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Old 05-05-2013, 02:07 PM   #1
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91 2.5L wont start

Hi, new member here. I have been reading the forum for the last few weekends while trying to get my YJ going again and appreciate all of the help that I have already received.

I have had the jeep for less than a year (bought from my sister who owned it for 15 years).

2.5 4cyl
170XXX miles
It is completely stock (for now)

I went out to start it a while ago after it had been sitting for about a month. It would turn over and almost fire ... but not start.

I checked and had spark.
Replaced the plugs and wires anyway.

Same thing ... turn over wont start.

Checked and no fuel at the rail. Did not hear fuel pump at all.

Replaced fuel pump and fuel filter and installed new battery.

Still no fuel at the rail but I here the fuel pump come on for a second when I turn the key to run position. (I am checking for fuel by depressing valve on rail) Fuel regulator was replaced about a year and a half ago by PO.

Also noticed that fuel gauge now spikes, so I found the ground wire by the brake pedal and tightened it. Did not fix.

Now when I try to start it, it will crank for a second, but engine will not turn over at all. I am looking for advise on what to be looking at? I wondered if I should replace crankshaft position sensor?

I am going out to try cutting the end off the ground wire at the parking brake and getting to fresh wire and seeing if that resolves the spiking fuel gauge (which I am assuming is a ground issue).

What would you be testing/checking next if it were your. I am frustrated that it seems to be farther away from starting than when I started !

Thanks for any direction/insight!

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Old 05-05-2013, 03:26 PM   #2
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Welcome,

Ok first thing first .. sit down and take a deep breath. You mentioned you had spark but didn't have fuel, then mentioned replacing the CKS which effects spark


Lets problem solve and clear this up a little. Have you checked to see if you have any Check Engine Light (CEL) codes? Research how to check if you haven't done so.


In very simple terms an engine needs fuel, spark and oxygen to fire.

Sounds like you are saying your engine cranks (turns over) but will not fire (start).


If you are showing no codes time to problem solve:


1) Check to see if you have spark by pulling a plug and wire (or use screwdriver). Go on youtube if you don't know how do do this.


2) If you have a STRONG spark start looking at fuel. If you do not have spark at the plug pull the coil wire off the distributor and check for spark.


3) If there is spark at the coil and not at the plug check cap, rotor, grounds, camshaft position sensor (CPS aka pick-up coil), computer etc.


4) If there is no spark or weak spark at the coil check grounds, crankshaft position sensor (CKS), coil, computer etc.


5) Do you have fuel at the cylinder? Can you smell fuel when you crank the motor? Does the spark plug smell like raw fuel? Is ther fuel at the fuel filter? Did you check the fuel pump relay? Have you checked the fuel pressure?


Do a little more trouble shooting and report back to us and we'll do our best to get your jeep back on the road.


Jeep cranks, but won't start is usually an easy fix. Number one reason is CKS failure.

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Old 05-05-2013, 04:01 PM   #3
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Thanks for the reply!

I have not checked for any codes. I will do a search about how to do that and report back.

I did have spark before changing the fuel pump (checked with screw driver on 1 plug then borrowed timing light to check all of the wires. )

After changing the fuel pump, the engine will not turn over, so I am not sure if it still getting spark.

I do not have a fuel pressure gauge, but there is no fuel getting to the fuel filter (so obviously not making it to the rail.)

I was going to replace the fuel pump relay to see if that was the issue. With the fuel gauge pegging when I turn the key, I am still wondering about a ground issue.

I can usually fumble through mechanical stuff, but I have not spent much time trying to diagnose electrical.

I just dont get why it is not turning over now?
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Old 05-05-2013, 04:23 PM   #4
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Checked engine codes and get :


12: Direct battery input to PCM was disconnected within the last 50 key-on cycles.

33: An open or shorted condition detected in the A/C clutch relay circuit.

(Vehicle does not have A/C)
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Old 05-05-2013, 05:38 PM   #5
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Location: Southern MN
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With all the issues you are having, I would look at grounds. On the block below the farthest back plug, there is a bolt with a bunch of wires attached. This is the main grounding point. Take the wires off and clean it all up. Give that a try and let us know. Also when you turn the key over, does the check engine light come on?
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Old 05-05-2013, 05:45 PM   #6
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Yes the CEL does come on.

I will look for those grounds and clean/up check them out.

Thanks.
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Old 05-05-2013, 06:19 PM   #7
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When you say the engine won't turn over ... to me that means you turn the key and get nothing .. no clicking .. or any sounds at all.

You said you put in a new battery. Is the battery dead like something drained it over night?

Try turning on your headlights to see if you have a full charge. If the lights are dim and fade your battery is dead or does not have a good connection.
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Old 05-05-2013, 10:49 PM   #8
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Battery was brand new this afternoon and lights and wipers work strong.

When I turn the key I hear the fuel pump prime, there is 1 click, the motor tries to turn for about 1 to 2 seconds and then stops.

I did find that the starter and the wires to the starter have a coating of oil on them from a leak at the valve cover. I am thinking this might explain why it tries to turn for a second and then stops.

I was wondering if the no fuel at the rail issue is because the engine has not been cranking since I changed the fuel pump (due to oil on the starter/wires)? Is the initial "prime" when the key is turned on enough to build the pressure back up in the system or does the engine need to crank to activate the pump to bring the pressure up?

I did clean up/tighten all the ground wires and do not seem to have any change in symptoms.
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Old 05-07-2013, 05:05 PM   #9
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Turn the key to on position, leave in neutral with ebrake on. Bridge the two big posts on the starter solenoid with a screw driver or starter button (youtube has videos) and see if it starts. That will help us eliminate a few things.

If it does not start could you get a few buddies to push start you?

If oil gets into the brushes on the solenoid/starter it can cause problems, but you will be able to push start.

I am assuming you have a manual .. no mention above unless I missed it.
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Old 05-09-2013, 12:51 AM   #10
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Thanks!

Yes it i a manual.

Work sucks this week, so I am a going to have to wait until Saturday to get back to diagnosing the YJ. Luckily this is not a DD.

I will check out the youtube video for the screwdriver trick.

I appreciate all the help

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