Complete Rebuild: Wont idle, or Rev. SAFC, Z32 MAF - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

msanchez · 01-05-2011, 01:19 AM

Here's the sitch
Did a complete rebuild: valve job, bearings, rings, hg machine work, etc.
Put it back together, and the car fired right up. It will idle, but it idles pretty rough with misfires and will eventually die if i leave it alone for a minute or two. The idle will jump from 800 to 1700rpms. It idles like the timing is off, but i cant set ignition timing with the rpms bouncing around. Cam timing is spot on. I tried adjusting the iacv, but that did nothing to alleviate the symptoms.
I have fuel and spark.
The safc is set to 2in 6out.

So what does this sound like? I need somewhere to start, so i can start eliminating the possible problems. Iacv? tps? temp sensors? boost leak somewhere? Help me out.

Ps. the harness was already wired for a z32 maf, and the safc came pretty cheap so i went with it. i know there is no need for it yet, so please dont bother me with your negative safc comments.
Motor : freddy, 264 cams, tubular header, t25, stock injectors, pbm midmount, safc2, z32 maf.

ZenKi_373 · 01-05-2011, 09:18 AM

had a similar problem with it fluctuation from 700-1100.

found a vacumm leak and turned the dizzy back a tooth and it now idles great w/o dying.

nismoman · 01-05-2011, 09:24 AM

Did you Install the safc after the rebuild? If not I would say timing is the first thing to check. Loosen the distributor and adjust it a bit without a timing light to see if it makes any difference. You might wanna try to Restab it too. Might be off a tooth

msanchez · 01-05-2011, 01:21 PM

It could be off a tooth.. Ill recheck.
yes, the safc was installed after the rebuild.
Ill check for vacuum leaks again, havent been able to find any thus far.

msanchez · 01-06-2011, 01:35 PM

Ok, we rewired the stock maf back in. that solved some of the problems. The z32 maf was a known, working unit, so i guess my safc settings must have been off? i dont know.
also, the tps voltage was off. I set it up the first time using the safc, which isnt accurate. reset it with a multimeter. Finally the cam timing was a tooth off. but that was impossible to fix until the maf an tps problems were worked out.

Just some info for future searchers. Z32 maf settings for a redtop MIGHT NOT BE 2in, 6out on the safc2

01-05-2011, 01:19 AM	#1
msanchez Zilvia Junkie Join Date: Jan 2009 Location: Sacramento, California Posts: 324 Trader Rating: (3) Feedback Score: 3 reviews	Complete Rebuild: Wont idle, or Rev. SAFC, Z32 MAF Here's the sitch Did a complete rebuild: valve job, bearings, rings, hg machine work, etc. Put it back together, and the car fired right up. It will idle, but it idles pretty rough with misfires and will eventually die if i leave it alone for a minute or two. The idle will jump from 800 to 1700rpms. It idles like the timing is off, but i cant set ignition timing with the rpms bouncing around. Cam timing is spot on. I tried adjusting the iacv, but that did nothing to alleviate the symptoms. I have fuel and spark. The safc is set to 2in 6out. So what does this sound like? I need somewhere to start, so i can start eliminating the possible problems. Iacv? tps? temp sensors? boost leak somewhere? Help me out. Ps. the harness was already wired for a z32 maf, and the safc came pretty cheap so i went with it. i know there is no need for it yet, so please dont bother me with your negative safc comments. Motor : freddy, 264 cams, tubular header, t25, stock injectors, pbm midmount, safc2, z32 maf.

01-05-2011, 09:24 AM	#3
nismoman Zilvia Junkie Join Date: Jul 2005 Location: Bowie, MD Posts: 412 Trader Rating: (0) Feedback Score: 0 reviews	Did you Install the safc after the rebuild? If not I would say timing is the first thing to check. Loosen the distributor and adjust it a bit without a timing light to see if it makes any difference. You might wanna try to Restab it too. Might be off a tooth __________________

01-05-2011, 09:18 AM	#2
ZenKi_373 Zilvia Member Join Date: Aug 2010 Location: El Paso, TX Age: 31 Posts: 221 Trader Rating: (3) Feedback Score: 3 reviews	had a similar problem with it fluctuation from 700-1100. found a vacumm leak and turned the dizzy back a tooth and it now idles great w/o dying.

01-05-2011, 01:21 PM	#4
msanchez Zilvia Junkie Join Date: Jan 2009 Location: Sacramento, California Posts: 324 Trader Rating: (3) Feedback Score: 3 reviews	It could be off a tooth.. Ill recheck. yes, the safc was installed after the rebuild. Ill check for vacuum leaks again, havent been able to find any thus far.

01-06-2011, 01:35 PM	#5
msanchez Zilvia Junkie Join Date: Jan 2009 Location: Sacramento, California Posts: 324 Trader Rating: (3) Feedback Score: 3 reviews	Ok, we rewired the stock maf back in. that solved some of the problems. The z32 maf was a known, working unit, so i guess my safc settings must have been off? i dont know. also, the tps voltage was off. I set it up the first time using the safc, which isnt accurate. reset it with a multimeter. Finally the cam timing was a tooth off. but that was impossible to fix until the maf an tps problems were worked out. Just some info for future searchers. Z32 maf settings for a redtop MIGHT NOT BE 2in, 6out on the safc2