[jpsimon]

I recently had injectors 1-3 replaced (because #1 died). Since I've had the car back from the dealer I've noticed way more timing dropouts than I've seen before (only under heavy load, it idles perfectly fine/smooth), especially weird since the weather is so great now (low 30's at night). Last spring in much warmer weather my logs looked much better with higher boost.

Could partial misfires due to bad coils be causing this phenomenon, and is it possible partial misfires wouldn't throw a code? I've just recently passed 50k miles, the coils are the original ones (they were not replaced when I had the injectors replaced).

[dzenno]

Unless you get a code it's hard to tell...typically to figure out it's a coil you start swapping them around, changing places from say cyl 1 to 3, and seeing if misfire codes follow the swaps..if they do you know it's your coil..Possible your meth is puddling? I'd check that nozzle, when was the last time you checked it? Mr. 5 recently had similar issues only when on meth...try turning it off

[jpsimon]

Originally Posted by dzenno

Unless you get a code it's hard to tell...typically to figure out it's a coil you start swapping them around, changing places from say cyl 1 to 3, and seeing if misfire codes follow the swaps..if they do you know it's your coil..Possible your meth is puddling? I'd check that nozzle, when was the last time you checked it? Mr. 5 recently had similar issues only when on meth...try turning it off

This is without meth

[enrita]

Yeah you should definetely change coils with 50k. Dont even think about it, just do it and yes that could be the cause.

[jpsimon]

has anyone ordered from this place?

http://www.partsgeek.com/catalog/200...tion_coil.html

[Ilma]

Originally Posted by jpsimon

I recently had injectors 1-3 replaced (because #1 died). Since I've had the car back from the dealer I've noticed way more timing dropouts than I've seen before (only under heavy load, it idles perfectly fine/smooth), especially weird since the weather is so great now (low 30's at night). Last spring in much warmer weather my logs looked much better with higher boost.

Could partial misfires due to bad coils be causing this phenomenon, and is it possible partial misfires wouldn't throw a code? I've just recently passed 50k miles, the coils are the original ones (they were not replaced when I had the injectors replaced).

JP.....I have noticed this also in the last few months.

Seems like my car has been struggling to maintain smooth timing curves consistently.

Some of the logs show perfect timing and then some show dropouts, even though I have not changed any parameters.

To me it seems indicative of an intermittent problem that is manifesting once in a while. If you do enough datalogs you catch it when it happens.

Sounds like that may have happened in your case.

I suspect I have an injector or fuel pump on it's way out, which may give the occasional hiccup and cause a knock event to register.

Right now out of three consecutive datalogs, one of mine will register a timing dip.

For now I have gone back to old school and turned autotune off and am running higher octane and 75% ignition correction simultaneously to see if I can stabilize my timing curve to be consistent.

If not, then I can be pretty certain that a fuel/ignition component is acting up.

[OpenFlash]

JP- I know it's a bit coincidental with your recent work at the dealership but could you also be seeing the effects of the winter gas formulation change? IIRC, they start rolling that in around October.

[jpsimon]

Originally Posted by shiv@vishnu

JP- I know it's a bit coincidental with your recent work at the dealership but could you also be seeing the effects of the winter gas formulation change? IIRC, they start rolling that in around October.

Past winters the logs have been solid, running pretty aggressive settings though. It's hard to compare, but I don't ever remember seeing it like this. I should probably change the coils anyways now that I'm past 50k miles no? It seems like dealers do this whenever they replace the injectors

[OpenFlash]

Originally Posted by jpsimon

Past winters the logs have been solid, running pretty aggressive settings though. It's hard to compare, but I don't ever remember seeing it like this.

Hmm... Then my only guess is that the new injectors weren't calibrated properly by the dealership. When you log wideband AFR, do both banks give nearly identical readings?

[jpsimon]

Originally Posted by shiv@vishnu

Hmm... Then my only guess is that the new injectors weren't calibrated properly by the dealership. When you log wideband AFR, do both banks give nearly identical readings?

How identical are we talking? What would you consider "strange"? For instance on any given pull, one bank is always .5-1 point higher than the other

[OpenFlash]

Originally Posted by jpsimon

How identical are we talking? What would you consider "strange"? For instance on any given pull, one bank is always .5-1 point higher than the other

0.5-1 point is too big of a spread at WOT. They AFR logs should be almost right on top of each other. If one bank is consistently leaner than the other, that would suggest a miscalibration of injectors. Which makes sense since this issue only happened after 1 injector bank was replaced.

[jpsimon]

just emailed you a log

[Quisp]

I am curious how do you monitor the timing? Is it with BT Scan or something else? I am having problems with the idle dropping out like a misfire and when I am acceleratintg i get little hiccups but no codes. Had isfire codes then went to dealership and they cleaned the valcves. Dont get the codes but still have the problems and thought it might havbe to do with the timing.

[jpsimon]

Originally Posted by Quisp

I am curious how do you monitor the timing? Is it with BT Scan or something else? I am having problems with the idle dropping out like a misfire and when I am acceleratintg i get little hiccups but no codes. Had isfire codes then went to dealership and they cleaned the valcves. Dont get the codes but still have the problems and thought it might havbe to do with the timing.

I log timing with the procede software

[marinellie]

JP- when you get a minute e mail me or PM me. I have to ask you something. Thanks.

Medic976@yahoo.com

[335xiRT1]

i am having the same issue right now.
the car drives fine in stock map...
once i put it on a higher boost map it misfires. I got a code for cylinder number five, i swapped the plug and still getting the code.
im at 47k miles original coils.

that site is a good find anyone else order from there??

[Quisp]

I do not have procede so i cant do it that way,but thank you for responding.

[jpsimon]

Originally Posted by 335xiRT1

i am having the same issue right now.
the car drives fine in stock map...
once i put it on a higher boost map it misfires. I got a code for cylinder number five, i swapped the plug and still getting the code.
im at 47k miles original coils.

that site is a good find anyone else order from there??

You might need new injectors if swapping coils around doesn't fix it.

My issue is that I get no codes, and the car runs perfectly smooth... but there are just way more timing dropouts than before I went to the dealer for new injectors for the one bank.