Running lean and detonation

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Kong76

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I've seen threads on intake manifold cracks at this forum. Some get them seriously cracked to the point of getting CELs, but some say they got mild symptoms long before things got worse.

Is there a way to know if your IM is sucking some air?

I might be paranoid, but I think mine might have some mild air leak. And this would explain fuel beeing too lean and detonation.
I used propane and a tube to shoot gas around the base the best I could while the car was idling. No change in rpms. Not a full proof method. I am probably going to need a smoke test done to be sure.

The dealership did pull the intake manifold a year back to check the runners due to the tick. They ended up replacing timing chain tensioners . I wouldn't be surprised it didnt go back on right... maybe pinched gasket or like you said small crack.

I am wanting to try everything before taking kit off. If I take it off and everything is fine, I will not put it back on.

 

accel

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I used propane and a tube to shoot gas around the base the best I could while the car was idling. No change in rpms. Not a full proof method. I am probably going to need a smoke test done to be sure.

The dealership did pull the intake manifold a year back to check the runners due to the tick. They ended up replacing timing chain tensioners . I wouldn't be surprised it didnt go back on right... maybe pinched gasket or like you said small crack.

I am wanting to try everything before taking kit off. If I take it off and everything is fine, I will not put it back on.
Hm... interesting approach with propane. Smoke test - do you mean smog test ? Would it show that there's manifold leak for sure?
 
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Hm... interesting approach with propane. Smoke test - do you mean smog test ? Would it show that there's manifold leak for sure?
Its a smoke machine that will use a vacuum line or another outlet to check for leaks. If the intake manifold is cracked or leaking the smoke will show where.

I would need to block the intake somehow.
 

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My gen 2 showed 5 to 7% lean fuel trims pretty much across the board with the pp2.

Do you have something that will log to a csv file?

I'd consider it normal. The car isn't lean on actual air/fuel ratio though. It's in closed loop from idle to wot at redline and adjusts to hit its target. The amount of trim control is rather large. Have had -30% and unable to tell from driving.

Fuel pressure is inferred, no sensor unfortunately.

Great explanation of ltft storage here and why you'll see different ltft in different airflow "blocks" yet stft can completely nullify the ltft. https://www.mustang6g.com/forums/th...ing-after-reflash-how-long.92063/post-2028500

Also its best to add ltft+stft for each bank to see actual fuel trim. Some areas will zero out with +5stft and -5ltft.

Ethanol content in the fuel will swing the trims too as the tune assumes e10 but pump can vary. Ford uses 14.08 as the stoich of e10. I've read others accept e10 as 14.13 or some variance.

Did the tensioner fix your tick?
 
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My gen 2 showed 5 to 7% lean fuel trims pretty much across the board with the pp2.

Do you have something that will log to a csv file?

I'd consider it normal. The car isn't lean on actual air/fuel ratio though. It's in closed loop from idle to wot at redline and adjusts to hit its target. The amount of trim control is rather large. Have had -30% and unable to tell from driving.

Fuel pressure is inferred, no sensor unfortunately.

Great explanation of ltft storage here and why you'll see different ltft in different airflow "blocks" yet stft can completely nullify the ltft. https://www.mustang6g.com/forums/th...ing-after-reflash-how-long.92063/post-2028500

Also its best to add ltft+stft for each bank to see actual fuel trim. Some areas will zero out with +5stft and -5ltft.

Ethanol content in the fuel will swing the trims too as the tune assumes e10 but pump can vary. Ford uses 14.08 as the stoich of e10. I've read others accept e10 as 14.13 or some variance.

Did the tensioner fix your tick?

No I don't have a way to log to a csv file. Under acceleration in closed loop my stft and ltft add to be +11. Ltft being 9ish and stft being 1-2. At idle it appears to be around +3 combined which is good.

My concern is when I go wot and the digital afr gauge in the car only drops to 13.7. That seems to me the car isnt getting enough fuel ( lean) or too much unmetered air. As mentioned on the stock tune the car would dip to 11.8-12.3 under wot. If I had a true vacuum leak i would imagine my stock afr on wot would not drop that low as well.

The tensioners did not fix the ticking unfortunately. Its slowly getting worse. Before it would go away after 1500 miles on new oil. Now it stays the entire time.

Ceratec helped quiet it down.
 


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Yes, I mean if you have an issue with fuel pressure, you'd feel it while on OEM tune as well.

So far everyone who rolls back gets rid of detonation and feels just fine on standard tune.

I personally went pp2, got detonation for weeks and rolled back to oem as I was planning some hpde event and did not want to take any risks.

Once back on stock tune - not a single issue.

Then I tried to reinstall pp2 again, was very thorough during reinstall to follow each and every step. Back to detonation. I drove like that for a while and rolled back to oem again since pinging was not going anywhere.

I still think I need to give it another try and this time be very throrough as far as air leaks are concerned.
This is what I was alluding to. You have at least some anecdotal evidence that the tune is the cause for the detonation.
 

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No I don't have a way to log to a csv file. Under acceleration in closed loop my stft and ltft add to be +11. Ltft being 9ish and stft being 1-2. At idle it appears to be around +3 combined which is good.

My concern is when I go wot and the digital afr gauge in the car only drops to 13.7. That seems to me the car isnt getting enough fuel ( lean) or too much unmetered air. As mentioned on the stock tune the car would dip to 11.8-12.3 under wot. If I had a true vacuum leak i would imagine my stock afr on wot would not drop that low as well.

The tensioners did not fix the ticking unfortunately. Its slowly getting worse. Before it would go away after 1500 miles on new oil. Now it stays the entire time.

Ceratec helped quiet it down.
That is leaner reading. Pp2 doesn't change the commanded wot lamda and dash should read like stock. it stays at 13.7 for the whole pull with your foot on the floor? fuel trims will swing heavier under transient accel/deccel, this is normal. Its steady state throttle we are interested in, usually 1-2seconds after you first increase/decrease the pedal. the car wont enter wot fueling until 90% pedal input either.

Do you have the in dash vacuum gauge? It read normal at idle , 20 ish inhg? If it went back to normal on the dash when stock tb and tune were last on I'd prob focus on Tb and adapter and fittings on intake tube. but id have expected your propane test to reveal any vac leaks, especially at idle where vac is highest. did you notice if idle fuel trims were impacted by the propane at all? no harm in continuing to verify no leaks if you already have the equipment.

the procal dongle will log with a laptop, if you do, select these parameters. its limited in what pids it will allow access to but at least some of the fueling is there. add TP commanded and MAF Rate to that list too. Idle TP angle should be around 1.2 degrees with 35lb/hr maf. if the mani is leaking, id expect TP angle to be lower.

procal logging.png


that sucks on the tic, mine does it too but ceratec cures it for now.
 

accel

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Its a smoke machine that will use a vacuum line or another outlet to check for leaks. If the intake manifold is cracked or leaking the smoke will show where.

I would need to block the intake somehow.
Interesting.... this smoke machine is interesting idea.
 
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That is leaner reading. Pp2 doesn't change the commanded wot lamda and dash should read like stock. it stays at 13.7 for the whole pull with your foot on the floor? fuel trims will swing heavier under transient accel/deccel, this is normal. Its steady state throttle we are interested in, usually 1-2seconds after you first increase/decrease the pedal. the car wont enter wot fueling until 90% pedal input either.

Do you have the in dash vacuum gauge? It read normal at idle , 20 ish inhg? If it went back to normal on the dash when stock tb and tune were last on I'd prob focus on Tb and adapter and fittings on intake tube. but id have expected your propane test to reveal any vac leaks, especially at idle where vac is highest. did you notice if idle fuel trims were impacted by the propane at all? no harm in continuing to verify no leaks if you already have the equipment.

the procal dongle will log with a laptop, if you do, select these parameters. its limited in what pids it will allow access to but at least some of the fueling is there. add TP commanded and MAF Rate to that list too. Idle TP angle should be around 1.2 degrees with 35lb/hr maf. if the mani is leaking, id expect TP angle to be lower.

procal logging.png


that sucks on the tic, mine does it too but ceratec cures it for now.

Yea it appears the car stays around the 13.7 afr during the entire wot. I will verify again. I have noticed like you mention the afr will drop when coming off throttle and then increase to normal.
At a constant highway speed and throttle input my afr bounces between 13.9 to 14.2. We do have E10 in our gas. That seems normal.

I did not pay attention to the fuel trims while doing the propane test. I was just listening for a change in engine speed. I do have the vacuum gauge and it reads around 19 at idle. Under wot it will drop to 0 and creep to about 3-4. After throttle release it will snap up to 22 which is healthy I believe.

I really appreciate all the advice guys. Be nice to get it running perfect.
 

accel

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At a constant highway speed and throttle input my afr bounces between 13.9 to 14.2.
Stock tune here. My AFR behaves the same - goes back and forth around that range. Maybe just a tad wider - 13.5-14.5.
 
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Stock tune here. My AFR behaves the same - goes back and forth around that range. Maybe just a tad wider - 13.5-14.5.

Yea everything seems to behave as normal except the ltft and the wot afr. I cant recall what my stft and ltft were stock tune.
 

accel

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I would be interested in this. I changed out the plugs a few months ago and no change.
 

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I would be interested in this. I changed out the plugs a few months ago and no change.
I found this https://performanceparts.ford.com/part/M-12029-M52 .

Expensive, but I might do some shoppi g for a better price around and get those.

How difficult will it be to replace coils? I've heard some spark plugs are pita, but would just couls be different? Or, would it be better to replace sparks and coils?
 
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Coils should be really easy. The only plug thats difficult is #4 on the firewall near battery tray. I would pull a front plug and look at itd condition. If its good then just try the coil packs. Just make sure they are the right coil packs. I know half way through 16' build they changed so I have my work cut out.


* looks like those might work for me as its build date 2/24/16 to 2017. My build says 5/8/16.
 
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