KA24DET questions

[ahmadseyam03]

I recently bought a 95 240sx with a ka24de-T motor. The car backfires if I dont downshift when slowing down or throw it into neutral soon enough...and its a LOUD backfire. Its also idling funny, RPMs keep jumping around...Im going to start by cleaning the MAF?. Its also running pretty rich due to the tune, and smoking a kind of clear smoke out of the back. I dont even know where to start on this. After driving I smell like ive been laying under an exhaust, and have a headache 4rm the smell. Any ideas on what 2 do?

[costa_rican13]

different tune, sounds like you have a rich problem like when you let off the gas, car runs way rich and gas hits the manifold and explodes much like a 2 step system. also if different tune doesnt work, change or clean the iacv really well. also the exhaust smell you get the head ache from could be from an exhaust leak(i had this problem). the smoke could be small amount of oil(meaning the piston rings are going out) FYL. or because it running way way rich.

[ahmadseyam03]

I know theres a definite exhaust leak because theres a hole where an O2 sensor should be on the pipe. Its a straight pipe all the way back so later on, Im planning on getting a high flow cat and a tip.

As for the rest...I hope to God the rings arent going out!!! I guess I need to see where I can get it retuned ASAP. Wish I knew my way around the SAFC. Thanks for the help man

[ahmadseyam03]

You think that would be a reason 4 it doing horrible on gas mileage? I know turbo cars arent the best for gas mileage, but I drove it 4rm dallas 2 kansas yesterday and stayed out of boost, and could barely make 175 miles on a tank

[costa_rican13]

That probably gona be because the tune. Like the safc is putting to much fuel. Hence your not using all of it. So its wasted. But I'm not exactly sure though. Just a probability

[hoodrich]

I have the exact same problem, i get tons of backfire when i downshift slowly up to a stoplight or am sitting in a high gear decelerating without my foot on the gas at all. Im sitting at around 14.6 air/fuel mixture on my wideband but mine also seems like its running way too rich. Ive cleaned my MAF but havent checked my IACV to see if its all clogged up because when i do idle its sometimes all over the place. I also have some pretty major exhaust leak off my turbo manifold which i thought all this backfire is comming from, i got a crack in the weld and the gasket also looks like its cracked in a few spots. My gas mileage is also horrible! Id say clean your MAF then IACV and if thats all good try and fix that hole in your exhaust and if that all fails check your safc

[costa_rican13]

any exhaust leaks before the wideband sensor will throw it off like crazy. fix those then see what happens. also i had a s*** idle, and when i took off my straight pipes exhaust, and then slapped on my new apexi noir. now it runs great doesnt even try to bog or die. i'm thinking exhaust leaks throw off not only the wideband but the stock narrow band sensor. because i have no leaks now and it runs great. but also clean the iacv and maf as well.

[kouki munster]

Ditch the safc and get at the very least a enthalpy or jim wolf tune, that will most likely fix most of your issues.

[ahmadseyam03]

What is enthalpy or jim wolf tune? Thank you all..this has seriously been very helpful. I'll let u know what happens with it after this wknd hopefully

[kouki munster]

You send them your stock ecu and a list of the mods to the engine(turbo size, injector size, what maf, ect.....) they will remap the ecu and send it back, it is the best solution for someone with a low budget build.

For more info google them and go to their websites.

[costa_rican13]

yea but make sure you get the full list, because they'll need to know everything for a good tune.

[Dittoz7]

I know theres a definite exhaust leak because theres a hole where an O2 sensor should be on the pipe.

Ummm plug an O2 sensor in there man! Also I would clean the already mentioned part here. Also go get a proven tune.