np20412

I have an auto 94 SC3, just wondering what everyone's engine idles at RPM wise once it gets warmed. i.e. if you put in P with the temp gauge at normal temp, what is your RPM reading? My car reads 800 RPM, is that low? Also today, I was sitting in the car with the car on (and in P) reading some mail, and I heard the exhaust notes changing (it sounded like it was sputtering). and immediately shot my view to the Tach which had temporarily fallen to 600. I immediately gave the car some gas to prevent a stall, which worked. I then spent the next 20 minutes trying to replicate what I had heard, to no avail. Any idea what happened and if it will happen again (is it anything to be worried about?)?

Cloud9

iTrader: (2)

that has never happened to me. for comparasion's sake, i have a SC300 5sp and it idles around 600-800 when fully warmed up.

RaynArt

if its dropping...... vacuum leak? ever happen when your in D?

mikevogel

was your ac on?

np20412

No sir, AC was OFF, since my windows were open, otherwise I may not have even heard the change in exhaust note. I fooled around turning it on and off after this happened, and noticed that the RPM stayed at 800 when I turned the AC ON, then as soon as I turned it off, the RPM rose to 900-950 and slowly fell back to 800. This has never happened before at all, I've never experienced any kind of bog or sputter in D.

97Soarer

iTrader: (2)

What's everyone RPM idle at when you FIRST start your car in the morning. I typically warm up my cars a lil and notice the RPM stays near 2,200. Is this normal? I have a IS300 w/ the 2JZ engine and it idles at 1,100 when first started. I run 5-10W oil so it doesn't take too long to get the oil moving.

RaynArt

cold start: summer time - round 1,500
winter time - round 2k

once i get to operating temp. its around 700/750, right around there. but i have a vacuum leak so when im in drive and it sits for a bit at a light it slowly drops. *sigh

np20412

Well, the worst that could have come of this problem occurred today. I was sitting at a red light today on my way to work and the engine did the same little sputtering as described earlier, except this time I was in D. I put the car into N and blipped the gas. The car returned to normal operation. No more than 10 seconds later (after I returned the shifter to D), the car sputtered again, this time MUCH more severely. The engine RPMs dropped to ZERO. My car stalled on me . Full stall, I had to restart the engine at the traffic light. What could have caused this, what is causing this recent sputtering/dropping of RPM while at idle? I know my air filter has not been replaced in a long time, is it possible that the engine is not getting any air during standstill and is causing this? Also my spark plugs are getting old and need replacing, I am about to hit 100k and don't think they've been changed since 65k. Also I am due for an oil change. I am going to do all this maintenance next weekend and see if the problem persists, but what else could possibly be causing a repeated sputtering like this at idle?

Note: A/C / Heater was OFF when this occured, stereo was on, lights were off.

Note2: Car was at normal operating Temp, as I was about 15 minutes into my drive. Also, as RaynArt mentioned, could there really be a vacuum leak? How can I check for this?

VJ RC51

1JZ with idle control motor bypassed, just screw on throttle body...

When its cold and cold out (50 degrees) = 500-600
Up to temp = up to 1000rpm

BLK13X

My motor is a 1JZ VVTi so I dunno if it's applicable BUT...
First start up idle: 1500~1700RPM then gradually reaches a steady 900RPM
Warmed up idle: 600RPM in any of the drive gears (D/2/L/R), 800RPM in Neutral or Park.

The stall could've happened due to a number of things...
* Faulty fuel pump
* Faulty fuel pump ECU
* Bad spark plugs or plug wires
* Faulty AFM...

The list goes on. Process of elimination is the key here. In the case of my old car (which wouldn't hold a steady idle when the blinkers/hazards were on) it was bad grounding so I strapped another ground cable from the battery straight to the body and I never had any problems after that.




Jose

VJ RC51

ppl still use the fuel pump ecu????

BLK13X

If the car's stock most likely

np20412

Thanks for the list man, and you are damn right that process of elimination is the way to go. From my searching I found about 18 different things it could be. I doubt I have dirty injectors, I never run the car with less than 1/4 tank. I will change the plugs and dist. cap/rotor as well as an oil change soon and check for the Vac leak at the same time. If the problem persists (right now it seems to be ina very early stage, signs are pointing to a fuel pump ECU problem, one that can cause a stall once and not bring another problem of the type for quite some time) then I will check the fuel pump itself as well as teh ECU and MAF sensor wiring. Wow, what a multitude of possible causes. Wish me luck, I need my SC for 4 more years

The other thing I read about was a problem in the catalytic converters. I've had this fully custom catback exhaust system for a little over 5 years now, it's possible something is wrong there as well but how the hell do I check for that. If I have to end up going to a shop for that, I will have them take off my resonators as well

Psionic

Did you ever figure out your problem?

np20412

Nope, I just let it be for now. I have a feeling it's a clogged fuel filter, from what I gather with service records and what not, it's never been changed.

It doesn't happen as often anymore, I never stalled out again after that day, in fact, I haven't even experienced anymore RPM drop.