Revmeter again.

dthebuk · April 09, 2009, 03:04:46 PM

Ok so after spending silly amounts of money replacing the ignition coils, the car still has the same problems, except not so bad.

Basically driving along, the rev meter will go straight down, then kinda come back up and the engine will judder. also Sometimes when going slow the revs will go and then the engine will just cut out and the lights will all come on. The when i try to start it will fire up then die straight away, and then sometimes it will just work.

At the moment i think its a bad connection behind the dash. Is there anything else it could be? I really don\'t want to be pulling dash out, I NEED A CAR

thaaanks

Brett · April 09, 2009, 03:19:17 PM

Have you checked all the earths?

dthebuk · April 09, 2009, 03:29:18 PM

don\'t know where they even are tbh. Do you have a rough description?

oh also. Apparently the ignition coils for the egi are the same as ones for a beetle?!?

Brett · April 09, 2009, 03:32:38 PM

Should be one coming from the top of the inlet manifold going to bulk head, another near the engine bay fuse box.

dthebuk · April 09, 2009, 03:43:23 PM

well they seem to be fine, though they\'re looking a bit puney!!

Brett · April 09, 2009, 03:44:23 PM

You do have the leads on the right way round, right?

dthebuk · April 09, 2009, 03:56:22 PM

i guess so? When the revmeter isn\'t playing up the engine is flawless.

Brett · April 09, 2009, 03:58:26 PM

Hmmm too busy to think at the moment - give one of the specialists a quick call - could sort you out in seconds

:wave

dthebuk · April 09, 2009, 04:19:36 PM

i did, they want me to take it in for an hour, which will "only" cost me Â£70 just so they can look! At that price i might aswell just take the dash apart myself and have a fiddle!

cheers for the help anyhu brett, i\'ll see what the electrical guru\'s have to say, then get set on taking it apart!

grinder · April 09, 2009, 04:25:10 PM

i cant see the revmeter causing all the probs - sounds like you have more issues to be honest

have you thought about running a MASSIVE earth lead from the battery to the shock tower ( i did just as an extra measure )

im sure if you search on here there are some diagrams which shows you all the main earthing points

there are the ones that brett says and there is one ontop of the gearbox aswell - not sure where the rest of them are though

have you checked the ECU earth - as i know that when i killed the ECU - the first sign of that was that the speedo and rev counter dropped to nothing - so thats a simple thing to check ( big black lead on the ECU harness in the passenger foot well )

i know it sounds silly - but do you know what wire runs the rev counter - as when the car is running right - if you disconnect this - does the car still run - if so you know its got naff all to do with the rev counter or this wire

Prof · April 09, 2009, 04:29:23 PM

that cutting out and starting issue sounds like a bad connector on the AFM - mine was lose and gave similar symptoms on the TII.

It does sound like a dodgy wire - perhaps it\'s time to \'waggle\' some wires and see if you can trip it up. Just go around systematically giving each of the sensors and so on a little tap / nudge / wiggle - what ever seems appropriate for the connector. Anything lose is going to show up right away.

grinder · April 09, 2009, 04:49:03 PM

right then after reading the best part of 25-30 pages of threads , i found the link i was looking for ...

http://www.rx7club.com/showthread.php?t=586921

this shows all the earthing points on the FC3S

pdtaylor18 · April 09, 2009, 07:50:24 PM

Revs comes off the coils does it not? did it do this before you replaced the coils or is it something that was there before. I think i did read your initial post about this problem and some may have pointed towards the distributer but you seem to have got it going so I guess it was not that. I do have a spare distributer you are more than welcome to try and see if the problem goes away(just pay postage) but you can have it for Â£20 posted, no cap but its all there and good as a spare.
I would imagine the rev pick off from the coil going to the ECU/dash may be at fault but i do not have a wiring diagram so any best guess. As Dave said its now the time to start moving a few wires and see what happens. If the earth was bad I would have expected you to have other problems as earths are shared by many components and few on any car are dedicated apart from things like starter motors.
Does the revs go up and down as well in tune with the needle or is this purely a dash related problem? It may well be your clocks?

dthebuk · April 09, 2009, 07:52:16 PM

Cheers guys. Don\'t know if you know grinder but the rev counter is actually linked to the ignition coils somehow, so this could cause the symptoms, well that\'s what the aa man said after looking at a wiring diagram! I\'m currently out so I\'ll look at it all in more detail 2mo. Oh also the counter doesn\'t always just drop, sometimes it kind of fluctuates, always under reads though. Thanks!

pdtaylor18 · April 09, 2009, 08:07:35 PM

I think your coils might have a spare \'rev\' cable connector on it but you could find where the pick off is and run a seperate wire all the way to the ECU. Tried looking at an online diagram but it was a pain to try and read sideways and upside down!! The one thing i am not too sure on is where the signal splits as it does have to power not only your ECU but you dash and cruise as well. I highly suspect all that will come from the ECU. Even if you dont have cruise the wiring will be there.