Electrical Interference gremlins on Kit Car
Electrical Interference gremlins on Kit Car
Author
Discussion

antnicuk

Original Poster:

351 posts

210 months

Sunday 24th May 2009
quotequote all
I have a rotary engined kit car, i'm using a universal kit car wiring loom for the car and the ecu is a standalone after market ECU (microtech) which had its own loom, I'm using a Koso digi dash and a shift light with a digi rev counter in the middle. The ecu has a little display unit showing whats going on with the ecu.

I have always had a very occasional issue with the dash, shift light and ecu display resetting or turning off or just giving scrambed characters on the screens. It only happened after high revs and as soon as the ignition is switched on/off it was all fine. Since re mapping last week for a new turbo it is doing it every time i high rev the car.

I have plenty of earths, everything in the dash is connected to an earth lead which goes straight to the battery. This fat wire also goes to the chassis and engine. I can drive for hours at normal revs and it will be fine but quick high revs ie 1st and 2nd gear makes eveything go haywire.

The ecu seems to be fine which is strange as the controller is wired directly to the ecu and not connected to anything else.

Could it be something to do with the new turbo, should i earth the turbo separately on its own?

Any help is much appreciated.

Pupp

12,824 posts

294 months

Sunday 24th May 2009
quotequote all
My immediate thought was earthing but sounds like you have that covered. Is it possible for turbos to make big static charges, given that they spin so fast? No idea or experience but for the sake of another strap on the housing, might be worth a try to earth that too...

If you have access to a 'scope, could be an idea to look at the various power feeds and see if you have any obvious noise going on

antnicuk

Original Poster:

351 posts

210 months

Sunday 24th May 2009
quotequote all
I dont have a scope and wouldnt know how to use one properly frown

I think i will add a strap to the housing as it can only help. the guy at the dyno said try sticking some suppressors on the wiring going to the digi parts which i will also try.

Just remembered, I put a voltage stabilizer on the battery a while ago as i thought it may be that.

Pigeon

18,535 posts

268 months

Monday 25th May 2009
quotequote all
Try taking the power feeds to the ECU and the controller both separately (via 2 separate wires) directly from the ignition switch.

antnicuk

Original Poster:

351 posts

210 months

Monday 25th May 2009
quotequote all
the controller has a specific lead that connects to the ecu, i cant wire it seperately, it also does it with the other electrical components so not just connected to the ecu.

GreenV8S

30,997 posts

306 months

Monday 25th May 2009
quotequote all
It could be EMF spikes on the power supply from the ignition. Do you know what HT resistance you're running? You can add resistance at the plugs or leads, or in the plug extenders if you use them. A resistive setup would typically be somewhere between 5K-10KOhms per cylinder.

annodomini2

6,962 posts

273 months

Monday 25th May 2009
quotequote all
Are there any filter capacitors fitted to the alternator?

Standard is 2200uF 50-60v rating (not electrolytic), they're not expensive, wire 1 across the supply to ground.

PhillipM

6,537 posts

211 months

Monday 25th May 2009
quotequote all
I had a microtech on a rotary, had nothing but trouble with the unit itself, now running a DTA which is sweet as a nut...

Capacitors on both the ECU feed and the +12v line to the coils are both a must though, the coils are fairly noisy at high revs.

Edited by PhillipM on Monday 25th May 21:15


Edited by PhillipM on Monday 25th May 21:16

antnicuk

Original Poster:

351 posts

210 months

Tuesday 26th May 2009
quotequote all
Thanks for the replies guys, I am a ley person when it comes to electrics and I'm not really sure what a lot of the above entails, I just about manage to wire up the car but when it comes to capacitors etc I'm a little lost,
I don't suppose you could put it simple terms for me and point me in the right direction for what I need

Pigeon

18,535 posts

268 months

Tuesday 26th May 2009
quotequote all
annodomini2 said:
2200uF 50-60v rating (not electrolytic), they're not expensive
2200uF 50V non-electrolytic "not expensive"???? It would be very expensive, and you'd also have a certain amount of difficulty getting it into the engine bay...

fatjon

2,298 posts

235 months

Wednesday 27th May 2009
quotequote all
GreenV8S said:
It could be EMF spikes on the power supply from the ignition. Do you know what HT resistance you're running? You can add resistance at the plugs or leads, or in the plug extenders if you use them. A resistive setup would typically be somewhere between 5K-10KOhms per cylinder.
I second this suggestion, seen it many times when non resistor plugs have been installed. Causing ECU resets and general nastyness at high rpms.

annodomini2

6,962 posts

273 months

Monday 1st June 2009
quotequote all
Pigeon said:
annodomini2 said:
2200uF 50-60v rating (not electrolytic), they're not expensive
2200uF 50V non-electrolytic "not expensive"???? It would be very expensive, and you'd also have a certain amount of difficulty getting it into the engine bay...
http://uk.farnell.com/jsp/search/productdetail.jsp...

79p cheap enough

Slinky

15,704 posts

271 months

Monday 1st June 2009
quotequote all
annodomini2 said:
Pigeon said:
annodomini2 said:
2200uF 50-60v rating (not electrolytic), they're not expensive
2200uF 50V non-electrolytic "not expensive"???? It would be very expensive, and you'd also have a certain amount of difficulty getting it into the engine bay...
http://uk.farnell.com/jsp/search/productdetail.jsp...

79p cheap enough
That's 2.2UF, not 2200UF... wink

annodomini2

6,962 posts

273 months

Monday 1st June 2009
quotequote all
Slinky said:
annodomini2 said:
Pigeon said:
annodomini2 said:
2200uF 50-60v rating (not electrolytic), they're not expensive
2200uF 50V non-electrolytic "not expensive"???? It would be very expensive, and you'd also have a certain amount of difficulty getting it into the engine bay...
http://uk.farnell.com/jsp/search/productdetail.jsp...

79p cheap enough
That's 2.2UF, not 2200UF... wink
Having one of my half awake moments again, should be 2.2uF not 2200. You are correct though.