Author Topic: KJET 8v to 16v swap  (Read 1881 times)

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Offline mk2mitch

  • Posts: 58
KJET 8v to 16v swap
« on: May 19, 2019, 12:33:59 pm »
I'm in the process of swapping out my 8v engine to a 16v ABF (that was swapped into a KR car before mine running KJET) I received it will all the KR loom, metering head etc, everything to get it running. Rather than hacking up my loom, I was planning on try run it on the stock 8v loom alongside the 16v electronic ignition portion of the loom as there is literally 2 wires to splice together (RPM wire) and a start/run power to power the ignition timing box.

A couple of things that I've come across:
1. The 8v runs a vacuum solenoid valve by the metering head and the 16v has a deceleration cut-off valve. Do these do the same thing? Can I plug my 8v loom into the 16v metering head?
2. The 16v throttle body closed switch has a three pin plug whereas the stock 8v one had a 2 pin plug. All it is is a button switch to sense if the throttle body is completely closed so I can't see an issue splicing the 2 pin plug to the 16v throttle closed switch.

I've wired it up as above to test and it will start and idle but when you rev it up, there is about a 2 second delay, it'll rev up to 3k then hold there and not drop back down. I'm thinking that there is a difference between the 8v vacuum solenoid valve and the 16v deceleration cut-off valve.
Is anyone done something similar before or able to share some advice?
- Golf MK2 GTI
- Golf MK3 GLI

Offline black16v

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  • paul
Re: KJET 8v to 16v swap
« Reply #1 on: May 22, 2019, 05:34:51 pm »
On the KR there are two valves by the metering head, one is the overrun cut off valve controlled by the idle stabilizing valve controller and the other is the diaphragm pressure switch (also called the vacuum time switch) which gets its power supply from the normally open terminal (pin 1) of the throttle switch. The normally closed terminal (pin 3) supplies power to the ISV controller and the electronic ignition control unit. The common terminal (pin 2) is ignition power. Note that normally open or closed refers to the switch action NOT throttle action. The ISV controller is located behind the center console. Do you have it? To set the base timing you well have to disconnect the connector by the coil ,if you don't the timing will do what it wants when you open the throttle.
1988 MK II GTI 16V

Offline mk2mitch

  • Posts: 58
Re: KJET 8v to 16v swap
« Reply #2 on: May 22, 2019, 06:33:28 pm »
Cheers for the info, hat's a lot of help. I've got the ISV controller as well but that only has 2 wires going to the ISV and the third one is not connected at all (which I believe is the different between a mk2 and a mk3 ISV) The wiring that I've got is a little modified so have been trying to work out what the cleanest of going about it all is cause the OCD in my wants to tidy up the new wiring if I'm going to stick that in my car as some things don't sit quite where I'd like them to (the factory way) Good thing the dash is already out of my car though.

What I was referring to throttle open/close is on the 8v. I made the assumption that whatever is currently in my car does a similar thing to the idle stabilising valve controller but it seems like the two systems are very different.
- Golf MK2 GTI
- Golf MK3 GLI

Offline black16v

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  • paul
Re: KJET 8v to 16v swap
« Reply #3 on: May 22, 2019, 09:46:45 pm »
I have a KR engine wiring diagram. If you want a copy PM me an email address.  Sorry I have no knowledge of the MK3  ABF.
1988 MK II GTI 16V

Offline mk2mitch

  • Posts: 58
Re: KJET 8v to 16v swap
« Reply #4 on: July 21, 2019, 05:49:39 pm »
Okay, I so decided to scrap all the 8v stuff and patch in and the 16v loom. Half of the wires were labelled incorrectly so after some wiring diagrams from black16v I was able to get everything to go to the right place.
I've done a lot of fiddling around with it but I can't get it to idle at all, it just dies.  When cold, it has a slight hesitation before revving up but once warm it revs pretty smooth but still wont catch idle.
I did originally thought it might have been the ISV due to it not vibrating too much when you put your hand around it. I stumbling upon a spare that I found on a junk 8v engine I had lying about (which I'm not too sure why it was on that engine cause I though the 8v and 16v ones were different) but not this one hums and vibrates heaps so it must be working now.

Anyone got any ideas?
« Last Edit: July 21, 2019, 06:14:24 pm by mk2mitch »
- Golf MK2 GTI
- Golf MK3 GLI

Offline johnp

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Re: KJET 8v to 16v swap
« Reply #5 on: July 30, 2019, 06:17:40 pm »
Vacuum leak.

Offline mk2mitch

  • Posts: 58
Re: KJET 8v to 16v swap
« Reply #6 on: July 30, 2019, 08:40:00 pm »
One of the first things I checked was for vacuum leaks but I couldn't find any. The package was removed from a running car so in theory it should all just run, right?  ???

I've had a but more tinkering around since my last post and have since gotten it to run and drive although it feels down on power probably because of the below.
To get it running I advanced the cam timing a tooth, wound out the idle screw so it only just idles at like 600rpm when warm (which is meant to be all the way in on the KR injection system) and unplugged the overrun cutoff value and the vacuum switch from the vacuum system as they made the car run way rougher.
I advanced the cam a tooth (cause that's how it was set when I got it) but the distributor still wants to advance more and the flywheel timing marks wont line up which is a bit weird. You can't even see the flywheel timing mark with everything lined up where it should be.

My theory at the moment is that the ISV controller isn't working quite right which I'm not even certain on that. The ISV 'buzzes' as it should but doesn't seem to do anything when you pinch the lines to it, nor does the overrun cutoff value or the vacuum switch next to it. I've probed all the leads on the controllers circuit on it and it appears to be getting power to all the correct places when you click the throttle switch etc so at the moment, I'm very stuck and not even certain on that either now...
- Golf MK2 GTI
- Golf MK3 GLI

Offline liv

  • Posts: 20
Re: KJET 8v to 16v swap
« Reply #7 on: August 03, 2019, 10:49:09 am »
any reason why you're running KJET on the ABF?  Ive got much respect for the KJET system, but the ABF has some serious potential with EFI

Offline ziptie.nz

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Re: KJET 8v to 16v swap
« Reply #8 on: August 03, 2019, 04:47:01 pm »
any reason why you're running KJET on the ABF?  Ive got much respect for the KJET system, but the ABF has some serious potential with EFI

The ABF is lame as crap on EFI apart from Consistant Troublefree/Boring Running.
MK2 GTI 16v, MK2 TDI - Rollin' Coal, Audi V8 Quattro, Audi A3 Sportback 2.0 TDI