Surge/Hesitation during accelleration. 91 KA24DE - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

aggiez32 · 06-27-2006, 01:11 PM

I get a hesitation/surge in accelleration that is fairly noticable through 1st and 2nd gear. After that, it seems to smooth out. It's been like this since I've installed this engine.

It's a 90 S13 that we've done a DOHC swap in. Engine was rebuilt from a car with a blown head gasket. Head was checked and milled VERY little. Valve seals replaced. 91 exhaust cam was installed in place of the intake came and clocked correctly. Timing is fine, that's not my issue. Block was honed, new rings, bearings, oil pump, etc. All new timing components. Everything is fresh.

We just adjusted the TPS. It was running at a .42, we rotated it to a .45 to get it in spec. Idles perfectly at 750-800. Timing is dead on 20. I just can't figure out why it's surging.

Any ideas?

Engine has less than 2000 miles.

5upra · 06-27-2006, 07:09 PM

check spark and fuel...and then if you can check for codes

Densetsu Motorsports · 06-27-2006, 09:53 PM

Check for vacuum leaks? It might be a bad maf too.

06-27-2006, 01:11 PM	#1
aggiez32 Leaky Injector Join Date: Nov 2004 Location: Texas Age: 44 Posts: 95 Trader Rating: (0) Feedback Score: 0 reviews	Surge/Hesitation during accelleration. 91 KA24DE I get a hesitation/surge in accelleration that is fairly noticable through 1st and 2nd gear. After that, it seems to smooth out. It's been like this since I've installed this engine. It's a 90 S13 that we've done a DOHC swap in. Engine was rebuilt from a car with a blown head gasket. Head was checked and milled VERY little. Valve seals replaced. 91 exhaust cam was installed in place of the intake came and clocked correctly. Timing is fine, that's not my issue. Block was honed, new rings, bearings, oil pump, etc. All new timing components. Everything is fresh. We just adjusted the TPS. It was running at a .42, we rotated it to a .45 to get it in spec. Idles perfectly at 750-800. Timing is dead on 20. I just can't figure out why it's surging. Any ideas? Engine has less than 2000 miles. __________________ Brady 91 Aztec Red 300ZXTT Stage III+ (RIP) 90 Black S13 FB - Awaitng a rebirth

06-27-2006, 07:09 PM	#2
5upra Users Awaiting Email Confirmation Join Date: Jul 2005 Location: O'fallon, MO Posts: 104 Trader Rating: (0) Feedback Score: 0 reviews	check spark and fuel...and then if you can check for codes

06-27-2006, 09:53 PM	#3
Densetsu Motorsports BANNED Join Date: Apr 2006 Location: Tucson, Az Posts: 225 Trader Rating: (2) Feedback Score: 2 reviews	Check for vacuum leaks? It might be a bad maf too.