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View Full Version : Issue with a 3.1 V6 Missing


Snakey
12-15-2009, 06:35 PM
Trying to help out a buddy I work with and wanted to get some others input as I'm a little lost at this point.

Background info he has given me:

1997 Olds Cutlass Supreme SL 3.1L V6 180,000 miles

Pretty sure that the upper intake has a mixture (antifreeze and fuel?) in it from having the intake gaskets going bad. Those were replaced about a year ago. "Service Engine Soon" light is always on because it is sensing the EGR valve is bad. EGR Valve appears to be pulling in this antifreeze and fuel mixture. Have been able to drive the car for quite some time with this situation.

A week ago the "Service Engine Soon" light started blinking and the car started idling at 3500 to 4000 RPM because of a vacuum leak on PCV hose. Rubber grommet on PCV hose near throttle body appears to have been sucked in and or fallen off. Changed PCV hose and idle problem was fixed for a day.

The following morning the car ran fine, started the car to leave work that afternoon and it acted like it was missing. I had the computer codes read at Advance and was told the EGR, and TPS were bad. Went to junkyard and have replaced both. Car is still missing. Had the codes read again and EGR, TPS, and misfire on cylinder 1. Checked cylinder 1 plug and wire last night and plug was loose wire appears OK. Tightened plug and car still acts like it is missing.

After car is warm, 15 to 20 minutes at 70 MPH, cancel cruise control and coast down to 60 MPH and the engine stops missing and the "Service Engine Soon" light stops blinking. Get back on the gas and the problem starts all over again.

That's what I have got from him. I've offered my ideas of the EGR and TPS being bad but he's not sure after replacing with recycled parts. Anyone elses input it much appreciated.
GRRRR8
12-15-2009, 07:32 PM
If a EGR valve is stuck open it can create a misfire code. Did you clear the codes after the repair to be sure you are not seeing old codes?

Disconnect plug wire with insulated pliers at plug and coil to make sure there is spark and let me know.
Snakey
12-16-2009, 04:19 PM
Not sure, I'll pass this along to him and get some input back.

I told him it might be worth getting a new one instead of the junk yard market but he's strapped for cash so I don't blame him.
Snakey
12-18-2009, 06:27 PM
If a EGR valve is stuck open it can create a misfire code. Did you clear the codes after the repair to be sure you are not seeing old codes?

Disconnect plug wire with insulated pliers at plug and coil to make sure there is spark and let me know.

He had the battery out for about 2 hours, not sure if that would clear the codes but seems to me like it should?

There's plenty of spark at the coil(s) he checked them all. Getting to the plugs is a bit difficult on this but he did note that the #1 plug was loose and he was able to take it out by hand. Could it be a bad plug/wire or crap injector maybe?
GRRRR8
12-18-2009, 08:13 PM
He had the battery out for about 2 hours, not sure if that would clear the codes but seems to me like it should?

There's plenty of spark at the coil(s) he checked them all. Getting to the plugs is a bit difficult on this but he did note that the #1 plug was loose and he was able to take it out by hand. Could it be a bad plug/wire or crap injector maybe?

A loose spark plug can create a misfire as well.
WickedMom
12-18-2009, 08:16 PM
a loose spark plug shouldnt cause the SES to blink though.
GRRRR8
12-18-2009, 08:21 PM
a loose spark plug shouldnt cause the SES to blink though.

? A loose spark plug is not grounded or intermittently grounding. If its a spark plug, plug wire, coil or injector the light will flash as it is designed to let you know of potential catalyst damage.
WickedMom
12-18-2009, 08:29 PM
one cylinder misfire, though? I mean... I see misfires all the time. even totally dead holes dont trigger the flash.
GRRRR8
12-18-2009, 08:44 PM
Most intermittent misfires under load cause the light to flash.

Here are 3 examples of cars in one week that came from local dealers.

1. 04 Isuzu Axiom - SES light flashing, obvious misfire underload. Codes P0300, P0301B. Had 6 new coils and plugs from dealer($1800!) Fix-Excessive carbon build up and I do mean excessive and #1 injector completely plugged with carbon.

2. 02 Suburban 5.3 flexfuel-SES light flashing, obvious misfire underload. Code P0302. Had 1 #2 coil, new plugs and wires and fuel pump from dealer and at dealer for 2 weeks!! Fix bad injector connector(2 strands of wire, harness was twisted from factory causing failure)

3. 02 Nissan Atlima 2.5s-SES light flashing, obvious misfire under load. New coils, intake gasket, spark plugs, O2 sensors, MAF sensor. Fix-found #1 plug gapped closed. Regapped and tested and it did it again. Found excessive carbon contacting plug and closing plug gap.

Scary what the automotive industry is coming to or I am just really fucking good! :)
todds87ss
12-18-2009, 10:47 PM
Scary what the automotive industry is coming to or I am just really fucking good! :)

likely both!
Snakey
12-19-2009, 12:57 PM
Latest update:

He has replaced the plug and wire in #1 Cylinder. Still missing and noticed that the plug is not actually sparking. Gets spark at the coil, but not at the plug. Possible that the coil pack is bad and not sending enough juice to the plug to allow it to spark?