Electronic interference with ECU - is this possibly?

[v8s4me]

rev-erend... said:

My first step would be to check the ECU gets power at the correct pins.

There are likely to be 2 pins that get power. 1 constant from the battery and the other from the ignition.

Also test the earth(s)....

Based on personal experience I'd agree this as a first step. My problem turned out to be a broken joint in the loom where TVR spliced the ECU connections into the main loom. So check your permanent live feed and also the connectors around the tune resistor. They might look OK at first glance but the wire could be broken inside the little plastic connector giving an intermittent connection. if you have this issue, combined with a faulty permanent/switched live feed you'll have all sorts of fun and games. Good luck.

[roseytvr]

v8s4me said:

rev-erend... said:

My first step would be to check the ECU gets power at the correct pins.

There are likely to be 2 pins that get power. 1 constant from the battery and the other from the ignition.

Also test the earth(s)....

Based on personal experience I'd agree this as a first step. My problem turned out to be a broken joint in the loom where TVR spliced the ECU connections into the main loom. So check your permanent live feed and also the connectors around the tune resistor. They might look OK at first glance but the wire could be broken inside the little plastic connector giving an intermittent connection. if you have this issue, combined with a faulty permanent/switched live feed you'll have all sorts of fun and games. Good luck.

Thanks both but both power supplies are going to different pins than DTA say on the wiring diagram so I am well out of my depth here. All I can say is the ground is good with 0 resistance!! I can do no more so its going to have to go back..........I will post up when sorted

[Challenger C4s]

roseytvr said:

It gets even worse unfortunately - the loom configuration to the ECU bears no resemblance to the wiring diagram issued by the now departed DTA Fast. I cant even make sense of the wiring to the two relays that I assume are for the ECU and fuel pump. For example Ignition on :

Relay 1:
Pin 87 12v
Pin 85 12v
Pin 86 12v
Pin 30 0v

Relay 2:
Pin 87 12v
Pin 85 0v
Pin 86 GND
Pin 30 0v
Completely baffled so its back to the installer on a trailer when he can fit me and no doubt hang on to it for another 6 weeks. Grrrr.
Well it.At least its Friday night

Pins 86 & 86 are the operating side of the relay so one of them absolutely must have switching voltage to connect the operated side of the relay. Terminal 30 is always the main voltage supply side and 87 ( & on a 5 pin relay 87b) are the switched sides. The difficulty sometimes comes when there are other units interlaced within a give circuit.
Without knowing about other circuits involved in your car I would say on a straight relay circuit, relay number 1 is wrong either of 85 or 86 Should be a ground ( even if thru' a second circuit). Pin 30 on relay number 2 should be 12 volts and 87 should only have 12 volts when the relay is activated by the 85 / 86 switching side.
Hope that is some help

Edited by Challenger C4s on Sunday 15th March 07:26

[roseytvr]

Okay update time.

Car has been back to installer - power loss to ecu was a wire fracture on the ignition side and this has now been fixed but cut out problem still there.

I have narrowed the cut out down to overrun only, if I dip the clutch when I slow down it wont cut out, so at least the car is useable. Its almost as if its a decell fuel cut out. I am trying to work out if there is a setting for decell fuel cut out so I can disable it.

I can now access the ECU through the pc so I am also learning how to follow the log to see if that tells me anything. I will share my learning's and findings as I go along!

Meanwhile any recommendations on an ECU/electrics guru I could take it too, get the problem sorted and car mapped whilst they are at it?

Ian

[spitfire4v8]

Do your revs decay too fast when you release the throttle? is that the issue? If so just add some extra ignition advance above say 1750rpm to slow the rate of revs decaying. Also make sure your idle mix and the mix below idle is good. If the revs overshoot below idle as you're slowing and there's not a good mixture or ignition timing under idle then it will continue towards stalling. Make sure you don't have any fuel cut on overrun enabled as well, this will not help you unless you have the rpm threshhold set quite high.

[carsy]

roseytvr said:

Meanwhile any recommendations on an ECU/electrics guru I could take it too, get the problem sorted and car mapped whilst they are at it?

Ian

Ian, take it to the man in the above post. He knows his stuff.

[QBee]

+ 1 for Jools - PM me if you need his contact details

[roseytvr]

Thanks Guys, Jools it is as I am well out of my depth here and don't want to take it back to the installer again!

Is Jools/Kits and Classics and V8s4me all one and the same?

Cheers
Ian

[QBee]

roseytvr said:

Thanks Guys, Jools it is as I am well out of my depth here and don't want to take it back to the installer again!

Is Jools/Kits and Classics and V8s4me all one and the same?

Cheers
Ian

Yes/No
SpitfireV8

[QBee]

Ian, YHM on your usual email