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View Full Version : Redtop s13,, Wont rev past 3000,


boms
12-30-2011, 07:28 PM
Ok long story short...
93 240sx with red top.
mods
z32,gt2871r,ras,greddy intake,greddy fmic,tubular exhaust, 3 in exhaust, stock injectors,stock fuel pressure regulator, jim wolf tune,

i recently rebuilt my motor. Stock specs, arp mains and head, cometic gasket, and so on,
Ran great,for about 300 miles. Then started to have issues. While driving after about 30mins the car would buck and lose power. Ok maf is going bad or is bad. no big deal. Tested it,checked it and so on.. Ended up buying a NEW maf. Still same thing. Wont rev past 3000, rich as hell,black smoke and fireballs.
So i took the harness off and went threw it. Fixed alot of the wiring. Checked all the wires. Made sure everything was good to go. No breaks in any wires. Put the harness on. started the car. It was then missing on number 2. Had spark, injector was no firing. Checked power. Had power to them all. Checked ground. All had ground besides #2. So i checked it at the ecu. Ecu was not sending the ground.. So it was fried. Ok no biggy. Replaced with a spare. Fired right up and ran great.....

put it on the dyno. Made some pulls, was making 275whp 230tq at 11psi. Afr was in the low 10's. Cool!! happy so far.. Took it out on the road. Cruised around, got on it in 2nd gear and BAAMM. Did the same thing lost power, Cant rev past 3000. Went back to the shop checked the maf and the connectors in the passenger side harness. Where maf gets power from. Blew them out started it.. Ran great. Took it down the road did good, Pulled hard. Then it did it again. So I checked the maf, changed the cas, check tps, no leaks.. My maf is grounded right, coil pack harness is grounded, and have engine ground under the manifold...

Im lost and cant get this figured out. Sorry for the long story just tring to narrow this down.

fliprayzin240sx
12-31-2011, 02:07 AM
Did you properly insulated the MAF wires? I'm talking about the wire with the metal sleve on it...

boms
12-31-2011, 06:38 AM
ya i went threw all that.. maf is wired correctly as far as 5v ground ground 12v

the sleeve. when i took the harness apart was cut and soldered back together and taped. like the ground strap that is inside of the shield... i took the tape off, and re wrapped it then wrapped the maf wiring

Edwin562
12-31-2011, 08:16 AM
usually these types of situation where the RPM wont pass 3k, its usually a MAF related problem. I have had this similar problem till pretty much re-wired my MAF harness and replaced my MAF. Zero problem as of today. also check if there is a boost leak as well.

cotbu
12-31-2011, 08:56 AM
Did you clear the mafs code after each failure? I cant remember whether it would drive correctly after the problem is fixed before the code is cleared or not. If you still have a Mafs code? I would redo the wiring, making sure the shielded and the signal strands stay away from each other, continuity test should do the trick.

boms
01-01-2012, 11:48 AM
ok well i believe it is lack of grounds.. i added 3 more and it cleared up.. im take them back off and see if the problem occurs again.. if so i know i dont have enough grounds. thanks for the help..