Cold Idle problem

[mirkoelek]

Here we go .... When car is cold... and I turn it on .... it works but rpms are raising then droping , rasing and droping .... weird !!! and it does that for every 2 sec.... then when it gets hot (after 2 min)....start to work very very rich....and turns off itself... after that i cant turn it back on .... I checked the wires that come on the top of the injectors (before when is cold and after when it gets hot) it shows different reading on the OHM tester... Before(cold) one wire that comes on the top of the injector has reading about 0.102(ohm or kohm not very sure) but when is hot it doesnt show any reading....(its open loop) infinite resistance ( this could be a key ) Dont know where to go from here!!!!! I thaught it could be MFI relay but not sure ... any ideas ?

 

[andymoraitis]

Have you tried unplugging the ISC and disconnecting the battery for a bit while cold to see if cold idle improves?

 

[topstreet]

It would be worth your time to open the ecu and inspect for a leaking CAP or bad inj. driver. (freeby) Is this an all of a sudden problem? Related to any current work on the car? Or has this been slowly building up and now its bad enough to do something about it?

Coolant temp sensors have a very large say in fuel delivery. Not saying thats what it is but making mention. When you are doing your resistance test on the Injector plug, are you back probing or do you have it disconected? Is this running, off completely, or key on engine off?

When the engine cools down, does the car start again?

 

[mirkoelek]

It would be worth your time to open the ecu and inspect for a leaking CAP or bad inj. driver. (freeby) Is this an all of a sudden problem? Related to any current work on the car? Or has this been slowly building up and now its bad enough to do something about it?

Coolant temp sensors have a very large say in fuel delivery. Not saying thats what it is but making mention. When you are doing your resistance test on the Injector plug, are you back probing or do you have it disconected? Is this running, off completely, or key on engine off?

When the engine cools down, does the car start again?

I swap ECU , same thing....

I was driving the car and it just happened... now i'm SOFL

When you are doing your resistance test on the Injector plug, are you back probing or do you have it disconected? Is this running, off completely, or key on engine off?

Doesnt matter key in or out the same thing....WHen i tested it black wire on the ground...

When the engine cools down, does the car start again?

Yes !!!!! and same thing again happens

 

[leet]

What.. in the Hell.. is wrong.. with your.. period key?..

 

[mirkoelek]

What.. in the Hell.. is wrong.. with your.. period key?..

I know

 

[topstreet]

Coolant temp sensors have a very large say in fuel delivery.

Have you inspected/tested the coolant temp sensor? If the only consistant you are seeing right now is the engine temp, then take a look at what the ecu is looking at.

Do you have any codes right now?

 

[mirkoelek]

Have you inspected/tested the coolant temp sensor? If the only consistant you are seeing right now is the engine temp, then take a look at what the ecu is looking at.

Do you have any codes right now?

No, i havent tested coolant temp sensor yet... I will do that next...can you tell me how that would affect anything.

thanks

 

[boosted spartan]

at first i thought it could be the BISS screw, but then i became skeptical. I say give it a shot at the BISS screw if its not it, atleast you will know thats one thing checked off the list.

good luck bro. btw your car is SICK!!

 

[mirkoelek]

anyone

 

[Spooling99]

Be sure to check the Coolant temp sensor as stated before. Check you plugs to see if you car is flooding. Also try to unplug the ISC as Andy stated, its just a stepper motor and you can run off the Biss. Good luck.

 

[topstreet]

can you tell me how that would affect anything.

thanks

Coolant temp has a MAJOR affect on the amount of required fuel. Cooler, denser air being burned. The spark plugs have not heated up to operating temp. Pistons have not yet expaned to the bore causing a higher leakdown.

These are all the same reasons you dont pound the crap out of your car when the engine is cold.

Do you have a any malfunction codes?

Jake

 

[Kevin Jewer]

You have DSMlink apparently, so log what your coolant temp is. If it is -40F you have a broken sensor or wires. This will make you run very rich, and also prevent you from ever entering closed loop fuel control.

 

[mirkoelek]

OK, I'll check the temp sensor and swap the TB with new ISC and BISS .... thanks for reponds , i'll let you know if that fixed the problem