Turn the key, engine cranking but doesnt start, sec time it does

Tonnes1977 · Post by **Tonnes1977** » Sat Feb 18, 2023 1:53 pm

Hi Guys,

A Volvo V70 (2001) with an B5234T3 engine doesnt start when turning the key for the first time, the starter works great (engine rpm is there)but further no sign of life. When you turn the key back in position 0 en turn back at pos 3 (start position) the car will start directly. There are no trouble codes stored in the ECM.

I measured the relation CRANK vs CAM and it seems ok. I measured the relation between crank/cam vs ignition and injection and i see big differences.

When the car start you see that the ignition and injection corresponds with a certian flank of the CAM. But when the car doesnt start there is a big difference in ignition/injection vs CAM flank, it seems switched compared when the car will start.

I have no idea what can cause this problem.

I hope you can help me!

Thanks in advance!

wiki38andy · Post by **wiki38andy** » Sat Feb 18, 2023 6:02 pm

I had a Nissan Navara D23 2017 with the some issue. First attempt not any sign, no mater long you try. Second, start straight away. This happen every single time. Finally, I replaced the ECM.

Choppered&Whoppered · Post by **Choppered&Whoppered** » Sun Feb 19, 2023 6:43 pm

If you have access to a WPS pressure transducer and can examine the fuel pressure, intake pulse pressure, and exhaust pulse pressure during both your cranking event and when running, you may be able to identify an anomaly. Steve Smith likely has created videos available on YouTube that might help to explain my diagnostic direction.

PS: I come from the Toyota world in the U.S.A. and may not have a firm grasp of what life is like in the Volvo world, or worse, the diesel world.

Good luck!

volrem · Post by **volrem** » Mon Feb 20, 2023 3:35 pm

Ignition and injector signals are triggered in wrong crank revolution. 360 degrees off from correct position.

Any history of the car? Transmission removed or belt changed?

Do you still have that car? Can you make a new capture (cam, crank, cop, injector) with high sample rate and 500 ms/div timebase? Both no-start and start conditions. No-start 2-3 captures.
Cam pattern is 2 short and 2 long high signals.

When you have no-start then there are three long cam high signals. Either sensor is reading incorrectly or cam is not turning initially (VVT issue). From that pattern ECM thinks that engine is in another revolution.

Tonnes1977 · Post by **Tonnes1977** » Wed Feb 22, 2023 4:31 pm

Hi Volrem,

Thanks for your input

We've got no history of the car and the car is recently bought by the customer.

Anyway,

There is something strange going on. When i disconnect the cam sensor the problem is the same. The car doesnt start the first time. We've got a nother car from same type,age and milage, when we do the same disconnect the cam sensor the engine starts all the time.

i want to add new files but they are to long, can i send them by mail?
Thx

wiki38andy · Post by **wiki38andy** » Wed Feb 22, 2023 11:02 pm

Double check if the ECM part nr is the same with donor car one and swap it. Do the key prog in your car and it should start.

Tonnes1977 · Post by **Tonnes1977** » Thu Feb 23, 2023 7:47 am

Hi all,

@ wiki38andy, the other car is an customer car too, and swapping Volvo Ecu's is a bit hard to do cause of immo in eeprom and in flash.

Thanks!

wiki38andy · Post by **wiki38andy** » Mon Feb 27, 2023 7:32 pm

Any update?

Rfmotors1 · Post by **Rfmotors1** » Fri Mar 03, 2023 6:07 am

Hi Tonnes1977,
There is good known waveform in the waveform library uploaded by "kostelectronics"
See the attached files, (could not upload directly for some reason, so link to Google drive here):
https://drive.google.com/drive/folders/ ... sp=sharing
With the same reff. markings the file from kostelectronics shows cam angle 92.4 and your file 63 deg on the same cam edge.
If your engine running normally, then your cam or crank target wheel is wrong, if it runs not well, your cam setting/timin is out.
I would record the compression waveform if you have pressure transducer, just cranking will do the job, then it will be clear whats wrong.
The Waveform library is valuable source of information.

Hope it helps,
Roman

wiki38andy · Post by **wiki38andy** » Sat Mar 11, 2023 3:47 pm

Hi Tonnes 1977,
could you keep us update with this interesting case?
Thank you.

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