|Topic Review (Newest First)|
|11-04-2019 02:02 PM|
If I recall correctly my key on engine off rail pressure hovers around 60psi. Engine cranking rail pressure around 300psi, and idling rail pressure just above 4000psi. I don't recall where I read it, but these pressures are about normal. Not sure if 6000 idling is too high but something to consider.
Mine hasn't yet timed out due to excessive cranking. It sometimes cranks for uncomfortably long though. There is a definite correlation to plugging in the block heater with almost perfect starts. That's what got me thinking about the glow plug system.
At the same time I feel like I also have an intermittent fuel pressure issue. After noticing the slight momentary drop in rail pressure just as the engine revs past 1100rpm I poked around some more. The momentary drop exactly coincides with an light squeak/rattle from somewhere in the rotating assembly at the front of the motor. The sound is like a dry shaft/bushing quiet until hitting 1100rpm. Makes me wonder if the gerotor in the high pressure fuel pump is worn. If I graph the rail pressure right after a cold start it drops about 300 to 400 psi for a split second as it revs up past 1100rpm with the corresponding noise up front and the slight engine stumble. Almost seems like I'm answering my own questions as I analyze my findings. However, I still want to hear from others who may be familiar.
|11-03-2019 11:48 AM|
Thanks for posting an update! I had given up on mine but in rereading this thread, I got inspired again as we're experiencing the exact same thing. I feel like when one of us figures it out, it'll fix both of our Jeeps
I grabbed a fresh set of data during today's hard start. I wanted to get a good capture of engine RPM vs fuel rail pressure, but I forgot to enable actual data logging, leaving me with just graphs. Since I've got to wait a few hours for the engine to return to cold again, I'll post what I've got. It's probably not too helpful, but I figure if we'll get something useful between our sets of data.
I hadn't noticed until now, but the rail pressure was steady at ~6K PSI on the first start attempt, then ~4K PSI on subsequent starting attempts and when idling. It seems that 4K PSI is normal - I wonder if 6K PSI is over-pressured...
|11-03-2019 11:07 AM|
|badgerwithhands||Maybe the glow plug controller. It's a known issue with these CRDs.|
|11-02-2019 11:55 AM|
It's been over a month since the 2 new injectors and new battery and it still stumbles and cranks a bit much during cold starts. Probably about 5 seconds then lurches and stumbles when it does start, but it starts every time and the stumble clears up within seconds. Outside temperature doesn't matter, if the engine is cold it'll rough start even in warm weather. Within seconds it's running perfect and no problems driving. No codes or MILs. Warm engine and block heater starts are perfect.
However...I kept analyzing and also noticed a definite stumble at about 1100rpm soon after a cold startup. Checking deeper with my scanner I see a corresponding momentary drop in the high pressure fuel rail just as the rpms pass 1100. I can make the stumble pronounced if I rev the engine to about 2000, let the rpms drop but throttle up again just before it drops below 1100. If I do this repeatedly there is a definite stumble just as it's revving up again past 1100. After doing this a few times the stumble clears up.
To me it seems like an issue with the glow plug system in addition to a fuel issue. But I am getting nothing for codes or MILs. It otherwise runs great after the stumble clears up, usually seconds. Any ideas?
|10-01-2019 11:33 AM|
|08WK7180||I kind of heard that too about the learning process. I hope that is the case because the startup stumble is fairly apparent. It's kind of turn over almost start, crank for a couple seconds then lurch and chug abruptly as it starts. It's been a few days since the swap so I've noticed the colder the start the worse the stumble. It doesn't happen with warm or hot starts. The slight stumble cruising at about 1000rpm happens cold or hot. Other than that it runs perfect and starting is strong. I'm a bit at a loss.|
|09-30-2019 09:37 AM|
|Grinmaul||Don't they need some time to learn?|
|09-28-2019 10:30 AM|
|08WK7180||Fuel injectors seem to be perfect. However, after swapping in the 2 I notice a stumble during startup and a slight amount just above idle. A little more pedal and it clears up. The hard starting from before the 2 new injectors I discovered was partly due to an old dying battery that I changed yesterday. Any ideas what would cause this slight stumble now? Seems like it began after the fuel injector swap so my thought was air trapped in the rail? Is that possible and is there a way to bleed the system?|
|09-26-2019 05:05 PM|
|08WK7180||I put my battery on a conditioner charge last night. This morning I checked the voltage, 13v. Then I started the engine while watching the voltmeter, cranking was slow and it hiccuped, but started. Volts dropped during cranking to 12.3v and got the battery light again. Volts went back up to about 12.6v after starting and stayed until I rev'd the engine just a little and the alternator brought it up to 14.7v and held. I think the battery is definitely not holding sufficient capacity.|
|09-25-2019 08:33 AM|
Originally Posted by 08WK7180 View Post
Voltage test (stopped and running) will tell you if the alternator is charging.
WRT to the alternator, investigate the replacement carefully. Several members have reported off-brand aftermarket ones (both new and rebuilt) have resulted in performance issues and illuminated MIL's. You may wish to consider a MOPAR rebuilt instead. Mine (for a 5.7L HEMI) was about $236 and came with a warranty. The factory unit went 190,000 miles.....hoping for the same on this rebuilt one.
Not sure about the CRD's, but the voltage regulator for my 5.7L HEMI is in the PCM.
|09-24-2019 09:30 PM|
No codes related to glow plugs, but I do have new low voltage and Generator codes. The same day that I replaced the fuel injectors I got a dead battery after the procedure. I had turned the ignition to the on position a couple of times to build pressure in the rail before trying to start. I did this with the first injector and then again with the second injector replacement.
After completing both installs I was going to run to the store but the battery had went dead. Since that day, approximately a week now, at start up about 50% of the time I get a battery light and system voltage at 12.5 and dropping. But that clears up as soon as I rev the motor. Using my OBD scanner I see that voltage stays at a steady 14.6 or higher. Just for some reason at startup sometimes charging does not initiate until I rev the engine and then it's fine. So what you're saying about battery and charging system causing hard starts makes me wonder if my battery is on its way out or the alternator or both? The battery is 5 years old the end of this year so...
|09-24-2019 09:08 AM|
Are you getting any trouble codes? In my experience, this Jeep is good about telling you if you have bad glow plugs.
Order I'd go in to test/inspect/replace:
- New fuel filter. New o-rings on the WIF sensor. Routine item.
- Low-side fuel hoses.
- Glow plugs. Somewhat routine item. Mine seems to consume them like candy every winter, even with a new GPCM.
- GPCM. Can't really test it but definitely worth replacing if you burn through glow plugs. Just be sure to get the right voltage - MB sprinters are different than WK Jeeps. I can dig up notes if needed, just let me know.
- Check fuel pressure during crank, running, and acceleration. It's all available with an OBD II reader.
- Check RPM during crank. Engine needs at least 200 (300?) to start. Starter or battery are the likely culprits if RPMs aren't high enough.
- WIF sensor. Can't really test this as far as I know.
- Fuel rail solenoid. Located pm passenger side rail, on the back.
- High pressure fuel sensor. Located on the HP fuel pump.
That's what comes to mind on a whim. All stuff I've been through, so let me know if there are any questions.
|09-23-2019 06:31 PM|
|08WK7180||So the two injectors replaced quite easily. They work great. So now I just need to get at the water pump swap and maybe a new turbo soon. Unfortunately I'm still noticing intermittent hard starting. Just a few extra cranks too many but still concerning. I suppose glow plugs are my next check? Any ideas there?|
|09-18-2019 10:00 PM|
Good info thx. Best to consider all possibilities before just throwing parts at problems. I did however order and recieve 2 oem remanufactured injectors today. They look like brand new! I went with a local Bosch certified diesel service shop mainly for the ease of warranty claims should the need arise. These are 2 year warranty items. Also, they were $300 each, which is pretty competitive with online suppliers. I know idparts.com has them for $260 but I opted for the ease of local.
I'll install the injectors tomorrow most likely. I also recieved the new water pump today from idparts.com, which I am not looking forward to installing. Looks like a p.i.t.a.! But since my current water pump seems to be limping along ok I'm in no rush. Next on the list will be replacing the turbo cartridge or the whole thing if I find a good deal.
|09-18-2019 04:42 PM|
I would definitely replace injector 4 (driver's front) and probably 5 as well (driver's mid). Their "flow rate" looks to be at least twice that of the other 4.
FWIW, I've also been battling hard start issues for over a year now. I've resigned to just living with it, mostly because I have other vehicles. There are some good threads on it if you haven't reviewed them already:
|09-18-2019 10:55 AM|
Yes you nailed it. That's the locations of the max flow. I stopped there because the first injector driver's side was flowing fast enough that even a few drops went into the attached bottle. To me that told me enough after comparing the differences.
Btw, a head up to others; when doing this test you should have replacement return fitting o-rings ready. I didn't and within a few days 3 of them were leaking like a sieve all over the heads. The detach/reattach process compromises old o-rings. Advanced auto has them, I just brought in one of the old ones and they matched it to what they had. So far no leaks... yet lol.
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