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Topic Review (Newest First)
09-07-2008 11:04 AM
yellowbeast01 take a wrench to your starters leads cross them make sure you hear it, then get in your jeep and try starting it then.

i had a similar problem and thats what i did, it turned out to be my computer.
09-06-2008 12:50 AM
Triple88a ^ simplified, it looses pressure once the fuel pump is off.

try priming the fuel pump.
09-04-2008 12:17 PM
Jerry Bransford
Quote:
Originally Posted by rico4335 View Post
Humm, I have a similar issue on a '97 4.0, but my issue is it will almost never start on first try but always will on second. Usally after sitting for a while. I will try the same fuel pump test, any other ideas?
That's normally caused by a leaky anti-drainback valve located inside the pressure regulator on top of the fuel pump. When it leaks, it allows all of the fuel that is supposed to stay put in the fuel injector fuel rail on the engine to instead drain down back into the fuel tank. The long start time after that happens is the length of time it takes for the fuel pump to get the fuel back up to the injectors again.

You can often find pressure regulators for sale on eBay sold separately so you don't have to buy the entire fuel pump assembly from the dealer.
09-04-2008 10:40 AM
rrich Interesting!
He says he has no SPARK - so everyone thinks it's FUEL related? From the pump, the relay, to throttle body have been blamed for a NO SPARK CONDITION!

Are you guys politicians or what? They don't deal in reality either.

Have a close look at the coil - take it out to look. Look for any signs of burned marks, grayish smoke like streaks. If any, replace. TJ coils are not like older oil filled coils, they are air insulated and have a reputation for flashing through the insulation. A new coil is certainly much cheaper, and easier, than a new pump!!!!!!!!!!!

And - yes, it IS possible to ruin a coil by leaving the coil wire disconnected - there's no place for the voltage to go but to itself, shorting out the coil. BUT - A coil with good insulation shouldn't do that. If the insulation was weak anyway (old or a cheapie) , it'll flash through.

To check to see if the coil is getting it's pulse - connect an analog voltmeter from ground to the pigtail on the harness right by the coil. Crank it - you should see the meter bouncing up and down. Or, a Dwell meter will do the same. If it's getting it's pulse but no coil output - replace coil.

Defective Jeep coils are common.
09-04-2008 09:57 AM
rico4335 Humm, I have a similar issue on a '97 4.0, but my issue is it will almost never start on first try but always will on second. Usally after sitting for a while. I will try the same fuel pump test, any other ideas?

Also have an '88 2.5 that had starting spark issues and come to find out it was the connection points where the coil mounts to the ecu, they were dirty. Cleaned them and fires right up now! (not that it helps but FYI)
05-05-2008 11:22 AM
Deadhed106 is there a way to test the sensors in the throttle body, or do you just have to replace them as you go?
05-03-2008 08:24 PM
Triple88a What about the little sensors in the throttle body?
05-03-2008 06:35 PM
Pierce07 could it possibly be the distributor? I'm having the same problem and when i hit bumps the engine cuts out.

I don't know if it's possibly but maybe there is a way to hook up a psi guage to your fuel line and you will be able to see the drop in pressure, if there is some, and if not you know to look somewhere else for a problem.
05-03-2008 06:14 PM
Deadhed106 i understand the fuel pump bit, but the issue is the pump is turning on and off. I can turn the key and here the pump buzzing for about 3 seconds then turning off, unless its cranking. The throttle bottle is spotless, and looks great. I tried that trick just to see if I could make it fire. Now its back to cranking and cranking with no fire. I do not want to try the carb cleaner again.... Is there any sensors in the air cleaner that could cause it not to fire.
05-03-2008 04:19 PM
Triple88a fuel pump... go inside the jeep, open the door.. buckle your seat belt and turn it to on (not crank), you should hear a whine from the back for 2 seconds. That is the fuel pump. It will turn off after the 2 seconds. From you spraying carb cleaner (not a good idea since you have a throttle body not a carb) this points me to believe yoru problem is throttle body related. If its ur fuel pump it will run for maybe a minute and it will die. Take some Throttle body cleaner and clean the Throttle Body.
05-03-2008 04:12 PM
Deadhed106 Okay, I am back. Here is the short story, I sprayed some carb cleaner in the air intake and the wrangler fired and it cleaned out the throttle bottle. The wrangler ran fine for a about a day. Now its back to doing the exact same thing again. Is there a way to test the fuel pump other than the starting method, thats not working. I really cant afford to replace the fuel pump if it does not need to be replaced. Also is there a way to test the ignition? I just read in the posts about the relay might be a problem, is there a way to test that as well?
04-30-2008 09:02 PM
Jerry Bransford
Quote:
Originally Posted by Triple88a View Post
He said something about excessive electricity building up in the secondary side of the coil and melting the windings.
No such thing, he was either filling you full of smoke or he is electrically/electronically challenged as are most mechanics, even a shop teacher.
04-30-2008 06:03 PM
Triple88a He said something about excessive electricity building up in the secondary side of the coil and melting the windings. It sparked few times on to the block and when we pulled it away for couple seconds it died. We put it back to the block but no sparks.
04-30-2008 05:58 PM
Jerry Bransford
Quote:
Originally Posted by Triple88a View Post
thats what my auto teacher told me AFTER we burned up some kids coil on his truck in auto class
Hate to say it but your auto teacher was wrong, or you simply misunderstood the situation or what he really said. Ignition coils and electronics don't work that way.
04-30-2008 05:52 PM
Triple88a thats what my auto teacher told me AFTER we burned up some kids coil on his truck in auto class
04-30-2008 09:40 AM
Jerry Bransford
Quote:
Originally Posted by Triple88a View Post
Keep in mind, running a coil with the spark plug disconnected and no other place to hit ground can damage the coil so when doing tests allways make sure the coil can hit ground
Sorry but that is absolutely not true.
04-30-2008 09:39 AM
branty I just browsed the threads so I appoligize if I duplicate anyones anwser. I had a similar problem last week and it ended up being a relay to the fuel pump. On first impression, my mechanic thought it was a crank sensor on the engine. He said they are very common to go out. You might want to check both.
04-30-2008 07:38 AM
jpdocdave ya, usually you can put the tester on the coil and ground the other side. sometimes you gotta get creative and just make a little jumper wire.
04-29-2008 11:47 PM
Triple88a Keep in mind, running a coil with the spark plug disconnected and no other place to hit ground can damage the coil so when doing tests allways make sure the coil can hit ground
04-29-2008 09:58 PM
jpdocdave computer is very rare. you need to see if you have injector pulse, that's gonna be a good clue. just cuz a coil ohms ok, doesn't mean its good. is spark coming out of it? like i said, it needs power and ground in, and spark is supposed to come out.
04-29-2008 08:17 PM
Deadhed106 I checked the coil earlier today, and the readings i got from my ohm meter where with in the ranges of a normal acting coil. I was wondering if there might be a sensor switch that could be telling the engine to shut down? Could my computer be defective? I have ran the test for the computer to give me a reading and nothing is happening. Could this be a sign of the computer?
04-29-2008 07:45 PM
jpdocdave check power to coil, if power and ground go in, and no spark out, coil is bad. usually with bad cam or crank sensors you'll have no injector pulse.
04-29-2008 07:43 PM
Jerry Bransford Have you looked at your camshaft position sensor? It serves a similar function to and works in the same way as the crankshaft position sensor. It's inside the distributor, located under the plastic shield that is just below the rotor.
04-29-2008 07:38 PM
Deadhed106 Okay, up date, I have replaced both the camshaft position sensor and the crankshaft position sensor and still no spark. I have test the plug with a light and removed the plug and looked for a spark, and still have nothing. Any suggestions on where to go.......
04-29-2008 02:49 PM
elch469 I had the same cranking problem with my 97 4cyl firsth clearly identify the problem like Jerry said if it starts up right away after being parked no more than a few minutes but struggles to start after parked several hours it's a fuel pressure regulator $137 located at the top of the gas tank.
04-29-2008 01:01 PM
jpdocdave
Quote:
Originally Posted by nater344 View Post
I'm having the same problem now after the dealership did the recall on the fuel sending unit....now you have to turn the key a couple of times before it will start. Otherwise it just cranks and cranks and eventually starts. I called the dealership and the sevice a**hole said, "obviously your jeep worked last week when you drove it out of here or it would still be sitting here now would it"........pissed me off!
what a jag, ask for the service manager, and just explain this started happening right away. sounds like a faulty unit they installed.
04-29-2008 10:30 AM
nater344 I'm having the same problem now after the dealership did the recall on the fuel sending unit....now you have to turn the key a couple of times before it will start. Otherwise it just cranks and cranks and eventually starts. I called the dealership and the sevice a**hole said, "obviously your jeep worked last week when you drove it out of here or it would still be sitting here now would it"........pissed me off!
04-28-2008 08:51 PM
jpdocdave ya, something is weird. i've never seen a cps make a long crank condition like this started as. no start sure. might be more than one thing goin on here, shorted wires could have caused a fuse to blow or something. hopefully its just one prob. i think once it gets the no spark thing fixed, there still will be a long crank condition, hope not.
04-28-2008 08:40 PM
richp I wonder if the shorted CPS could have taken a fuse out..
04-28-2008 07:28 PM
jpdocdave
Quote:
Originally Posted by Deadhed106 View Post
okay, spliced everything back and still acting the same and no spark. Checked the distributer and rotor button and everything seems to be okay. Is there a way to check the ignition coil?
put your spark tester on the coil instead of spark plug side.

so you've gone from hard start/long crank. to no start, w/ no spark? check fuel pressure, and injector pulse also, make sure you didn't lose anything else. no pulse and no spark would point to crank, or cam sensor prob possibly
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