Silvertop 20 Valve -Soooooo over it!

[ONCE-NA]

What seems like aeons ago I bought a Silvertop 20V from a guy who had it in an 86.
The wiring was a bit of a mess but i got it in and running. But initially super rich.
After many months of dicking about with it, swapping out a number of sensors etc and its running a lot better but still a bit rich and just in neutral it stummbles a bit at 2500-3000 RPM and seems to limit at 4000RPM if you take it up slowly but you can work it past that point by kicking it or holding the right throttle opening.
Not getting any ECU codes unless I force them.
I've swapped out the AFM, changed to COPS, the ECU, the Knock sensor, the injectors, the spark plugs, the TPS.
Unpluging the water temp sensor doesnt throw a code, -I havent tried swapping that as I havent got another at the moment.
I'm starting to suspect the DLI converter it came with. (an unbranded thing in a diecast metal box like you would get from Dicksmith or Jaycar)
There are no names on the board or anything either.

In short, im over it, and just want to drive it before I let it go.

[t-nol]

Thats no good mate. I too am over my 20v, such a slow POS.....

[Matt]

Couple of quick things first...

What ecu you running?

Secondly earth out the ignitor bracket to the engine somewhere , this seams to help allot... I've had the knock sensor do this in fwd format exactly the same symptoms you have described.

[slide86]

sounds like its massively retarded........not as in 'der brain' but as in cam timing.

id be checking the ignition and cam timing

[ONCE-NA]

just the factory ECU, Ive tried one that I had to replace the caps and onother that was okay already. Timing is at 10deg BTDC with the TE1 and E1 pins bridged.
THe DLI uses 2 x factory ignitors and 2 coil packs but only uses 3 of the pins. it doesnt send a IGF signal to the ecu from the ignitors and i can only assume that the IGF comes from the DLI box. when I tried 1NZ COPS i also tries the IGF signal from them directly to the ecu but it made no difference. Using the COPS i dont have to use the ignitors at all.

One option is to do the waste/waste spark COP conversion people are doing on 20V's and that would do away with the DLI box, but that would kinda be going backwards and I dont know how much of the original stuff I need to go backwards is there.

[Matt]

Sometimes the leaky caps damages the board and the ecu isn't salvagable unless you really are good at fixing electronics.... Post up what is written on your ignitor , you could very well have a 16v ignitor which will let the car run, but it runs like arse

[Sam-Q]

I have had something similar happen to me with my silvertop and in the end it was a bad wiring loom that caused it all. Changed and ecu and loom and picked up about 30% more power in the mid range, no exageration. Would slaughter a blacktop on a stock ecu as well.

Here's your options you buy a new ecu and loom and go with the benefits of that or you pay the cash and get a new loom made from scratch for what you have now. Budget $700 for that.

[Lurkin]

Option (1) - cheapest option.

Give it to me. solved.

Option (2) - fix yourself

Check timing.

check ECU caps.

Start painstakingly testing loom.

Option (3) - pay someone else to fix it.

or bite the bullet and pay someone else to check it for you.

[ONCE-NA]

Yeah I might start tracing all the wires through on the weekend, check continuity and resistance.
Ordinarily I would just buy an aftermarket ecu but things have been tight with another kid and my GF not back at work yet