Mitsubishi GTO 6G72 TT Not starting

[David.wynne.jones]

Hello guys,

Finally sorted all the wiring, everything is timed, trigger 1 and 2 signal is strong, timing has been done with a timing light. This car is triggering on the back of the flywheel with equally spaced notches equivalent to the crank angle sensor spacings on the second gen motors. This is a first gen and the crank signal was on the cas which was faulty, trigger 2 is still strong though. Many other cas I tried has a similar issue with faint or weak crank pulses.

Attached is the map I'm using, had a fiddle with pretty much everything I can think of and it doesn't even sound close to starting. It's got 6 coil on plugs and all of them have been tested and working. Fuel pressure is good and been tested, factory pressure regulator seems to be running it at around 35 psi ish.

It had one brief sign of life on initial crank but nothing else seems to be happening unfortunately.

The car won't start for the life of me, open to any suggestions. Saved a bit of a log file too. 

Cheers guys

6G72 GTO no start.pcl Log 25-11-22 4;12;08 pm.llg

[David.wynne.jones]

New spark plugs and she was away with minor changes to the base map. Hopefully the map helps some of the other GTO's get running as I couldn't find any on the net. The plugs must have been fouled from the changes to fuel when starting and the numerous starts trying to get it going. Cars getting a new oil pump and cambelt, will take to a tuners and update this with any changes they make. The OEM ISC still isn't working properly but the car still runs with the OEM idle control screw. Hopefully some more GTOs get a link and a tune, link has incredible technology. NB: The trigger offset will not be the same on your 6G72, I have triggered off the back of the flywheel using a hall effect sensor mounted into the sandwich plate. The location of the 3 teeth on the flywheel were chosen pretty randomly (120 degrees apart still obviously) so it's unlikely to be similar for others. The crank signal on the CAS was too weak for the link to pick up, with multiple different CAS they all had very poor crank signals. Must have been a bit of a design fault. The cam signal was fine so that was still used for trigger 2.

Current GTO Map.pcl

[Adamw]

Note the alignment between the crank and cam patterns must be very close to the original CAS.  If they are not then some start attempts will sync on the wrong crank tooth which may explain your no start condition.  

[David.wynne.jones]

Thanks for the input Adam, I was mindful of the high/low signal duration when fabricating the tabs on the back of the flywheel, however it was difficult for me to know the location of these tabs relative to where they were originally on the CAS in relation to the cam signal. Eventually got running fine in the end so I was able to neglect the difference using the trigger offset function, unless I somehow managed to align the tabs exactly where they were on the cas, which I'm sure I didn't given the trigger offset was different to the other basemap on the only other 6g72 thread I saw. There is currently a misfire under high load and high rpm however I *think* its not trigger related. I fabricated the flywheel tabs based on the dimensions of the gen 2 6g72 trigger plate (gen 1 has only cas) and it seemed to work well. There really was no other way I could think of to do this on a GTO given the tight space in the engine bay near the pulley, I couldn't find a good place to mount a sensor near the pulley on the block. I was told to run a custom trigger wheel off the pulley but there was really nothing to attach the sensor to on the block, without complicated fabrication to attach to a bolthole on the block and cut holes through the plastic belt covers. I'd be interested to know how others have done it on a gen 1 if they didn't use the cas.