JDM turbo touring wagon (1990): not running correctly

wagonist · Post by **wagonist** » Tue Nov 10, 2015 12:14 pm

So I'm trying to get my JDM turbo touring wagon running.

The fuel pump isn't working (but works when powered directly from the battery)

Using the check connectors, I'm getting error code 22, which I'm told is the knock sensor.

The positive side of the fuel pump wiring works ok. The relay turns on for a few seconds with the ignition at "ON" & then stays on when cranking the engine.
If I bypass the earth side of the fuel pump directly to the body, the car runs (kind of).

I've got 5 gold coloured ECUs here.

the JDM one that came in the car. A USDM version that came form a turbo, an ADM NA version that I pulled from a wreck myself, and 2 from a mate which he says are from turbo XT's.

The JDM & USDM have an extra circuit board. Neither of these ECUs will make the car run. Both of these flash code 3 with the green check connectors joined indicating turbo automatic.

My ADM NA & the 2 from a mate don't have the extra circuit board. These all flash code 7 indicating NA. All of these make the engine run & I drove the up the street and up my steep front yard with my ADM ECU last night.

The questions I have are:
1. is the extra circuit board for turbo models only?
2. what does this extra circuit board do?
3. is there anything else tied into the knock control circuit? I find it curious that a fault there would stop the car from running
4. can I disconnect the knock sensor without any bad effects?
5. how the heck do you undo the plug for the knock sensor? It's position down underneath the back of the throttle body make it difficult to get to (especially with the turbo)
6. does this ECU need to run boost control?
7. Can I run the car on an NA ECU?

steptoe · Post by **steptoe** » Wed Nov 11, 2015 7:23 am

maybe list the part numbers of the ECUs you have - there was 20 for EA82 around the world !
one or two wires to knock sensor? they are a squeeze and pull with a dry o ring I think. Lube it up, maybe some heat may help things flex a bit

I ran my 3 plugger with its separate KCM disconnected with no ill effects

may just a resistor accross the knock sensor wire to earth may get rid of the code ?

three pluggers were two wire knock sensor white inside after plug disconnect, 4 pluggers one wire and green inside

wagonist · Post by **wagonist** » Wed Nov 11, 2015 4:58 pm

Aust NA
22611 AA620
A11-000 148

JDM turbo (came in car)
22611 AA400
A11-000 R14

US turbo
22611 AA630
A11-000 141

knock sensor is single wire & I can unplug it no worries.
Resistor is an interesting idea, but asking around, no one can explain why a faulty knock sensor would cause the ECU to not turn on the fuel pump...

I dunno if this is related or not, but the warning lights (except the check engine) stay on dimly even if the car is running. I'm going to do a search through the wiring & check for bad earth connections. Doesn't help when the car's outside & the weather's bad...

Silverbullet · Post by **Silverbullet** » Wed Nov 11, 2015 6:08 pm

wagonist wrote: I dunno if this is related or not, but the warning lights (except the check engine) stay on dimly even if the car is running.

Sorry I can't help with your ECU troubles but, this could be a bad alternator

If you rev the engine a bit higher and they get dimmer or go out, means the alt isn't charging right.

wagonist · Post by **wagonist** » Wed Nov 11, 2015 10:30 pm

no, the lights are on the same all the time, except when they should be on (they go bright)

steptoe · Post by **steptoe** » Thu Nov 12, 2015 7:35 am

a guess would be if you find an extra circuit board inside compared to NA Oz unit, that would likely be the KCM built in rather than an etra box the first three plug ecus worked with.

Have you actually tested the knock sensor ? All I did with my 3 plugger and separate KCM was to have it idle, timing light hooked up, also had dmm on the test wire of 3 pluggers near coil, whacked engine block with end of a 1/2" extension bar, saw the 1.7V from test wire go to 4.5V as expected and timing stepped back from `20 DBTDC to `10 and staggered back to 20 when block tap stopped.

wagonist · Post by **wagonist** » Thu Nov 12, 2015 2:15 pm

It's a bit hard to do your method when I can't get the engine to start with the proper ECU...

something I just read for trouble shooting said something about an open circuit causing a knock sensor error. I do need to check the wiring to check for shorts, etc. This may explain why it still won't start even though the knock sensor was unplugged.

Still find it really strange that a knock sensor error would cause it not to run. you'd think that this error would simply make the ECU run on a "too-rich" map instead...