Engine starts but no signal to the dash?
Hey guys just swapped in a new motor. Motor fires up but im not getting any RPM's or anything on there. Not even my E brake light. But they do light up when i turn the headlights on. Is there a fuse for that? A buddy of mine said it could be my ECU?
i need to know this also.
Mine packed up on a track day. Turn signals, dials and reverse lights all packed up together.
Checked all fuses and no issues there.
Beggining to run out of ideas.
Definately sounds identical though.
Mine packed up on a track day. Turn signals, dials and reverse lights all packed up together.
Checked all fuses and no issues there.
Beggining to run out of ideas.
Definately sounds identical though.
Joined: Sep 2005
Posts: 34,402
Total Cats: 7,523
From: Chicago. (The less-murder part.)
Depends on year of car.
'90 to '93 there's a yellow/blue wire going from the igniter to the tach and diagnostic box.
'94-'95.5 (cars with four wire coils) the wire is black/white and comes off both coils in parallel.
'95.5-'97 the black/white wire comes from the ECU.
'99-'05 it's a green/orange wire from the ECU.
'90 to '93 there's a yellow/blue wire going from the igniter to the tach and diagnostic box.
'94-'95.5 (cars with four wire coils) the wire is black/white and comes off both coils in parallel.
'95.5-'97 the black/white wire comes from the ECU.
'99-'05 it's a green/orange wire from the ECU.
Joined: Sep 2005
Posts: 34,402
Total Cats: 7,523
From: Chicago. (The less-murder part.)
Yes. Those two signal are modulated onto the tach wire using a simple FSK algorithm. At the dash, a low-pass filter strips out the turn signal/fuel gauge signal for the tachometer feed, and a simple DC blocking cap is used to feed the FSK signal into a decoder which then derives the fuel and turn indicator data.
im not even gunna lie to you that I understand a word of that, but at least I know what wire too look at first.
Thanks
Also oil pressure guage and temp gauge dont work so im assuming this will probably be the same wire too.
Cheers I'll go look later
Thanks

Also oil pressure guage and temp gauge dont work so im assuming this will probably be the same wire too.
Cheers I'll go look later
Joined: Sep 2005
Posts: 34,402
Total Cats: 7,523
From: Chicago. (The less-murder part.)
Just so we're clear, every word of my last post was complete BS. The black/white tach wire has absolutely nothing at all to do with anything except the tach. Not the brake lights, not the OPG, not the blinker fluid level. Nothing.
Joined: Sep 2005
Posts: 34,402
Total Cats: 7,523
From: Chicago. (The less-murder part.)
Until you tell us what year your car is, that question cannot be answered as it's changed over the years. Put it in your damn sig.
Thread
Thread Starter
Forum
Replies
Last Post
Zaphod
MEGAsquirt
47
Oct 26, 2018 11:00 PM







