hey guys, we went to dyno my friend's 88 FC today. it has a stock s5 turbo, 2.5" exhaust, stock TMIC. i tuned it the other night on the street on 6.5psi and all was well, no problems, high 10's/low11's AFR, no hesitations. well, we went to the dyno today to try to run 12psi and tune the AFR's to the low 11's and i was getting a nasty "plink" sound as soon as we'd get to about 4500rpms at ~11psi. i rezero'd the timing to double check that i didnt have it too advanced and the timing zero'd out lined up, locked at -5 it was right on the yellow -5 mark on the pulley. i docked the timing back 6* across the board just to verify that i didnt have the ignition too advanced and the problem actually got worse... i am guessing this was bad (and audible) pre-ignition, so at that point we decided to cut the dyno time short and make sure we didnt blow anything up

SO, i was wondering if someone could check out my ignition settings and tell me what they think. the advance is relatively conservative and the trail split is very conservative, so i am really confused and dont know what could be causing this problem. i will post the whole map later when we can get it off of the laptop.

here is the Ingition Setup menu
trigger angle (deg btdc) 58
tooth offset 11
spark output constant charge
spark edge falling
constant period 3.5

here is the Trigger Setup menu:
trigger angle (deg btdc) 58
trigger type multitooth
teeth no 24 tooth offset 11
trigger input internal reluctor reluctor gain 1 motronic filter 0
trigger edge falling
home input internal reluctor reluctor gain 1
home edge falling

at 12psi i have the advance at about 14*
at 12psi i have the trail split at 14*

 

Split is kinda high.
Don't most people max it out at around 10-degrees?
I wouldn't think this would matter.

What I worry is that the ignition inputs are wired correctly?
Can you confirm that at higher RPM's, the advance is correct?
For example, rev the engine at like 3kRPM - shoot the timing.
Does the timing mark stay at the correct advance position at that RPM?


-Ted

 

Do you have 12* of split or is the trail timing 12 degrees just like the leading? cause if the trail is identical to the leading you might get preignition, also, put the timing light on T1 and lock the timing, if its at -20 (red mark on the pully) and you rev it and it isnt climbing as the revs go up, then its fine, if you get a wierd timing reading on T1 then you're trailing plugs are wired backwards, or your coils.

What ECU is this?

 

its haltech e6x ecu

there is a 12 degree split between the leading and the trailing. so the trailing timing is firing 12* after the leadings.