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View Full Version : SR20DET cutting out at boost, possibly bad MAF?


igreek
11-07-2011, 04:40 PM
I've finished my S13 SR20 swap and I'm having problems. As I described in this thread (http://240atlanta.com/forums/showthread.php?71161-SR20DET-cutting-out-when-nearing-boost), it breaks up when it gets into boost. Bought new plugs, gapped them at 0.28, adjusted TPS, did a boost leak test and didn't find anything. Plugged out coilpacks, one by one and engine bogs a bit with each one. Plugged out injectors one by one and does the same thing. So, those seem to be fine. Otherwise, double checked everything else.

What is making me think that it's the MAF is how it reacts when I mess with it. If I unplug it, it'll bog down for a second but then build up and have a better idle then when it's plugged in; plugged in it revs, but cuts out when it hits boost, and plugged out, it hits that normal no MAF wall. Also, when it's plugged in vacuum is at 18-19 and 22-23 when plugged out. Doesn't something seem strange there? Decided to pull ECU codes and I'm getting 12; which I'm reading is the MAF. Does all this point to a bad or going bad maf?

It works fine WOT, until it hits boost and then everything cuts out. Could it be that the MAF is going bad and it messes up during boost? I'm pretty much stuck at this point. Do you guys think it could be the MAF?

harrypotter
11-07-2011, 05:02 PM
What spark plugs?

igreek
11-07-2011, 05:07 PM
NGK bkr6e-11s. I thought it was spark blowout at first, but I'm really doubting it at this point.

jr_ss
11-07-2011, 05:42 PM
Swap your MAF with someone that has a known good one. Trial and error. You could also pull voltage on your MAF to see if it's within range.

harrypotter
11-07-2011, 10:04 PM
Maybe igniter chip thingy

cotbu
11-12-2011, 03:05 AM
A lil late but...
Pulling the mafs plug while running will cause a code. You have to clear codes do a pull then check for codes.
This doesn't seem like the mafs based on that, but rather a fuel problem and or timing.
Check timing and fuel pressure, also do a power balance injector, and coil pack test.
These power balance tests are at idle, you should pass both.

I'm not saying it's not mafs related as it could very well be, a wiring problem.
If you're losing a connection during boost or mafs fails during boost, checking codes at that point will indicate a bad mafs and or wiring.

just another> s13
11-25-2011, 03:35 AM
NGK bkr6e-11s. I thought it was spark blowout at first, but I'm really doubting it at this point.

I'd put ngk bkr7e/4644 plugs in it. My car didn't like the 6's, guess its to hot of a plug. My car would break up coming into boost with them so I switched to the 7's and it cleared up, not sure if this will work in your case, you might be having other problems.

anarchyperf
11-25-2011, 03:56 AM
Your running a S15 turbo? What are you tuning with and what fuel pump do you have?

Kingtal0n
11-25-2011, 04:18 PM
Do a boost leak check

rcdad123
11-25-2011, 11:28 PM
if the plugs are fouled, you could be experiencing ignition misfire. i would definitely go with a colder set of plugs. i like the NGK BKR7E gapped at .015. yes .015. use a feeler gauge to measure the gap. also check your engine harness grounds. a loose ground can also cause the same problem, happened to me. good luck