Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[philhoward]

Now this is a previously running engine (although not in an Omega now).

It started misbehaving a while ago - would start then stutter and stall.  I've changed the fuel pump (twice) and the crank sensor (twice - one genuine, one pattern) but still nothing.  I appear to have fuel (plugs smell a little after repeated cranking) so I assume I've got signal to fire the injectors. 

Paper clip test shows an O2 sensor (bank 2 - is that offside or near side?), 31 (to be expected when not running) and 57 Idle Air Control voltage low.  Still won't start if I give it a bit of throttle. Is it just the ISCV duff or a clue to something else?

Any clues welcome..

[05omegav6]

Bank 2 is the 246 side

[philhoward]

 

Makes perfect sense!

[Bojan]

Won't start if you give it a bit of throttle  or if you don't give it?

[philhoward]

No throttle or some throttle - no joy either way 

I did wonder if the ISCV was duff it still might fire with a little throttle - not even a cough though.

[Bojan]

Any luck if you give it a full throttle?
Do you have spark when cranking?

I pressume that you don't have access to diagnostics tool?

[philhoward]

I did try full throttle but assumed that was "flood clear" mode so didn't expect that to work.

Will check again for spark (had spark before I think) although didn't check yesterday.

[philhoward]

Not sure if it's a red herring or not but the ECU light goes out after a few seconds of cranking - in the past its stayed lot if there was a major problem.

[Bojan]

This engine is in other make of car now, right?
Was it running after it was installed?

Have you found out if there is a spark?

[philhoward]

Yes, it has been running in its new home for 3 years. 

Spark tester is on its way - as soon as it arrives I'll be checking for sparks.

[05omegav6]

Yes, it has been running in its new home for 3 years. 

Spark tester is on its way - as soon as it arrives I'll be checking for sparks.

Does it still have the original relays? If yes, check both small purple relays for any signs of scorching... if in doubt swap for known working ones to confirm... one powers the pump, second powers the injectors

[philhoward]

Done both relays - even bypassed the pump one "just in case"..and happily heard fuel (and got 3 bar pressure according to my gauge) flowing through.

[05omegav6]

 

Where was the 'genuine' crank sensor from?

And Autovaux/ebay isn't the correct answer...

[philhoward]

Crank sensors - ah yes.

I have (from a friend who isn't running Motronic anymore) one Bosch and one Siemens sensor (both rounded plug versions).  I think he got them from Vauxhall but might have been elsewhere.  They are genuine though - he wouldn't have spent c.£80 a piece on junk ones.  He bought them trying to find an issue that turned out to be his shiny new ECU, not the crank sensors after all.

Anyway - have tried both and a £20 eBay cheapie (worked last time proving another fault).  Same result - no start

If it's any use, I'll get the numbers off the actual sensors - I have a feeling the one should only be fitted to a specific 2.5 variant?

[Kevin Wood]

There is an issue that has cropped up with the 2.5 in the past, that the sensors are different lengths. Some appear to have a shorter nose than others and don't reach the reluctor ring on the crank to get a reliable signal.

Do you have access to an oscilloscope? Just wondering if you can check the output from the sensor?