WH Stops and hard to start

[hotqld]

My WH wont start 3rd time now after travelling for 30 to 60 minutes turn off and it wont start with the fix being leave it for 3-4 hours.
Error code B212D ignition run circuit open, clear the code and it does not reappear so looks like a intermittent fault measuring between the IPM fuses 29 and 30 to the ORC resistance is .5 ohmns and 12.5 V at the ORC module.

Swapping run relays is not possible as the run relay is not a serviceable part on the junction box under the steering wheel. Wiring looks fine resistance check confirms this.

Also noticed fuel pump runs for 30 seconds even when only turned off for a minute or two.
Has the fuel pump a built in non return valve? Or is there a non return valve in the system? Have just replaced fuel filter and fuel lines there are no fuel leaks? Could this explain hard to start? Starts best when cold.
Also will just stop at idle far too often now!
Has anyone installed a non return valve, I have not noticed the fuel pump going for 30 seconds then turns off when the system is pressurised a little.

Any thoughts on getting this Jeep to behave again?

[Clarky]

Just did a quick google and I think the b212d code is a result of the long crank not the cause (only my opinion)

code is set when there is less than 6 volts on the ignition voltage supply circuit for more than 15 seconds

If it starts best when cold I am thinking its not a fuel pump thing either.

Have you considered the crank angle sensor? Just thinking out loud.

Merc recall - http://www.thetruthaboutmercedes.com.../pdfs/SM72.pdf

[Clarky]

I have a spare crank sensor if you want to give it a try.

[vk2jdh]

Originally Posted by hotqld

My WH wont start 3rd time now after travelling for 30 to 60 minutes turn off and it wont start with the fix being leave it for 3-4 hours.

Any thoughts on getting this Jeep to behave again?

What year? 2007 have a Crank Position Sensor issue. ( but it will throw a code), if it has not been replaced . Remove it and check the date code.
Inspect the Crankshaft Position Sensor for the Julian date. The Julian date is located
on the sensor opposite side from the hold down flange (just above mounting surface).
• An example of a Julian date on the sensor reads as follows: 07 T 59
• 07 represents the year, 59 represents the day, (59th day of 2007).
5. Is the Julian date 07 T 59 or lower?
a. Yes >>> proceed to Repair Procedure


To get my one to restart after stopping ( while driving for about 10-15 min) I disconnected the battery for a few minutes.

Similar but not the same as your issue.

[hotqld]

Originally Posted by Clarky

I have a spare crank sensor if you want to give it a try.

Thankyou for the offer, today I brought a $22.00 8mm non return valve from the diesel injector repair shop and installed it in the fuel line after the filter.

Appears to have solved the starting problems, time will tell but so far so good.

[ren0vator]

Originally Posted by hotqld

Thankyou for the offer, today I brought a $22.00 8mm non return valve from the diesel injector repair shop and installed it in the fuel line after the filter.

Appears to have solved the starting problems, time will tell but so far so good.

That'll be an easy fix, if it works. Hears hoping.
If this works then I'd be thinking there is an issue with the pump in the tank?
Couldn't find a specific diesel in tank pump.
Maybe they're the same as the petrol ones?

[hotqld]

I consider the non return valve was worthwhile, very easy to start hot or cold
foot off the accelerator 2- 3 seconds and it starts, no more stalling.


But after towing 70 - 80 klm about 60-80 minutes at highway speeds 2800kg, we stopped, turned the jeep off and it would not restart.
We left it for 3-4 hours and it then started great as described above.
Attached are the active codes
I think I can discount the B212D code open run circuit as there is 12.5v at the ORC.

Which is leaving U1414 / U1414 faulty ORC or front control module.
My thoughts are to test if the supply and ground are good for both modules
and read up further methods for confirming a dud module, broken wires.

I was leaning towards crankshaft sensor but it should be throwing a code saying its dud. I appreciate the comments and help any further thoughts out there?