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idle problem.

well, out of no where, the car wont idle anymore. I haven't changed anything except for having a logger plugged in for awhile. It ran fine this morning until I plugged the logger in to view the LTFT and STFT. I just put new BPR7ES yesterday.

It will surge to 1200 then too 1000 then to about 500 then die. I have checked for vac leaks, its not throwing any codes either.

the logger has been plugged in for a few hours, can that screw with anything?

I reset the ecu (unplugged battery for 3minutes) and the problem is still there.

what are your thoughts?
 

toybreaker

iconoclast
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Apr 30, 2006
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What's your iac count?

One of the most common causes for idle problems with a sudden onset is a shorted coil in the iac.

A resistance test as found in the vfaq can be done with an ohmeter.

A visual inspection of the ecu will also tell the tale. If one of the coils has shorted out, one of the black rectangles will be blown to smithereens.

Be a good time to check up on the ecu caps, and general condition of the board in your ecu. Many times having the caps done after they have leaked only borrows you some time. Eventually the residual acid will eat traces on the board, and then you'll start getting weird and random issues. A quick look will rule this out as a causative factor.

 
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the ecu caps have been replaced last year.

rpm isc airflow
1250 99 131 Hz
1156 70 75
1500 64 56
968 33 31
1031 45 43
1000 40 43
1218 21 50
500 29 0
906 18 25
406 47 0
531 57 56
375 39 0
 
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toybreaker

iconoclast
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Apr 30, 2006
Messages
3,581
Your mas showing zero a few times isn't a good sign, and it might be a good idea to give the wiring a quick visual inspection at the connector.

Is this still the stock mas?
 

grocery_getter

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Messages
1,225
Location
Kent - industrial suburbs of Seattle, WA
What else did you do when you were putting in the new bpr7es?
 

2g Mas
560cc injectors
ecu chiped for both.

changed the plugs and took the turbo j-pipe coupler off to install a heat sheild. I have checked the coupler, and its not leaking.

btw thanks for helping guys.
 
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toybreaker

iconoclast
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What did you gap the plugs to?

Other than the idle issue, how does the car run?

If it skips/misses under load, one of the plug wires may not have fully seated on the plug, may have come loose at the coil, or otherwise been damaged.

edit Check to be sure the o2 sensor is firmly plugged in and none of the wires were damaged finangling around with the heat shield.
 
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the car runs awesome, just the idle is screwy. I'll get back to the car in a bit. My dogs just killed a opossum and I have to take care of the red snow/evidence. I didn't gap the plugs I have always just put them in out of the box, so that will be something to look into.
 

toybreaker

iconoclast
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Messages
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Just saw your other thread in the newbie section.

I see you have a 255 fuel pump. Do you have an adjustable fuel pressure regulator? Some cars have issues with fpr overrun running a 255 against a stock fpr, leading to a rich mixture at low fuel demands.

Were the plugs that you removed black/carbon fouled?

edit Rich mixture on a cold plug will foul them up, and that can lead to a wonky idle. Especially if you do a pull or two on a carbon fouled plug. It'll melt the deposits onto the plug, glazing it and causing all kinds of ignition related weirdness.

At the very least, you should pull them and check/reset the gap. Shooting a pic of them would also help us help you rule some stuff out.
 
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grocery_getter

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Jun 20, 2004
Messages
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Location
Kent - industrial suburbs of Seattle, WA
Quoting chicagoboostin:
2g Mas
560cc injectors
ecu chiped for both.

changed the plugs and took the turbo j-pipe coupler off to install a heat sheild. I have checked the coupler, and its not leaking.

btw thanks for helping guys.




Check for vaccumm leak at the point where the injector enters the head. Did you use fresh insulators at the end of the injectors and are they seated right on the head?

Boost leak test your system, don't just do a visual inspection.
 

The old plugs I got rid of because I was going to tune the car. The plugs are gapped @ .028. Boost leak test 2, tomorrow. I just tested all of the plug wires and inspected the o2 sensor wire and mas plug, they look fine. Hopefully the second boost leak test proves a different result.
 

Just did the boost leak test everything was good. Its still can't hold an idle. I'm not sure where to go next.
 

rpm tim o2-r
1128 5 .80
937 7 .76
1093 6 .78
1031 6 .78
1000 4 .78
875 9 .48
437 6 0.00
468 -5 0.00
1281 11 0.00
1531 8 .64
1562 13 .78
1343 15 .80
1218 14 .78
875 13 .74
312 6 0.00
0 -5 0.00

maybe my ignition timing could be causing the problem? I see its -5 with the car off, not +5. Thats the only thing I can come up with. The car has driven fine for 200 miles. The boost leak test didn't show any leaks. I am out of ideas.
 

2of9

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Location
IGH, MN
Well...just a thought here. Dirty or low voltage TPS?
 

grocery_getter

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Joined
Jun 20, 2004
Messages
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Location
Kent - industrial suburbs of Seattle, WA
Quoting chicagoboostin:

maybe my ignition timing could be causing the problem? I see its -5 with the car off, not +5. Thats the only thing I can come up with. The car has driven fine for 200 miles. The boost leak test didn't show any leaks. I am out of ideas.



What's your base timing set at?

Is your idle switch working?
 
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It looks as if the base timing is -5 (according to the logger with the car off)
how do I check the idle switch?
 

grocery_getter

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Joined
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Messages
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Location
Kent - industrial suburbs of Seattle, WA
Use a timing gun, and make sure you ground the pin to keep timing at base.
 

Just replaced an injector o ring and timed the ignition. It's still stalls.
I crank it, it goes to 2K then it drops to 1500 then to about a 500 then the lights will get bright and it will shoot back up and surge then drop and die.
 
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