dash cuts out and accelerations ropey :(

[KrissJ]

Just wondering if anyone knows what might be wrong?

A while ago my dash started cutting out every now and again. This means that the speedo and everything stop working and I've also noticed that the heaters 'clickety-click' sometimes which could be connected. I took the dash out to see if there were any loose connections but everything looks OK so not sure whats up. A couple of short sharp smacks on the top of the dash usually sorts it out but its a bit scary n annoying.

Also, in the last couple of weeks the accelerations started to get a bit ropey. If I accelerate on part throttle it sort of hesitates and then the increase in speed is very unsmooth and jerky. At full throttle it jerks then goes but again not very smooth. It boosts properly and I had the turbo virtually rebuilt not long ago because of cracked housing.

Any advice or ideas would be very much apprecited as I'm gettin very frustrated with the car at the moment. As soon as I fix 1 problem another appears :x

 

[KRS]

If your getting a short to earth, could explain why your car is not running smooth, would be playing havoc with a lot of stuff.

Hard to say where it might be

 

[KrissJ]

Cheers.

I know you said its hard to say where it might be but do you know where the earth points usually are cos I could check them and try and trace them back through the car as well?

 

[KrissJ]

Why would a shorting to an earth point give me ropey acceleration?

 

[KRS]

Im not to great with automotive electrics, but im pretty good with electronics so ill explain as best as i can figure, if im wrong someone correct me plz.

Your cars whole body acts as an earth or ground.

So if anything with any voltage shorts even for a few seconds with the body of your car the ECU will begin to receive bad signals from its sensors hence causeing you car to run lumpy, or in some cases not at all.

The reason its hard to locate is because it really could be anywhere, I suggested this may be the problem because if you dash is cutting out, you must have some kind of fault in the system and a short to earth from a main cable for your dash could have that kind of effect.

Its only a shot in the dark though, but it does sound like a possable explanation for both your problems.

 

[KrissJ]

Cheers

If it could be anywhere do you think its the sort of thing a car electrician could locate without much trouble or would it simply be trial and error and so -probably knowing my luck with cars- cost me a fortune cos its taken them forever to find?

Would it be obvious for me to see if I came across it considering I have o experience in that sort of thing?

Thanks for the advice, it makes sense to me now

 

[geetee]

That could be a complete git to track down.

I'd start by looking at extra wiring added for accessories like gauges, boost controllers head units etc., as the stuff in the loom itself 'should' be more or less protected.

Other place to look is the after market delimiter (if it's an import) behind ur speedo...

Then disconnect ur battery completely and with the ign off see if you have continuity from the live wire to chassis earth. If you do, start pulling a fuse at a time and see if any of them cure it - at least then you have a clue what circuit to look at....

But it is a bit needle in a haystack...

CHeers
GeeTee 8)

Duplicate post deleted

 

[KrissJ]

Cheers for that, it'll help.

I put my headunit in and had to iwre my own earth up so I can try that, but I'm suspecting its OK.

Then disconnect ur battery completely and with the ign off see if you have continuity from the live wire to chassis earth.

What does that mean though?

1 thing I have thought though is that it could be connected to the plastic connector on the back of my driver's side head light. For some reason some of its melted away and the main light stopped working a while back. I got it fixed but its started not working properly again

 

[Toady]

check the way your ecu is mounted and the wires/terminals on the ecu as that controls the speedo.

 

[geetee]

The headlight connectors often melt or break on these cars.

Toady - the ECU doesn't control the speedo AFAIK... the speed sensor wire goes to the speedo first and then onto the ECU. That's why most delimiters are fitted behind the speedo to modify the signal before it hits the ECU.

Cheers
GeeTee 8)

 

[Toady]

The headlight connectors often melt or break on these cars.

Toady - the ECU doesn't control the speedo AFAIK... the speed sensor wire goes to the speedo first and then onto the ECU. That's why most delimiters are fitted behind the speedo to modify the signal before it hits the ECU.

Cheers
GeeTee 8)

ahh yeah, think i was thinking of the rev counter! :roll: