hesitation from idle

[di_rosa]

well finally got this new engine running, and it's running pretty smooth, but whenever i give it gas, it'll hesitate for a second, then rev up. the rpms drop a bit, then rise quickly.


things i've tried/though:

• thought it was lack of fuel, so i upped the fuel pressure 10 pounds at idle
  
• vacuum leaks: checked, nothing. pulling 20.3 in/hg at idle warm, so no.
  
• tps calibration: double checked, it's on. even shows 0% on my avc-r

the only other thing, is that i'm pulling code 13 (crank/cam sensors) but the car runs fine, so i doubt that would cause a slight hesitation. also, this wiring harness/ecu was working perfectly in my other supra, so unless something happened when i swapped it, it should be fine.

thanks

 

[THE1JZSPECIAL]

A) It Could Be That The Motor Is Choking With Too Much Fuel, If You Run A Walbro 255lph Pump With No Piggyback Or Standalone To Tune It, It Will Do That

B) Your Spark Plugs Could Also Be Bad


C) Check The Wiring To Both Crank And Cam Sensors Make Sure There Is A Good Connection If There Is Go Ahead And Change Both Sensors

 

[mobes]

The pump isn't going to matter, that's what the regulator is for. Base FP should be about 30 with the vac line on the regulator, or 40 without.

If the cam/crank sensor clips are loose, try replacing the housings. They are part 90980-10947. Your timing might be off because of a bad signal there.

 

[di_rosa]

i figured out the code13, stupid adjustable cam gears i bought 2 years ago wore down, and was not aligned properly, was causing me to throw code13.......that seems to have fixed the hesitation

thanks guys

 

[THE1JZSPECIAL]

The pump isn't going to matter, that's what the regulator is for. Base FP should be about 30 with the vac line on the regulator, or 40 without.

If the cam/crank sensor clips are loose, try replacing the housings. They are part 90980-10947. Your timing might be off because of a bad signal there.

the pump matters compare air fuel ratios on a walbro to stock pump air fuel ratios. u can even smell the richness from the exhuast on a stock 1jz with a walbro

 

[mobes]

the pump matters compare air fuel ratios on a walbro to stock pump air fuel ratios. u can even smell the richness from the exhuast on a stock 1jz with a walbro

You can smell the richness on a stock 1JZ anyway.

Explain technically why it matters.

 

[THE1JZSPECIAL]

You can smell the richness on a stock 1JZ anyway.

Explain technically why it matters.

The increased flow rating of fuel (VOLUME of fuel) being supplied to injector duty cycles with a constant and more than adequate supply ,a substituion like higher fuel pressures. Causing the engine to run rich fowling spark plugs and creating miss fires