So.... I've been having some "fun" over the last 4 days trying to get the engine to idle nicely.
On Monday I was working with the IAC and idle but couldn't get it to run smoothly on 'open loop'. I put a multimeter on the IAC pad on the DStage TC and notice that the voltage was fluctuating only slightly 1.2 down to 0.8v every few seconds. The idle was OK but wondering a little. The engine would only seem to run for up to 5 seconds before dying.
When I switched over to no idle input the voltage at the IAC pad would sometimes read 0v and sometimes read 5v. It scared the hell out of my wife when she started the thing and it went right to 4000 rpm
Tuesday I desoldered the connection from pin 37 to the DStage IAC pad. I spent the day trying to work out why the boat would stall randomly. Sometimes it would run for 5 seconds then stall other times it would run longer then stall. It didn't seem to matter whether I had it idling fast at 1200 or slower at 700 rpm. At the end of the day I threw up my hands and imported Apollard's VE table. To my surprise she ran fine! I could go inside get a coffee, come back and she was still running. I was so excited I saved the tune as Tuesday Great.msq
Wednesday I thought I was ready for the next stage but I was back to square one. The engine would start, run for a little while and then die randomly. I decided to buy 6 new cables and rewire the TPS to ECU, this was the last thing on the boat that I haven't rewired yet!
This morning (Thursday) I finished the new TPS to ECU harness, started her up and she ran like clockwork. I could have her idling at 550 without any issue. I went to work, came home, started her up and she ran well again the first time but the second time onwards she has been diabolical. She starts well (as long as it's primed at 2.1 seconds) but only runs for a second or two then dies.
I have a fuel pressure gauge on the fuel rail and it always reads 60 psi.
The air intake is clear and the butterfly responds accordingly.
The plugs have been cleaned.
I have a constant 12v to the computer when the engine is running.
I've noticed that the Inlet Air Temperature sensor will read 0. As I don't have an IAT I'm wondering if this should be turned off somehow? Could this be influencing how the ECU is delivering fuel?
Since rewiring, I've recalibrated the TPS with the ECU but not with the controller. I didn't do this as the difference in the ECU calibration was very minor. I should go out and do this to make sure it's spot on.
I also noticed that when the engine stalls if the ignition is not turned off the injectors will remain open filling up two of the cylinders. I've removed my fuel rails to test that the injectors hold pressure without leaking and they seem to be fine.
I've tried to get a log but can't keep her running more that a second or two at this point.
The bluetooth connection is also acting diabolically, only slightly better than my direct usb connection. Sometimes it will connect fine other times it will disconnect and only connect again through the communications settings. I have a Mac, is there a way I can improve this...?
At the moment I must look like a lunatic to my neighbours. I connect through bluetooth, start the boat, run to the hose, run back to the boat to turn the ignition off when the boat stalls then run back to turn the hose off.
Anyway, I'm out of ideas for now. I guess I'll get after it again tomorrow.
Any thoughts would be appreciated as always.
PS I tried uploading my tune but it says submitted form invalid. I will try again in a few hours.