[yem514]

Case solved: Fuel Pump!!!
Everyone in the forum told me it was the fuel pump but 5 different shops told me otherwise. I replaced a lot of uncessary parts, which sucks but at least it is fixed!

Jeep Grand Cherokee 2007 3.7L (85K) No check Engine.
I have been having these strange starting issue since 113 000km (70k) it now has 137 000 km (85k). Always happens after 3rd startup or up when running errands.

I.E.: 1st startup of the day, no problem. Drive 10-15mins, stop the car.
Bank for about 10mins. Then restart the car a 2nd time, all is good.
Drive again 10-15mins, stop the car. Grocery Store for about 15mins.
Restart car for the 3rd time and this happens!! Or sometimes the 4th startup.
After this happens, the car would fire up again as if nothing happened...

Transmission fluid and spark plugs serviced at dealer. Crankshaft sensor replaced. No Check Engine, no stored codes!!
Live data revealed nothing when it is hooked up... Only seem to do this when it is not hooked up...

All your suggestions would be greatly appreciated !!

 

[Defender2000]

Sounds like it might be a fuel pump or injector issue. Get your fuel pressure tested. That would certainly keep it from fully starting and it wouldn't throw any codes.

Also in the first video, looks like your water pump is awful wobbly. I could be wrong. It's tough to see on the phone though.

 

[yzjwk]

Sounds like it might be your fuel pump to me . You should hear it prime when you turn the key to on or when command starting. If you can get it to not start while using command start ,run to the back and smash on the fuel tank with with your hand or soft malot . That usually works if it's your pump just starting to go.
Good luck

 

[yem514]

Thanks for the reply guys I will be checking that tomorrow as I am going for my oil change as well.
15k and a little more than year later, one would think whatever is suppose to break is supposed to be broken already!
Will keep you guys posted!

 

[JKM]

Any updates?

 

[yem514]

In a few days... had to take my other truck to go out of town. Although, I could have used the jeep but I did not want to deal with this issue...
I did 3 round trips to Niagara Falls,Ontario from Montreal, Qc. It's about 670 km (410 miles), about 7 hours one way...
Just wanted to throw out that this issue never happens on long distance trips... just when I am running small errands... maybe it has something to do with the issue?

I will definitely keep you guys updated and please keep throwing in suggestions!

 

[kuker]

Bet money it's fuel pump, or psi regulator. When a pump is weak it will run a long time, but with a distributorless ignition it will NOT send spark until the ECM reads X psi. Setting vary for example, a 99 Chevy Tahoe with a 5.3 will run on 18 psi fuel, but it absolutely not start until 42 psi. The old trick is to beat on the fuel tank to get the last week out of the fuel pump

 

[yem514]

Bet money it's fuel pump, or psi regulator. When a pump is weak it will run a long time, but with a distributorless ignition it will NOT send spark until the ECM reads X psi. Setting vary for example, a 99 Chevy Tahoe with a 5.3 will run on 18 psi fuel, but it absolutely not start until 42 psi. The old trick is to beat on the fuel tank to get the last week out of the fuel pump

3/3 say it's fuel pump or fuel related. I will definitely get my fuel system checked out.

It has been more than 1 year and about 15K has been added on the mileage I have this issue! I never had to beat on the fuel tank...
It would somewhat fire right up after a couple of crank or the crank just after the "hesitation?" (If we can call it that)...
Apparently we are now 3 forum members with this issue....

 

[yem514]

oil change yesterday, left them the jeep until this evening.
They could not replicate the problem, and everything check out all good when they tested things...
Is there some kind of APP for iphone or android that can:
1. Do LIVE DATA
2. Read sensors
3. Read voltage
4. Read air/fuel output
The shop would not let me borrow there 10k$ scantool... Which I understand...
Thx again guys

 

[yem514]

A little update:
My technician buddy told me that I need to replace:
1. Tensioner
2. Idler Pulley
3. Power Steering Pump
4. Water Pump is a bit shaky also...

I am not sure if it will resolve the issue, I will keep you guys posted!
And hope this fixes the problem - or maybe this is the consequences of the primary issue ...

 

[JKM]

I have a similar issue once in a while with my 2005 3.7L with 145K KMs. Let me know if you get to the bottom of it. Do you know if the mechanic tested your fuel pressure? Could be a injector leaking off pressure, a failing fuel pump, or a bad wire going to your fuel pump (saw this once in a post here)

 

[yem514]

Fuel pressure: always on point when we are doing live data.
I do need to replace my Air temperature sensor. P/N: 56028364AA. 30$ CAD.
I went to the dealers and talked to the car parts guy and we talked to 2 technicians.
I was told to replace the Air temperature sensor, it is possibly a solution...
I am waiting for part to be available, I will keep you guys updated.

And for you guys who are experiencing this: my belt tensioner pulley + idler pulley + water pump + power steering pump is failing because of the shaking. It means that you guys will eventually get to this point if the solution is not found = BIGGER REPAIR BILLS.

 

[nateberg]

My 2007 WK with the 3.7L has had this exact same problem intermittently for the past six months. However my jeep shows me "transmission over temp" on the dash whenever it happens. I had to change my alternator about three weeks ago and have not had this problem since. I am keeping my fingers crossed that it does not come back.

 

[yem514]

I will be changing my alternator then, how did your mecanic go about finding out it was a bad alternator? Did he do a fuel pressure checks? And have you been using it alot for errands? Seems to happen when I do errands... Please keep me posted and about 2-3 other people lol

 

[JKM]

YEM514, was the sensor giving you an error code (check engine light) or did the dealer simply suggest changing it?
And the bigger question - did replacing the sensor fix the issue for you?

 

[yem514]

JKM: No check engine light - when it was connected to the scan computer (from independant garage),
It was showing that the Air Charge Sensor was off by +30 degree Celsius. Then speaking with the Chrysler dealer's car parts guy, he suggested replacing it because it can possibly be a fix. Something about the hotter the engine is the less fuel it needs to start. Btw the car parts guy was nice enough to bring me to 2 techniciens to talk about this issue because he did not want to sell me random parts cool guy.

They did not have the part in stock they told me they had it for the next day, but I am out of town for 1-2 weeks without the jeep... So I cant tell for now if it will fix...

Nateberg: mine does it too after the shaking. It seemed to be unrelated - but a lot of Trans Over Temp messages are due to battery and electronic stuff from what I read on the forum. Maybe there is something going on with the alternator...

 

[yem514]

I forgot to add:
2 days ago I pulled out the Fuel Pump Relay and started the car.
It made the car shake like in my videos.... Do you guys think its related?
I did switch out relay with another one, too see if the relay was the problem, it was not.

 

[Nejeep]

If pulling the pump relay re-creates the no start symptoms, then your fuel pump or the wiring to the pump is likely the problem. As someone ask earlier, do you hear the pump prime when the ignition switch is first switched ON (without cranking the engine)? If the pump primes the wiring is likely good, but if it does not build adequate pressure (50psi) the engine will not start.

 

[JKM]

YEM514 - did changing the Air Charge Sensor make a difference for those warm starts that you were having problems with?

 

[yem514]

JKM - Have been to busy going out of town and working... I have not gotten around to doing anything with the jeep... I will keep you guys updated if anything