Cranked but wouldn't fire - (re) solved?

CGman · **Posted:** Tue May 13, 2014 8:41 am

Just an FYI for everyone out there that might have this frustrating issue.

History:
Timing belt changed about one month ago, fuel filter changed three weeks ago, no other issues recently except new glow plugs failing.

Last night after sitting for two hours the Jeep would crank but not fire.

I have had several instances of air in the fuel filter since changing the filter last month; I now have dedicated 11mm wrench and rags to deal with it, so I bleed the system and cranked it again. No dice! :furious:

I whip out my OBDII scanner and plug it in and all I get are the two dead glow plugs! :grim:

After a quick consulation of the LOST CRD section I try unhooking the battery for several minutes; still no attempt to fire!

By this point sheer terror has set in and I'm calculating the scrap value of the thing as I dial up road side assistance and have them send a tow truck out to me! :dead:

After five minutes on the phone I decide to try one more thing which I had forgot to try before; swap ASD relay! Guess what, she fired right up! :BINGO:

I end this experience with the frustration of a vehicle that can be completely unable to run, but not even give an error code as well as marveling at the engineering of such a fine beast that run as well as this infuriating thing when everything is working! :banghead:

CGman · **Posted:** Tue May 13, 2014 11:23 pm

Part Deux:

I'm starting to think this thing has a mind of it's own, or at least a sense of humor...

I went and bought a new (generic) relay and installed it with no problem over lunch.

I went to leave work and guess what!! Same symptoms: cranks fine, no firing at all. :furious:

Fuel filter - check, no fire: switch relays - no fire :banghead:

Called security for jump just to check that box...as I'm waiting the 10 minutes it takes them to get there I decide to unhook the battery trick.

As the security car is pulling up I rehook the battery and turn the key...and she fires up like nothing happened!!

I've put a new battery in tonight, so we'll see that happens now....stay tuned.

jeepdan · **Posted:** Tue May 13, 2014 11:35 pm

Sounds like the Crankshaft Position Sensor might be starting to fail.
Been there, done that.
Total frustration with no trouble codes.

CGman · **Posted:** Wed May 14, 2014 11:15 am

Part Tres:

Engine started fine after new battery installed. Also started fine this morning after sitting all night. BUT, after stopping and trying to restart 30 minutes later she was back to her finicky self. I disconnected the battery for a couple minutes and she started. I can hear the FCV Cycling so I think something is preventing the injectors from firing.

CGman · **Posted:** Mon Jun 16, 2014 4:26 pm

I've now completed the intank lift pump mod. I was hoping that would solve the starting issue but it hasn't. Once every couple of weeks or still will refuse to fire during cranking. Mechanic said 3 hours for crankshaft sensor replacement. I think that included removing some part of exhaust manifold? ?? Is that true? ? This is getting irritating! :banghead:

CGman · **Posted:** Mon Jun 16, 2014 8:16 pm

Another interesting symptom, it seems that I let the car sit for about an hour or two with the battery unhooked the problem goes away.

ATXKJ · **Posted:** Mon Jun 16, 2014 8:45 pm

CGman wrote:

Mechanic said 3 hours for crankshaft sensor replacement.

I think that's 15 mins to change the sensor and 2:45 for the coffee break

http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?p=734354#p734354

pix 8/9
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=98&t=74594

thermorex · **Posted:** Mon Jun 16, 2014 9:18 pm

ATXKJ wrote:

I think that's 15 mins to change the sensor and 2:45 for the coffee break

Lmao!

CGman · **Posted:** Sat Aug 02, 2014 11:30 pm

Just a quick update to end this discussion.

First of all, changing the crankshaft position sensor was not a 15 minute job! It took me that long just to get my ASFIR skid plate off!!

Second of all, make sure you know what tools you need before you crawl under the vehicle! I couldn't find a good socket combination to get around the turbo exhaust pipe and I couldn't get enough room/leverage to use a wrench.

Third, you can't see the sensor while laying under the vehicle, so the first time is a learning experience. :furious:

The good news is I've now been running with a new crankshaft position sensor and intank pump for a month and I've had 100% reliability. Of course, now that I'm talking nice about her, she'll start throwing a fit!

The only interesting thing I've noted is my fuel mileage. One of the first trips I made I was towing a car on a car dolly and I thought I had plenty of fuel due to the mileage I was getting and that my new fuel pump had caused the gauge to prematurely show I was on empty. I get to the gas station and put in 19 gallons and I realize the indicated mileage was off by 5 mpg vs the normal 2 mpg!! :banghead:

It hasn't been off that much just driving around town, but I'm wondering if I have a small fuel leak due the system being pressurized that is causing my mileage issue.

user113 · **Posted:** Sat Aug 02, 2014 11:54 pm

I don't know how many gallons you expected to put in, but even if you only expected to put 18 in, there is still one gallon that is missing; that is NOT an insignificant amount of fuel. If you figure on about 15 drops per ml (this is just a quick and dirty approximation), and since there are almost 3,800 ml in one gallon, that gives about 57,000 drops of fuel per gallon. If the drive took you 3 hours, or 180 minutes, that would translate to a bit over 300 drops per minute, or 5 drops per second, and that's only if you were short only one gallon. You should be able to see that relatively easily if it were a leak, and I wouldn't call that a "small" leak!

DLR

flash7210 · **Posted:** Sun Aug 03, 2014 9:14 am

CGman wrote:

The only interesting thing I've noted is my fuel mileage. One of the first trips I made I was towing a car on a car dolly and I thought I had plenty of fuel due to the mileage I was getting and that my new fuel pump had caused the gauge to prematurely show I was on empty. I get to the gas station and put in 19 gallons and I realize the indicated mileage was off by 5 mpg vs the normal 2 mpg!! :banghead:

It hasn't been off that much just driving around town, but I'm wondering if I have a small fuel leak due the system being pressurized that is causing my mileage issue.

I dont understand.
You were towing, what mpg were you expecting to see? What mpg did you actually get?
How did you calculate mpg?
You already know the EVIC is wrong, so what were you comparing to?

CGman · **Posted:** Sun Aug 03, 2014 3:14 pm

flash7210 wrote:

CGman wrote:

The only interesting thing I've noted is my fuel mileage. One of the first trips I made I was towing a car on a car dolly and I thought I had plenty of fuel due to the mileage I was getting and that my new fuel pump had caused the gauge to prematurely show I was on empty. I get to the gas station and put in 19 gallons and I realize the indicated mileage was off by 5 mpg vs the normal 2 mpg!! :banghead:

It hasn't been off that much just driving around town, but I'm wondering if I have a small fuel leak due the system being pressurized that is causing my mileage issue.

I dont understand.
You were towing, what mpg were you expecting to see? What mpg did you actually get?
How did you calculate mpg?
You already know the EVIC is wrong, so what were you comparing to?

The display normally shows around 28-29 mpg and my rough calculations will show 25-27 mpg. On this trip it was showing 25 mpg, but distance/gals ended up being more like 20.5 mpg. No it's not scientific, but I do it the same way everytime. So there may be other things at work here besides a fuel leak, but does anyone else have this indicated mpg issue when towing vs regular driving?

I know it's not leaking too bad, because I start it and let it idle for around 5 minutes every morning in my garage and there's no puddle on the floor.

papaindigo · **Posted:** Sun Aug 03, 2014 3:24 pm

Your actual towing mpg is not unreasonable. I've seen as bad as 18.5 pulling a yard equipment type trailer with virtually no load but it felt like I had a boat anchor dragging down the road behind me vs. 21.5 overall average (viewtopic.php?f=5&t=69117&p=739421#p739421) on a cross country trip where you could feel the trailer but not in a boat anchor way.

flash7210 · **Posted:** Sun Aug 03, 2014 4:03 pm

CGman wrote:

flash7210 wrote:

CGman wrote:

The only interesting thing I've noted is my fuel mileage. One of the first trips I made I was towing a car on a car dolly and I thought I had plenty of fuel due to the mileage I was getting and that my new fuel pump had caused the gauge to prematurely show I was on empty. I get to the gas station and put in 19 gallons and I realize the indicated mileage was off by 5 mpg vs the normal 2 mpg!! :banghead:

It hasn't been off that much just driving around town, but I'm wondering if I have a small fuel leak due the system being pressurized that is causing my mileage issue.

I dont understand.
You were towing, what mpg were you expecting to see? What mpg did you actually get?
How did you calculate mpg?
You already know the EVIC is wrong, so what were you comparing to?

The display normally shows around 28-29 mpg and my rough calculations will show 25-27 mpg. On this trip it was showing 25 mpg, but distance/gals ended up being more like 20.5 mpg. No it's not scientific, but I do it the same way everytime. So there may be other things at work here besides a fuel leak, but does anyone else have this indicated mpg issue when towing vs regular driving?

I know it's not leaking too bad, because I start it and let it idle for around 5 minutes every morning in my garage and there's no puddle on the floor.

Considering you were probably towing about 4000 lbs, 20 mpg is pretty good.

jeepdan · **Posted:** Sun Aug 03, 2014 7:01 pm

[/quote]Considering you were probably towing about 4000 lbs, 20 mpg is pretty good.[/quote]

I agree.
The best that I ever got towing 4000 lbs, was 18.5mpg on flat, Ohio interstate. And I was quite pleased with that

Cranked but wouldn't fire - (re) solved?

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