Jump to content
SAU Community

Recommended Posts

Idling then dies

IDLING ISSUES!!
Hey guys, I have a 1994 r33 gts25t auto (rb25det). On cold start I have to use the throttle to get it going and use the throttle to warm it up. When it's warm 5 mins later I release the throttle for it to idle and it slowly dies. Start it back up with no throttle and she runs mint for 30 seconds then it dies again. Within that 30 seconds I can touch the throttle and it will idle until 30 seconds is up then again....it dies. Try to blip the throttle after that 30 seconds and it dies again. I have...

Resoldered the afm and fitted another working afm.
Replaced aac valve.
Set tps to .45V.
Fitted another relay for a constant 12V to the fuel pump.
Opened up cold start valve and it was clean as.
Vacuum tested the intake and no leaks occurred.

Removed and cleaned throttle body right up.
Checked ecu for codes, nothing appeared.
Replaced temp sensor.
BCPR6ES gapped to .8.
Cleaned cam angle sensor.
Checked ecu for any burn or corroded connections inside.

 

Anyone please help me if they have had this issue, I've never heard of it happening.

Link to comment
https://www.sau.com.au/forums/topic/471382-idling-then-dies/
Share on other sites

I pressurized the inlet system for any vacuum leaks and there aren't any, visually looked at all the lines also.

 

While driving I have to double foot it so it won't die at lower speeds and stopping. (Just the same idling issue) I feel like something is drawing the current iswell because it won't start after a couple days of not starting. It slow cranks when that happens but then some times it's starts up ? it is charging, I checked with a multi meter. Maybe need to do another test of some sort? 

Pressure test the fuel system. FPRs rarely fail but good to check. have you replaced the fuel filter in the engine bay? Long shot if you can swap out the ecu with someone just to eliminate that as a problem.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • @Haggerty you still haven't answered my question.  Many things you are saying do not make sense for someone who can tune, yet I would not expect someone who cannot tune to be playing with the things in the ECU that you are.  This process would be a lot quicker to figure out if we can remove user error from the equation. 
    • If as it's stalling, the fuel pressure rises, it's saying there's less vacuum in the intake manifold. This is pretty typical of an engine that is slowing down.   While typically is agree it sounds fuel related, it really sounds fuel/air mixture related. Since the whole system has been refurbished, including injectors, pump, etc, it's likely we've altered how well the system is delivering fuel. If someone before you has messed with the IACV because it needed fiddling with as the fuel system was dieing out, we need to readjust it back. Getting things back to factory spec everywhere, is what's going to help the entire system. So if it idles at 400rpm with no IACV, that needs raising. Getting factory air flow back to normal will help us get everything back in spec, and likely help chase down any other issues. Back on IACV, if the base idle (no IACV plugged in) is too far out, it's a lot harder for the ECU to control idle. The IACV duty cycle causes non linear variations in reality. When I've tuned the idle valves in the past, you need to keep it in a relatively narrow window on aftermarket ecus to stop them doing wild dances. It also means if your base idle is too low, the valve needs to open too much, and then the smallest % change ends up being a huge variation.
    • I guess one thing that might be wrong is the manifold pressure.  It is a constant -5.9 and never moves even under 100% throttle and load.  I would expect it to atleast go to 0 correct?  It's doing this with the OEM MAP as well as the ECU vacuum sensor. When trying to tune the base map under load the crosshairs only climb vertically with RPM, but always in the -5.9 column.
    • AHHHH gotchaa, I'll do that once I am home again. I tried doing the harness with the multimeter but it seems the car needed a jump, there was no power when it was in the "ON" position. Not sure if I should use car battery jump starter or if its because the stuff that has been disconnect the car just does send power.
    • As far as I can tell I have everything properly set in the Haltech software for engine size, injector data, all sensors seem to be reporting proper numbers.  If I change any injector details it doesnt run right.    Changing the base map is having the biggest change in response, im not sure how people are saying it doesnt really matter.  I'm guessing under normal conditions the ECU is able to self adjust and keep everything smooth.   Right now my best performance is happening by lowering the base map just enough to where the ECU us doing short term cut of about 45% to reach the target Lambda of 14.7.  That way when I start putting load on it still has high enough fuel map to not be so lean.  After 2500 rpm I raised the base map to what would be really rich at no load, but still helps with the lean spots on load.  I figure I don't have much reason to be above 2500rpm with no load.  When watching other videos it seems their target is reached much faster than mine.  Mine takes forever to adjust and reach the target. My next few days will be spent making sure timing is good, it was running fine before doing the ECU and DBW swap, but want to verify.  I'll also probably swap in the new injectors I bought as well as a walbro 255 pump.  
×
×
  • Create New...