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.

[dumbass]

find out y its running rich
fuel pressure?
air flow meter adjusted wrong
i dont think the dli unit will make it run rich

but it might be the cause of the limit at 4000
id throw the dli unit in the bin and go aftermarket ecu
u will spend many hours of fking round and get nowhere
so just throw a cheap aftermakert ecu on it

[senn]

Sure it hasn't jumped a tooth on the timing belt? Distributor adjusted correctly(or the sensor that feeds the DLI)? Compression test? IIRC i vaguely recall something about knock sensors and ~4000rpm, but don't quote me on that..

[TERRA Operative]

The knock sensor thing is on the MAP 4AGZE, at 6400RPM.

I assume you've been over the loom with a fine toothed comb? Make sure there are no beaks, corrosion or extra wires?
I would be suspecting the DLI unit, can you return the ignition system to stock and see what happens?

[Moppitt]

The knock sensor thing is on the MAP 4AGZE, at 6400RPM.

I assume you've been over the loom with a fine toothed comb? Make sure there are no beaks, corrosion or extra wires?
I would be suspecting the DLI unit, can you return the ignition system to stock and see what happens?

Thats my thought as well. It sounds like you have checked everything else, the last two items are the harness itself and the DLI stuff.

Stupid question - are the shields on the shielded wires (umm, was it TPS? CAS?) earthed at one end? I wouldn't expect that kind of fault to be the result of interference but stranger things have happened/are happening to your car.

[Bazda]

What was the point of the initial post?

[CILAchainsaw]

My Silvertop did run pretty rich that time I forgot to plug the AFM (and therefore the temp sensor) back in after doing some work, if that helps.
I would defs also try swapping over the water temp sensor if you haven't already done so, as well as what was suggested above.
Post a photo of the circuit board of the DLI converter, I or someone else may be able to identify it and help you out with it. Alternatively you could chuck it my way, I'll put it to good use
And above all else, I'd keep the 20V

[knightrous]

If you think it's a problem with the DLI crap, why not switch over to the 1ZZFE coil packs.
There is some information for running them from the stock computer.
http://s-86.com/s-20vrwd.html

3- Four coil-packs/COP's: This most unusual method shouldn't work but it's a proven solution. This involves using the coilpacks off late model Toyota's (See the Coilpack info guide) with built in ignitors and firing them all at once off the single output of the OEM 20V ECU. The reason this sounds impossible is because at any one of the engines strokes the fuel/air fix is being sucked in just as the coil is firing! However due to the short duration of spark, the lack of comrpession and in the overlap period there is no combustion. Some people use the original 20V coil in place to send the firing singal back to the ECU and run the tacho but some just use a single one of the coils to send the signal.

Circuit and wiring guide here:
http://www.86garage.com/forums/viewt...73ce9f7a30773e

[CILAchainsaw]

Veeeeery interesting - I likey!
Perhaps you could even hook up the unused stock coil to a spark plug in an unused bung in your exhaust?

[dumbass]

interesting
seems u would weaer out yr plugs abit quicker than normal
since they r all firing all the time

[CILAchainsaw]

You'd be using the Platinum/Iridium plugs in it anyway, so you wouldn't have to worry about it for a while. I'd imagine you would have the benifit of extra power from the newer technology and having it so much closer to the plugs as well, just my theory though. My 20V had a 3SGE coil put into it anyway, the terminal for the ignition lead is way bigger than the male terminal on the end of the lead so it keeps arcing and mucking up the terminals, so I'm prepared to give it a go if only to solve that problem. I mean, if there was something wrong with it, I suppose you wouldn't see so many people doing it...

[ONCE-NA]

Im running 1NZ Cops but through the DLI converter. I dont think I have an original ignitor and coil to hook up COPS in wasted spark like the diagram above but that may be my final option before and aftermarket computer. probably selling the car anyways so didnt really want to spend any more significant $ on it...

[Rens]

Have you checked that there is voltage at the AFM?

[CILAchainsaw]

Just a thought: you're not by any chance using an auto ECU, are you? Any auto I've been in will shift around 3000-3500rpm and won't shift above 4000rpm even at WOT, just thought maybe that could be causing the issues at 3-3.5G and limit at 4G...

[dumbass]

The autos change way over 3500 rpm
And in a manual car should be at about 7500 or so if it's auto ecu

There setup is not std so it's going to be shitfight to solve