fast377

iTrader: (52)

Is there a way to log injectors individually, or only the default bank to bank? I'm trying to learn how to tune, and my car feels like it has a bad miss when I give it throttle (idles bad too). I just changed plugs and a few of them looked brand new, where the others were fouled. My coils are firing, so I was wondering about the injectors.

jimmyblue

iTrader: (11)

Bank-bank control means the injectors all get the same
electrical pulse width. You can do an injector balance
test, and you can look at cylinder mode misfires to chase
individual injector problems, swap the suspicious ones with
good ones and see if the signature moves with.

fast377

iTrader: (52)

How do I do the balance test, and where do I find the cylinder mode misfires? I don't have any misfire dtc's.

I see a cylinder balance...is that what you are talking about?

fast377

iTrader: (52)

Here are the results of the cylinder balance test. The 4 cylinders with the 7x% were also the ones with the clean plugs. Something is out of whack.

fast377

iTrader: (52)

For some reason that file doesn't work. I think it is because when I closed hptuners it said something had changed and asked me to save and I clicked no. I did take a screen shot though...so here it is. Well I can't make the image small enough to upload and still be visible, so I'll copy the info.

RPM Ref: 1084 Idle (IAC) Control
#1: 978-90% RPM 1000
#2: 864-79%
#3: 850-78% Steps 17
#4: 982-90%
#5: 993-91%
#6: 994-91%
#7: 840-77%
#8: 785-72%

fast377

iTrader: (52)

I was wrong, not all the cylinders with the 70s% had the clean plugs...it was a mix between them all.

Could a vacuum leak cause this? Like if one or more of the intake runners were not properly seated?

jimmyblue

iTrader: (11)

There's something lumpy in the gravy but it appears not to be
a clean, bank-to-bank problem.

For misfires, you just want to log the Misfire Current Cylinder
1,2,3,...,8 and look at whether any of them stand out at idle
or low cruise or accelerating. Not so much the absolute number
as whether one or four of the cylinders are unusual.

Though if this has been going on long, maybe all clean plugs
is not a bad idea. Depends on whether they are "dirty" or
fouled enough to cause their own set of problems, whether or
not they were the initial trouble.

Four vacuum leaks on nonadjacent cylinders seems kind of
unlikely. But you can get some crazy trimming with only one
runner leak, and then over-enrich everybody else to "fix it".

fast377

iTrader: (52)

I thought a vacuum leak was kind of unlikely...at least for my problem. This is a conversion car that I have been working on for a while, so these have been the only times it has run.

How do you log cylinder misfires individually? I don't have any misfire codes, but when I give it gas, it sure does feel like there is a cylinder or two off. But then again, around 4k it doesn't seem bad.

And I put fresh plugs in it...problem still persists. I'm thinking about taking out my injectors and cleaning them. Can't hurt.

BobDoLe

iTrader: (11)

to log cylinder misfires individually:

open up the table display that shows all the PIDs you're logging,
right click, insert: engine diagnostics -> misfire -> misfire current cylinder #
it'll use up 8 PIDs

after you drive around doing stuff that makes you think you have a misfire, save the log, but also "Export Data" (found under Scan in the toolbar). that will drop an excel file that you can work with.

i did this and found a miss that didn't trigger a code or that i couldn't feel - turned out a spark plug wire was loosening up.

fast377

iTrader: (52)

Great, thanks! I'll hopefully be able to try that tomorrow. Is there anything else I should look for?

fast377

iTrader: (52)

Should I do a case learn? Since it is a new pcm with a new os, and all kinds of mis-matched stuff. Or do I need to get this miss straightened out first?

fast377

iTrader: (52)

I think I found my problem...at least a huge part of it. I took all my injectors out to clean them. A few were kind of dirty/clogged, but two of them were completely stuck shut. So I cleaned them all out and hopefully that will fix my problem. I'll have to wait until next week to do it though...fingers crossed.

fast377

iTrader: (52)

It's amazing what clean injectors will do for a car. Once it built up fuel pressure and decided to start it runs great (at least as great as a semi-half *** tuned cammed car runs). Everything seems okay...no misses or anything.

Would someone mind looking at my scan to see if everything looks okay or if I missed anything.

Thanks for everyones help!