3100 misfire on Hot-restart only **FIXED**

[Bens71442]

Hello 3100 fans:

I've been a bit puzzeled, about this engine misfire I keep getting in a 1996 Cutlass Supreme SL coupe, with the 3100 sfi V6 Gen III engine ? (right?)

Its a hot-misfire issue: after the engine is shut down for NO-less than 5 minutes and not much more than 10 minutes, I get a really bad missfire, (threw a service engine soon light on) diagnosed code was PO300, cyl mis-fires on cyls# 4,5 & 6!

After the following "horror stories" from a Mr.Goodwrench ("head gasket blown!")> I wanted to shoot myself........("leaking intake manifold")>.....I wanted to cry badly.........to a ("set of wires and plugs")>.....big sigh of relief.....and oh yahh, (throw a set of coil packs when you put the plugs in)>....wanted to cry again.......to a possible (leaking injectors)>...I wanted to shoot myself again

What leads me to possible (leak down of injectors, specifically #4, 5 & 6) is that the mis-fires stop after about 1 minute to 1.5 miutes after wide opening the throttle, or raceing the engine in park. ITS ACTING LIKE ITS FLOODED during this mis-fire, (reason I come to the conclusion of a flooding issue) is that it #1 clears up after about a minute, #2, will not mis-fire if say its been sitting for a 1/2 hour or longer.

I have dumped several brands of injector cleaner, on a almost empty (higher concentration, less diluted gas tank) But this has NOT fixed the problem.!!! Which is causing me to suspect that this may be an ignition related probelm as upposed to injector issues.

Times are tight right now especially for the Holidays, (financially speaking) so I'm worried

I really hope someone out there who has had this similar problem in their 1996 or 1997 [3100 sfi V6] in a W car, (i.e. Olds Cutlass Supreme/Pontiac Grand Prix, and whatever the hell else a W car is, Buick Regal?

If someone out there had had this issue, can you send me a email and tell me what you found on your car. I'm hopefull its just plugs and wires, but on the cars I've driven I seldom find a spark plug wire go bad, (especially 3 of them at the same time) and plugs for that matter....which leads me to more serious issues that makes me want to stay in bed and hope it (the car) gets stolen in the driveway so I can by a FORD! (kidding of course)

I'm really hopeing for wires and plugs....HOWEVER..this stupid engine is supposed to have Platinum plugs, (Good for 100K miles of service) before recommended replacement (right?) I'm at 74,000 miles now.

ALL parts under the hood appear to be original to this car. PLug wires never tampered or replaced. So I'm guessing the plugs are original and the coil packs and module are too!

Problem started in late October 2004..........cleared code PO300 2 weeks ago, still sets a service engine soon light on occassion, but now the light came on for a day, Then went off, (stayed off currently) engine continues this hot-restart misfire.

Update:
Now this week, a (anti-lock brake light is on) stays on.......and NO-anti-lock function....Probelm #2 that just started this week!!!!!

And a great big THANK YOU, GENERAL MOTORS, for such high QUALITY and RELIABLE Automobiles!!!!! yaah Right< I'll bet R.E. Olds is Turning in his grave as I speak!

No more Oldsmobiles Huh!!! I'll be driving a 2005 Ford Mustang when they start showing up on the used car lots, (If I can find one) Thats if someone really wants sell their Mustang, because maybee they would like a different color in 2006!

I'm also the owner of a 1971 442 W-30 Holiday coupe..........AN automobile that is 100 times more reliable than the newer front wheel drive W cars.......... (sorry guys, I had to vent)!!!

and yes, I am a fan of the Oldsmobubbles! They'll be burying me inside the 442 when I drop some day!

--Ben

[TheProfessor]

if you have the origional plugs in there still start by changing them even though they are 100000 mile plug i would never run them that long but thats just me
your coil packs should be fine and last forever
if your rotors and or pads need to be changed badly they can trip the ABS sensor and trigger the light
p.s. sometimes the only way you can tell if your brakes need service is if you take off the wheel and look

[Rhedalert]

Get a tuneup. 100k is really pushing it and really would be ideal for highway driven cars, if at all. It's building up fury on the igntion system. Also this can give the mechanic an indication of what the problem is, just by the condition of the plugs. Get the wires changed while you're at it.

[DEI37]

I'm dealing with a cylinder 1 misfire, and multiple randoms on the other five cylinders as well. Think mine needs wires, the plugs (platinum) are new enough, and look good enough that I'm not worried. Wires are 145,000 miles old. I'm still trying to figure my problem out, but yours sounds ignition related. Cylinders 4 and 6 are up front, #4 being the middle cylinder, and #6 being the right hand cylinder. Cylinder #5 is on the right side in the rear bank. It is possible that a coil pack is bad/weak...I can't remember which cylinders are together...but I think is 1/4, 2/5, 3/6. Change the wires and plugs...and use GM parts. No gimmick wires or plugs. Good luck...hope it's an easy fix for ya.

[TheProfessor]

i would suggest for you to change your wires as well DEI37

[Bens71442]

3100 Miss-fire Hot ReStart Only

Hello again 3100 V6 engine Fans...... my 3100 V6 now at 76K miles

U'mmmmm ok, where to begin. Posted a message back on December 11th, 2004 about a "Hot Miss-fire" on a 3100 V6engine in a 1996 Cutlass Supreme SL coupe.

Problem continues since it started, back in, last November........On February 23, 2005 I replaced the Ignition Module..........forgoing the possibility of plugs and wires which everyone had suggested I replace first......and Not replacing engine coil packs.

Tech II scan tool at a Cadillac Dealer, I diagnosed the PO 300 code, (which told me that the engine is missifiring, NO KIDDING!!!!) in all cylinders, (not just 4,5,&6) ALL cylinders were missifiring after Hot - Restarts........

Problem seems worse at higher ambient air temperatures......... WILL Missfire after a 10 minute hot soak, and after the missfire goes away AFTER about 1.5 minutes of missfiring......engine SMOOTHS OUT and WILL NOT missfire again!!!! During that next run cycle.

Engine Will Not Miss fire COLD.........Only missfires after a 10 minute heat soak, after engine is shut off, in closed loop, (hot soak only) IF engine was allowed to cool down enough.....it will not miss fire.

OK, so I replaced the Ignition Module (ONLY) on Wednesday Feb 23. I DID NOT REPLACE THE COIL PACKS.

STILL MISSFIRING!!!! After $176.00 dollars to GM Service parts!! OK My fault, I tried throwing a new part at it (HOPING) it would fix the problem.
I failed at my guessing, and it cost me $176.00 dollars

Just came back from Sears auto Service center............They allowed me to come in and look at the car without charging me!!! Very NICE folks at Sears Auto Service.

I took them threw all the steps, on how to make this car missfire.........We ran the car until it was HOT HOT HOT..............hooked up a Snap On Scan Tool to the ALCL....... ALLOWED THE CAR TO SIT FOR {10 Minutes} Started the engine............ ENGINE MISSFIRED LIKE CRAZY just like its supposed too ......................We sprayed down the wires/coil packs/ spark plugs with water......Like I tried already.......NO Sparks, No Shorts, NO ARking...........NO change of the missfiring.........Engine continues to miss like CRAZY! Ambient air temp of shop 75 degrees or so.

ENGINE NOW STALLS during this testing as we were watching the scan tool...........looking at the current PO 300 codes...........missfiring on ALL Cylinders, (not just 4; 5 and 6)

1st Engine stall, water had already evaporated from the wires...before this stall. Engine DID not want to re-start!!! Getting interesting now!!!!

We removed a vacuum line to the plenum, (intake) and shot a few squirts of Starting Fluid........Engine stumbles....but begins to run now. Missfiring now worse and is not clearing up!!!!

SO>>>>>I've been chasing Ignition system problems for the past 3 1/2 months.........but Now it seems to be an INJECTOR Issue....FUEL DELIVERY related problem. Engine fired right away with the starting fluid

Nope, have'nt hooked up a Fuel psi gauge, ( I would have had to pay someone if we got that far)

Going back to my friends at the Caddy Dealer, to do a fuel pressure test on Friday, February 25th, 2005.........

Will keep everyone posted on What is ailing my 3100 60 Degree POS V6

I am NOT happy, with the quality of this Olds Cutlass Supreme......this engine missfire has been explained to many reputable GM service Techs who Also haven't a clue what could be causing the missfires.

I do admit, it appears we are narrowing down the possibilities..........from the ignition system....to now the FUEL SYSTEM.

I will find out what is causing this very UNUSUAL PROBLEM.....and will no doubt FURTHER SCORN this 60 Degree V6 engine my Olds has.

I have been and always will be a proud OLDSMOBILE OWNER. ITS THE CHEVY engine in my car thats GIVING ME THE PROBLEMS.......

I CAN"T Stand the idea of a Chevy motor in a Oldsmobile.............its NO WONDER Oldsmobile went out of business!!!!!

By the way.....loving the now worseining....COOLANT leak at the INTAKE MANIFOLD GASKET...................Happens to All 3100 and 3400 motors.....I'll bet Hondas and Toyotas don't have CRONIC problems like this Chevy Garbage MOTOR has!

IF I cold pull this motor and Install a TOYOTA ENGINE in my Merry Oldsmobile I would!!!

WILL POST the FIX when I determine what is causing the intermitten lean missfires, (HOT-Restart Miss-fires) of this 3100 60 Degree V6 motor!!

--Bens71442
1996 Cutlass Supreme< with JUNK 3100 motor!
1971 442 W-30 Holiday coupe 1 of 247 4 speeds, and my PRIDE AND
JOY!

[Doubt_Incarnate]

get ahold of an icm. its the brains behind the ignition. and being on the motor, it vibrates. mounted behind the coils. they do go bad. it is man made after all. they were on the pricey side last i checked tho. i see them on ebay with coils go for 20-25 bucks. it might be a fix. then again not. just dont get anything from autozone or advance. if you did, that your problem right there.

dont know if this was stated yet, i get slepy when reading books...

[Rhedalert]

RE: 3100 Miss-fire Hot ReStart Only

Have you pulled at least one or two spark plugs to see what the deal is? I'm also a tad surprised it'd be the injectors if you've never gotten a lean code, rich code, etc from the computer. Well, figure this...if you get the injectors replaced, get the lower manifold gaskets done at the same time. Mine went bad on my 3100 just recently (115k) and they were ALREADY replaced once, but the installer overtorqued the manifold bolts and therefore cracked the gaskets.

[Bens71442]

3100 miss-fire Hot start &quot;Update&quot;

3100 engine fans.....

Finally measured fuel pressure today, at 26 psi. Specs for a 1996 Cutlass Supreme 3100 V6 is; 35-47 psi..... broad range.

Obviously I'm on the low side........so I'll install a new fuel pump.

Will update "IF" the new pump fixes this crazy motor.

You'd think if it was a failing fuel pump......that the condition would reveal itself at all operating conditions!!

We shall See!!!

--Bens71442
96 Cutlass Supreme

[Rhedalert]

RE: 3100 miss-fire Hot start &quot;Update&quot;

Nice! At least you found something out of spec. The fuel pump died on my sister's car '93 Cutlass Supreme 3.1), before it died, the engine would stall on occasion for no reason... After replacing the pump it hasn't done that. Them things suck!

[George]

Please let us know if the pump solves the problem, I hope a plugged up fuel filter is also not part of your problem. 26 psi is too low for proper injector operation.

[DEI37]

I'd almost just replace the filter first, and see if that fixes it. If it's clogged, then that's your problem right there. Plus, it's MUCH easier than dropping the fuel tank!

[Bens71442]

3100 hot-miss-fire Think its FIXED!!

3100 fans......

Well, the 96 Supreme got a brand spanking new....... GM AC/Delco fuel pump today at $347.00 bucks! $195 for labor (to drop the tank) + $142.00 fuel pump, which includes a 20 dollar sock!!! That doesn't come with the new fuel pump!!! If any one out there works for ac delco, (than may you take this personally) you are an idiot!, for NOT including the sock that is supposed to go with a brand new fuel pump!!! NO WONDER GM is doing so badly these days....any one got stock in GM...I feel sorry for U

And after paying my bill, I started my search for a new low-beam headlight today...... I love this car...... .......drove to a couple of parts stores.........engine hot........sat for the 10 minutes while I went shopping for a new mini headlight........NO miss-fires...(so far).....!

Will continue to test the beast and will update in a day or two!

Ohh yaah, Loving the $25.00 dollar price tag at Murrays and Pep Boys for a low beam headlight (mini lamp) for my 2 dr, Cutlass Supreme!!!! $53.00 dollars through GM!!!! LOLOLOLOLO I told them they only WISH I would pay them that much for a head light!



[/i]

[geoffinbc]

Did you change the fuel filter too?

GM parts>Generic parts store parts.

[Bens71442]

3100 hot-missfire &quot;was fuel pump&quot;

3100 fans.........

Well, it appears a failing fuel pump, was the culprit for the past 4 months, Re: a hot miss-fire, on a 3100 V6, in a 96 Cutlass Supreme.

Several times today, on a hot engine, it started and ran smoothly with no signs of the miss-fire.

You can add this problem, in the anals of automotive weird and mysterious problems........Especially for previously known symptoms, of a car with a (f'd) fuel pump!

Car ran on 26 psi of fuel pressure, and (it ran just fine) except for the miss, after it was started hot, and sitting for greater than 10 minutes, only.

For a re-cap:
It did not miss-fire cold. It did not miss-fire after repeated restarts hot, and NOT waiting 10 minutes or longer.

It did not missfire, after the car sat for longer than 45 minutes, going from hot to warm, to just starting to get cold.

The above were the symptoms I encountered with this 1996 3100 V6, with evidently, a (failing fuel pump).

I was educated by a GM service program at my local community college, just a few miles from GM power train itself, in the early 90's.

I always thought a failed fuel pump exhibited the following conditions; for example; #1 no start condition; #2 start and immediate stalling; #3 lean miss-fire with a rough run (all the TIME!!) #4 engine shut off at speed, with no -restart.......i.e>call AAA raodside and get it towed to a mechanic.! Leaving you stranded in BFE, most likely.

SO> Can anyone explain, how this Cutlass Supreme started and ran fine every morning so far this winter, on the way to work.............Started and ran just fine on my Lunch break.....BUT after I ate my lunch and went to start the car, (It would miss-fire for aout 1.5 minutes) then SMOOTH right Out! and not missfire again, returning to my work place.

How can a car run fine at idle and all cruise speeds with 26 psi of fuel pressure? Cause MY CUTLASS CERTAINLY DID!

For my fans that have been reading my posts.........This is what My 1996 Cutlass Supreme (exhibited) and now completley Threw out, all that I thought I once knew, about a fuel injected car, with a Bad Fuel Pump!

--Bens71442

p.s.> Ha! found a mini-headlight (low beam) at the junk yard, off a
mid-90's Camaro; Very nice shape, for $10 bucks even! $53.00 dollars though GM service parts; $24.95 at Murrays, Pep Boys, and Auto
Zone! (Thought I did well on the $$ for the lamp) and just wanted to
post. >Even more surprised on the easy of remove and replace on
this POS Olds!