Multiple attempts required to start

[oldsoul]

I have a 2013 CJAA with Rawtech DPF/EGR delete, and have done the following over the last week:

• Timing belt
• Fuel filter
• Thermostat

Car sat, and was not started between jobs. Went through the step my step posted here for timing belt, following it closely. Took my time and made sure everything was reassembled correctly, double checking hose and electrical connections. Went through the VCDS pump priming process and then tried to start the car. Cranks as usual, fires, then immediately stalls. Occasionally the stater seems to try to re-engage in the short time the engine is running. Eventually, with enough attempts, the car stays running and runs normally. This happens with a cold engine, and at full temp.
I did have the battery out for a day or so for access while doing the t-stat. Wondering if this is the cause, or if there is something else. Maybe I missed something? First time I've attempted a job this big, and not sure where to start to diagnose the current issue. Any help is appreciated.

 

[super1]

I have a 2013 CJAA with Rawtech DPF/EGR delete, and have done the following over the last week:

• Timing belt
• Fuel filter
• Thermostat

Car sat, and was not started between jobs. Went through the step my step posted here for timing belt, following it closely. Took my time and made sure everything was reassembled correctly, double checking hose and electrical connections. Went through the VCDS pump priming process and then tried to start the car. Cranks as usual, fires, then immediately stalls. Occasionally the stater seems to try to re-engage in the short time the engine is running. Eventually, with enough attempts, the car stays running and runs normally. This happens with a cold engine, and at full temp.
I did have the battery out for a day or so for access while doing the t-stat. Wondering if this is the cause, or if there is something else. Maybe I missed something? First time I've attempted a job this big, and not sure where to start to diagnose the current issue. Any help is appreciated.

So just to be clear, the car was starting and running fine before you did all this work?

 

[oldsoul]

Yes, it wasn't getting up to temp, hence the t-stat swap. Otherwise it was running fine.

Doing more research, I'm wondering if the HPFP is off by one rib. I had some trouble keeping the tool in place to keep the sprocket from moving.

 

[super1]

QUOTE="oldsoul, post: 5880199, member: 560014"]
Yes, it wasn't getting up to temp, hence the t-stat swap. Otherwise it was running fine.

Doing more research, I'm wondering if the HPFP is off by one rib. I had some trouble keeping the tool in place to keep the sprocket from moving.
[/QUOTE]
Yes, go back and recheck your timing with the pins/tools

 

[oldsoul]

That's what I feared. Thanks.

 

[oldsoul]

Ok so I went though the timing belt process again. No issues, everything checks out fine now. Still the same issue. Tried new key battery, and touching battery leads together. No solution yet.

 

[super1]

Ok so I went though the timing belt process again. No issues, everything checks out fine now. Still the same issue. Tried new key battery, and touching battery leads together. No solution yet.

Did you do a full system scan with VCDS?

 

[oldsoul]

I'm very unfamiliar with how to use VCDS, so, no I have not. I assumed that, as with most other cars, the engine needs to be running to do a full scan.

Additionally, I have not yet taken the time to learn how this is done. I'm sure it's not hard, just haven't educated myself yet.

 

[Beewi]

If you have one, it really is super simple! You'll go online and download their software (free!) to a laptop that you'll bring with you to the car. Once you're done with the setup instructions (available as a video or written list) you just reach under the dash to your OBD port, plug the cable into that on one end, and into the laptop on the other, turn the key to "on" (no startup needed!), and run an autoscan.

If you really want to, you can get the car running with the cable hooked up and look at individual sensor feeds for things like cylinder pressures or oil temp. If it saves you even 2 hours of diagnostic time at a garage, it has already earned back the $200 price tag.

 

[oldsoul]

I do have one, and used it to prime the fuel system.

Is it possible that a bubble or two of air got passed the HPFP? I'm planning on purging the injectors then do an auto scan. I'll see what happens.

Thanks for your help.

 

[oldsoul]

Had just enough time to do auto scan. No current issues found except low voltage from several days ago when I ran the battery down trying to get it started.

I'll be doing the injector purge tomorrow.

 

[oldsoul]

Did the injector purge, and some air came out of each injector line. I also ran the fuel system priming with VCDS, again. Still doing the same thing. Did get the engine to run a couple times, seems to be running smoothly. I'm really at a loss here, any other ideas?

 

[Beewi]

I know that if there is even a small leak of fuel from a hose nipple feeding the hpfp on the CR engines it can give you an issue where the first start of the day is a hard/long crank.

Starting from the point that the tank fuel line enters the engine bay, can you see any signs of diesel leaks or drips, particularly around connections and joints? It sounds like either that either all the fuel isn't going where it should, or that air is being sucked in where it shouldn't.

When you went to swap your fuel filter, could it be possible that one of the four hoses that go in and out of that housing formed a crack when they were moved? That would allow air intrusion or fuel loss ahead of your hpfp.

 

[oldsoul]

I have looked for that, even when cranking/ running and no evidence of leaks.

 

[Beewi]

Well, if you're able to purge air from the injectors it's getting in somewhere, right? Somewhere, the flow of fuel is generating suction and drawing in air. It may be worth taking a dropper of fuel and seeing if it can be pulled into one the joints where rubber fuel lines go over metal lines. You had to pull out the whole fuel filter housing when you did the timing belt, are you sure all those connections got crimped down tight?

During the timing belt or thermostat swap, did you ever have to disconnect or loosen the fuel rail or the unions that hook up to it?

 

[oldsoul]

I reused all the same clamps, so I'm assuming that all the lines are secure... I suppose it is reasonable to suspect that one or more clamps is no longer up to the task though.

The only tampering after the HPFP was when I purged the injectors.

At least this gives me somewhere to go from here.

A thought, not sure if it would work or if it's a good idea but, I have an oil extractor for oil changes, is there a place I could hook in to pull fuel through the entire system and then work backwards from there? Connecting at various points to see where the air is coming from. It has opaque lines, so I believe I would be able to see any air as it when through. Obviously I would then need to reprime the system again, but is this something that would work? Is it a bad idea? I don't want to cause more issues by trying to find the current one.

 

[oldsoul]

Ok, so I finally had some time and went through all the fuel connections under the hood using VCDS(oil extractor method did not work as I'd hoped) to operate the pumps. The only place I found any bubbles develop and couldn't prime them out was AFTER the mid pressure pump. Replaced all the clamps from the mid- pressure pump input to the HPFP. Still have bubbles, but they are very small, similar to foamed fuel, and pretty minimal, less than 10% of volume.
No luck.
I saw a post from Oilhammer suggesting that the pump may be faulty. So, as described, I unhooked the fuel rail pressure sensor.
Still no luck.
Not sure what else to try here. Is it time to seek a trusted shop's help?

 

[Beewi]

10% of the fluid at the outlet of a pump being gas bubbles would suggest that either you have cavitation of the diesel or that the pump is sucking in outside air and introducing it to the fuel. Either way, it would mean that the HPFP is seeing less delivered fuel than it should and likely at a lower inlet pressure than is intended.

Unhooking the rail pressure sensor might keep the car running if the issue was that the HPFP was intermittently failing to deliver the specified pressure to the injectors, but if the issue is that not enough fuel is present to operate the engine, I don't think that would help...

Either way, given that the common point for the cp4 HPFP failures seems to be a loss of lubricity, I would be a little iffy about having any air bubbles going through it. OEM replacement looks to be around $500, but I have zero idea about the difficulty of doing that swap.

 

[oldsoul]

10% of the fluid at the outlet of a pump being gas bubbles would suggest that either you have cavitation of the diesel or that the pump is sucking in outside air and introducing it to the fuel. Either way, it would mean that the HPFP is seeing less delivered fuel than it should and likely at a lower inlet pressure than is intended.

Are you thinking I need a new mid-pressure pump then? Would I need to test anything else to be sure?

 

[Beewi]

I'm not a mechanic, I just play one on the Internet with other peoples' cars, time, and money. But I do know a bit about fluid handling and controls from my real job.

Are you absolutely certain that the bubbles you saw leaving the auxiliary fuel pump did not flow into the auxiliary fuel pump from the auxiliary fuel pump's inlet? Because if that inlet line is good, if the seal on that inlet line to the inlet nipple is tight, and the nipple has no cracks that would allow air to enter the pump, then there is something wrong with that pump.

 

[oldsoul]

Took some videos of start and stall, and start and run.

https://drive.google.com/file/d/1OSF3_FDNz9t2Qb-78x7tRTEa37b1UqiN/view?usp=drivesdk

https://drive.google.com/file/d/1ORIlA_0POeJv_b6yrdG1lJPmFszfEI0-/view?usp=drivesdk

https://drive.google.com/file/d/1OMCF6YrD2YGv0Vil93_XC7wsLBT9ig0M/view?usp=drivesdk

 

[super1]

Took some videos of start and stall, and start and run.

https://drive.google.com/file/d/1OSF3_FDNz9t2Qb-78x7tRTEa37b1UqiN/view?usp=drivesdk

https://drive.google.com/file/d/1ORIlA_0POeJv_b6yrdG1lJPmFszfEI0-/view?usp=drivesdk

https://drive.google.com/file/d/1OMCF6YrD2YGv0Vil93_XC7wsLBT9ig0M/view?usp=drivesdk

Can't access videos

 

[oldsoul]

Can't access videos

Sorry, should be working now.