Am I on the right track

[dellyend1]

Hi All,

A call for collective wisdom if I may.

Car has developed a very occasional stall if breaking harsh(ish) upto a junction. At low speed / moving through the gears coming up to a stop the car is fine. The idle is also not settling and whilst not hunting, moves from 1000 - 1300 whilst at idle.

Car chararcteristics :


1993 4.3
Speedo not working
No misfire
peforms perfectly well under load
Cold start works fine anc cold start idle
Stepper motor checked and cleaned but was really quite clean anyway
Just changed the water sensor next to dizzy but made no difference.

I'm thinking that it may be the ecu input from the speedo and that as the speedo is not working the sensor may be dead and this is causing the occasional stall from higher speeds to a swift stop. Am I right in thinking that the speedo sensor is on the diff and the ecu sensor for speed is on the gear box ? I'm assuming I have an early SD1 gear box as well.

Or is it a fuel starvation issue ? if so what could be main culprits ?

Many Thanks All

Jeremy

[KKson]

Jeremy, nice to see you're back in TVR world. Was the Merc a bit boring? 350i is still going great, but it was a bit lonely at night so just bought a 390SE to keep it company. Cheers Keith

[ChimpOnGas]

dellyend1 said:

I'm thinking that it may be the ecu input from the speedo and that as the speedo is not working the sensor may be dead and this is causing the occasional stall from higher speeds to a swift stop. Am I right in thinking that the speedo sensor is on the diff and the ecu sensor for speed is on the gear box ? I'm assuming I have an early SD1 gear box as well.

Yep , your on the right track, the ECU needs that speed signal.

I had the very same thing, in my case I traced it to a bad connection at the back of the speedo, once I sorted the the dodgy connection the speedo returned to normal service and the stalling after a quick stop from a high(ish) speed completely disappeared.

Your dead speedo and stalling issue are very much connected, fix the speedo and the stalling will go.