speedo is causing my car to run crap?

[VTECANDY]

Hey everyone

i got a jdm prelude with a H22A engine in it, somethings gone wrong lately and its not healthy:thumbdwn:

ive noticed, particularly when its cold, or in the mornings, my speedo gives wrong readings, i.e jumps to 140 when im doing 40 or so and the gears (its auto) change as well and it runs like crap. once i booted it when it was happeninng and it topped itself out past 180 and sounded like the engine blew up (but it didnt). i have no friggen clue what it is.. speed sensor? what is it? how do i fix it? are my main two questions, the speedo just constantly changes, like the needle free-flows itself and makes the car run shit. also could it be the o2 sensor? im not sure.. but no check engine lights come on or anything like that.

cheers

[markismaximus]

sounds like the VSS (vehicle speed sensor) could be playing up. It sits on top of the gearbox and is relatively easy to remove.

If you aren't confident looking at it yourself take it to a mechanic, or you could just be creating more issues.

In regards to the car running badly, is it well maintained? Regular maintenance, plugs, fuel filter, oil, etc changed regularly?

ps. "booting" your car because something isn't work properly is more likely to break it further than fix it

[VTECANDY]

its an auto.. so it will be sitting on top as well yeah? thats what i thought it could be.. and yeah man, oil every 4-5k, iridiums, fuel every 15-20k, CAI :) but thanks for your reply appreciate it :)

[trism]

being an Auto, the VSS has an effect on the gear changes. so if it is playing up, itd be sending weird signals to the ecu, which would make the shifts all sketchy and abnormal.

[VTECANDY]

that would make perfect sense.. why does it only happen in the morning though? or when the car is cold? because once you drive it and start it up within 8 hours or so, it will work fine.. maybe its on its way out? also does anyone know where the location of the VSS is on the h22a prelude? i.e picture diagram?

[Nepolian]

VSS, like a square sensor thing that generally sits back/centre of gearbox. Not exactly sure on a H22 tho. The speedo will start skipping and so on and will eventually just die and then you would wish that you had fixed it properly 6 months earlier.

[VTECANDY]

http://www.ebay.com.au/itm/93-94-95-96-97-Honda-Prelude-VSS-Vehicle-Speed-Sensor-/130453860345?pt=Motors_Car_Truck_Parts_Accessories&hash=item1e5fa7eff9 is that it?

[dc2r-0636]

yeh, giv that a go its only $25