Weird idle and starting problem...
 

Hi guys,

I have this weird problem here.

One fine day, my car started with crappy idle, the rev was so low that the car died. Try to start again, manage to get it started but after a few cranks. Still, the rev is so low and it died. After that, it can't be started any more. Brought to my mech, he changed the plugs and claiming the the rich AF killed/shorted the plugs. (never happend before and no additional mods took place)

It was running fine the first day, and on the 2nd day, same thing happened. Started the car with crappy idle and same problem. Sent it to another mech, he too said the plugs we killed/shorted (but didnt mention about rich AF), so he replaced a used one and clean the thorttle body. Same story, was fine the first day and 2nd day, same thing happend again. Any idea what contribute to this? I'm sure if they change the plugs again, it will be fine for 1st day and 2nd day same shit will happen again.

FYI, no lost of coolant or what so ever. The car was running fine the pass 2 yrs and no additional mods we done.

Thanks in advance for the advices :)

Your injectors could be leaking. Have you tried to unflood it before starting it the second day?

For the 2nd time, on the 2nd day, it can be started, but with crappy idle. Do i need to unflood it? I thought i need to unflood it if it can't be started.

By the way, why does leaking injectors contributes to killing plugs?

If its flooded, it will not start. Does it smoke, and what color?

Is the MAP sensor working properly, check the connections. Its located on the drivers side firewall and between the plenum/throttle body. A small black module

Next time, do a compression test. The apex seals could be seizing and making it hard to idle. Low reading on adjacent rotors and high on one is an indicator.

Smoky black.

i am kinda having the same problem. starts up but doesnt die. the rpms start out fine, then slowly drop to around 1k or less. my a/f reads medium rich back and forth when idoling, but when i'm cruising in a high gear with little throttle it reads fine(a/f very low). it stays at a low 500 rpms when i stop at a light. i thought just cause it being 40 degrees, havnt started it up in 3 weeks, and a having a very low fuel tank, that this would make it act strange. any ideas? sorry to thread jack, i just wanted a second opinion(have trouble trusting my own)

Its hard to find a solution with so little information. You could either have a simple or complex problem, what led to your current situation? Did someone work on it previously and what type of work?

Black smoke and fouled plugs, sounds like incomplete ignition. Is your O2 sensor working, how about the MAP sensor?

There could be some thread here dealing with similar cases?

Sorry can't give a direct answer to your question.

4CN A1R.....do you have a stock computer? If so, don't worry about the a/r at startup idle reading rich. It's set that way and will compensate after warmup and high gear driving. I have the same indications, have a rebuilt engine with less than 6,000 miles.

13B engine idle should be around 700 rpm, 500 rpm, did you replace your vaccum hoses?

Be careful about low tank (less than 1/4) because during tight turns, the fuel lines may starve and produce lean mixture. You could blow the apex seals especially when boosting.

well hell, i'm fine then...i was getting worried over nothing. yeah most of the hoses i swaped out with silicone ones(all visible ones, some in rats nest, and all the ones around the turbos) why did you want to know about my hoses?

and i know a great deal about gas starvation around tight turns. had a friend blow his engine because of this...i usually run with 1/4 or less because of street racing.(gas is heavy) but from wat i've been hearing, the more fuel in the tank, the better it runs

I have also encountered this same problem since it's been getting colder. But i'm sure i have a leaky injector b/c there is a very rich fuel smell coming from the engine and i can smell it from the vents. So definitely prolly that problem...it's such a pain some times.

I think my problem is solved. Changed injectors and monitor for few weeks, seems ok now.

my car idles like its running on one rotor when I crank it cold for first time in the day until it hits exactly 140F

I believe there is some kind of cold start fuel pressure ramp.

My fuel pres reads 60PSI when I first crank it up and the exhaust smells like pure gas...if I start her up cold and dial out a bunch of fuel at idle map the car runs completely normal and then stalls at 140. So theres obviously some kind of cold start extra injection