Hey guys, I recently did a 1uzfe swap into my s13. The motor is fully rebuilt with arp hardware, acl bearings and oem internals for extreme longevity and mild boost in the near future. I've put about 20 miles on the motor so far, but have a few annoying issues that are effecting drivability.
Firsly, the car idles around 650 when fully warm with a 14.7 to 15.2 AFR and a consistent 40psi oil pressure. If I give the car a quick rev to say 2,000rpm, the motor will drop down below the 650 idle, sound like it wants to die, surge for a second and then come back up to 650. The worst of this is about 50% of the time when I'm driving and start coming to a stop and put my tranny in neutral (Manual tranny), the same thing happens but the car dies instead of surging back up sometimes. I have no idea what's causing it.. I've checked and fixed all the vac leaks I could fine (Doused every part of the intake manifold and intake in carb cleaner to find leaks, only ones I had were at the injector to manifold seals which were cracked, so I replaced those and that fixed that leak).
I do however have some codes.. Most of which I've read don't matter at all and won't throw the car into base map, but I do have one that I know that will - code 24 for the IAT sensor in the maf.
All the codes are.. 24 (iat), 27 (secondary o2), 29 (other secondary o2) and 78 (No fuel pump ecu).
The other problem I'm having is that the car's throttle can be very unresponsive sometimes while driving. If I'm say, in 3rd gear and back off the gas to let the engine decel, and then get back on the gas - there's a very apparent bog like the engine isn't picking up with the throttle opening for a second or two. Like, my foot goes into the throttle - no acceleration for a second, and then it starts to go. Almost like the car cuts power with throttle on for a split second - doesn't always happen, but it's enough to be annoying. Also, it bucks / cuts power for a split second when backed off the throttle and then accelerating in first at a super low speed (like 5mph)..
Any ideas? I'm lost.
My guess is my MAF is on the way out and that's what's caused all the issues - I haven't tried running the car without the maf to see if it would get rid of the bucking and hesitation - but I have a new maf that will be here tomorrow.
Here's a picture of the motor in the car.
Firsly, the car idles around 650 when fully warm with a 14.7 to 15.2 AFR and a consistent 40psi oil pressure. If I give the car a quick rev to say 2,000rpm, the motor will drop down below the 650 idle, sound like it wants to die, surge for a second and then come back up to 650. The worst of this is about 50% of the time when I'm driving and start coming to a stop and put my tranny in neutral (Manual tranny), the same thing happens but the car dies instead of surging back up sometimes. I have no idea what's causing it.. I've checked and fixed all the vac leaks I could fine (Doused every part of the intake manifold and intake in carb cleaner to find leaks, only ones I had were at the injector to manifold seals which were cracked, so I replaced those and that fixed that leak).
I do however have some codes.. Most of which I've read don't matter at all and won't throw the car into base map, but I do have one that I know that will - code 24 for the IAT sensor in the maf.
All the codes are.. 24 (iat), 27 (secondary o2), 29 (other secondary o2) and 78 (No fuel pump ecu).
The other problem I'm having is that the car's throttle can be very unresponsive sometimes while driving. If I'm say, in 3rd gear and back off the gas to let the engine decel, and then get back on the gas - there's a very apparent bog like the engine isn't picking up with the throttle opening for a second or two. Like, my foot goes into the throttle - no acceleration for a second, and then it starts to go. Almost like the car cuts power with throttle on for a split second - doesn't always happen, but it's enough to be annoying. Also, it bucks / cuts power for a split second when backed off the throttle and then accelerating in first at a super low speed (like 5mph)..
Any ideas? I'm lost.
My guess is my MAF is on the way out and that's what's caused all the issues - I haven't tried running the car without the maf to see if it would get rid of the bucking and hesitation - but I have a new maf that will be here tomorrow.
Here's a picture of the motor in the car.
