing the Blowfish bracket and will change the diff fluid...

 

[302BOB]

BnB, it sounds like you got your hands full trying to solve the mysteries of your ride............best of luck!!!!

 

[BackInBlack]

Did the diff fluid today. That was way more work than I expected... Maybe worth paying to have it done! Couldn't remove the diff cover without removing panhard bar, and the passenger side panhard flag nut was on backwards so I had to remove the sway bar links too. Was on a flat lift, so torqueing everything was difficult, but got it done! Not too much shavings, everything looked good. So now I don't need to do that again for a long time! Didn't have enough time to get anything else done. I'll have to do the other stuff next time.

I bought a Valvoline hand pump for the diff fluid but the cap didn't fit the Motorcraft quart bottles. It worked, I had to hold it in place though. Stock Boss rear end with Torsen, took less than 2.5 quarts until it started spilling out the back. I did put the friction modifier in there though, so altogether probably around 2.3 quarts. So 3 quarts is what I need for next time. I think the volume of the big Torsen diff reduces this number a little.

Anyone know a hand pump for gear oil that'll fit regular quart sized oil bottles?