Help! switch that acts like a choke on a injection engine

[festival500]

Hi all,
this is my first post

2 weeks ago i picked up my first ever VW, Camper, T25 best thing Iv ever done!

Basically the van is a 1990 T25 and has had a mark 2 1.8 golf gti engine in it at some point (i did not fit it)

There is an aftermarket switch on the dash with i have to used to get it started in the mornings, the switch seems to effect the engine in the same way a choke does but obviously its not a choke because its an injection engine. It will adjust the idle as necessary to stop it from stalling and increases revs by a few hundred rpm.

1st problem is, what is this switch and how does it work? why does it require this? normal mark 2 golfs wouldn't require this and it is running on a stock mark 2 ECU? baffled!

2nd is when this switch is 'off' i get bad flat spots/ hesitation at 25mph in 2nd 35 in 3rd and so on.

Me and my mechanic (who is clued up and a VW enthusiast) have no idea what and how it works.

Iv heard that there was companies doing conversions like this before, could this possibly be a custom chip or mod to the ecu to richen up the mixture manually?

I anyone can shed some light on this I would be so grateful!

Happy camping,

Dan

[AdrianC]

1st problem is, what is this switch and how does it work?

Gawd knows! You're going to have to work backwards to eliminate whatever bodge a previous owner's inflicted on it, then find and fix whatever problem the bodge was intended to work around... Since it's an engine swap, good luck - you're gonna need it! <grin>

Standard injection on a 2.1 "knows" when the engine's cold from the "TempII" temperature sender in the side of the thermostat housing - different one to the dash gauge - and adjust the idle mixture in the ECU. The idle speed's adjusted by separate circuitry and the idle air valve. I have no idea about Mk2 Golfs... The basic principles apply to any injection, but the actual implementation can differ slightly.

[California Dreamin]

K Jetronic

Cold start enrichment is controlled by a seperate (timed) injector in the end of the inlet manifold (12)
Fast idle controlled by the auxilary valve (14) which basically bleeds air past the butterfly valve...again, on a warm up cycle....perhaps the thermo switch controlling this has been replaced by the manual one on your dash.

http://www.ffp.fi/index.php?mid=2&pid=105" onclick="window.open(this.href);return false;


Martin

[Kermit'skeeper]

Early mk2 gti's had the k-jet system mentioned above and later ones had an electronic fuel injection system. If you post a few pictures of your engine bay we will be able to tell which system is fitted and possibly which bit has been bodged.

[max and caddy]

I don't think any t3 bar maybe SA versions had k jet fitted..

[Kermit'skeeper]

It's got a mk2 golf gti engine fitted.

[max and caddy]

So it could be k jet...but that would be fairly involved due to locating the metering head in a suitable place...I suspect it's more likely to be on digifant but pics will help.

K jet is different to KE jet as above as well, but the golf gti didn't get KE unless fitted with a CAT, or to put it another way German..and even then only the 16v to my knowledge.

KE jet is a unreliable troublesome system, k jet is simple and trouble free as long as fuel is clean, digifant is generally good in a golf, not so good in t3 form as it was very over complicated but generally ok in the golfs...better without the flappy air flow meter though.

[ELVIS]

All sorted now chaps!

The switch was wired into water temp sender to turn the signal off to the ECU by PO.

Once this was sorted it was idling very high.1800 rpm Not only was one of the wires on the throttle sender broken, it was unplugged anyway

Throttle body cleaned as was ISV.

Dan is going to fit an oe water temp sender this week and get timing/emissions set up bob on.

Reports that its running like a dream now without doing this

[max and caddy]

So it's digifant then love?

[ELVIS]

Yep,ecu reference in first post gave it away

[max and caddy]

Yeah...but then someone piped up about k jet but with a link to KE jet...and KE does have a ecu, as does the 16v k jet engine in fact...no mention of number of valves anywhere..

[ELVIS]

Not getting drawn into one of your hater threads.

[max and caddy]

Go on...you know you want to..

[California Dreamin]

My fault for linking to KE...meant to be just K Jetronic but in my rust to post linked to a KE pic.....

Hater Threads? I thought we were all here for the right reasons, to help others? not a pissssssing contest surely!

Martin

[max and caddy]

It's just Elvis and his sense of humour...it because he wants me so bad but can't have me you see..sends him crazy