s13 blacktop fuel cut during low acceleration need help! - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

lowz 94 · 03-05-2014, 02:43 AM

like the title says i have a s13 blacktop i just recently swapped it in. it runs great at idle will rev up and build boost in neutral. now when i try to take it out on the road it gets to about 2000 to 3000rpm im guessing. (tach doesnt work i need to get a dohc tach) then hits fuel cut and either drops down in rpm then kicks back in or it just shuts the motor off completely. i have dug around for vac leaks and cannot find one. i have a walbro 255, new FPR, new ngk iridium plugs, new chasebays harness, and new greddy profec boost controller. would love some more ideas to trouble shoot.

sleepyS14se · 03-05-2014, 07:43 AM

see it is posts like this that make me hope and pray my blacktop s13 sr20det runs correctly. I just picked my swap up a few days ago and am about to order a wiring specialties pre made harness. my swap is going in my zenki s14

OnTheChip · 03-05-2014, 08:19 AM

Check the ECU for codes? Sounds like a MAF voltage low problem which puts the ECU in limp mode (actually switches to alpha-N and limits rpm to 3000).

cotbu · 03-05-2014, 09:20 PM

Your building boost in neutral? not possible, unless timing is so retarded it allows yo to do so. Check ecu for codes and verify base and idle timing. If it's also mafs you should have mentioned the jerking back and forth while driving, when you try to rev above 2500 also black smoke could be present.

lowz 94 · 03-05-2014, 10:12 PM

It wont build boost I mean spike like a pound or 2. Ecu reads 55 normal. And tried 2 mafs and unplugged and there was a difference so maf is functioning thers no jerking just either fuel or ignition cut

Sent from my SGH-M919 using Tapatalk

ultimateirving · 03-06-2014, 01:28 AM

Start with a boost leak test my friend. Will work wonders for you

lowz 94 · 03-14-2014, 06:03 PM

okay did a boost leak test and no leaks. what next?

03-05-2014, 02:43 AM	#1
lowz 94 Join Date: Jun 2012 Location: champaign il Posts: 13 Trader Rating: (0) Feedback Score: 0 reviews	s13 blacktop fuel cut during low acceleration need help! like the title says i have a s13 blacktop i just recently swapped it in. it runs great at idle will rev up and build boost in neutral. now when i try to take it out on the road it gets to about 2000 to 3000rpm im guessing. (tach doesnt work i need to get a dohc tach) then hits fuel cut and either drops down in rpm then kicks back in or it just shuts the motor off completely. i have dug around for vac leaks and cannot find one. i have a walbro 255, new FPR, new ngk iridium plugs, new chasebays harness, and new greddy profec boost controller. would love some more ideas to trouble shoot.

03-05-2014, 07:43 AM	#2
sleepyS14se Zilvia Addict Join Date: Jul 2013 Location: Georgia Age: 32 Posts: 880 Trader Rating: (3) Feedback Score: 3 reviews	see it is posts like this that make me hope and pray my blacktop s13 sr20det runs correctly. I just picked my swap up a few days ago and am about to order a wiring specialties pre made harness. my swap is going in my zenki s14 __________________ 95 S14 se RB25DET 348whp

03-05-2014, 08:19 AM	#3
OnTheChip Zilvia Junkie Join Date: May 2013 Location: Burgaw, NC Posts: 311 Trader Rating: (0) Feedback Score: 0 reviews	Check the ECU for codes? Sounds like a MAF voltage low problem which puts the ECU in limp mode (actually switches to alpha-N and limits rpm to 3000). __________________ NismotronicSA - Speed-Density Tuning for Nissans

03-05-2014, 09:20 PM	#4
cotbu Post Whore! Join Date: Sep 2005 Location: SWFL Age: 47 Posts: 3,318 Trader Rating: (3) Feedback Score: 3 reviews	Your building boost in neutral? not possible, unless timing is so retarded it allows yo to do so. Check ecu for codes and verify base and idle timing. If it's also mafs you should have mentioned the jerking back and forth while driving, when you try to rev above 2500 also black smoke could be present. __________________ LoverTechnologies "Half Broken Things!"

03-06-2014, 01:28 AM	#6
ultimateirving Zilvia FREAK! Join Date: Nov 2010 Location: arizona Age: 33 Posts: 1,519 Trader Rating: (1) Feedback Score: 1 reviews	Start with a boost leak test my friend. Will work wonders for you __________________ Z32 with lq4 swap Desert Street Scene \|\| Dssevents.com

03-05-2014, 10:12 PM	#5
lowz 94 Join Date: Jun 2012 Location: champaign il Posts: 13 Trader Rating: (0) Feedback Score: 0 reviews	It wont build boost I mean spike like a pound or 2. Ecu reads 55 normal. And tried 2 mafs and unplugged and there was a difference so maf is functioning thers no jerking just either fuel or ignition cut Sent from my SGH-M919 using Tapatalk

03-14-2014, 06:03 PM	#7
lowz 94 Join Date: Jun 2012 Location: champaign il Posts: 13 Trader Rating: (0) Feedback Score: 0 reviews	okay did a boost leak test and no leaks. what next?

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