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I dont think ESS is the cause here...

Correct me if im wrong, but the ESS can only effect starting, not running?... Once the pcm sees the 'ok to go' signal and the engine is started, the ESS has no ability to shut the engine down...

Harness change is a shit job in a VT...

How about a CAN bypass? A least it will prove the issue is/isn't the ESS

I was under the impression that was tangled into the engine harness in all sorts of ways. Never having seen one I could be wrong. There is zerobinfo anywhere about it

The ESS is linked to the BCM/ECU security and uses the same anti theft value as them so they all need to be linked.
What I think is happening when I log with Tunerpro I tell the BCM to shut up while logging, there is some vehicle reset being done that is affecting the ESS that then causes it to look for this message, when it doesn't get it it then drops the fuel pump out stalling the car.
When using Tazzis program the vehicle looses rpm, then surges then looses rpm again but when you lift off it settles down again.
Not sure why only at higher revs and loads though, possibly a back feed from the ignition module?

Oh yeah, forgot about the fuel pump relay control via ESS, bypass the relay, easy

hmmmm I wonder if tunerpro causes the fuel pump to drop altogether because it tells everything to shut up, but tazzis program is syncing with the heartbeat but not leaving enough time on the bus for extra ess packets causing the ess to miss say every 2nd security frame, and dropping the fuel pump relay in and out, like a PWM, causing a flow drop noticable only at high load and rpm.

I thought it was to do with the logging originally too, but disconnected all my gear and car still surges in the same way as when Tazzis program was running so pretty sure it is vehicle hardware related.
Have found out car was ok when motor first built but then started pinging later, so think there is something going on with the spark as all fuelling looks ok on narrowband.

Jayme wrote:hmmmm I wonder if tunerpro causes the fuel pump to drop altogether because it tells everything to shut up, but tazzis program is syncing with the heartbeat but not leaving enough time on the bus for extra ess packets causing the ess to miss say every 2nd security frame, and dropping the fuel pump relay in and out, like a PWM, causing a flow drop noticable only at high load and rpm.

I was just thinking that may have been the issue right there. But.. I didnt think the ESS actually sends any packets.. its the stalker of the car and listens..