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View Full Version : SR20: Engine starts sputtering at 2500 rpm, MAF is good, what else should I check?


icapture
04-05-2010, 01:09 PM
Hey guys,

I had this motor installed by a local shop that does primarily SR20's into classic Z cars (the car is a 1975 280z) - when I picked it up they said that it idles fine, but wouldn't rev above 2500 rpm because the MAF sensor was bad. So I bought a new MAF finally, installed it, but there was no change in engine performance.

When I unplug the MAF there is also no change in performance, it still starts to cut out at the same RPM.

There is a strong fuel smell when the car is running, so I presume that means that fuel delivery is not the issue.

I should also mention that there is no sound coming from the BOV, and when i drive it around the neighborhood the turbo does not produce boost. I think because I am not getting to 3000 rpm, which is usually when boost initiates.

What else should I be looking at? Could it be the cam angle sensor? Could it be the computer causing this? Could it be a vacuum leak? The intercooler is brand new, all the silicone IC piping connections look to be airtight.

I'm stumped.

I have taken two videos. In the first video I give it a small rev in order to show that it sounds fine when i don't go above 2500 rpm, but as i give it more and a more gas you can see it starts to cut out. The second clip is from inside the car in order to show what RPM the cutting out corresponds to.

I would definitely appreciate some help here guys. I want to try and figure this out before I call the shop and start insinuating that they didn't wire the car properly.

Thanks a lot,

Adam

Video:
YouTube - engine performance (http://www.youtube.com/watch?v=GUH0MbJ-XNY)

cotbu
04-05-2010, 02:53 PM
Assuming you have the correct mafs. check the ecu for codes verify mafs code!
Then check the wiring from mafs to ecu. (pin location on mafs to ecu pin location)
post order here.
after you fix the mafs issue?! check or reset timing or both.

army240
04-05-2010, 03:00 PM
What MAF are you using? Any tunes on the ECU, SAFC??? What is the maf voltage at the ECU? Also, I would check the fuel pressure!

Frank

icapture
04-05-2010, 09:33 PM
So I plugged the MAF sensor in, tapped into the white wire with the volt meter, and when i hit the trottle there was an increase in power. So this tells me that the MAF is working, correct?

icapture
04-05-2010, 10:58 PM
Assuming you have the correct mafs. check the ecu for codes verify mafs code!
Then check the wiring from mafs to ecu. (pin location on mafs to ecu pin location)
post order here.
after you fix the mafs issue?! check or reset timing or both.

I definitely have the correct MAF. Bought it from Panda Garage here in SD. As for checking the wiring from mafs pin to ECU pin, how exactly do you do this? Do you have to cut the wiring harness open and physically check the entire wire?

cotbu
04-05-2010, 11:38 PM
The cats' at Panda Garage are humans, they sent me an rb down pipe... When I ordered an Sr dp. They did correct the mistake. Much Love 4 PG in SD!

Do you have to cut the wiring harness open and physically check the entire wire?
No. all you have to do is make a diagram ABCD continuity test the wire to the pin on the ecu plug. A----pin# B----pin# etc. Now! during your test, if you get no tone on the wire for the known pin location, then you may have to pull apart the harness or run a wire parallel to the harness whatever.

P.S. you don't have to post any of this if you get an fsm. The answer will just smack you in the face.
If, you have the wrong mafs for the ecu or vise versa. It's not going to matter much if the wiring is correct!

rubhamusan
04-08-2010, 02:41 PM
http://www.sr510.com/tech/SR20DET%20ECU%20S.doc
wires on maf are
white-signal
black-sensor ground
black w/white 12v power
sounds like the signals not rite that's what causes the 2 step effect.

malemodel69
04-17-2010, 11:48 PM
Sounds exactly like how my car ran when my intercooler coupling came off last week. Check for boost leak? Just an idea. I also had these exact symptoms when my coupling had a hole in it. Hope you get this problem sorted out :hug: