CRD fuel return test - JeepForum.com
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post #1 of 17 Old 09-14-2019, 06:58 PM Thread Starter
08WK7180
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Okay so in the past month and a half my CRD has been hitting me left and right with issues. First I had a low boost fault code and limp mode that has been somewhat fixed with a new turbo actuator, then I noticed the turboshaft was a little bit loose so that is pending expensive fix, then heard timing chain rattle that I fixed with a new tensioner, then cold starts cranking too much, and just two days ago my water pump bearing started squealing. But don't feel sorry for me I'm going to attack them all one at a time.

Right now I just did a fuel injector return seals leak test. I suspected cold starts cranking excessively was due to rail pressure dropping overnight. Look at my attached photos, this was running the engine for about 1 minute and the amount of return fuel per injector. Take a look at driver's side first and second injectors ... any opinions on whether that's too much for one minute of run time. As you can see the other four injectors flow far less.
15685097019044431384100501396964_1568509748659.jpg1568509764810257943223604002888_1568509807568.jpg

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All stock 08 GC Laredo CRD except for swirl motor resistor mod
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post #2 of 17 Old 09-17-2019, 10:28 PM
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I have many questions but to start: in your photos, it's hard to tell where the fuel stopped in the lines. Is this accurate?
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post #3 of 17 Old 09-18-2019, 10:55 AM Thread Starter
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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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post #4 of 17 Old 09-18-2019, 04:42 PM
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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:
https://www.jeepforum.com/forum/f67/...olved-4343249/
https://www.jeepforum.com/forum/f67/...inion-4279449/
https://www.jeepforum.com/forum/f67/...fixed-4237258/
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post #5 of 17 Old 09-18-2019, 10:00 PM Thread Starter
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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.

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post #6 of 17 Old 09-23-2019, 06:31 PM Thread Starter
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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?

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post #7 of 17 Old 09-24-2019, 09:08 AM
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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.
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post #8 of 17 Old 09-24-2019, 09:30 PM Thread Starter
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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...

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post #9 of 17 Old 09-25-2019, 08:33 AM
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Quote:
Originally Posted by 08WK7180 View Post
.... 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...
Your battery is likely overdue for replacement. I normally get 3.5 to 4 years battery life. WK's are finicky about adequate battery capacity. Auto parts stores can perform a Battery Capacity Test to confirm if there is sufficient energy storage in your current one.
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.

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post #10 of 17 Old 09-26-2019, 05:05 PM Thread Starter
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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.
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post #11 of 17 Old 09-28-2019, 10:30 AM Thread Starter
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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?

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post #12 of 17 Old 09-30-2019, 09:37 AM
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Don't they need some time to learn?

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post #13 of 17 Old 10-01-2019, 11:33 AM Thread Starter
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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.

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post #14 of 17 Old 11-02-2019, 11:55 AM Thread Starter
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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?

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post #15 of 17 Old 11-03-2019, 11:07 AM
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Maybe the glow plug controller. It's a known issue with these CRDs.

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