sr20det Problems starting when motor is hot. - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

t.vo408 · 06-01-2010, 04:22 PM

When I start the motor cold it starts up just fine, idles at around 1000, when its all warmed up it idles at around 6-700. But if I try to start it up right after a drive (at operating temp) it will sputter, try to stay alive, then bog out. But if I give it a little gas to help keep it alive for a few seconds then she will idle just fine at around 6-700 without dieing. Drives fine.

I thought this was a vacuum leak, but I couldn't find any leaks and its odd that it only happens when the motor is warm or hot. HELP!!

I have a stock sr20det with front mount, exhaust, and recirculated BOV. Pretty confused..

Sileighty_85 · 06-01-2010, 05:55 PM

Check ECU for codes

but sounds like the coolant temp sensor for the ECU

*ManoNegra* · 06-01-2010, 06:18 PM

check your TPS
same thing happened to me once,
turned out to be a poorly plugged TPS connector

240Zfunahollic · 06-03-2010, 08:27 PM

Id say cts too, but it bogs when driving... also, isnt idling at 6-700 a little low?

t.vo408 · 06-03-2010, 09:42 PM

I checked the connection on the TPS and it seems good with no dead spots. I am also thinking it is the coolant temp sensor, I'm going to go ahead and change both of them when I get the chance since my gauge reads hot hot after warm up. I am also thinking I might have an injector leak or bad injector o ring because I am getting some knarly gas fumes. BUT that may also be caused by a bad CTS making the car run rich. I'll let you guys know what happens.

BTW I have a 93 with a s13 blacktop. Will a CTS and Coolant switch from a 89-94 240sx ka24de work with the sr20det? I think it will but just wanted to make sure.

t.vo408 · 06-04-2010, 01:19 AM

What should stock idle be? Another thing, I think the car may be running rich. At stoplights and idle I can smell exhaust/gas fumes that are abnormally strong. I am really hoping this is a symptom of a bad CTS as well.

t.vo408 · 06-05-2010, 01:44 AM

Another thing I noticed after driving awhile. After warmed up sometimes the idle will be hunting from 500-1000 at stoplights, and will sometimes stal coming to a stop light... Bought some maf cleaner, contact cleaner, and ECT and temp switch for the gauge too. Will clean up the connections and maf first to see if there are any improvements. Then will try swapping out the sensors. Fingers Crossed!

djcobra · 06-05-2010, 02:00 AM

Try Cleaning the IACV or try adjusting it, counter clockwise to increase idle and clockwise to decrease idle. (this is for the S14 SR should be the same on the S13).

t.vo408 · 06-05-2010, 02:40 AM

Will try that in the morning. I was just messing with that earlier today and say that it was fully shut (all the way in) to begin with, is that normal?

inyowindow · 06-05-2010, 02:59 AM

Make sure there arent any leaks in your intercooler piping

t.vo408 · 06-06-2010, 05:09 PM

Success!! Then failure.

So, I changed out the temperature switch, cleaned all the connectors with contact cleaner, and cleaned the IACV, then adjusted the closed loop idle to 900 via the plastic screw and all seems to be well. Drove it around for about an hour and found out 1/4 tank actually means empty.

The way I cleaned out the IACV was to remove the idle adjustment screw, and the hose that runs to the cold pipe and sprayed MAF spray in the screw hole until it shot out the other side, then let dry overnight. Then I took crank sensor off and fuel fuse out and cranked it a few times just to make sure the MAF cleaner doesnt flood the cylinder. EVEN with the new temperature switch (single prong ones that goes to gauge) my gauge it still reaching the 1st hot dot on the gauge, which is kind of pissing me off.

Because it ran so well, I decided to make it run not so well by venting the BOV to atmosphere to see how it sounded. It was running great, but had slight compressor surge. No stalling or idle problems, but oddly enough it sounded about the same loudness as recirc'd. So I was adjusting my cheap type s knockoff and accidentally stripped the threads and that cheap shit aluminum. So I'm out of commission until that gets fixed.

My hot idle and hot start problems were gone though! But with these things you gotta test them for a few days to make sure, so I'll keep you guys updated when I fix that damn BOV.

DDP288 · 11-23-2014, 11:35 PM

I no this post is like 4 years old but im having the exact same problem ive replaced my cts (2pin) and cleaned my iacv and even tryed another one off another car cant find any vacuum leaks,cheaked earths. anyone got any ideas running a sr20de + supercharger setup with a apexi ecu with power fc controller. also replaced dizzy cap rotor cause they were stuffed and new plugs leads are prety new also.

06-01-2010, 04:22 PM	#1
t.vo408 Join Date: Apr 2010 Location: CA Posts: 47 Trader Rating: (0) Feedback Score: 0 reviews	sr20det Problems starting when motor is hot. When I start the motor cold it starts up just fine, idles at around 1000, when its all warmed up it idles at around 6-700. But if I try to start it up right after a drive (at operating temp) it will sputter, try to stay alive, then bog out. But if I give it a little gas to help keep it alive for a few seconds then she will idle just fine at around 6-700 without dieing. Drives fine. I thought this was a vacuum leak, but I couldn't find any leaks and its odd that it only happens when the motor is warm or hot. HELP!! I have a stock sr20det with front mount, exhaust, and recirculated BOV. Pretty confused..

06-01-2010, 05:55 PM	#2
Sileighty_85 Post Whore! Join Date: Dec 2006 Location: Misawa, Japan Posts: 6,815 Trader Rating: (8) Feedback Score: 8 reviews	Check ECU for codes but sounds like the coolant temp sensor for the ECU __________________ 後輪駆動車１番 1989 Built SR GT2871R -363whp 1998 S14 W/RB25- 250ish (For Now) 1986 SR86 - 200ish 1990 R32 GTR - 320hp Don't Buy Engines from JDM-Online http://zilvia.net/f/businesses/207457-jdm-online.html Don't Buy XS-Power or SSAC Shit

06-03-2010, 08:27 PM	#4
240Zfunahollic Zilvia Addict Join Date: Aug 2003 Location: South Carolina Age: 37 Posts: 607 Trader Rating: (35) Feedback Score: 35 reviews	Id say cts too, but it bogs when driving... also, isnt idling at 6-700 a little low? __________________ Visit My Trader rating page http://zilvia.net/f/traderratings.html?u=15347

06-05-2010, 02:00 AM	#8
djcobra Zilvia Junkie Join Date: Aug 2006 Location: Calgary Age: 45 Posts: 306 Trader Rating: (1) Feedback Score: 1 reviews	Try Cleaning the IACV or try adjusting it, counter clockwise to increase idle and clockwise to decrease idle. (this is for the S14 SR should be the same on the S13). __________________ S14 326 whp, 311 tq @ 15 psi HKS F-CON V-PRO

11-23-2014, 11:35 PM	#12
DDP288 Join Date: Nov 2014 Location: Tauranga Nz Age: 29 Posts: 2 Trader Rating: (0) Feedback Score: 0 reviews	same problem I no this post is like 4 years old but im having the exact same problem ive replaced my cts (2pin) and cleaned my iacv and even tryed another one off another car cant find any vacuum leaks,cheaked earths. anyone got any ideas running a sr20de + supercharger setup with a apexi ecu with power fc controller. also replaced dizzy cap rotor cause they were stuffed and new plugs leads are prety new also.

06-01-2010, 06:18 PM	#3
ManoNegra Guild of Skullduggerous Intent Join Date: Jan 2004 Location: Socal Posts: 7,841 Trader Rating: (48) Feedback Score: 48 reviews	check your TPS same thing happened to me once, turned out to be a poorly plugged TPS connector

06-03-2010, 09:42 PM	#5
t.vo408 Join Date: Apr 2010 Location: CA Posts: 47 Trader Rating: (0) Feedback Score: 0 reviews	I checked the connection on the TPS and it seems good with no dead spots. I am also thinking it is the coolant temp sensor, I'm going to go ahead and change both of them when I get the chance since my gauge reads hot hot after warm up. I am also thinking I might have an injector leak or bad injector o ring because I am getting some knarly gas fumes. BUT that may also be caused by a bad CTS making the car run rich. I'll let you guys know what happens. BTW I have a 93 with a s13 blacktop. Will a CTS and Coolant switch from a 89-94 240sx ka24de work with the sr20det? I think it will but just wanted to make sure.

06-04-2010, 01:19 AM	#6
t.vo408 Join Date: Apr 2010 Location: CA Posts: 47 Trader Rating: (0) Feedback Score: 0 reviews	What should stock idle be? Another thing, I think the car may be running rich. At stoplights and idle I can smell exhaust/gas fumes that are abnormally strong. I am really hoping this is a symptom of a bad CTS as well.

06-05-2010, 01:44 AM	#7
t.vo408 Join Date: Apr 2010 Location: CA Posts: 47 Trader Rating: (0) Feedback Score: 0 reviews	Another thing I noticed after driving awhile. After warmed up sometimes the idle will be hunting from 500-1000 at stoplights, and will sometimes stal coming to a stop light... Bought some maf cleaner, contact cleaner, and ECT and temp switch for the gauge too. Will clean up the connections and maf first to see if there are any improvements. Then will try swapping out the sensors. Fingers Crossed!

06-05-2010, 02:40 AM	#9
t.vo408 Join Date: Apr 2010 Location: CA Posts: 47 Trader Rating: (0) Feedback Score: 0 reviews	Will try that in the morning. I was just messing with that earlier today and say that it was fully shut (all the way in) to begin with, is that normal?

06-05-2010, 02:59 AM	#10
inyowindow Leaky Injector Join Date: Sep 2006 Location: NorCal Age: 37 Posts: 53 Trader Rating: (1) Feedback Score: 1 reviews	Make sure there arent any leaks in your intercooler piping

06-06-2010, 05:09 PM	#11
t.vo408 Join Date: Apr 2010 Location: CA Posts: 47 Trader Rating: (0) Feedback Score: 0 reviews	Success!! Then failure. So, I changed out the temperature switch, cleaned all the connectors with contact cleaner, and cleaned the IACV, then adjusted the closed loop idle to 900 via the plastic screw and all seems to be well. Drove it around for about an hour and found out 1/4 tank actually means empty. The way I cleaned out the IACV was to remove the idle adjustment screw, and the hose that runs to the cold pipe and sprayed MAF spray in the screw hole until it shot out the other side, then let dry overnight. Then I took crank sensor off and fuel fuse out and cranked it a few times just to make sure the MAF cleaner doesnt flood the cylinder. EVEN with the new temperature switch (single prong ones that goes to gauge) my gauge it still reaching the 1st hot dot on the gauge, which is kind of pissing me off. Because it ran so well, I decided to make it run not so well by venting the BOV to atmosphere to see how it sounded. It was running great, but had slight compressor surge. No stalling or idle problems, but oddly enough it sounded about the same loudness as recirc'd. So I was adjusting my cheap type s knockoff and accidentally stripped the threads and that cheap shit aluminum. So I'm out of commission until that gets fixed. My hot idle and hot start problems were gone though! But with these things you gotta test them for a few days to make sure, so I'll keep you guys updated when I fix that damn BOV.