S1 K jetronic fuel injection system

[Sunnysu]

I've been having problems with this. The car was not running properly, stalled at low revs and junctions, wouldn't hot restart easily after a run. Just had the jetronic stripped and rebuilt. Drove the car back from the garage, beautiful acceleration, no stalling at junctions . . . but . . . switched the engine off when I got back. When I came to try to put the car into its gargage . . she didn't want to start again. After several attempts (and swearing) did get it started but not happy with the situation. Has anyone else experienced this? Is there a fix or a work round? The guys at the last TVR meet were talking about S owners moving back to twin carbs due to fuel management probs.

[Barry S1]

I have the same problem always been like it had the four years now, I've had a new cold start rely, just the same you can try unplugging the Blue connection on thetend of the engine it sometimes helps, I find if you hold the throttle pedal right down it always starts but very annoying

Edited by Barry S1 on Sunday 1st February 12:30

[glenrobbo]

Sunnysu said:

I've been having problems with this. The car was not running properly, stalled at low revs and junctions, wouldn't hot restart easily after a run. Just had the jetronic stripped and rebuilt. Drove the car back from the garage, beautiful acceleration, no stalling at junctions . . . but . . . switched the engine off when I got back. When I came to try to put the car into its gargage . . she didn't want to start again. After several attempts (and swearing) did get it started but not happy with the situation. Has anyone else experienced this? Is there a fix or a work round? The guys at the last TVR meet were talking about S owners moving back to twin carbs due to fuel management probs.

I've only heard of one S owner reverting to twin carbs, and he has the Cosworth engine fitted, not the 2.8 V6 Cologne engine.

Our resident expert on the K-Jetronic system is Richard, greymrj, who was telling.me that he has finally nailed this problem after a LOT of perseverance.

Richard!!!

[Loach1]

Can you ask the folks that rebuilt the system what they set the main pressure, cold and hot control pressures at? Did they check the emissions when they finished? These are critical to doing the job properly and having a reliable system. Once set correctly, they shouldn't need attention for a very long time.

A stubborn hot start is often caused by an over rich mixture, and if you are happy with the overal performance it might just need a small tweak on the idle mixture screw. You can experiment without much risk if you have a long 3mm Allen key, just give the screw a very small anti-clockwise adjustment next time you have hot start problems. The screw is the one on the metering unit down the hole that is next to the rubber plenum.

David

[Sunnysu]

Martin at Top Gear Automotive stripped down the Jetronic and rebuilt it.

[CJD2005]

I had exactly the same experience with my S1 when I first bought it and it was as simple as corroded wiring connections serving warm up regulator etc etc. you will find a lot of the main wiring loom associated with this near the passenger side front wheel arch which is usually exposed to the elements, check this befotre spending big money! Check each connector carefully for continuity with a meter, as it is usually the connectors that are the problem.

[greymrj]

glenrobbo said:

Richard!!!

Yea, over the snowy hills of the northern lands the call of the Messiah was finally heard! And the call to the (S1) faithfull was answered.

Ok Glen, not sure if I can make any claim to being a 'guru' on the K Jetronic, just a persistent old bugger who is too mean to take the car to an 'expert', but one can only do one's poor best .

Rather than try to do a diagnosis through PH I have emailed Su Carlin and suggested she rings me .

Having said that I must get round to doing a post about the specific problem I eventually found, as I suspect all S1 will suffer from it at some time if owners do not deal with a corrosion issue. More to come.

[chiefyo]

Good detailed wtite up on Bosch K in January issue of Practical Performance Car including fault finding