KA24DET rich bogging/stalling on decel, not catching idle

[Chugpuppy]

Originally Posted by tayloray

I know someone already mentioned this. But I had the same problem with my old rb20 setup. Turned out to be a leaky bov. Which may make sense because if you rev, start to build boost then release, you loosing metered air. Causing a rich condition. Have you tried a new maf?

Disconnected the vac line and covered the BOV so it didn't open, still no change. Not the BOV. I haven't tried a new MAF yet, but I will this weekend. Problem is, this started (albeit it was much less serious) before I was turbo, when I had a stock KA with the stock MAF. Current Z32 MAF has been cleaned multiple times with MAF spray cleaner.

[tayloray]

Yeah I know what you mean. It just can't really be anything else. There's only so much that controls fuel

[c-los13]

i actually read your whole thread
i had 2 friends w the same problem
"ka-t's dying when after the left off the gas"
they both went with a different kinda tune since the never figured it out, one of them even tried for a whole year
they both got a "blow through" setup and theyre problems were gone!
it was actually done by Enthalpy (again, Martin is awesome)
I know many ppl is done without going that route but at least my 2 friends couldnt.
just my .02

[tayloray]

Maybe the injector driver in your ecu is going bad and not shutting off the injectors when you let off the gas like it should?

[Chugpuppy]

Originally Posted by c-los13

i actually read your whole thread
i had 2 friends w the same problem
"ka-t's dying when after the left off the gas"
they both went with a different kinda tune since the never figured it out, one of them even tried for a whole year
they both got a "blow through" setup and theyre problems were gone!
it was actually done by Enthalpy (again, Martin is awesome)
I know many ppl is done without going that route but at least my 2 friends couldnt.
just my .02

I've been trying to figure it out for close to a year haha. I'm thinking it has to do with either the MAF wiring, or a vortex effect created by the turbo that's causing the MAF to read incorrectly. Checking voltages tomorrow.

Just sending the ECU in to get tuned for blow-through would be easier though.

Also, I tested the idle air controller systems today by unplugging the IACV/AIV/that other one and blocking off the IACV air feed. Cracked the throttle plate via the throttle cable adjustment nuts, revved it, and still got the same old stalling shit. Gotta be MAF.

[c-los13]

damn, if your ka was running good before it was turbo'ed then it has something to do w your set up
also, one of my friend did mess bolt on the TB so the TB could stay slightly open
not the wire!!!
not the best option but it works
good luck

[sleepyeyeds14]

I seem to be having the same exact problem as you. Do you ever get your car to idle for a small period of time then it jumps from ~500rpm to ~2000rpm? im completely out of ideas as to why mine is doing this. BTW im NA so you could most likely rule out any of your turbo stuff as the culprit. And please keep us posted when you find the solution to your problem! i have found many threads on this same issue, but no one ever tells us how they fix it...

[c-los13]

i had a rebuilt a ka before i got my sr
i had all kinds of idle problem before the rebuilt
my best advice is to delete all the emission and clean out maf, also itd be a good idea to clean up your iacv
check voltage on tb sensor
spray brake cleaner around the intake area and see if idle changes
thats just basic stuff

[Chugpuppy]

Originally Posted by sleepyeyeds14

I seem to be having the same exact problem as you. Do you ever get your car to idle for a small period of time then it jumps from ~500rpm to ~2000rpm? im completely out of ideas as to why mine is doing this. BTW im NA so you could most likely rule out any of your turbo stuff as the culprit. And please keep us posted when you find the solution to your problem! i have found many threads on this same issue, but no one ever tells us how they fix it...

Yeah it's so annoying, all the threads I've found never have a clear answer as to how they fixed it. I'm PRETTY sure it has something to do with the MAF in my case. I'm gonna go check out the voltages.

[Chugpuppy]

Originally Posted by c-los13

i had a rebuilt a ka before i got my sr
i had all kinds of idle problem before the rebuilt
my best advice is to delete all the emission and clean out maf, also itd be a good idea to clean up your iacv
check voltage on tb sensor
spray brake cleaner around the intake area and see if idle changes
thats just basic stuff

All emissions are removed and securely blocked off, MAF has already been cleaned once, IACV has been cleaned also. Voltage on TPS is spot-on .5v closed 4.35v WOT. I have no vacuum leaks, pressure tested to 25 psi.

[LBK S13]

I had the exact same problem on my old s13 before I sold it and just as you have done I went through everything replacing all the little stuff and nothing changed. My MAF was getting good voltage and seemed to be working fine but I changed it out for a mustang MAF and it got better but still had problems when letting off the throttle. It ran fine WOT so I made it a drift slut and sold it. That said my money is on MAF just because it's getting good voltage doesn't mean it's actually sending proper signals. IMO MAF=nightmare

[sleepyeyeds14]

Originally Posted by Chugpuppy

Yeah it's so annoying, all the threads I've found never have a clear answer as to how they fixed it. I'm PRETTY sure it has something to do with the MAF in my case. I'm gonna go check out the voltages.

What voltages are we supposed to be looking for. I want to check mine too, but i havent been able to find the specs for what the voltages are supposed to be. Also, did you ever suspect the probablem being lack of fuel pressure? Cuz i finally was abe to get my car to start today but only for a quick second, then it died as if the fuel pump decided to stop pumping...

[LBK S13]

There is a thread with all the MAF/MAP specs. If you can't find it I'll post a link

[sleepyeyeds14]

Originally Posted by LBK S13

There is a thread with all the MAF/MAP specs. If you can't find it I'll post a link

my search button wont work... so if you could post the link i would really appreciate it...

[LBK S13]

ImageUploadedByTapatalk1343118428.495791.jpg

I hope this helps. I still can't find the thread I was looking at earlier but I will keep searching and if not I will do some research google wide to find all I can to help because I'm sure at some point my car will have the same problem. As it has happened to my other ka in the past

[Chugpuppy]

Originally Posted by sleepyeyeds14

What voltages are we supposed to be looking for. I want to check mine too, but i havent been able to find the specs for what the voltages are supposed to be. Also, did you ever suspect the probablem being lack of fuel pressure? Cuz i finally was abe to get my car to start today but only for a quick second, then it died as if the fuel pump decided to stop pumping...

My fuel pressure is fine, the car's dying out because it's bogging RICH, not lean like most vacuum/fuel pressure related problems.

I'm pretty sure I just need to extend the MAF away from the turbo or go blow-through, I've been talking to Martin at RS Enthalpy and gotten some good information. These things are apparently very sensitive, so he recommends placing the maf 18 to 24 inches away from the turbo. I'm gonna rig something up for now, and if it works then I'm cutting a hole in my inner fender, boxing it to protect from dirt/dust, and stuffing the maf/filter down there. Top-mount sucks for space.

[waxball88]

I have been fighting with the same issue for a while. I'm hoping its just vacuum leaks. After i put my manifold on today i will know 100%
Things i've tried
Replaced wastegate(was leaking)
Different throttle bodies/TPS
Injector seals/cushion rings
Different n62 mafs
Boost leak testing
Timing check
Fuel pressure regulator/filter
Cleaning IACV
Moving maf away from turbo with 90* bend
Converting pre-tb to IACV tube stuff to push lok AN (never leak again)
Tried isis egr block but it leaked, so i just had the hole welded shut.

Manifold going back on today. It will be the most optimum set up to prevent any sort of leak.

[jmac636]

Before going blow thru just try extending the distance from the turbo to the maf. Do it as a temporary experiment first. Your maf is most likely too close to the turbo creating a turbulence of some sort that your maf doesn't like. Z32 mafs are far more sensitive to this. If you go blow through with the z32 maf you will blow off the sensor cover if you don't reseal it with epoxy. Blow through will make the car feel like it was turboed from the factory. No stalling or ill effects. Make sure you don't have any reducer in front of the z32 maf.

[Chugpuppy]

Originally Posted by jmac636

Before going blow thru just try extending the distance from the turbo to the maf. Do it as a temporary experiment first. Your maf is most likely too close to the turbo creating a turbulence of some sort that your maf doesn't like. Z32 mafs are far more sensitive to this. If you go blow through with the z32 maf you will blow off the sensor cover if you don't reseal it with epoxy. Blow through will make the car feel like it was turboed from the factory. No stalling or ill effects. Make sure you don't have any reducer in front of the z32 maf.

Are you running blow-thru? I'm gonna move the MAF farther away using a temp setup tomorrow, but I'm not quite sure how I could go draw through if it did work. What's your setup look like?

[lysticalz]

any updates chug?

my cars been doing the same thing after i switched from safc2 to an enthalpy tune and z32 maf a long while back.

[Chugpuppy]

Originally Posted by lysticalz

any updates chug?

my cars been doing the same thing after i switched from safc2 to an enthalpy tune and z32 maf a long while back.

I put at least 2" of pipe between the MAF and my 20g, and that helped a LOT. Way better response, drivability, and AFRs all around. It was running PRISTINE for about half an hour, then I shut it off and tried hooking up the idle air control systems and resetting the throttle cable. Now it runs rich EVERYWHERE. Screwing around with it some more when I get home from work today.