Very Low Idle?

[EagleTalonTim]

Ever since I got my car running, more and more things have been going wrong. Got to love DSM's! Here is my problem....

When I first crank the car up in the morning when the motor is cold, it idles anywhere from 600 to 900. I was told to put a new coolant temp sensor on it and a new O2 sensor so I did....it still does it and sometimes it stalls if I take off then left of the gas quickly. I just did a boost leak test on the intake then the turbo and IC and only found a small leak around the TB. Not sure where exactly, but it sounds like it is coming from the bottom of it and if I open the throttle all the way, the sound weakens, but I still lose pressure just as fast. I can pressurize the system to 15 psi and it will take about 20 seconds to go back to 0. If I pump the brakes really fast, the idle will go up until I stop pumping them. Not sure if this is normal or not.

Thinks I have checked:
Boost Leaks : small one around TB
Timing : 5 Deg from TDC
ECU Codes : None
Voltage to Coolant Temp Sensor : Good
Coolant Temp Sensor ohms : Good - changes as it gets warmer or colder
Boost while driving : 9psi at 2700 RPM's and up, -19 at idle
Compression Test : 155 across the board
Gas Mileage : 13.96mpg - that really sucks!
Turbo spinning at idle : yes
Turbo shaft play : none side to side or in or out.

 

[ndsti]

Fix boost leak! Then unplug ISC and screw out BISS alittle, plug ISC back in and turn car on to see where rpms are. O2 sensor good?

 

[bling5tatus]

why unplug the isc? Just ground the idle speed set connector and the pin on the aldl connector and set the idle properly.

 

[ndsti]

Grounding does the same, just another way.

 

[EagleTalonTim]

I set the biss screw after I was done setting the timing. I did ground the plug out that i needed to.

 

[EagleTalonTim]

With the timing ground like it is supposed to be when you set the time, the idle is at 900 if the car is fully warm with no accessories on.

What would cause it to have such bad gas mileage and idle so low in the morning even if the things you posted are ok besides the small boost leak?

 

[ndsti]

Like I stated before is your O2 sensor good? When they go bad you run extremely rich and mpg drops like crazy.

 

[EagleTalonTim]

The O2 sensor is brand new from Oreilly's and it is not the universal one. It is the OEM one with the plug already on it. There is no CEL either.

I am stumped.

 

[EagleTalonTim]

Ok, I just got new exhaust put on the car hoping that it maybe it was the Cat. Unfortunately, it was not. The car still idles at 600 when I first crank it then slowly goes up to 1,000. The O2 sensor is an OEM direct replacement from Orielly's and is brand new.

Please help!

 

[bling5tatus]

sounds like your isc might be toasted.

 

[ndsti]

Here's the directions for testing ISC.

There are six pins on the ISC. They are labeled 1 2 3 across the top and 4 5 6 across the bottom. (see left) Measure the Resistance between pin's 1-2, 2-3, 4-5, and 5-6 Each pair of pins measured should read 28-33 Ohms Note: The values should measured with the car off and cool! If any of the "coils" (which is what you're testing) are bad then your ISC needs to be replaced If all the coils were good there's one other thing to check on the ISCUse a 6volt battery (lantern or camera battery) and apply 6 volts to the ISC motor. Use jumper wires to connect the positive (+) terminal of the battery to terminals 2 and 5 of the ISC and the negative battery terminal to terminals 3 and 6 of the ISC. If there is no movement or vibration from the motor, then it is bad Note: The use of a 12volt battery will destroy the ISC motor!!

 

[EagleTalonTim]

come to find out, the ISC was bad so I put another one on it that worked and tested out fine. It does not leak either.
It idles fine now but it is still running ungodly rich.

What would cause that? There is only one small boost leak around the TB but I have not found it yet. It still holds pressure for 20 seconds from 15psi. I am getting 9 pounds of boost at WOT with the stock 13g turbo and stock injectors. Sometimes, if i take off at a stop sign, it hesitates really bad, then goes....especially if I just mash it to the floor. The turbo does have a crack on the exhaust side where the clamp is and you can see that it has blown out a little exhaust. With the car running, I blew smoke down by the turbo and revved up the engine to see if the smoke would push away from the crack and it did not. I tested the spool up time and it completely spools by 3200 rpm's.

 

[ndsti]

sounds like your having fuel problems; got anything upgraded on the fuel system? When was the last time you replced the fuel filter?

 

[mochilli]

I just started having a similiar problem: i noticed that if i leave my car in first and let off the gas completley while already driving like 15 km/h...the rpm goes to like 500...it didnt stale or anything like that. This just started happening last night. When i first start my car, it idles fine. I should also note that since i bought my car last september, the oil pressure gauge always goes to practically zero when im at idle, as soon as i start moving, the pressure goes back to normal.

I just took it out for a test drive, and when i went into first and let off the gas, the RPM did stay at 700ish...maybe bc its a new problem and not that serious yet. However, when im in first, i put the clutch down, rev it to about 3,000rpm and release the clutch again, the RPM will drop to 500, ill give it a lil gas (1,500rpm) and it will drop back down to 750ish. Also, when i was in neutral in my driveway: i reved it to like 4,500 RPM and it dropped to 500 after, i reved it again to 4,500RPM and it went to 700-800 ish, so im confused . My car normally idles at 750, but as of recently, it bounces from 700-800rpm, i dunno what this means.

Someone Please Help