Engine loom help, wire#46 / #46C

[karabas 21]

Hi, I'm trying to find a problem on my Phase 2 Jectronic car thus I took out the engine loom. 
Found these wrong connections;
46C --> SAD ( I found an unattached earth and changed with 46C )
46 --> Alternator (there is an additional cable between ign switch and starter, I think this is to cure cranking)
I know #46 is for starter (when I pull out the cable, battery light on)

I'm looking at Haynes diagrams to find what is 46C but no clue.
I have a spare loom but its the same, #46C sitting in the loom connected nowhere. 

-What is thin #46C ?
-If I pull thick #46 cable and connect to starter, will battery light off? Should I connect something inplace of it?

 

many thanks.

 

[opticaltrigger 52]

Hi Hakan,

What was the original problem that you were trying to find ?

 

O.T.

Edited May 10, 2020 by opticaltrigger

[karabas 21]

Hi Opticaltrigger, 
I have an awkward problem. Engine runs normal when its cold. After 2-3 mins it's starting to run like 3 cylinder. It can be driven only betwen 3000rpm +-200 (normal engine sound I hear) . Then after , Although the ECU Temp sensor mounted in place, I've connected the 2nd ECU Temp and hanged it on bulkhead. With this way car runs&revs normal. But in long drives when engine compartment get hot, same symptoms. I thought there would be engine loom problem due to I overhauled it.
Briefly, injection is changing badly with the engine heat.

[DamirGTI 323]

Wire 46C goes onto the SAD ... i think it's 12V (or near battery voltage) live with the ignition ON .

 

Could be mixed up ECU temp. sensor and SAD connector , so mixed up/connected this two other way round ... check as they're the same 2pin connectors  , only different color connector .

 

 

D

[karabas 21]

Hi Damir,
The diagram you shared is for XU9J1/Z/L I think. Mine is XU9JA w/o cat.
So as far as I understand 46C is not used on my engine type.
I'm checking all connectors wire to wire couldn't find any sensible reason.
I can see ECU reads ohm from Temp sensor by pin 10 but I can't understand changing what or why on system. If you can tell me ECU triggers which part regarding to engine temperature, I can chahge it in order to find if its faulty.

[DamirGTI 323]

Yes it's the XU9J diagram ... and it's the only one where i actually found wire No. 46C .

 

Sorry (not sure if i understand the question) , you wish to know which ECU pins are for the temp. sensor ?

 

Now thinking a little bit about this ... heat + misfiring , this sounds to me like you're having ignition problem - kinda characteristic for the faulty ignition module , or perhaps the coil too . 

 

Try with an known good spare ignition module (don't forget the thermal paste !) , and see what happens ..

 

D

[karabas 21]

39 minutes ago, DamirGTI said:

Now thinking a little bit about this ... heat + misfiring , this sounds to me like you're having ignition problem - kinda characteristic for the faulty ignition module , or perhaps the coil too . 

 

Try with an known good spare ignition module (don't forget the thermal paste !) , and see what happens ..

 

D

This is my main problem. The loom is on my table now. I need to wrap it and put back. I have a spare ign amp. I will do it. Thank you Damir.

 

By the way I read what Opticaltrigger wrote about ignition system. 

[DamirGTI 323]

Pretty much all the ignition components tends to be commonly problematic after warm up period , warm/hot engine and when under load .

 

Heat vibration and moisture are three things which ignition system simply doesn't like .

 

Try to test replace one by one (not all at once) :

 

- ignition module

- coil (if you have later square inlet manifold mounted coil .. they're prone to failure)

- spark plugs ..

 

If you can isolate one particular cylinder which is faulty (misfires) after the engine warms up , swap the spark plug from that to one of the other working cylinders .. and see if the problem moves by doing that on another cylinder .. do/try the same with the injectors , mark position then swap places in between the cylinders , and see what happens .

 

I had on a few occasions spark plug failing creating misfire , always and only when hot (starts fine from cold , after warm up period shuts down one cylinder) .. and mostly just one spark plug out of 4 which somehow "craps out" internally .

 

 

D

[karabas 21]

I found an untouched engine bay loom and I saw #46C is connected to SAD (as Damir said). Regarding to Haynes (XU9JA engine) SAD earthed with #M24 instead of blue #46C . This meant to me that Haynes is not 100% correct.
Then I changed SAD wiring again. I cut the additional wiring from ignition key to starter and took it out.
Today I put back wiring and now engine cranking with its original wiring.
But this time no battery charging with charging light on the panel. I checked the battery with a multimeter while engine running.
This weekend I will search posts for alternator wiring to find what to check.
Here in Turkey every weekends we have lockdown and last week 4 days lockdown during Ramadan Bayram thus I can't find enough time to work on car.

 

Many Thanks

 

[karabas 21]

All problems sorted out.
- I learned that the alternator is not a self excited one. When the other phase connected to + all done.
- Found that fuel pressure was under 2 bars then fuel filter and pump changed.
A few months ago fuel pump was changed with a brand new one so I didn't give any chance to fuel pressure.
 

Thanks a lot for helping me.