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CA18det cold start idle 

19 replies to this topic

#1 rtr_510

  • Joined:13-June 06

Posted 11 August 2006 - 02:00 PM

in the mornings my car idles rough around 750rpm sometimes as low as 600rpm... usually when the car is cold, the air regulator should send a signal to the ecu to make the car idle around 1500rpm, until it is warm... and drop backs down.

my ca doesnt do that, it would just idle rough / unstable

i have cleaned the following connections and check for broken wires:

AFM
Coil leads
coil packs
all injector connectors
air regulator connector
a.a.c connector
coolant temp sensor connector
i hvae advanced the ignition timing
adjusted idle screw
adjusted TPS

Now when it is warm the car idles fine.. but cold morning idle is very unstable. I have done an ecu diagnostic test and got 2 errors,

coolant sensor

and

detonation sensor

any ides??

#2 bradkh888

  • Joined:04-November 04
  • Location:Australia QLD
  • Car:pos

Posted 11 August 2006 - 02:39 PM

well..if it was the coolant sensor, wouldnt the heater gauge not work?

neways, gl, i have the same problem so some1 help us both out.

#3 bradkh888

  • Joined:04-November 04
  • Location:Australia QLD
  • Car:pos

Posted 11 August 2006 - 02:58 PM

o btw..you've forgotten to check one thing.

the IAC (idle air controller, different from AAC i believe) which
sits just in front of and below the throttle body.

#4 skyquez

  • Joined:13-May 05
  • Location:Australia VIC
  • Car:350GT

Posted 11 August 2006 - 05:36 PM

I have the same problem and you can't seem to really adjust the idling... <_<

#5 wokstrx7

  • Joined:03-August 05
  • Location:Australia VIC
  • Car:s13 silvia

Posted 11 August 2006 - 07:55 PM

replace the CTS and clear the fault codes on ur ecu and u will find ur cold start idle will be stable again. worked for me and fixed my fuel ecconomy problem. im assuming ur car is CA?

#6 s13nut

  • Joined:02-January 06
  • Location:Australia VIC
  • Car:nissan s13

Posted 12 August 2006 - 11:13 AM

hey fellers the temp gauge on the dash is not controlled from the engine temp sensor it goes striagh to the ecu i had that fault on my ecu and i just changed over my engine temp sensor worked fine. made shit all differ but ey

#7 rtr_510

  • Joined:13-June 06

Posted 12 August 2006 - 05:40 PM

yes its a ca...

#8 sogoob

  • Joined:22-October 05

Posted 12 August 2006 - 09:37 PM

[quote name='wokstrx7' date='Aug 11 2006, 08:08 PM' post='2463712']
replace the CTS and clear the fault codes on ur ecu and u will find ur cold start idle will be stable again. worked for me and fixed my fuel ecconomy problem. im assuming ur car is CA?
[/quote

What is the CTS because i have the same problem with mine

#9 wokstrx7

  • Joined:03-August 05
  • Location:Australia VIC
  • Car:s13 silvia

Posted 12 August 2006 - 10:44 PM

coolant temp sensor^^^^

#10 sogoob

  • Joined:22-October 05

Posted 14 August 2006 - 12:51 AM

where abouts is the cts i gotta find this prob on mine too! cheers

#11 Lucius

  • Joined:20-April 05
  • Location:Australia NSW
  • Car:S13 Silvia

Posted 14 August 2006 - 12:28 PM

if your coolant temp sensor and knock sensor are gone then you will be experiencing amoung other things, retarded timing and richer fuel mixtures. Both of which wouldn't be any good for your cold starts...

if your knock sensor is gone you will also notice really crap performance on boost...

Quote

the IAC (idle air controller, different from AAC i believe) which
sits just in front of and below the throttle body.

The IACV system consists of the AAC, FICD and idle adjustment screw, all of which are located on the topside of your engine, between your intake and cam covers, the part underneath the throttle body that you are refering to is called the Air Regulator.

#12 rtr_510

  • Joined:13-June 06

Posted 14 August 2006 - 12:52 PM

View PostLucius, on Aug 13 2006, 03:11 PM, said:

if your coolant temp sensor and knock sensor are gone then you will be experiencing amoung other things, retarded timing and richer fuel mixtures. Both of which wouldn't be any good for your cold starts...

if your knock sensor is gone you will also notice really crap performance on boost...

Quote

the IAC (idle air controller, different from AAC i believe) which
sits just in front of and below the throttle body.

The IACV system consists of the AAC, FICD and idle adjustment screw, all of which are located on the topside of your engine, between your intake and cam covers, the part underneath the throttle body that you are refering to is called the Air Regulator.

correct, my cts is stuffed, i do have another spared on, so i will be chucking that in tonight, well c how it goes... my car under boost sh1ts out alot of black smoke so that could also be the problem... i have an e-manage hookup and it has stop the 'detonating'.

well c how it goes, and hopefully any1 else with the same prob will be able to fix theirs to

i will be checking up on the air regulator to see if there is anything stuck in the opening ( carb/ dirt/ wateva).

will keep u guys informed.

#13 Lucius

  • Joined:20-April 05
  • Location:Australia NSW
  • Car:S13 Silvia

Posted 14 August 2006 - 01:00 PM

Quote

correct, my cts is stuffed, i do have another spared on, so i will be chucking that in tonight, well c how it goes... my car under boost sh1ts out alot of black smoke so that could also be the problem... i have an e-manage hookup and it has stop the 'detonating'.

you shouldn't have any detonating if the knock sensor is malfunctioning (unless your emanage is tuned really badly) as the standard ECU will automatically retard the timing as a safety precaution. This retardation becomes far more apparent when on boost, resulting in poor combustion, and a higher occurance of backfires.

#14 Mr. Conservative

  • Joined:08-September 05
  • Location:Australia QLD
  • Car:180sx

Posted 14 August 2006 - 05:38 PM

hey,

On cold mornings before work, about 15-20 degrees, my car holds steady idle at about 1200 RPM upon start up. It then slowly drops over about 3-4 minutes to about 900-1000 RPM, then i start to drive. Is this cold start idle too low? Would it mean something is f**ked?

Thanks,

MaTT

#15 g_odagi

  • Joined:18-July 06

Posted 14 August 2006 - 08:45 PM

View PostORACLe__, on Aug 14 2006, 06:21 PM, said:

hey,

On cold mornings before work, about 15-20 degrees, my car holds steady idle at about 1200 RPM upon start up. It then slowly drops over about 3-4 minutes to about 900-1000 RPM, then i start to drive. Is this cold start idle too low? Would it mean something is f**ked?

Thanks,

MaTT

no your engine is fine lol when you first start the car the air pressure regulator keeps the revs higher about 1000-1500rpms, then once the engine gets warm sits on about 800-900. Thats IF you have adjusted your idle properly

#16 DeBastaard

  • Joined:24-February 06
  • Car:200SX S13

Posted 14 August 2006 - 10:05 PM

Idle can be a bitch on the CA18's.

My car had idle problems as well.
Coldstart usually went okay, but the idle was shite. (500rpm, 1000rpm, 300rpm, 700 etc. etc.).

Once I Drove the car for a while, shut the car down and then wanted to start it again, it was having difficulties.

The problems become worse after a while, the engine dropped dead when idle'ing etc.

After reading various stuff on the internet, checking all sensors (engine temp, AAC, etc), they were all okay...

Then some dude gave me the hint, spray some brake cleaner on your inlet manifold when the engine's running, if it makes a difference, you're gaskets are f**ked.

Guess what, they were f**ked! After unbolting the inlet manifold, we immediatly saw that the gaskets were gone at various places. Placed in new ones, problem solved!

That's what I would check if I was one of you, it's a simple test, but can save you much time, and loads of frustration...

BTW, Does your AAC react on the idle-screw ? Mine didn't, because of the vacuumleak at the inlet gasket (Heard a loud suction noise as well).

#17 g_odagi

  • Joined:18-July 06

Posted 14 August 2006 - 10:29 PM

or you could just run a compression test?

#18 DeBastaard

  • Joined:24-February 06
  • Car:200SX S13

Posted 14 August 2006 - 11:55 PM

Compression was good :)

#19 rtr_510

  • Joined:13-June 06

Posted 15 August 2006 - 10:25 AM

no my idle adjustment screw does work...

*UPDATE**

I HAVE JUST PULLED OFF THE AIR REGULATOR AND IT HAD HEAPS OF CRAP (CARB N DIRT ) IN IT... GAVE IT A CLEAN... UT NOTICED THERE WAS SOMETHING BROKEN IN THE REGULATOR, EVERYTHIME I SHOOK IT AROUND I COULD HERE SOMETHING BROKEN INSIDE... NEED A NEW ONE.

#20 DeathFiend

  • Joined:17-December 05
  • Location:Australia NSW
  • Car:1991 Nissan Silvia Q's

Posted 18 December 2006 - 11:35 AM

My CA18DE is rough on cold starts, round 200-400rpm then either eventualy comes good or stalls. After the engines warm it starts fine but Ive also noticed when accelerating the car seem flat and slower then usual... Any ideas?

My car has allways used alot of fuel and not long ago i threw in some new sparkies and the car came good and was running nicely but the last 2 or 3 weeks its been like this.

Could it be the sensors said earlier in this thread?





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