KA-T weird issue - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

NameOfUser · 05-19-2019, 12:49 PM

What's up guys... I've run into a bit of a problem here. A couple weeks ago my car (ka-t s13) was running rich and dying due to a bad vacuum leak. Got that fixed up and she ran good as ever, dont have insurance on it though so it sat for about 2 weeks.

I went to start it a few days ago and it ran fine, with good AFRs, for like 30 seconds at most. Then it begins to run rich, have bad/delayed throttle response, bogs and dies. It does this every time I start it. It also shoots out some black soot as it bogs/dies. Checked for codes and got the all clear code 55.

I now have the upper intake manifold pulled off. The IACV is spotless, the throttle body is pretty clean too. I hadn't checked those since I bought it so I figured I'd do that first. Just wondering what else I should check. I haven't run into this problem before, anyone have any ideas?

It's got an enthalpy tune, t28, 550cc injectors and a z32 maf. Let me know if you need more information, and thanks for any and all help

silviaks2nr · 05-20-2019, 07:21 AM

Just some things I would check- mafs voltage with key in on position and at idle, fuel injector o-rings, and fuel injector pulse (stuck injector). Save up for a stand alone and dyno tune. The mail order tunes are really hit or miss long term.

tuzzio · 05-20-2019, 08:02 AM

Typically a vacuum leak causes a lean condition..

But yes, silvia pretty much hit the nail on the head. Also, if none of that solves it...check your grounds. You'd be surprised at what weird stuff they'll do.

05-19-2019, 12:49 PM	#1
NameOfUser Join Date: Apr 2019 Location: Michigan Age: 24 Posts: 8 Trader Rating: (0) Feedback Score: 0 reviews	KA-T weird issue What's up guys... I've run into a bit of a problem here. A couple weeks ago my car (ka-t s13) was running rich and dying due to a bad vacuum leak. Got that fixed up and she ran good as ever, dont have insurance on it though so it sat for about 2 weeks. I went to start it a few days ago and it ran fine, with good AFRs, for like 30 seconds at most. Then it begins to run rich, have bad/delayed throttle response, bogs and dies. It does this every time I start it. It also shoots out some black soot as it bogs/dies. Checked for codes and got the all clear code 55. I now have the upper intake manifold pulled off. The IACV is spotless, the throttle body is pretty clean too. I hadn't checked those since I bought it so I figured I'd do that first. Just wondering what else I should check. I haven't run into this problem before, anyone have any ideas? It's got an enthalpy tune, t28, 550cc injectors and a z32 maf. Let me know if you need more information, and thanks for any and all help

05-20-2019, 07:21 AM	#2
silviaks2nr Nissanaholic! Join Date: Nov 2004 Location: SC Posts: 2,105 Trader Rating: (10) Feedback Score: 10 reviews	Just some things I would check- mafs voltage with key in on position and at idle, fuel injector o-rings, and fuel injector pulse (stuck injector). Save up for a stand alone and dyno tune. The mail order tunes are really hit or miss long term. __________________ '98 240sx 5spd

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05-20-2019, 08:02 AM	#3
tuzzio Nissanaholic! Join Date: Oct 2013 Location: Western Mass. Posts: 2,254 Trader Rating: (3) Feedback Score: 3 reviews	Typically a vacuum leak causes a lean condition.. But yes, silvia pretty much hit the nail on the head. Also, if none of that solves it...check your grounds. You'd be surprised at what weird stuff they'll do.