During a recent tune session I've noticed my IX has been acting quite a bit strangely. It won't take any kind of timing and will knock on the current map which is running nearly 2-3* of less timing with a richer AFR's. Why would this be happening? When I flash back to other maps that I've gotten from other tuners with more aggressive tunes I get the same result, the knock count gets up to 5-6 counts of knock where as these tunes were fine before. The only thing that has changed since my previous tunes were the addition of AMS 780cc injectors.

I've already had Zeus open up the valve cover to inspect the cams and cam gears and do a boost leak test, and inspect the spark plugs. I recently also sent out the 780cc injectors in hopes that maybe one was not functioning properly, but the results came back negative. All of the injectors were running fine and well within 2% of one another. All of the other variables checked out fine, i.e. the boost leak and cam and cam gears. The only other thing I have left to do is a compression test, but other then that what else could I possibly do to cover more ground?

Also to note, the car has been idling very funny. The afr's are all over the place during idle and sometimes the rpms at idle will come up and dip down. Other times it idles flawlessly.

Here are my mods:

Catless TBE w/Megan o2 Housing
GSC S1 Cams
WOT 65mm TB w/port match intake mani
Walbro pump w/AMS 780cc injectors
AMS LICP + ETS UICP + Perrin FMIC
Denso IKH24 plugs


Anyone have any advice/suggestions?

I really hope it isn't any engine damage that would require any major work. I was also suggested that it could be a bent valve, could that really be a possibilty?



Update:

Just got my compression test done it was

140 - 150 - 145 - 145

And there were/are no exhaust leaks.

Any other variables from anyone?

Thanks in advance.

 

Did you ever switch the injectors back?

 

Not yet, they will hopefully go in during the time of the compression test.

 

are you on stock headstuds? compression test should reveal if they need to be upgraded due to the stock ones stretching/causing a leak.

 

Well if the stock ones stretched or leaked, wouldn't my head gasket also have gotten toasted? If it were in fact the head gasket, I would have seen oil in the coolant over flow tank and a milky residue in the dipstick right? Neither of which have been seen. Is it possible for headstuds to be stretched and not cause the headgasket to go?

 

Hot spots on pistons can cause it. Weak motor. Too bad Mitsu's dont have cylinder roughness monitors like Subi's.

I would compression test it and just what the results are.


Mitch

 

But how could my pistons get hot spots or how could the motor just all of the sudden become weak? I mean I barely if ever drive my car hard, I change the oil every 2500-3000 miles, I've never tracked it. I just don't understand how motor damage could be possible. I don't ever recall my knock count ever going over 9, not that it's something to brag about or anything.

 

Is your cylinder head / pistons carboned up? eg were you running an uber rich tune at some period recently?

 

heres a few things to check:

1. bad tank of gas
2. oil in the upper intercooler pipe (signs of bad turbo seals, or to much oil coming through the breather) oil will hurt your octane rating.
3. how much timing do you have at peark torque and at red line? it might be just to aggressive of a tune.
4. compression test will tell you if you have a bent valve in a second.

 

5. check your CEL if its on. a bad front o2 sensor wil cause your idle to wander big time, and is easy to see if it is bad if you are in open loop at idle.

 

I replaced my front o2 just a few weeks ago and it did nothing.

If it were a bad tank of gas, I'm sure it wouldn't had effected the dozens of logs I had done during my current tune process you know? I understand if this happened between one logging session within one fill-up, but this has been pretty consistent across the span of multiple logging sessions within a span of multiple days and gas fill-ups.

I'll try and see if the UICP can be checked out at the time of the compression test.

The thing about the timing is in my previous tune I was running leaner and more timing without knock and now in my current tune I'm running almost. 4 richer and 1-2* less timing and am knocking, so I'm sure I'm not running too much timing.

Thanks for your theories Kevin, I really appreciate it.

 

I mean I just changed to 780cc injectors and was around the mid 10.x's in afr's for a few logs, not many, just 4-5 logs so I imagine that isn't my problem, especially considering being in the mid 10.x isn't uber rich at leeast in my head.

Thanks

 

bump for more suggestions

 

something loose causing phantom knock?

 

No. I doubt this is it because how would something just randomly come loose? I mean everything has been visually inspected nearly half a dozen times and nothing seems loose at all.