Intermittent no-start problem- cranks fine, but no start

bpadlows · **Joined:** Tue Dec 18, 2012 3:10 pm **Posts:** 7

I have a serious problem with my 2006 Liberty CRD. Over the last month, at times the engine will crank beautifully but will not start. On three occasions, this happened while the engine was warm. Once it occurred when the engine sat overnight. Most times it will start after 10 minutes or so of trying, cranking for 5 seconds or so at a time. About the time this condition arose, the check engine light (the outline, not the full one) came on, so I assumed it was related. I do not have the code reader, so I don't know what the code was. Then I had one or two incidents where the engine cranked for 3-4 seconds and THEN fired, which is unusual; my CRD usually starts instantly, with a second at most of cranking. Next I had an incident of cranking but no-start; after 5-10 minutes of trying, it eventually did start. Then last week when I got in the truck to drive to work, the engine cranked perfectly but refused to start. I tried for about 15 minutes, but all I got was cranking, no ignition, nothing. I was unable to start it at all. I had it towed to the Jeep dealer (one I trust) and they said the code was for a bad air sensor. They replaced the sensor and the truck started right up.

Well, I got the truck back and after 2 days, again experienced a no-start. I assumed it was an electronics issue, so I tried to put loads on the system by turning the radio, headlights, etc. on and off and tried again. After 10 minutes or so of intermittent cranking, the truck started but only after 3-4 seconds of cranking. I immediately drove the truck to the dealer. They called me yesterday, after having the Jeep for 2 days, and said 1) there appears to be no codes thrown, and 2) the truck starts right up.

Obviously, there's a problem. The Jeep's not reliable at all at this point. I've googled for answers like mad and encountered a few that had this problem, but their comments read "I have fixed this problem", without explaining HOW it was fixed- not helpful!!!

Can anyone shed some light on this issue?

Thanks!

Hexus · **Posted:** Thu Aug 08, 2013 1:57 pm

Your first line of action, since you already took it to the dealer and they warranty their work (though usually with much argument and arm twisting) should have been to take it back to them.

Are you running the original fuel head?

When is the last time you changed your battery?

Have you read the Noob Guide?

Answer all that, then come back!

Welcome to the forums!

geordi · **Posted:** Thu Aug 08, 2013 2:08 pm

If either the camshaft sensor or the crankshaft sensor (both are Hall-effect magnetic pickups) are not functioning, the computer will not know where it is in the cycle and will not start.

The camshaft sensor is easier (marginally) to get to, located under the CCV puck and at the back of the intake on the exhaust cam side. I would suggest changing that one first and see what happens. These sensors don't go bad often, but when they do, the results can be as you describe.

It is highly annoying that it doesn't have any codes to hand the clueless dealer, but that just means the computer hasn't exceeded its programmed threshold of problem yet... Making no notice of the no-start problem. This is one reason why ACTUAL diagnostic technicians are worth their weight in gold, and as rare as hens teeth these days. A real tech won't need the computer to tell him what is wrong.

FYI: Do NOT let the dealer chimpanzees try to tell you that the sensor is fine, but it must be the camshaft or flywheel pickup that is bad! This happened to one member, and they charged him for replacing the exhaust camshaft... Because the 'pickup' on the camshaft is a SOLID BLOCK OF METAL that cannot be replaced or ever go bad! :banghead:

My feelings about dealerships might be extreme... But they have well and truly earned their reputation.

papaindigo · **Posted:** Thu Aug 08, 2013 2:46 pm

Thoughts on intermittent no start. When you turn the ignition key it turns a plastic rod under the steering wheel that engages in the ignition switch on the other side of the steering column which then more or less tells the ECU to see if the battery has enough charge to give permission to start the engine.
1. old batteries without full charge do odd things
2. that plastic rod can break or crack or the ignition switch can go bad (ignition starter switch 4793576AB - alternative BWD CS812 or Airtex 1S5932 and ignition switch actuator pin assembly Dorman # 924704, see http://www.dormanproducts.com/p-45278-924-704.aspx for how to remove and install - apparently no dealer equivalent)
3. the 2 sensors geordi mentioned are crank position sensor - Bosch 0281002434 and cam position sensor - Bosch 0281002667. Crank position sensor when it goes bad gives wildly variable signals when temperatures change (hook up meter, heat with hair dryer, watch meter go nuts) and doesn't throw any code when it does go bad.
4. could be air in the fuel - bleed fuel head, see how to in Sam's NOOB guide, and get 2n gen head.

I'd be curious what PN they replaced that they called a bad "air sensor". Not pointing fingers but there is nothing on the CRD that I'd call an "air sensor" but there are several things that could be called that.

Hexus · **Posted:** Thu Aug 08, 2013 3:40 pm

papaindigo wrote:

I'd be curious what PN they replaced that they called a bad "air sensor". Not pointing fingers but there is nothing on the CRD that I'd call an "air sensor" but there are several things that could be called that.

MAF or MAP probably...

bpadlows · **Joined:** Tue Dec 18, 2012 3:10 pm **Posts:** 7

I haven't posted recently because I wanted to only report if and when the "fix" actually worked.

I returned the Jeep to the dealer once again because it did not start, same as before: cranks great, but nary a pop. A code was thrown illuminating the check engine light.

The dealer read that the code showed a problem with the Mass Airflow Sensor, and said that Jeep says that this can cause a crank-but-no-start problem. The truck has 104K miles on it, and since the "official" Jeep dealer notes say that this can cause the problem, I told them to change it. I took the truck back, and it started up great for about 2-3 days, then the same symptom occurred: cranks beautifully, but no start. Towed the jeep back to the dealer (thank God for AAA Gold!!!!).

The dealer said that I still had the old fuel filter head, and once again, their service manual says that this can cause the problem. While my filter head did not have any melted plastic around the heater plug on the head, I OK'd the change. They did cut me a break on the service fees, charging for the part only and no charge for the labor.

BTW, the mechanic did notice that before he changed the filter head, the active ODB codes shown while cranking showed NO fuel pressure in the high-pressure side of the fuel pump when it refused to start. That's also why he felt it might be the filter head. He changed to the new design, and I took the truck back; it ran fine for a few weeks, and then, same deal: cranking, no starting.

After reading posts on this forum, I wondered if it could be air in the fuel line. I did notice that when it's hard to start, the primer pump atop the fuel filter head goes soft.

I decided to install a lift pump as some here have done. I needed a quick(er) fix and had no time or energy to install an in-tank pump, or even a lift pump AT the tank. I tried to buy one of the Facet cube pumps which some here have used successfully, but the best I could do was a "Mr Gasket" model 12D lift pump. I installed a clear plastic filter before the new pump, wired the pump to the "Fuel Prime Pump" relay, and plumbed the outlet of the new pump to the fuel filter head inlet.

After installing the pump and bleeding the fuel filer via the bleed screw atop the filter head, the truck started instantly. As some have reported, I also noticed that the engine ran quieter with less clatter and responded faster to the throttle than before.

My joy was short-lived, however, as the no-start condition returned after a few days of driving. This time, I noticed that there was a lot of bubbles mixed with the fuel spurting out of the bleeder fitting atop the filter head. Once all the air was out, the Jeep eventually started.

So this tells me that the problem is actually air getting into the fuel, probably from the hokey push-on quick connect fuel fittings. I believe that if I had an in-tank pump, this wouldn't happen as the fuel is being pushed, not sucked, toward the filter.

My question to you experts out there:

1. Where are these "quick connect" fittings located?
2. How do I eliminate them from my fuel lines? A few on this forum just stated "bypass them", but gave no specifics. Are the fuel lines plastic? Steel with a barbed end? Steel with quick connect steel fittings? Plastic fittings?

Here's hoping that someone out there knows these answers and will be specific about how to fix these fuel air leaks.

ebbnflow · **Posted:** Sun Oct 13, 2013 9:35 pm

There are 2 quick fittings on the top of the fuel tank. They are designed to be pressurized, but on our tractors, they literally suck fuel and sometimes air. You will need to drop the tank, chop off the quick fittings and replace them with marine rated fuel hose and worm clamps. I had air in fuel head issues, but my facet pump solved them without the need to drop the tank. I mounted my facet in the engine compartment right by the battery.

CATCRD · **Posted:** Sun Oct 13, 2013 9:39 pm

I don't think your problem is air in fuel. It really sounds like a failing crank position sensor. It rarely throws a code and causes your exact symptoms. I know first hand. Have the dealer replace that before mucking around with fuel lines or in tank pumps.

bpadlows · **Joined:** Tue Dec 18, 2012 3:10 pm **Posts:** 7

Is replacing the crank position sensor a big ($$$) job?

At this stage, I am getting fed up: first the dealer is sure it's the Mass Airflow Sensor, then he's sure it's the fuel filter assembly, etc....!

CATCRD · **Posted:** Sun Oct 13, 2013 11:11 pm

bpadlows wrote:

Is replacing the crank position sensor a big ($$$) job?

At this stage, I am getting fed up: first the dealer is sure it's the Mass Airflow Sensor, then he's sure it's the fuel filter assembly, etc....!

It's a $50 part, and you can do it in your driveway if you are so inclined. There are many threads about it here.

geordi · **Posted:** Mon Oct 14, 2013 12:56 pm

The crank sensor is bolted to the bell housing area, on the passenger side about half-way up. There is a single wire held by a hold-down bolt right on the edge of the cover, this will probably be the easier part to find, then just follow the wire to the sensor. It is under the turbo, facing (poking into) the flywheel on the engine-side of the flywheel housing.

As for the quick connectors: There are 2 fuel lines coming off the tank, and one has a quick-connect that will be outside of the tank and easily accessible with the tank in place. The nipple side of this connector is the send-to-the-filter line. If you mount your Mr Gasket under the body right next to the tank, you can slip some fuel line over both ends of that quick connect (cut off the socket-side of the connector) and just hose clamp it in place. That may help greatly on the bubbles in the fuel line.

papaindigo · **Posted:** Mon Oct 14, 2013 1:19 pm

For the crank sensor see viewtopic.php?f=98&t=74594 . It's behind the rectangular heat shield on the left in the first 2 passenger side pics and right up front in the 4th one. The heat shield, if you look closely has 1 bolt in the upper right and might or might not have one into the bell housing in the lower left .

fenwood · **Joined:** Wed Oct 30, 2013 5:12 pm **Posts:** 9

Did the crank sensor work? I've had my lib in the driveway far too long. No codes. 74k, all noob stuff done.

Things checked/replaced: cam sensor, 2nd gen filter, voltage at injectors. exchanged fuel rail. It has had a p0093 for a long time (2 years) but went away since I cleared codes with new rail and 2nd gen filter. Any way to check if crank sensor is bad? Anyone ever change the cp3 solenoids with success or had codes to change them?

Symptoms: took off cold, 1/4 tank, drove 5 miles, immediately died/no sputter. poo93, 1250 codes. changed fuel rail, voltages all good at injectors, filled fuel tank, brand new battery, timing belt intact. Rail has pressure but don't know if enough.

Help?

papaindigo · **Posted:** Tue Nov 12, 2013 4:04 pm

Typical crank sensor failure seems to be due to heat. Easiest diagnosis method I've seen is pull it off; attach multimeter; apply hair dryer to sensor body; if meter goes nuts sensor is bad.

jkbkwarner · **Posted:** Tue Nov 12, 2013 4:12 pm

Air in the fuel line, was corrected after replacing the quick release from the tank to the metal portion of the lines. Until then I was bleeding air out after 40+ mile commute, to prevent the inevitable stall.

Short time later, had the crank position sensor replaced. Couldn't do it myself without towing it back home.

Wish I could have, but regardless, no more random shutdowns. :BANANA:

weeks101 · **Joined:** Mon Jul 30, 2012 3:29 pm **Posts:** 747

Happened to me last winter. Wiggled my harness connecting to my ECU, good to go.

fenwood · **Joined:** Wed Oct 30, 2013 5:12 pm **Posts:** 9

OK, just for giggles, and desperation, I shot a small sniff of ether in the airbox. It started. I shut it off after a minute. Did not restart. Small sniff of ether, fired right up. Drove it 2 miles, came back and shut it down, no restart, just cranked. Thinking that there is not enough rail pressure. Glow plugs have resistance. I have crank sensor in hand and will put it in and try. I wiggled, blow dryed the crank sensor to no avail. Crank sensor here I come....anyone thinking solenoids on pump? Local injector service says the only cp3's he sees are out of duramax motors with bad fuel solenoids. Might pull it over to have him scope rail pressure but that's 100 bucks. Anyone ever change the solenoids on a lib cp3?

CATCRD · **Posted:** Wed Nov 13, 2013 10:13 pm

That doesn't sound like the crank sensor if it starts with ether. One or two people here had P0093 and starting problems and it ended up being injectors.

fenwood · **Joined:** Wed Oct 30, 2013 5:12 pm **Posts:** 9

Not the crank sensor. Did a bleed test and no fuel coming out of bleeders. Fuel out of front rail but don't know how much pressure at rail. Anyone with a cheap way to check rail pressure? Rebleed system. Still no start. Pulled ecm overnight. New code "p0093 fuel leak". Urgg. Anyone still thinking injectors? Anyone ever change the cp3 solenoids? I just can see pulling the pump yet.

jtz54 · **Joined:** Tue Apr 03, 2012 11:37 pm **Posts:** 73

I had the intermittent hot start problem for several months replacing crank and cam sensors and a couple of the injectors. Turned out one of the new injectors I bought off eBay was actually a used one cleaned up. I suspect it was worn and the check ball was sticking at hot (common problem). After I replaced it been running fine for six months.

Intermittent no-start problem- cranks fine, but no start

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