Hot no start update

jeepdan · **Posted:** Wed Jan 04, 2012 5:59 pm

mozzio wrote:

Left it in for now. I thought it was only 5 psi when i was looking to install one.
It's been a while so I really don't know for sure.
When are you doing your injector pump?

Your mechanic could put a gauge on at the air bleed to check the lift pump pressure. Others have used this pump without any trouble. Maybe the lift pump I installed brought a existing problem to head, I don't know. I just don't want to take a chance with a new CP3.
I removed the old CP3 yesterday evening, I'm now waiting for the UPS man, should be tomorrow.

jeepdan · **Posted:** Wed Jan 04, 2012 6:25 pm

From the;
KJ VM Diesel Fuel System Operation and Diagnosis student workbook, " when the fuel pressure entering the Cascade Overflow Valve is more than 72.5 psi. (stage 3), the overflow circuit sends fuel back to the INLET side of the gear pump, which ultimately limits maximum fuel pressure to 72.5psi. in the P2 circuit" (inlet to the cascade valve and the Fuel Quantity Solenoid inlet).
"Lubrication fuel also continues to flow through D3 into P3 (lubrication circuit) during this stage. Excess fuel is sent back to the tank through the return circuit"
So with 16psi inlet pressure, it sounds as if the cascade valve could not keep the pressure below 72.5psi entering the lubrication circuit and to the inlet of the Fuel Quantity Solenoid.
I don't know what determines the amount of fuel that is sent back to the tank through the return circuit.
If some will help me, I can scan the CP3 circuit drawings and post here.

mozzio · **Joined:** Thu Jan 17, 2008 7:03 pm **Posts:** 59

mechanic finished the injector pump install and test drove the libby.
Seems to think it 's fixed. Got it hot, waited 15 minutes and it restarted.
Did it three times this am.
My jeep only has 46000 miles on it. I hope I dont have to do this again in the near future.

jeepdan · **Posted:** Thu Jan 05, 2012 4:38 pm

mozzio wrote:

mechanic finished the injector pump install and test drove the libby.
Seems to think it 's fixed. Got it hot, waited 15 minutes and it restarted.
Did it three times this am.
My jeep only has 46000 miles on it. I hope I dont have to do this again in the near future.

That sounds really great mozzio :BANANA:

Keep us posted of any issues.
Wow, only 46,000 miles.

nursecosmo · **Posted:** Thu Jan 05, 2012 6:48 pm

dkenny wrote:

I've changed a CP3 in a Jeep.P0093 was the code..I think it was the FCV/Mprop valve not the CP3, but I cannot prove it.
I have the CP3..in pieces..care to make on offer?

-dkenny

A P0093 code is for air in the fuel(in theory). It will also trip that code (in theory) for a plugged fuel filter or any time that it can't get enough fuel for some reason.

A bad Mprop will (in theory) trip a low rail pressure code.

Sometimes the IP will be able to get just enough fuel through a restricted filter or with a smaller air leak to run roughly or even stall but still not trip a code.

mozzio · **Joined:** Thu Jan 17, 2008 7:03 pm **Posts:** 59

jeepdan wrote:

mozzio wrote:

mechanic finished the injector pump install and test drove the libby.
Seems to think it 's fixed. Got it hot, waited 15 minutes and it restarted.
Did it three times this am.
My jeep only has 46000 miles on it. I hope I dont have to do this again in the near future.

That sounds really great mozzio :BANANA:

Keep us posted of any issues.
Wow, only 46,000 miles.

It'swas at the dealer for 3 out of 5 years. They just weren't interesred in trying to fix it.

mozzio · **Joined:** Thu Jan 17, 2008 7:03 pm **Posts:** 59

Well my little Jeep seems to be running fine after the injector pump swap.
I haven't ran it very much yet, but it did restart the first time I tried.
Jeepdan I hope all goes well with your install and it fixes your problems also.

jeepdan · **Posted:** Fri Jan 06, 2012 3:13 pm

mozzio wrote:

Well my little Jeep seems to be running fine after the injector pump swap.
I haven't ran it very much yet, but it did restart the first time I tried.
Jeepdan I hope all goes well with your install and it fixes your problems also.

Thanks, Keep those encouraging reports coming

As for mine, the new CP3 is in and reluctantly, the Airtex in tank lift pump is out.
Gonna finish buttoning things up as soon as I finish my grilled cheese sandwich and and beer.

jeepdan · **Posted:** Fri Jan 06, 2012 9:12 pm

After two, fifteen minute test drives, the only positive thing that I can say is that my air problem appears to have been eliminated without the need for a lift pump.
The hot start problem has not changed. :cry:

Starts fine cold, but after setting for a minute hot, it will not start. Wait about 10 minutes and it will start right up quickly. The second time after setting for 10 minutes, it repeatedly started up the six times that I tried without any issues. Could not make it not start.
Where should I turn next?

mozzio · **Joined:** Thu Jan 17, 2008 7:03 pm **Posts:** 59

After driving around town a little today my poor little libby seems to be getting harder to start when it's hot.
It hasn't not started yet, but the crank time is definitly getting longer.
Really had hoped it was fixed but I'm not so sure now.

WolverineFW · **Posted:** Sat Jan 07, 2012 4:44 am

I am starting to think you guys are having some kind of electrical problem. Have you traced back the wiring from your CP3 to your ECM? Checked for continuity and resistance hot and cold?

jeepdan · **Posted:** Sat Jan 07, 2012 6:03 am

WolverineFW wrote:

I am starting to think you guys are having some kind of electrical problem. Have you traced back the wiring from your CP3 to your ECM? Checked for continuity and resistance hot and cold?

No, I have not checked the wiring other than a visual look. I will start researching pin locations out of the manual today.

2mopar_diesels · **Posted:** Sat Jan 07, 2012 9:33 am

Another thing to consider is cylinder compression test...........a blown or cracked head gasket could explain the cold easy start but hot no start. If a cylinder pressure test both cold and hot checks out fine, is only gonna be one of two things...........a fuel injector situation or electrical gremlins...........I'm good with figuring out and fixing mechanical stuff, but ignorant when it comes to the electrical side..........it can be the most frustrating thing, beating your head against a wall trying to figure it out.

As for the electrical...........I would start at the wiring of the cp3, then the injector solenoids.......you have to pull the valve cover to get to those..........look for any frayed/loose/chafed wires. I'm leaning to the injectors though...........cause it does seem too much like a fuel issue, even if it is electrical...........these injectors sit inside the valve cover and stay soaked in a hot oil bath.........if one or more solenoids on the injectors is overheating, it could very well cause this. The reason being, its that the injector would hold pressures just fine and pass the leak down test, but if their solenoids are not working properly, the situation you have could be the result.

nursecosmo · **Posted:** Sat Jan 07, 2012 2:01 pm

Which if any codes are you getting?

mozzio · **Joined:** Thu Jan 17, 2008 7:03 pm **Posts:** 59

nursecosmo wrote:

Which if any codes are you getting?

Mine never throws a code. I have been thinking it's something electrical for a while. just don't know where to start, or which direction to point someone in.

jeepdan · **Posted:** Sun Jan 08, 2012 3:17 am

The jeep started easily this morning and I drove the to work with no problems. After working a 16 hour shift, the jeep would not start cold.

While waiting for my wife to come rescue me, I continued off and on to try to start it. As the battery was about to give up, it fired momentarily. After waiting about 15 minutes for the battery to recover, it fired up easily.
I pulled in the garage upon returning home, let it idle for a minute and then shut it off. After closing the garage door, I tried to restart it and all it would do is just spin over happily but no fire. :evil:

After spending about five minutes filling the outdoor wood stove, I came back in the garage and tried to start the jeep. It fired up instantly :dizzy:

Tomorrow I'm going to check all ground connections and try to check for continuity on some of the sensor circuits.

whitedog · **Posted:** Sun Jan 08, 2012 5:05 pm

I have been reading this and following along, hoping for a good and definitive outcome. I come from the VW TDI world and on some of the cars, there was some stock mapping that makes for hard starting when hot, but a tune takes care of that. Now, i know that this isn't a problem with the stock tuning like in my Beetle, but is it possible that somehow the mapping has become corrupted? I hate to throw out a wild theory without a suggestion on how to test it, but maybe Keith at GDE would have a suggestion?

Actually, now that I think about it a moment, if my Beetle is hot and I unplug the CTS, the ECU thinks it's cold, so it reverts to the cold start map. Maybe there is a comparable way to fool the ECU into thinking it's cold?

Just a thought.

mozzio · **Joined:** Thu Jan 17, 2008 7:03 pm **Posts:** 59

Well it lasted for two days and now it's right back to were it was.
Gets hot and won't start. I'm at a loss what direction to go.
Maybe driving it off a cliff or into a lake is the answer.

Roostre · **Joined:** Sun Oct 24, 2010 3:57 pm **Posts:** 195

It sure sounds like an electrical gremlin.

I wonder if pulling all the connectors and cleaning them with an electrical contact cleaner and reassembling with dielectric grease to seal them might help? I have seen cars that were repeat MAF killers cured by such a tactic... But I am really at a loss and following along in hopes that someone figures this out.

Have any of the afflicted CRD's been run in deep water at any time? Just trying to see if there are any common denominators in all this.

GreenDieselEngineering · **Joined:** Sun Jun 07, 2009 5:10 pm **Posts:** 1111

Mozzio,

Can you find a used relay box (BCM/TIPM) for the CRD in a junkyard? This is the relay box assembly in front of the battery. On a couple vehicles with hot start issues, when the box was changed it solved the issue. Not sure what fails on it, but it might be a last ditch effort for your CRD. GDE

Hot no start update

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