Speed Sensor

[viperclive]

Would anyone know the part number for the speed sensor fitted in the gearbox of a mk1 2.3 manual box and would it send a signal to the ecu as im having problem bringing my tick over down when stopping.

So far I've changed the following, cam sensor, crank sensor, throttle sensor, maff sensor,water temp sensor,throttle valve, throttle cable and her valve.

Just ordered the 3 vacuum valves and map sensor. It's been on 3 OBDII testers but nothing found, she's also on lpg and rpm sits at 3000rpm when you stop in both modes, if you slow engine speed with clutch (brake on) to 1000rpm n let her go she shoots up then settles down at 1000rpm, but sometimes stalls.

Don't want to have her put down yet but getting close!

 

Any ideas guys?

 

Viperclive

[BrianH]

Would anyone know the part number for the speed sensor fitted in the gearbox of a mk1 2.3 manual box and would it send a signal to the ecu as im having problem bringing my tick over down when stopping.

So far I've changed the following, cam sensor, crank sensor, throttle sensor, maff sensor,water temp sensor,throttle valve, throttle cable and her valve.

Just ordered the 3 vacuum valves and map sensor. It's been on 3 OBDII testers but nothing found, she's also on lpg and rpm sits at 3000rpm when you stop in both modes, if you slow engine speed with clutch (brake on) to 1000rpm n let her go she shoots up then settles down at 1000rpm, but sometimes stalls.

Don't want to have her put down yet but getting close!

 

Any ideas guys?

 

Viperclive

Microcat shows 7203354 as being the only sensor fitted to the manual gearbox on a mk1, any engine. I'd try unplugging it if you can first?  It unscrews from the gearbox, hasn't worked its way loose has it (does the speedo work??) If your anywhere near me I can find the one off the MK1 gearbox I've got in the workshop if you want to try, have a suspicion your in Yorkshire though? (Milton Keynes here)

 

I did have the same problem with my mk1 - It was down to the boot on the end of the cable not wanting to stay on the throttle body stub causing it to pull on the cable. I was going to swap the throttle cable to fix it, but temporally bodged it with a cable tie (round the bottom end of the boot and push it onto the stub bit so its in the correct position). That worked fine for the last few months of the car's life only coming off once (when i was under the bonnet for some other reason and knocked it off again anyway). It did tend to be a bit intermittent, but mostly caused it to rev too fast when parking up more than any other time or idling.

 

Vacuum leak might cause it? beyond the usual pipes that split on the galaxy (the one to the brake servo etc) have you checked the one that runs between the vapouriser and wherever it joins the manifold? Both to see if its leaking air, or if the vapouriser is leaking gas? (even with it switched to petrol the gas in the vapouriser will still have enough pressure to allow it to leak until it equalises if the vapouriser is leaking, which does happen and can take a few minutes to equalise).

[viperclive]

Hi Brian

Cheers for that number now located one on the internet, my Speedo works fine but the 3 wires connecting to speed sensor via 3 pin plug was a mess, insulation shot and all potentially touching, anyway sorted that n re-wired my thought was maybe the shorting may have damaged sensor? Especially if a signal is being sent to ecu. Can't seem to locate air intake sensor either, if I un plug mine nothing happens to engine tickover speed. Also if revs stick at 3000rpm when on gas if i switch over to petrol revs drop down to normal tickover. Also changed lambda sensor, I'm in Gosport so may have to bite the bullet and put her into a garage in Southampton that also do gas conversions to get the lot checked out.

[BrianH]

Hi Brian

Cheers for that number now located one on the internet, my Speedo works fine but the 3 wires connecting to speed sensor via 3 pin plug was a mess, insulation shot and all potentially touching, anyway sorted that n re-wired my thought was maybe the shorting may have damaged sensor? Especially if a signal is being sent to ecu. Can't seem to locate air intake sensor either, if I un plug mine nothing happens to engine tickover speed. Also if revs stick at 3000rpm when on gas if i switch over to petrol revs drop down to normal tickover. Also changed lambda sensor, I'm in Gosport so may have to bite the bullet and put her into a garage in Southampton that also do gas conversions to get the lot checked out.

 

I'd have a look at your vapouriser - the vacuum line will just pull off (no clips required). I would guess when you have pulled it off you may find that its leaking gas out of there. In which case the vapouriser diaphram has a hole in it. Its possible for the injectors to gum up though i'd suspect you'd notice rough running like that.

 

Checking it into somewhere to get the lpg checked over not a bad idea long as your sure its that, provided you can find somewhere who knows what they are doing. If its getting on somewhat you can find some electrical issues with the older kit (some have a feed from the lambda sensor and I've had one that started putting .32 of a volt down that connection and screwing up the fuel trims as a result, though the feed isn't really needed so can be disconnected, its just there for tuning purposes)

 

MAF sensors on the petrol I've never found much difference when you unplug them, just when they go faulty that you notice the car running richer than it should (smelly exhaust).

[viperclive]

Hi Brian I have a prints lpg system fitter are you talking about that vaporizer? I fitted a new diaphragm recently and 2 new yellow dot injectors n filters and rpm module, the car goes well in both petrol n lpg its just tickover thats the problem.It does suffer from white foggy exhaust at times and stinks like he'll but I put a new maff On! One problem I do have is the engine wiring loom insulation falling to bits so been re-wiring everything I touch back up to good cable so may have a problem there which means opening up the lot for inspection lol. Any idea's what the map sensor does as I'm waiting for that one to replace.

Cheers