datamaster is showing 17 knock !!!!!!!

[typhoon4ever]

everytime i start my truck while datamaster is on, it jumps to like 10 to 17 knocks. then when i turn off the truck, it jumps to like 25 knock counts. what the hell is causing this. last week i put on new knock sensor, new ignition module and new cap and rotors. help!!!!!

 

[charles]

Someone correct me if I'm wrong, but I think that is just caused by the normal engine shaking during start-up and shutdown.

 

[typhoon4ever]

it does it even when datamaster is recording first then i turn on the truck. what gives?

 

[myclone]

Lemme see if I got this right (correct me if Im wrong..).

You start recording before you start the truck? As in, you turn the ign key to "run" then you start logging data. Then you start the engine?

If so Id agree that its noise (signal spikes) that the ECM/Datamaster is getting when the starter is pulling all that current to crank the eng.

Are you running the laptop off the cig lighter or are you using the puters bat power with no connections to the truck for power?

As for why it spikes when you shut it off I got an idea but it'd take forever for me to explain it and its just a guess anyway at best.

Oh, try running a ground wire from the stand offs (where the cable screws attach) on the com port on the puter to chassis ground. Its helped a few ppl with "noisey" trucks. If its still there and youre using the sig lighter to power the puter get ya a big electrolytic capacitor and put it in parallel with the pos and neg of the supply wires to the puter. Thats basically what the cheapy filters are that you can buy at radio shack.

Check all the grounds on the eng/bat/ECM too..

One last thing... What are the KR #s while the truck is actually running? If they are normal and it only happens on start up/shut down then my money is on "noise"..

HTH..

 

[typhoon4ever]

barely ever knocks on a normal run. just acts crazy during start and shut down. Im using the battery that came with my laptop. any ideas?

 

[typhoon4ever]

any idea?

 

[JoeLutz]

On 2002-01-15 12:47, typhoonrider wrote:
any idea?

Start datalogging after the engine is cranked and stop before shutting down.

 

[typhoon4ever]

i do datalogg after the engine is crancked and right when i press record, it jumps to like 15 knock counts

 

[bdubb]

so looks like somthing is making a noise. have somebody start it, and go under it with a sethoscope and listen for what is causing your problems, we cant look at your truck for you.

 

[manitoufs]

The knock counts are stored and are reported no matter when you begin collecting data. The count gets reset after the ignition terminates.

High counts at startup appear to be noise not associated with detonation. I ignore them. Maybe I am hiding my head in the sand.

 

[0-60N4]

If it's like Diacom, you can set how many previous frames you want to capture when you hit the record button. Sounds like when you hit the record button, it's capturing several past frames and possibly the false noise from the engine starting. Try waiting longer before hitting the record button or reduce the number of previous frames to capture. The purpose of the previous fram feature is so if you experience a problem, you can hit record and capture what just happend. I'm sure you're not hitting the record button hard enough to shake the truck