A miss, I think

[Wally]

Somebody give me some advice here. I'm reasonably sure that I have cylinder that is misfiring. It's not totally dead it just doesn't seem to fire quite right. It's audible and causes a slight vibration. Truck is going in to the dealer Thursday to check this and a couple of other minor issues. Wicked Wanda the service writer says that if it hasn't set a code they don't have a snowball's chance in Hades of fixing it.
Help! There has got to be a way of detecting which one is doing this. I realize the engine has no combustion feedback system but it seems that if the TechII software Gurus had there dooky together there would be a way to adjust each cylinder individually.
Any body else have any thoughts on this? Kennedy?

[SoCalDMAX]

Wally,

It amazes me that they want to call themselves technicians yet if the Tech II doesn't tell them exactly what to swap out, they're lost. :rolleyes: I've always respected the grizzled veteran who could tell you what was going on internally using the "long screwdriver to the ear" trick. Prior to the advent of the triple-chrome plated stethoscope that the young-uns leave hanging on the wall.

IIRC, the Tech II will tell injector balancing rates between cylinders as well as cylinder misfires. This is recalled from John Kennedy's informative posts.

If these "technicians" can't find something this simple, they aren't gonna be able to find their cranial receptacles with both hands and a map. ;)

On the positive side, have faith and ask if they'll duplicate the conditions under which it occurs and then use the Tech II to log data for analysis. It should be pretty simple.

Good luck!

Regards, Steve

[Kennedy]

Im not completely sure what the spec is, but IIRC, it is in the 2.5-3.0mm range where they condemn the injector.

Should show up on a Tech II like Steve said.

[SoMnDMAX]

I too have an intermittant miss in my truck. I'm going in later this week hopefully, for a reflash to the latest software, and some air conditioning issues, so I'll have my SM do a balance check. Seems to me when John checked my truck earlier this spring I had two injectors that were up around 4 for the balance rate....

I get some nasty black smoke sometimes too, especially if the truck sits and idles for more than 10 minutes....

The engine was built 11-00, and so far I've been lucky, not exhibiting some of the "early" injector woes that some people have had...

[Kennedy]

I have seen mention in software update "bundles" stating improved misfire detection.

Sounds to me like mine in high idle on standby after reprogramming the set and resume speeds. It is kind of a slur type of idle situation.

I guess it would be interesting to see if the rail pressure isnt hanging up and maybe the ECM is fighting to drop the idle speed, but needing to actually drop cylinders to do so...

[Wally]

Thanks folks!
I'll print a couple of the less incendiary ones and take them with me to dealership.
The misfire on mine seems to be very consistant at any speed between idle and pilot injection cutoff, although I can hear something in the exhaust at idle that sounds like a partially firing hole. Very light and only detectable by listening to the exhaust pipe. The miss seems to go completely away above pilot injection cutoff.
Since this is my second Dmax I know that what I'm experiencing isn't normal.

[Wally]

I should post another topic titled" Dealers Pull A VACUUM!" But I'll save the bandwidth and rant here.
Took truck in this morning.
Three items
Misfire between idle to pilot injection cutoff
Check the accelerator pedal position with tech II
Charging system acting screwy and one battery has a black eye.

I mentioned to the Service writer that there should be a way to read injector balance numbers from the Tech II. She said their drivability tech knew all there was to know about the Tech II and trusted him. Of course I got the "cannot duplicate customer complaint" on the job ticket. I did get to talk to the tech (that's another story I'll tell in a minute). He said that the truck had set no codes so he didn't feel there was a problem. He assured me that if the truck had the slightest problem it would set a code. I asked him if he had done a balance check of the injectors and all I got was a blank stare. I really don't think he had a clue what I was talking about and I didn't want to embarrass either one of us any more so I let it drop.
He did see that I have a slight issue with the pedal but if you continue to push it into the carpet it will get to 100%
They determined that I did indeed have a bad battery. However, not the one with the black eye. Replaced the drivers side battery.
I picked the truck up at 1pm and the first thing I noticed was that the outside temp indicator is showing 68 degrees. I drove around for an hour in 95 degree heat waiting for it to straighten up. Climbed to only 74. Dropped back by the delaer and asked what replacing a battery would have done to the temp indicator. Service writer told me that I needed to calibrate it. My response was, "are you sure you're not thinking of the compass?". She called the tech up to the bay and told him what my problem was. He jumped in my truck and said, "get in". I'm not making this up! We drove out to the vacant area of the parking lot and he began driving in circles. After about ten circles he figured out that it wasn't doing any thing to the temp. He got out walked inside and said he would do some checking.
I left the dealer and noticed that as the afternoon wore on my temp indicator was getting closer and closer to the real temp. I finally realized that they had washed the truck. The holder for the temp bulb will hold water and while this water is evaporating it cools the temp bulb. Mystery solved!
I got home and decided to check under the hood to see what they had done for a battery. I have a new one allright but it's a little bitty thing that looks like it came out of a Cavalier. 560CCA compared to the original 770CCA. I also noticed that the remaining original battery doesn't have the negative lead hooked up. Just a bolt in the terminal that I guess they used to load test the battery. Now I'm wondering if they replaced the correct battery!
This is the dealer that I have had so much grief with before. I bought the truck there and have had a long talk with the service manager and my salesman about the service I recieved on the previous truck and they assured me that things were better now. So I decided to give them a try again. I'll admit it I'm an idiot!

[Kennedy]

You know what to do when the customer satisfaction survey comes in the mail!

Of course, Id push for a new battery, and ask politely if the "Technician" can spare 5 minutes to hook up the Tech II and show you the injector balancing rates. IIRC, theay are in Data Display/Engine data/Fuel system. Either that or Engine data 2. Been there many a time, just harder to explain than do...

[ 06-27-2002: Message edited by: kennedy ]</p>