Staccato Backfire at 6000 rpms?

[Marc91GSX]

Ok first off I have searched every possible cause that I know of and my problem does not match any of those. It does not feel like fuel cut plus I am running a GM maf in the stock location so I am going to assume that it is not fuel cut.

I am currently breaking in my engine so most of my performance mods are not on the vehicle (ie... turbo, mbc, and fmic). The car is running at stock boost and I am running the 750s ( I know WTF ) but i sold my stock injectos like a DA so I was really stuck there. I am running DSM link with base settings for the injectors so I should be ok there. I cannot log anything because my old datalogger is busted (ordered a new one and it is not in yet) and my laptop is having trouble communicating with the ecu through the link.

Ok now that you know my current setup I will give you a description of my problem. As the title says I am having a stacatto back fire at 6000 rpms. It seems like I am hitting my rev limiter but I thought the stock limit was set somewhere between 6500 and 7000 rpms. This happens no matter what boost level I am at and does not happen when I am in full boost at lower rpms. I do not have any boost leaks and I have swapped the ignitor for a friends that I know is good. I have not changed coils yet. I have concluded that it is electrucal but I have no clue what it is. Please help

 

[Maverick3169]

It could be a number of things. You still could be running too rich, and you may be hitting fuel cut.
It could be ignition related (IE, plugs, wires, ect). Check your A/F's, plug gap, and wires.
Also, check out your TPS, that could cause a lot of things to mess up.

You say you don't think its fuel cut... does it feel like you're hitting a brick wall, or does it backfire multiple time while still accelerating slow?

 

[Maverick3169]

Oh, and the stock rev limit is 7500 rpm.

 

[Marc91GSX]

It could be a number of things. You still could be running too rich, and you may be hitting fuel cut.
It could be ignition related (IE, plugs, wires, ect). Check your A/F's, plug gap, and wires.
Also, check out your TPS, that could cause a lot of things to mess up.

You say you don't think its fuel cut... does it feel like you're hitting a brick wall, or does it backfire multiple time while still accelerating slow?

No it does not feel likeI am hitting a brick wall and it is multiple backfires. I did find that one of the wires was unplugged going into the TB. Not sure what it controls, it is the single blade plug that is on top of the TB on the firewall side. My AEM wideband is showing in the high 10s at WOT which I think is too rich but not sure if that is the problem.

Thanks for any help.

 

[evi1clipse]

had a a similar problem as soon as I hit 5800 rpms it'd just sputter and I can feel the car going slower nothing on the lines of fuel cut. but I know it was something fuel related once I started adding fuel cleaners one night it help and didn't do it for about a week, still working on whats going on with it but it's my work car so I'm not in a rush you may wanna check your fpr or fuel pump.

 

[Marc91GSX]

had a a similar problem as soon as I hit 5800 rpms it'd just sputter and I can feel the car going slower nothing on the lines of fuel cut. but I know it was something fuel related once I started adding fuel cleaners one night it help and didn't do it for about a week, still working on whats going on with it but it's my work car so I'm not in a rush you may wanna check your fpr or fuel pump.

I have tried raising and lowering my fuel pressure to see if it would help but so far not much of a change. I do know that it is fuel related now because I just eased up to speed with no boost and I was able to rev to almost 7000. As soon as I went into boost it did the backfire again ( almost sounds like a machine gun going off which is cool because I have just an open DP right now and it was fun watching people hit the deck). I have tried every combination from a base of 32 psi to a base of 46 to see what changes it would have. So far it has not changed at all and I am tired of fooling with it right now so it is back to the stock pressure of 37.

 

[eclipsegsx1736]

Is it always at the exact RPM? I assume you already made sure you don't have a 2 step stutterbox set up in DSMlink, and that the switch isn't activated...

 

[Marc91GSX]

Is it always at the exact RPM? I assume you already made sure you don't have a 2 step stutterbox set up in DSMlink, and that the switch isn't activated...

Well that is the problem. I do not know what I have with DSM link right now because I cannot communicate with my ecu. I keep getting a timed out error on my laptop but I have asked for help on that in another thread. My logger is supposed to come in tomorrow so I will be able to find out for sure ( fngers crossed).

I also do not know whether it is the same rpm anymore because my alt belt jumped last night and my tach quit working ( of course it's accuracy was always debated by me anyways) It sounds and feels like it is around 6000 rpm (when the tach was working it would happen between 6000 and 6200 rpms like clock work depending on the gear and this even occured with my spare ecu that did not have DSM Link. I am really about this one and I am about to give up until I can get my laptop and ecu straightened out.

 

[The Wave]

Hey guys, I took my car out today and drove it hard for the first time since almost a full build (I have a new (used) ecu in it too because the old one crapped out.). My setup right now is stroked 4G63 eagle/wiseco combo yada yada yada. Head is HKS 272/272 with crower springs/retainers and new ferra valves. The problem I am having is at about 6000-6200 rpm the car sputters and looses almost all power. This happens in first and second gear, I haven't been able to take it that high safetly in any higher gear yet. I am running 750's with an aeromotive FPR and walbro HP pump, so I doubt I am hitting fuel cut. I am using a SAFC-II for tuning at on average -30% and getting A/F readings consistantly between 11-14:1. Boost is set to 22 psi, and I am not getting a lot of knock (normally <3). Anybody have any idea what is going wrong?

 

[pitbull419]

SAFC II Doesnt like the 750's
They tend to not get along sometimes.

 

[Burnett03]

Its not a honda vtec no need to rev past 6000rpm You shouldnt be reving that high in a stroker anyways.