car runs poorly!!! barely idles, can't rev - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

alpalwal1 · 08-06-2006, 06:39 PM

My car is finally running, but poorly. It's a built KA-t with msd 50lb injectors and a safc

first off my boost gauge only says 10" of vac at idle and it should be at 20. I tried the boost leak tester and i didn't find anything. What else could lead to low vacuum?

second, when you try to rev the engine up at all it just dies. i've gotten it up to like 1.5k with like 2% throttle, but any more and it dies.

the safc was all set up for my old sohc ka with 450's. besides leaning the injectors out a bit, is there anything else I should have changed between sohc and dohc?

*NemeGuero* · 08-06-2006, 06:58 PM

How did you do the boost leak tester?
If you have low vacuum at idle, you have a vacuum leak. Spray carb cleaner around the intake manifold (with the engine running) and when you hear the engine revv up.. you will have found your leak.

What MAF are you using?

An SAFC isn't really the best especially with 50lb injectors.

punxva · 08-06-2006, 06:59 PM

it does sound like a fuel issue, you need to use a wideband to actually tune it, not just mess around with the settings, thats how you mess something up bro.

alpalwal1 · 08-06-2006, 07:15 PM

alright... for the safc i just turned everything back about 4 %.... not the best tune but not bad enough to do this.

for the boost leak tester i put a coupler with a cap and a plug at the beginning of my charge piping and then pressurize it with a compressor.

the safc will go away when i get my enthalpy after break in

stock maf

.. and i do have a wideband, i just havent tuned yet

lastly... if i give it any gas it dies... lightly over 30% throttle give or take, and any sudden movements and it dies almost instantly.

alpalwal1 · 08-07-2006, 11:06 PM

up up and away for an answer.... i know there has to be a semi simple fix for this.... help!!!

bongnak · 08-07-2006, 11:42 PM

ka-t? dual or single try checking the injectors especially if its a dual cam; since theres two o-rings they might have been messed up when installed.

alpalwal1 · 08-08-2006, 03:36 PM

what about the injectors? they fire and im almost positive theyre in the right order.. whaht else to check?

08-06-2006, 06:39 PM	#1
alpalwal1 Join Date: Oct 2005 Location: Ca Posts: 46 Trader Rating: (0) Feedback Score: 0 reviews	car runs poorly!!! barely idles, can't rev My car is finally running, but poorly. It's a built KA-t with msd 50lb injectors and a safc first off my boost gauge only says 10" of vac at idle and it should be at 20. I tried the boost leak tester and i didn't find anything. What else could lead to low vacuum? second, when you try to rev the engine up at all it just dies. i've gotten it up to like 1.5k with like 2% throttle, but any more and it dies. the safc was all set up for my old sohc ka with 450's. besides leaning the injectors out a bit, is there anything else I should have changed between sohc and dohc?

08-06-2006, 06:58 PM	#2
NemeGuero No more nissan. Join Date: Jan 2003 Location: RAIN, Washington. Age: 40 Posts: 8,132 Trader Rating: (10) Rides Gallery: NemeGuero Feedback Score: 10 reviews	How did you do the boost leak tester? If you have low vacuum at idle, you have a vacuum leak. Spray carb cleaner around the intake manifold (with the engine running) and when you hear the engine revv up.. you will have found your leak. What MAF are you using? An SAFC isn't really the best especially with 50lb injectors. __________________

08-06-2006, 07:15 PM	#4
alpalwal1 Join Date: Oct 2005 Location: Ca Posts: 46 Trader Rating: (0) Feedback Score: 0 reviews	alright... for the safc i just turned everything back about 4 %.... not the best tune but not bad enough to do this. for the boost leak tester i put a coupler with a cap and a plug at the beginning of my charge piping and then pressurize it with a compressor. the safc will go away when i get my enthalpy after break in stock maf .. and i do have a wideband, i just havent tuned yet lastly... if i give it any gas it dies... lightly over 30% throttle give or take, and any sudden movements and it dies almost instantly. Last edited by alpalwal1; 08-06-2006 at 08:10 PM..

08-07-2006, 11:42 PM	#6
bongnak Zilvia Junkie Join Date: Jan 2005 Location: So-Cal Age: 41 Posts: 337 Trader Rating: (3) Feedback Score: 3 reviews	ka-t? dual or single try checking the injectors especially if its a dual cam; since theres two o-rings they might have been messed up when installed. __________________ Zzzz

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08-07-2006, 11:06 PM	#5
alpalwal1 Join Date: Oct 2005 Location: Ca Posts: 46 Trader Rating: (0) Feedback Score: 0 reviews	up up and away for an answer.... i know there has to be a semi simple fix for this.... help!!!

08-08-2006, 03:36 PM	#7
alpalwal1 Join Date: Oct 2005 Location: Ca Posts: 46 Trader Rating: (0) Feedback Score: 0 reviews	what about the injectors? they fire and im almost positive theyre in the right order.. whaht else to check?