CRD Hard/No Start - JeepForum.com
 
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post #1 of 9 Old 09-16-2017, 05:26 PM Thread Starter
Jambalam
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CRD Hard/No Start

MY 2007 CRD has been having very hard starts as of the last week. It's been a bit of a sporadic problem that's only become regular as of late.

Temperatures are near 80F degrees in Denver currently (60s at night).
Glow plug indicator light has always seemed to turn off way too quickly, I allllllways give it 30 seconds of ACC before ignition. (starting to suspect this has been an after affect of my hard start issue)
Battery is tip top, testing at nearly 13 volts cold, and around 12 flat while starting. However Jeep did fire up with a jumpstart (on the 3rd or 4th attempt) after dying at a carwash. Could have just been coincidental timing with the building fuel pressure (mentioned later in this post) and/or too many attempted cranks at the carwash. Though, I was keeping an eye on battery voltage during and it seemed fine.
No CEL codes.
Fuel filter replaced 4k miles ago.
Just recently resolved an intermittent almost-limp mode problem with a new Exhaust Gas Pressure Sensor. That would occasionally throw code P0417, which has not returned since.
Had a good shop install a new OEM turbo about two months ago and don't think this issue is related.
110,000 miles on her, with proper oil changes.

Plugged her into a non-Starscan scanner; fuel rail pressure set point was near 4800PSI but actual was closer to 1200.

Thoughts? I know the Crankcase position sensor (CPS) can cause some similar symptoms however my Jeep has never stalled, just hard/no start occasionally (regardless of outside air temperature). After she does start, she runs seemingly tip top. Does the Fuel Rail Pressure Set Point vs acutal difference rule out the CPS? If so, is there a fuel pressure sensor? With no thrown codes, would that point to a mechanical (not a sensor) issue? perhaps the high pressure injector pump is going bad? Anyone have info on the Fuel Rail High Pressure Relief Valve?
It seemed like we could watch the rail pressure build and build and build on the scan tool up to 1200-ish PSI and then she'd fire up.

Any estimation of expected prices for replacement parts is also appreciated!
Thanks All!!!


2007 Grand Cherokee Limited CRD, Denver,CO. Member since Jan. 2017.
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post #2 of 9 Old 09-18-2017, 01:32 PM
underscore
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Quote:
Originally Posted by Jambalam View Post
Glow plug indicator light has always seemed to turn off way too quickly, I allllllways give it 30 seconds of ACC before ignition. (starting to suspect this has been an after affect of my hard start issue)
Why are you waiting so long? From my limited testing waiting too long after the light goes out makes it harder to start.

Quote:
Originally Posted by Jambalam View Post
Battery is tip top, testing at nearly 13 volts cold, and around 12 flat while starting.
Voltage alone doesn't show the whole picture. My old battery tested fine for voltage but multiple times it failed to have enough jam to turn over the motor. If you have a battery from another vehicle with similar specs that you can swap in for troubleshooting that might be a good idea.

Quote:
Originally Posted by Jambalam View Post
Thoughts? I know the Crankcase position sensor (CPS) can cause some similar symptoms however my Jeep has never stalled, just hard/no start occasionally (regardless of outside air temperature). After she does start, she runs seemingly tip top. Does the Fuel Rail Pressure Set Point vs acutal difference rule out the CPS?
Why would you be looking at the CPS if you don't have any codes for it or symptoms of it failing?

Quote:
Originally Posted by Jambalam View Post
If so, is there a fuel pressure sensor?
If you're looking at the fuel pressure on a scan tool then there has to be, unless your scan tool is capable of witchcraft.

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post #3 of 9 Old 09-18-2017, 03:20 PM Thread Starter
Jambalam
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Since I got her (in Denver January cold) the glow plug indicator light has always been on and off in less than a few seconds, initially I would fire as soon as it went out and she would have a hard time starting if at all. I started giving it 30 seconds and she would always fire up.
Do you have a suggestion how I can test my battery without a second battery? Mine looks very clean and says 5/13 (date I assume). Also My Jeep doesn't fire up right away with a jump, i wasn't jumping from another diesel but she sounds very strong after multiple start attempts.
CPS problems seem to have very similar symptoms, for $60 it's worth a shot.
Do you know where the fuel pressure sensor is or the process of replacing?

Thanks for the input!
New CPS sensor put in today and she fired up faster than normal however has trouble restarting after a drive, suspect engine heating up is a factor. The search continues....
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post #4 of 9 Old 09-18-2017, 04:34 PM
underscore
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Quote:
Originally Posted by Jambalam View Post
Since I got her (in Denver January cold) the glow plug indicator light has always been on and off in less than a few seconds, initially I would fire as soon as it went out and she would have a hard time starting if at all. I started giving it 30 seconds and she would always fire up.
Interesting, mine is only a few seconds even in the middle of winter as well. Initially I set my remote starter to 20 seconds but it was having a harder time starting than when I gave it 7 (the light only seemed to be on for 4-5).

Quote:
Originally Posted by Jambalam View Post
Do you have a suggestion how I can test my battery without a second battery? Mine looks very clean and says 5/13 (date I assume). Also My Jeep doesn't fire up right away with a jump, i wasn't jumping from another diesel but she sounds very strong after multiple start attempts.
I think they can be load tested, I've never done it though. My battery and the battery in my friends diesel died sooner than expected though, and they both had issues with randomly being unable to start or slow to start.

Quote:
Originally Posted by Jambalam View Post
Do you know where the fuel pressure sensor is or the process of replacing?
I'm not sure where it lives, but if it's reading pressure properly then I doubt it's the issue. I don't know how fast the high pressure pump is supposed to build pressure but if yours is slow then that might be something to start looking at.

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post #5 of 9 Old 09-18-2017, 05:20 PM Thread Starter
Jambalam
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Interesting indeed! Since I began the 30 second hesitation to fire things seem better but this new no-start issue has me second guessing myself; do the glow plugs (GP) have built in safeties, i.e. could I have burned them out with 9 months of excessive GP warming? This would throw a code, no?

Know anything about the (not sure if this is the proper name) fuel rail high pressure check/relief valve?
From what I understand there is a valve that will open in the event of excessive pressure. If this valve is failing it can be stuck open when the engine is calling for high pressure and thus cause sporadic hard or no start.

Looking like my worst case scenarios could be high pressure fuel pump (Ive read it abbreviated as IP [injector pump?]) or some sort of overall injector issue, although I have no obvious signs of injector leaking.

Just seems way too much like a sensor or electrical issue that isn't being detected by the computer. Also, because there's this odd grey area between Mercedes and Jeep I hate to give money to either dealership for an expensive diagnostic test followed by a expensive rain dance.

1. Do GPs have a fail safe? Are they guaranteed to throw a code upon failure?
2. Fuel high ressure relief valve?
3. If battery is the issue, shouldn't she fire right up with a jumpstart from a running vehicle?

Thanks again bud! I appreciate all of it, even if its half just me talking aloud to myself! Lol

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post #6 of 9 Old 09-18-2017, 06:01 PM
SteveROntario
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In my experience glow plugs either draw current or they don't. I am not sure how much current they draw on the Jeep but they generally draw a lot. On my VW there were 4 of them and drew about 70 amps in total during the initial warming and for 2 minutes after start. I could use a DC clamp meter on the copper conductor feeding the glow plugs to determine if I'd had a glow plug die on me but there wasn't enough space to clamp between them to figure out which one exactly. Being that they see identical service I always changed them as a group. I think you could clamp on each wire for the Jeep based on a photo I've seen.

You can test old glow plugs by hooking them up to a battery using booster cables. They will turn RED hot and can be used as a branding iron so be careful. Be mindful not to cause a spark near the battery either. I've removed some glow plugs where they have had their tips burned off entirely.

You will need to get your battery load tested to determine if it can stand up to the job.

Steve
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post #7 of 9 Old 09-18-2017, 07:49 PM
underscore
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Quote:
Originally Posted by Jambalam View Post
Interesting indeed! Since I began the 30 second hesitation to fire things seem better but this new no-start issue has me second guessing myself; do the glow plugs (GP) have built in safeties, i.e. could I have burned them out with 9 months of excessive GP warming? This would throw a code, no?
To the best of my knowledge a bad glow plug always throws a code, same thing with the module. If there are no codes I would think they're functioning correctly. I'm not positive but I think the glow plugs turn off once the light goes out so I don't think it lets you warm them excessively. You could confirm that with a voltmeter though.

Quote:
Originally Posted by Jambalam View Post
Know anything about the (not sure if this is the proper name) fuel rail high pressure check/relief valve?
From what I understand there is a valve that will open in the event of excessive pressure. If this valve is failing it can be stuck open when the engine is calling for high pressure and thus cause sporadic hard or no start.

Looking like my worst case scenarios could be high pressure fuel pump (Ive read it abbreviated as IP [injector pump?]) or some sort of overall injector issue, although I have no obvious signs of injector leaking.
I don't know much about the high pressure system, other than that the pressures are very high (and therefore can be dangerous). If the engine is running fine once it's started I would think the pump is functioning properly.

Quote:
Originally Posted by Jambalam View Post
Just seems way too much like a sensor or electrical issue that isn't being detected by the computer. Also, because there's this odd grey area between Mercedes and Jeep I hate to give money to either dealership for an expensive diagnostic test followed by a expensive rain dance.
If there's a code for it then the computer *should* detect it properly. I'd look through the list of codes and see what isn't listed if you want to look for problems that wouldn't throw a code. Personally I don't trust shops and I definitely don't trust Jeep dealers so I can't say whether they'd be any good at figuring it out. If you can find a local diesel or Sprinter shop they'd be more knowledgeable about the diesel system.

Quote:
Originally Posted by Jambalam View Post
3. If battery is the issue, shouldn't she fire right up with a jumpstart from a running vehicle?
Not always. When my battery finally kicked the bucket it was so messed up that even a jump from a running vehicle wouldn't fire it up. But even now 9 months later it's sitting in my garage and can supply 12V to lights and things that I'm testing no problem.

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post #8 of 9 Old 09-21-2017, 12:39 PM Thread Starter
Jambalam
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Quote:
Originally Posted by underscore View Post
Not always. When my battery finally kicked the bucket it was so messed up that even a jump from a running vehicle wouldn't fire it up. But even now 9 months later it's sitting in my garage and can supply 12V to lights and things that I'm testing no problem.
Really?!

Shes headed into the diesel shop today, not sure when the'll be able to get to her but I don't like beating up my starter like she needs to fire up and they do have a loaner. Another reason I don't think it's my battery is that she will eventually fire up, even after cranking for a few cycles without a jumping vehicle or anything. I'll tell the shop to try a similar battery that is known to be working well. I'll be stoked if that really is my issue and I've way overthought it!

I'm thinking my hard start is in regards to my high pressure fuel. Does anyone know part numbers for the fuel pressure solenoid and sensor? Both Jeep and Mercedes numbers if possible.

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post #9 of 9 Old 09-21-2017, 02:48 PM
underscore
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Yes, it was the strangest death I'd seen a battery have. It would be fine, then one day it would be nearly dead and I'd jump it, then it would be fine for a while until it was randomly nearly dead again. Repeat several times until it couldn't even be jumped. It may have fired up on its own given a few more tries but I'm not sure, with how weak it was I just go right for the jump box.

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