captain satellite

Both the digital and analog speedos are going crazy. Guess the analog must be electronic, as it reads zero, then 11 or other random numbers, then the true speed of 80, or whatever I'm doing in sync with the small digital one.

Compounding this problem are lights flashing on and off, the green and red ABD and also the antilock light.

What should I do?

Leo

bart1

I think I would first take it out to make sure the connection was tight and clean. You can look up the DIY on www.p-car.com

samba-lee

Leo,

Did you ever sort this as I've just developed a very similar fault ...

Lee

JM993

Check your battery/alternator/ground connections before you begin pulling gauges. Bet you'll find a problem there.

Cheers,
Joe

nile13

Battery, alternator belt, alternator. In that order.

samba-lee

Battery and connections appear fine and the car starts fine.

Alternator belts are doing what they do.

How do I check the alternator connections ? could there be things in the engine bay fuse box that are connected to the alternator ?

Interesting that you jump straight to power source, you don't think it's anything to do with the speed signal ?

thanks for replying so soon

Lee

nile13

It has nothing to do with speed signal if your ABD and other lights come up.

Search.

JM993

Alternator check - With the car running connect a multimeter to each terminal on the battery. With the car running the meter should read approx 14V.

samba-lee

Given that it would be incredibly bad luck to have an alternator go at the same time as swapping the starter could a poor starter/body ground strap have the same effect as a failing alternator ?

I suppose the thing to note is that all the wiring around the starter has been disturbed including obviously the big battery/alternator ones.

Off to my garage now to have a pole around.

thanks and I'll check back here in a bit form any more thoughts and updates it's great having most of you guys in the middle of the day, probably sat in front of your computers

Lee

samba-lee

Checked and getting 13.8v at the battery with the engine running.

Took a big jump lead from the engine case right to the -ve battery terminal/body ground just to ensure the engine ground was ok (although it cranks fine so I couldn't see how it would be the problem).

Let me just reiterate, I'm getting the ABS light (not ABD), the spolier warning light won't go off and the speedo either doesn't work or is erratic.

Any chance it is the ABS ECU as speedo and spoiler warning relies on speed signal and the ABS unit is involved in that isn't it ?

Lee

JM993

YES! You didn't tell us about the starter change! I agree with your plan to check the starter wiring.

Cheers,
Joe

samba-lee

Joe,

All wiring around the starter looks to be good. The starter cranks as expected, I jumped the crank case directly to the battery earth so I can't see how it can be related to main power earth now as I effectively bypassed it and test it.

I read in a Porsche Tech bulletin about mismatching the ABS sensors (old and new part number) not being good and you should change them in pairs.

The front left seems to provide signal to the ABS which is then used to drive the Speedo/CEL including the spoiler controller. But we replaced that sensor. The fact that the speedo worked intermittently and erratically would say poor connection/failed sensor somewhere or failed ABS ECU as the speedo signal is processed through the ABS unit.

Check this post which discusses the source of the speedo signal...

Lee

nile13

Lee, I would take the battery to an autoparts store for a load check.

JM993

I'm having trouble getting past the coincidence of this problem occurring just after starter work. Also, you have multiple electrical problems. I would suggest rechecking the starter leads, alternator and battery. My guess is that it's still one of these.

samba-lee

I agree, although I've run out of things to check and the car starts perfectly, I'm getting good voltage and I've bypassed the earths. I'm kind of running out of ideas for the charging circuit.

The spoiler and speedo signal appears to originate from the ABS ECU which compounds the evidence for something not quite right in the ECU given that we already changed the sensor it was reporting faulty.

I suppose the shop "might" have spiked the ABS ECU in dealing with the starter issue but they know better and are well experienced and trustworthy shop that only work on sueprcars (inc. more electrically delicate F360's).

Thanks for you input - I'm feeling this is going to be more expensive...

Lee