91 240 ka24de running weird. - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

91240coupe · 10-31-2014, 12:33 PM

I got a 91 s13 with a ka24de with 149k miles. I just recently put in a new injen air intake and it ran perfect. Car has an exhaust leak right now from the cat and im going to get it welded soon.

Now when i park and let the car idle it would rev up to 1400-1900 rpm for about 30sec to maybe a minute then it would drop down to normal idle. Not sure if maf has a small leak somewhere or something else.

But i do know i have a bmc vacuum leak idk if its because of that leak my car is idling high then back to normal.

i hope i explained it good. thank you.

TheMechanic · 11-13-2014, 02:11 AM

check engine light when this happens? if so pull codes when it does it.. could be IAC tripping out... as far as the reason... could be dirty... could have an electrical problem

OnTheChip · 11-13-2014, 08:00 AM

A bmc vacuum leak will definitely cause idle problems.

TheMechanic · 11-13-2014, 10:28 AM

is that the egr modulator? ive heard the elbow likes to crack

91240coupe · 11-26-2014, 08:54 AM

Quote:

Originally Posted by TheMechanic

check engine light when this happens? if so pull codes when it does it.. could be IAC tripping out... as far as the reason... could be dirty... could have an electrical problem

No check engine light.

91240coupe · 11-26-2014, 08:54 AM

Quote:

Originally Posted by OnTheChip

A bmc vacuum leak will definitely cause idle problems.

Ive checked the hoses and not sure if the hoses are bad. Hoses looked pretty good

frankies1390 · 11-27-2014, 12:55 PM

try unplugging sensors first.. such as coolant temp sensor, maf, but id focus on idle air control valve pull it, check it, clean it

jza80king · 11-27-2014, 09:11 PM

Just recently bought and replaced all the vacuum hoses on my car. Take a spray bottle and add dish soap and water. Go around spraying carefully and you should be able to pinpoint any vacuum leaks with bubbles. Once that is done I would look into the IACV and clean as mentioned above.

kruked · 11-27-2014, 11:51 PM

Start w/ the obvious and fix the BMC leak first. Any vacuum leak will cause various problems.
Leave the IACV as the second thing to check once you fix/replace the BMC.

91240coupe · 11-29-2014, 01:44 PM

Thanks guys!!!!

trikk · 12-07-2014, 06:31 PM

did you ever fix the problem?

91240coupe · 12-07-2014, 09:48 PM

Quote:

Originally Posted by trikk

did you ever fix the problem?

Havent had time to check it out.

91240coupe · 12-24-2014, 03:59 PM

Ok update guys!! So i tried unplugging the iac and all of a sudden idle goes back to normal.... i would start it and bam it normal at idle 800-900

10-31-2014, 12:33 PM	#1
91240coupe Zilvia Member Join Date: Jun 2011 Location: San Diego,CA Posts: 154 Trader Rating: (0) Feedback Score: 0 reviews	91 240 ka24de running weird. I got a 91 s13 with a ka24de with 149k miles. I just recently put in a new injen air intake and it ran perfect. Car has an exhaust leak right now from the cat and im going to get it welded soon. Now when i park and let the car idle it would rev up to 1400-1900 rpm for about 30sec to maybe a minute then it would drop down to normal idle. Not sure if maf has a small leak somewhere or something else. But i do know i have a bmc vacuum leak idk if its because of that leak my car is idling high then back to normal. i hope i explained it good. thank you.

11-13-2014, 08:00 AM	#3
OnTheChip Zilvia Junkie Join Date: May 2013 Location: Burgaw, NC Posts: 311 Trader Rating: (0) Feedback Score: 0 reviews	A bmc vacuum leak will definitely cause idle problems. __________________ NismotronicSA - Speed-Density Tuning for Nissans

11-27-2014, 11:51 PM	#9
kruked Nissanaholic! Join Date: Feb 2012 Location: someone's sisters' pants Posts: 2,288 Trader Rating: (37) Feedback Score: 37 reviews	Start w/ the obvious and fix the BMC leak first. Any vacuum leak will cause various problems. Leave the IACV as the second thing to check once you fix/replace the BMC. __________________ I like my bikes how I like my b¡tches...naked! 2014 Triumph Street Triple

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11-13-2014, 02:11 AM	#2
TheMechanic Join Date: May 2014 Location: Chino, Ca Age: 32 Posts: 21 Trader Rating: (0) Feedback Score: 0 reviews	check engine light when this happens? if so pull codes when it does it.. could be IAC tripping out... as far as the reason... could be dirty... could have an electrical problem

11-13-2014, 10:28 AM	#4
TheMechanic Join Date: May 2014 Location: Chino, Ca Age: 32 Posts: 21 Trader Rating: (0) Feedback Score: 0 reviews	is that the egr modulator? ive heard the elbow likes to crack

11-27-2014, 12:55 PM	#7
frankies1390 Zilvia Junkie Join Date: Nov 2010 Location: Eugene Posts: 446 Trader Rating: (9) Feedback Score: 9 reviews	try unplugging sensors first.. such as coolant temp sensor, maf, but id focus on idle air control valve pull it, check it, clean it

11-27-2014, 09:11 PM	#8
jza80king Leaky Injector Join Date: Aug 2014 Location: Utah Posts: 92 Trader Rating: (0) Feedback Score: 0 reviews	Just recently bought and replaced all the vacuum hoses on my car. Take a spray bottle and add dish soap and water. Go around spraying carefully and you should be able to pinpoint any vacuum leaks with bubbles. Once that is done I would look into the IACV and clean as mentioned above.

11-29-2014, 01:44 PM	#10
91240coupe Zilvia Member Join Date: Jun 2011 Location: San Diego,CA Posts: 154 Trader Rating: (0) Feedback Score: 0 reviews	Thanks guys!!!!

12-07-2014, 06:31 PM	#11
trikk Zilvia Junkie Join Date: Oct 2005 Location: Farmingdale, New York Age: 36 Posts: 418 Trader Rating: (19) Feedback Score: 19 reviews	did you ever fix the problem?

12-24-2014, 03:59 PM	#13
91240coupe Zilvia Member Join Date: Jun 2011 Location: San Diego,CA Posts: 154 Trader Rating: (0) Feedback Score: 0 reviews	Ok update guys!! So i tried unplugging the iac and all of a sudden idle goes back to normal.... i would start it and bam it normal at idle 800-900