SR20 Forum banner
1 - 20 of 31 Posts

·
Tired!
Joined
·
10,149 Posts
Discussion Starter · #1 · (Edited)
ok guys, I have gone head first into a stock ecu/NA setup. I have been doing standalone setups for so long I think I have lost my skills. Here is my story:

I pulled the infiniti motor out of my 99 G20 and dropped it in my 99 sentra SE-L and put the SE-L back to NA form. It has AEM CAI and a 2.5" ssac header as the only mods. the car fires up just fine, but after a few seconds it stumbles and stalls. i have replaced the fuel filter, air filter, PCV, swapped the maf and the distributor and put new plugs/wires in. Luckily I had all that laying around in the garage. Still, no change. However, if I unplug the maf sensor (same for all three I have tried) the car will stay running in limp mode for as long as I want it to. The only things I have left to replace or test are the AAC and IACV, but do you think those would cause this? Adjusting them per the FSM doesn't seem to do any good. I sprayed a bit of carb clean in a couple spots but didn't get any rpm change so I don't think I have a vacuum leak to deal with. ANY IDEAS?

Brent
 

·
easy 400WHP
Joined
·
12,682 Posts
has the MAF harness been re-grounded? Sounds liek when you connect the MAF it gets a shitty ground and doesnt work correctly. But when you unplug it, it just goes to limp mode...as it should. I had similar issues w/ my B15 w/ a brand new MAF. Had to re-ground it for it to work properly...hope that helps...
 

·
Tired!
Joined
·
10,149 Posts
Discussion Starter · #3 ·
I am going to clean the IACV and reground the maf. It is a brand new maf (from my parts bin for the old 24 hour lemans). I kept a distributor, starter, alternator, maf and so on in there.

brent
 

·
easy 400WHP
Joined
·
12,682 Posts
yeah the maf is fine most likely but its the harness ground that seems to deteriorate over time..

it used to be common in B13/14's but like I said it was the only thing I could do that made my B15 run after replacing the MAF.
 

·
Tired!
Joined
·
10,149 Posts
Discussion Starter · #5 ·
I remember grounding the maf in the B13 days, never owned a B14 until now so i guess that is worth a try.

brent
 

·
working on it
Joined
·
3,781 Posts
I've had idle issues on my B14s too. MAF ground could be the culprit like jrod said. I'd also try cleaning the AAC. They get gummed up sometimes. Did you do the 'timing dance' to set the idle screw? I believe if it isn't locked in timing mode when you set the idle screw, the ecu will compensate to try to keep it where it was.
 

·
Tired!
Joined
·
10,149 Posts
Discussion Starter · #8 ·
Swiss, I already replaced the AAC and the IAC valves on the motor with brand new ones. I also put new ground cables on off th ebattery. The car fires up instantly with the turn of the key. It just won't stay running once it is started. It revs high, around 1800-2000 RPM, then slowly dies down to about 500 RPM then stalls. I grounded the maf and swapped out TPS with a known good unit and nothing. Still doing that! It acts like there is a vacuum leak, but I can't find one anywhere.

Brent
 

·
Tired!
Joined
·
10,149 Posts
Discussion Starter · #10 ·
Funny you mention that, I spent about 45 minutes looking for my tester cap last night! I think I will have to make one again and do that.

Brent
 

·
Premium Member
Joined
·
9,405 Posts
i don't think vacuum leaks affect the older cars like the newer ones. I had the back part of the VC gasket fall into the head and cause a huge leak on my VE car, and the car idled without a issue. On a friend's QR car, I missed 1 vacuum fitting that was hidden by the STB, and the car wouldn't start or stay running for long. I'm going with a MAF wiring issue on this one.
 

·
Tired!
Joined
·
10,149 Posts
Discussion Starter · #12 ·
So you think it is a harness issue on a stock harness? Great, that should be loads of fun for me! I will go there after I play with vacuum leaks.

Brent
 

·
Premium Member
Joined
·
9,405 Posts
Wouldn't hurt to check.
 

·
Tired!
Joined
·
10,149 Posts
Discussion Starter · #14 ·
Does anyone think this could be a low compression or injector problem?

Brent
 

·
pwnd
Joined
·
3,455 Posts
Did the car ever have a dial a boom box on it (sfac or whatever that apexi thing is)? if so then the harness is likely all hacky or prone to shorts. Also check your ecu harness. Make sure its fully seated all across the terminals and the bolt tight. And after clearning the codes, have you pulled codes again to see what the ecu really thinks the problem is? have a consult adapter? have you watched it after it is started to see if everything is fluxuating like it should be from the ecu's point of view?

Im going to bet bad wiring and/or maf. if it goes into limp mode when the maf is unplugged i think thats the key signal there. but then again...ive not owned a sr20 in a couple years :D so what do i know...
 

·
Tired!
Joined
·
10,149 Posts
Discussion Starter · #16 ·
the 99 ecu is consult 2 so my consult adapter doesn't work on it. the harness has never had anything spliced into it.

Pressure test is good (found two leaks from old cracked hoses)
compression test showed 175-185 across all cylinders with a warm engine (not bad for a motor with 225k miles)

I swapped in another maf in the past, but I can try it again later.

other than trying another maf and checking the injectors, anyone have any other ideas?
 

·
Tired!
Joined
·
10,149 Posts
Discussion Starter · #17 ·
tonight I do the coolant temp sensor, if that doesn't fly, this Friday I will do the fuel injectors/fpr. If that doesn't fly, i have no f'ing clue and I am parting out the car and selling the chassis.

Brent
 

·
Premium Member
Joined
·
9,405 Posts
When can I pick it up. I'll take it as is. :)
 
1 - 20 of 31 Posts
Top