Help with building your Speeduino, installing it, getting it to run etc.
#60819
LPG2CV wrote:If I recall, sheilding should only attach to ground on the board and nowhere else.
Do you have resistor type spark plugs?
Shielding is grounded to ECU ground at firewall only. if I could better explain, 3 wires at cam and crank sensors. Pos, neg and signal shielded wire, the shielded wire braid is earthed at the firewall connection. I could go right up to ECU but I don't feel its worth the hassle and am not seeing any interference on the scope to indicate this is the issue BUT I'm no expert!

hhhhmmmmm BP5ES not resistor plug, great pickup mate! I shall try work out some resistor plugs for it, was more concerned on heat rating overlooked the resistor! this could be it!

Just confirmed a few things;
Cam trigger definitely not required so I can throw that logic in the bin - not sure why I was convinced it made the difference early on. Tried suggestion of running with CAM sensor disconnected and issue still present. One thing I did observe though is that it seems perfect for the first 15-20 seconds from cold, is this luck or is my issue just getting warmed up? may be a clue.
Trigger type setting rising or falling - engine runs the same

Have to go to work now but ill play around with other ideas later on try work out a set of resistor plugs for it.

Cheers

EDIT: funny checking original notes for the build i had bosch WR8DC+ as the plugs to go for but some reason changed to BP5s, NGK do a lovely iridium resistor type at this heat but there 30 bucks a piece might try the bosch first at 10 bucks a pop and confirm any issue.
#60821
Mine was a conversion from carb to lpg injection. Lots of sync loss, and changing from standard to resistor plugs was like night and day.

Ensure you gap them correctly. :)

Edit

Did you bin the orginal plugs? They would most likely have been R type.
#60836
LPG2CV wrote:Mine was a conversion from carb to lpg injection. Lots of sync loss, and changing from standard to resistor plugs was like night and day.

Ensure you gap them correctly. :)

Edit

Did you bin the orginal plugs? They would most likely have been R type.
Thanks mate as soon as I read resistor plugs I had that lightbulb moment I was waiting for! Yeh long gone, original plugs were BP6s/5s, in all my pre EFI stuff I swear by NON resistor plugs but that's due to the presence of suppressor's on most of them(not this one though) and adding R plugs weakens the spark to much. I'm not sure why throughout the build I changed but stranger things have happened...

Now I've got a fresh set of WR8s to go in this morning, just have to set my gaps I had the BP5s at 0.7, factory for the TB42 is 0.8-0.9 and reading online then and just a quick refresh now 030" seems to be the spec for a turbo LS, I'm using LS coils and got a turbo 030" works out around .76mm so I think I've done alight but any advice appreciated.
I know we want to run tighter gaps with the turbo as its harder for our spark to jump the gap.

Will report back soon, didn't have time yesterday but wanted to update none the less.

Cheers

EDIT: plugs have fixed it! thank god i sat there nervously watching for any sync loss or rev drops, perfect! thanks for your input gentleman! now to play with the tune
#60838
Hamma929 wrote: Wed Jan 25, 2023 10:24 pmEDIT: plugs have fixed it! thank god i sat there nervously watching for any sync loss or rev drops, perfect! thanks for your input gentleman! now to play with the tune
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Just to follow-up; this is why we suggest a noise sweep. A simple pass with a pocket AM radio, or a 'scope with a wire "antenna" would pick that non-resistor spark plug noise up right away. Without the sweep noise check, if @LPG2CV had not mentioned it, you would still be pulling your hair out. Tricks of the trade. Congrats!

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