Scope traces of Bosch Crank Sensor 026 121 002

[zola1]

Guys,

Here are some scope traces from a test rig we have at work, (might help with a guide of what a correct signal looks like ? e.g when you diagnose some non start & misfires at various rpm stages ... issues people have with the 944 crank sensor Bosch one at the flywheel/bellhousing) etc










any q's please ask

[tr7v8]

Err yer pics aren't showing!

[Sean Smallman]

Derek

You need to change your pics to jpegs. The system doen't recognise Tif files.

[poprock]

Ah, the advantages of using a Mac. The TIF files show up just fine here. I’ve converted them to GIF files and attached them here for all the Windows users.

Bosch%206000%20Rpm.gif

Bosch%202000%20Rpm.gif

Bosch%20300%20Rpm.gif

[zola1]

Cheers poprock

[blacksuz]

Hi Zola, can you help as I have just read your post.

I have 944T which I do track days with and its now misfiring intermittently but mainly when I have driven it hard. It won't idle either and the starter motor has problems engaging sometimes, again intermittent. Can you explain a bit about the graphs as I need some context to make sense of it.

Are we saying that the Crank sensor develops a fault which causes misfire? This sounds identical to what is happening with my car. However, it appears to be fine at higher speeds.

best

blacksuz

[tr7v8]

Hi Zola, can you help as I have just read your post.

I have 944T which I do track days with and its now misfiring intermittently but mainly when I have driven it hard. It won't idle either and the starter motor has problems engaging sometimes, again intermittent. Can you explain a bit about the graphs as I need some context to make sense of it.

Are we saying that the Crank sensor develops a fault which causes misfire? This sounds identical to what is happening with my car. However, it appears to be fine at higher speeds.

best

blacksuz

Possibly sensors but more likely something else. Dirty injectors or low fuel pressure, air leak? Idle will be AFM or TPS, I'd also look at plugs, leads cap & rotor. Starter may not be connected & just need the solenoid cleaned.

[tr7v8]

Cheers poprock

Fantastic timing (SIC) Zola as I need to scope through Pauls after his car threw a fit & decided it wasn't going to France.
I know it isn't ECU as we've swapped it with mine & metered the sensors to the ECU & they show 930ish Ohms which looks about right.
Have downloaded a scope package for the Laptop which looks good enough & bought a stereo pot yesterday from Maplins to make a fly lead up.

Has anyone got any old connectors for the sensors then we could make a proper TIPEC breakout box?