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. All of which checked out fine. 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 have been told about a possibility of it being a blown head gasket, any thoughts on what other symptoms would be?

Thanks in advance.

 

from what I read your problem did not exist UNTILL you installed 780 injectors - hence my suggestions

#1 - you dont need those injectors - so I would suggest you change back to the stock ones and see if the problem goes away

#2 - have the injectors tested - a lean or rich injector not matched to the other 3 can cause the kind of problem you are having

Al

 

That's not a bad idea. I knew I should have had them cleaned before installing them. MY IDC's were at 100% based on Evoscan so that's why I got them.

So you're saying that a mis-match or bad flowing injector could cause the car to knock with less timing and rich afr's? I mean even if 1 were off, but the afr's were dialed in based on it being that way, the car should respond normal shouldn't it?

Thanks

 

No one else has any suggestions?

 

Did you retune after you installed the bigger injectors?

l8r)

 

Yes, they are scaled and what not and everything.

 

In that case I'd follow Al's advice and have them cleaned and flow tested to start with.

l8r)

... while I think about it, have you monitored your fuel trims, to make sure that the scaling is correct?

 

Yeah, the FT's are fine. The car cruises fine too. It's just idle and WOT that get kind of funky.

 

Also, wouldn't my plugs look off if one of my injectors were acting up? I mean then I'd be over-compensating for fuel so the other plugs with the correctly working injectors would be pretty fouled right?

 

No one has any other suggestions?

If one injector was sticking, it would cause one cylinder to run leaner then others, wouldn't this throw a CEL?

 

No, the car can only monitor the total output by all cylinders not each cylinder individually. If one injector was sticking on a little the other cylinders would go lean to even out the total AFR.

 

what make are the ams injectors? ihave precission 880's & sometimes my idle afr's get strange for no reason....

have you tried gas from a different station?

 

They are precision 780's.

I fill up from basically any Shell, Texaco, or Chevron I am around when I need to fill. Usually it is from the 2 that are nearest my house, but that isn't always the case.

I mean, if it were the stations by my house then wouldn't it happen more often? I mean the car just started doing this during my recent tune with the injectors. Before it was making good power and what not and taking much more timing too.

 

i wonder about my injectors & i got them new.

 

Well I am taking mine off and oging back to stock. I'll be sending them to get cleaned Asap, I'll post my results.