Cold start misfires. I think this is more serious than I thought!

[Beauwulf]

Originally Posted by bmorecam

I've heard many times that the plugs can tell a story alot more than most peoples think but I wouldn't know where to start. I know how to compare by looking at online plug pics but that's about it LOL. I know some peoples actually pull out the magnifier to read those things

I don't have any intake leaks so I was thinking it might be the injector. I guess I will find out soon enough.

Best thing I've seen for cleaning deposits is that "Sea Foam" stuff. Wonder if it would work on the DI? Maybe if the deposits are over the nozzle in the CC....

[bmorecam]

Originally Posted by Beauwulf

Best thing I've seen for cleaning deposits is that "Sea Foam" stuff. Wonder if it would work on the DI? Maybe if the deposits are over the nozzle in the CC....

That could be possible if the injectors were clogged, but I would think the injector is leaky if the engine misfire only during choke mode. I don't think it would hurt to seafoam even if nothing was wrong tho. How would I use seafoam on our camaro?? I heard you have to put it in through the brake booster??

[OOLIE]

Originally Posted by bmorecam

Uhhh kay... just talk to vince and he think I should just turn the choke mode off which it's primary function is for the catalyc converter anyway. I have no cats and choke mode is the only time when I have my little mishap happening when it does happen, so if it was only a dealer reflash that was needed than I should never have this problem again, but if it's leaking injectors or any other fault than I should know about it soon enough I'm sure.

Tomorrow is a big day!!

no disrespect, but it seems like a band-aid, it probably isn't serious, but turning off choke mode when no one, else including myself without cats, isn't having a problem is just a band-aid.

I am not saying be concerned, but in my opinion it would be better to find out what it is at some point than just tuning it out.

[BaylorCamaro]

Originally Posted by bmorecam

That could be possible if the injectors were clogged, but I would think the injector is leaky if the engine misfire only during choke mode. I don't think it would hurt to seafoam even if nothing was wrong tho. How would I use seafoam on our camaro?? I heard you have to put it in through the brake booster??

My buddy did it on his Mini Cooper, he put half a bottle in the gas tank and the other half through the intake. Also you're supposed to change your oil after you do this. This info comes from the Mini community so take it for what it's worth.

[bmorecam]

Oolie, Let's just hope that it's not a band aid. I know it's not the plug, coil, and I don't think it's the rings, pistons, or loss of compression which leave me with only two possible culprit, injectors or dealer TSB for cold start misfires. Vince just thought that it wouldn't hurt to try out to disable the choke mode since I don't have any cats and it won't hurt anything, if it help than I know it might of been as simple as the dealer reflash which adjust the choke mode, if it doesn't help and I still have rough idle and misfire than I know I have to check the injectors next. I was going to check the injectors anyway but I didn't realize it was such a PITA to take these high pressure injectors out, and not to mention, once you take those injectors out GM says that it has to be rebuilt before putting them back in. It look like I will need to have some GM special tools ready to deal with these injectors which is far from just open the hood and pull them out lol. So far it's been great, no misfires but the temp been in the 60's and 70's in the morning so that can also be a factor. After dyno today I will be back at it so don't worry, I'm not the type of guy that like to set it and forget it

Chris, do you mean put the seafoam inside the intake like literally? I thought you do it through the brake booster. Also, how long do I wait after putting the seafoam in the gas tank??

[Blade]

Jay have you ever received this on the DIC during these problems? "Engine Power Reduced!" The car rough idles like whoa afterwards?

[TooCool5]

Originally Posted by bmorecam

Oolie, Let's just hope that it's not a band aid. I know it's not the plug, coil, and I don't think it's the rings, pistons, or loss of compression which leave me with only two possible culprit, injectors or dealer TSB for cold start misfires. Vince just thought that it wouldn't hurt to try out to disable the choke mode since I don't have any cats and it won't hurt anything, if it help than I know it might of been as simple as the dealer reflash which adjust the choke mode, if it doesn't help and I still have rough idle and misfire than I know I have to check the injectors next. I was going to check the injectors anyway but I didn't realize it was such a PITA to take these high pressure injectors out, and not to mention, once you take those injectors out GM says that it has to be rebuilt before putting them back in. It look like I will need to have some GM special tools ready to deal with these injectors which is far from just open the hood and pull them out lol. So far it's been great, no misfires but the temp been in the 60's and 70's in the morning so that can also be a factor. After dyno today I will be back at it so don't worry, I'm not the type of guy that like to set it and forget it

Chris, do you mean put the seafoam inside the intake like literally? I thought you do it through the brake booster. Also, how long do I wait after putting the seafoam in the gas tank??

After I had the TSB re-flash done for misfire I thought I was good to go.
Apparently they just widened the parameters where the light will not come on any more.
The first 18 degree morning cold start did it again and I suspect GM knows what is going on with this motor but does not want to fix it properly.

[Blade]

I got a new ECU yesterday, and the tech said that he also intalled the new GM factory tune update for this car. The update apparently changes the timing for the crank.

[Blacktip]

Originally Posted by Blade

I got a new ECU yesterday, and the tech said that he also intalled the new GM factory tune update for this car. The update apparently changes the timing for the crank.

Wow, thats good news if does. wonder if there is a TSB for an update

[Blade]

Originally Posted by Blacktip

Wow, thats good news if does. wonder if there is a TSB for an update

I dunno....I haven't found it, I will ask the SM when I call later today on the status of my car.

[bmorecam]

Originally Posted by Blade

Jay have you ever received this on the DIC during these problems? "Engine Power Reduced!" The car rough idles like whoa afterwards?

Nope.. never had that come on. It does look like some cars are affected by this cold start choke mode or otherwise their wouldn't be a GM TSB for this. I actually have the TSB number somewhere but that is all I know about it.

I just hope that my car fall in this TSB. I would hate to deal with the injectors next

[Blade]

Originally Posted by bmorecam

Nope.. never had that come on. It does look like some cars are affected by this cold start choke mode or otherwise their wouldn't be a GM TSB for this. I actually have the TSB number somewhere but that is all I know about it.

I just hope that my car fall in this TSB. I would hate to deal with the injectors next

What's the TSB number?

[bmorecam]

I can't remember what the darn TSB number was but I will find it. Look what I just found tho..

Look like seafoam might not be a bad idea after all


#PIP3640: 3.6 LY7, 3.6 LLT Misfire DTC P0300 P0301 P0302 P0303 P0304 P0305 P0306 - keywords lean MIL rich SES - (Dec 2, 2011)


Subject: 3.6 LY7, 3.6 LLT Misfire DTC P0300 P0301 P0302 P0303 P0304 P0305 P0306


Models: 2010-2011 Chevrolet Camaro

2004-2011 Cadillac SRX

2004-2011 Cadillac STS

2004-2011 Cadillac CTS

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:
Vehicle may exhibit a low power concern or misfire DTCs. Diagnosis will lead to catalytic converter replacement. Back pressure will usually be out of specifications and restricting exhaust flow. After converter replacement vehicle may run fine but still have misfire DTCs for either bank.

Recommendation/Instructions:
Fuel trims will need to be reset. Disconnect the battery for a short time. Reconnect and retest.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.


#PIP3146D: Rough Idle Crank No Start Extended Crank Or Misfire When Cold Due To Sticking Valves Or Excessive Carbon On Top Of The Valves - (May 11, 2011)


Subject: Rough Idle Crank No Start Extended Crank Or Misfire When Cold Due To Sticking Valves or excessive carbon on top of the valves


Models: 2000-2012 All Passenger Cars with Gasoline Engines

2000-2012 All Light Duty Trucks with Gasoline Engines




--------------------------------------------------------------------------------

This PI was superseded to update recommended field, model years and engine list. Please discard PIP3146C.


--------------------------------------------------------------------------------

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:
Rough idle, misfires, extended crank, or crank no start when cold. The engine may run rough for up to 5 minutes after starting the engine and may exhibit a P0300 DTC too. This may be caused by sticking valves or excess carbon due to fuel contamination

Note: fuel oxidation and volatility concerns can often cause these issues as well, however they cannot generally be checked in service. Trying a different, high quality fuel is sometimes the best diagnostic.

When the engine is cold, the compression on multiple cylinders may be at 0 PSI. The engine also may pop through the intake or exhaust while cranking and the spark plugs may be fuel fouled when inspected. Some engines may also experience valve damage or cam followers that are out of position as a result of this.

This condition can occur in specific areas of the country for a period of time and then it will no longer occur after the suspect fuel source has been consumed in that area of the country.

Recommendation/Instructions:
If the SI Diagnosis leads to a compression loss due to sticking valves, the following information may help:

If there is no sign of valve damage or cam followers that are out of place, perform the following procedure to free up sticking valves and to prevent the valves from sticking again. If valve damage is present or if there are cam followers that are out of place, perform engine mechanical repairs as necessary to correct the concern and then perform the procedure below to prevent the valves from sticking again.

•Clean the fuel system by following the applicable "Fuel System Cleaning" procedure outlined in SI.
•Add fuel injector cleaner "GM Fuel System Treatment PLUS, P/N 88861011 (for U.S. ACDelco, use 88861013) (in Canada, 88861012)"... see This PI was superseded to update recommended field, model years and engine list. Please discard PIP3146C. bulletin # 05-00-89-078B, to the fuel tank in the approved quantities.
•Refill the fuel tank using fuel from a high volume, high quality filling station.
•Clean the induction system using GM Top Engine Cleaner. Follow the directions on the can but DO NOT force the engine to stall since forcing the engine to stall with liquid Top Engine Cleaner could cause the engine to hydro-lock. * If available use an atomizer with Top Engine Cleaner through the throttle body.
•Advise the customer to change fuel filling stations. They should use fuel from only high volume, high quality filling stations or they should use a Top Tier Detergent Gasoline if available. See 04-06-04-047I (U.S.) or 05-06-04-022G (Canada) for details regarding Top Tier Detergent Gasolines.

[Blade]

LOL........ya goof.