3.1 stalls only when coming to a stop

[94regal,3.1multiport]

92 regal with a 3.1 stalls when it comes to a stop, usually when it's coming up to temp, not cold. also "bucks" or "hitches" just a bit while driving. no check engine light or codes, but once after it stalled i was able to get a code 23- iat/mat, but it only flashes 12 now , even though it still has problem? i know i read that sensor is notoriously inacurate, but i hate replacing stuff if i'm not getting a code. also, when in park, idles fine and when i increase throttle slowly, when i get to 1/2 to 3/4 throttle it starts "missing" or "surging" something awful. let off and it's fine. take it down the highway and i can open it up and it does not do it? any thoughts appreciated- mike :P

[94regal,3.1multiport]

me again, now it turns over but wont start. still no codes? coilpacks maybe?

[bszopi]

Fuel filter? Or even fuel pump.

[94regal,3.1multiport]

i can hear the pump running and there's a good amount of fuel at the schrader valve. i guess the only way to be sure is a pressure gauge though. i'll check that after it stops raining. if that turn's out to be ok, what wuold you focus on next?

[rudefyet]

check the ignition fuses...just an idea

[614streets]

Find out what the factory resistance is on the ignition coils. The primary side should be .3 to .5 ohms and the secondary side should be 10-15k ohms. As always isolate and deenergize voltage from the circuit when checking ohms. Also if you have a spark board pull the secondary boots and crank the engine over with a starter button. Your alternator may be going south from excessive resistance or a bad diode in the rectifier regulator.

That should cover a electrical fault.

For fuel make sure the fuel filter is ok, the injectors should be fine and fuel should be fine.

Mechanical problems may be a lack of compression. Run a compression test.

Run the tests in that order.

If your engine uses a MAFS make sure its not restricted in any way.

[614streets]

Oh and make sure the battery is ok, should be no less than 9.5 volts when using a load tester..

[94regal,3.1multiport]

yeah did that , there all ok. gonna fool with it after my turkey dinner.

[94regal,3.1multiport]

oh ,i did'nt see the post by 614 streets. thanks, so by deenergize the circut you mean disconect battery? no i dont have a spark board and i honestly dont know what one is. gonna do a fuel pressure check, just have to borrow gauge from a friend. i checked that a while back when we started having problems and that was ok, but i will check again to make sure. car only has 100,000 miles on it and has lots of power so i'm not convinced compression is a problem. i did not check battery but it seems to crank over pretty strong, but i will to rule it out. i'm leaning toward coils. was hoping it was just an issue of spark or no spark. guess not. i'm old school working on cars and i have alot to learn on computer and electrical issues. i'll let you know how i make out.happy turkey day to all- mike

[614streets]

Yes disconnect the battery to deenergize and isolate voltage. Spark board is a small board which you plug your seconday leads (plug wire boot end) into the board and check for a nice blue spark. To check coil resistance, use an ohm meter and to check primary go from coil ground to coil primary lead (make sure to deenergize and isolate!) , should read .3 to .5 ohms.


Secondary resistance is from either coil ground or coil primary to coil seconday (plug wire boot end) , should be 10 to 15k ohms.

Just that easy.

[614streets]

You can also check volts , volts should be 100-300 vdc on the primary size, with a volt meter using a dva , peak voltage recorder.

[94regal,3.1multiport]

thanks, i think i got a handle on that. i'm heading out now to check it out- mike

[94regal,3.1multiport]

well, it's not a fuel issue. 44 pounds a schrader valve, with key on and while turning over. battery also checked out ok as well. i pulled a plug and it has decent blue spark while cranking over. i then disconnected battery and the 3 plug leads going into left and right side of coil. set my multi meter to check resistance and all i seem to get is " OL". i dont think i'm doing it right. it's not the meter. oh yeah, one other thing, while cranking it over it cranked somewhat "erratic" or almost " fetched up " for a sec. , like timing is off.? is icm different than ecu because we replaced ecu about a month back, unnecessarily i might ad, and i know timing is all electronic on this motor and i thought that was different. ruled out a couple things but i'm still in dark on where to go with this?- mike

[bszopi]

The ICM is the plate which they coil packs mount to. There is a good change that it could be faulty, but its hard to imagine you getting a good spark and the ICM being bad. But you never know...

[94regal,3.1multiport]

so what do you make of how it's turning over?????