bucking when driving

[dsmnoob91]

i just put a na motor back in my car well i build my tt motor, nut now when i drive at a constant speed it bucks almost like a miss fire but if you drop a gear and keep the r's up it goes away also it has a issue with popping the cig lighter fuse and wont allow the car to start but if you unplug cyl1 fuel injector it starts and you can put the fuse in and drive the car... and starting the car is a pain in the ass too... any ideas? i am going to put a new fuel filter in tomorrow the one now is the original and i am still using my walbro 255 fuel pump.

[mb3000]

Sounds like you are having some light load "surge".

[dsmnoob91]

What's that how do I fix it?

[mb3000]

Basically at such a low load/rpm the turbos fight against each other, when the air from the turbos hits the tb it's blocked (partially) and sent backwards through the ic piping, stopping the turbos and making its way back out the intake.


You can mess with the ic/intake pipes but there isn't really anything you can do about it besides a balance tube.

[GTOJOE]

try running with the MAF unplugged and see if the bucking is still there.

[dsmnoob91]

It's not turbo anymore

[mb3000]

Are you still using the tt ecu?

[MR2]

try running with the MAF unplugged and see if the bucking is still there.

this.........................

[Blackmount]

Had a similar problem with my old Laser, it would buck hard at low rpms, and it got worse and worse and worse till it was like It was like i had 3000rpm revlimiter where car wouldn't even free rev past 3k. it turned out to be the ECU, but it would always throw the code for MAF, and somedays the car would flood so I'd have to unplug injectors to get it to start, then plug them back in before it died. Sometimes similar problems are caused by bad vacuum leaks tho.

[dsmnoob91]

I'll try the ecu and my clutch that has 200miles at most on it is slipping now too