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Unread 08-29-2014, 01:15 PM   #1
jjs89yj
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1989 YJ Wrangler 
 
Join Date: Jul 2010
Location: Austin
Posts: 76
Crank but no start troubleshooting help

Hi Guys,

I need some help troubleshooting here. I have an 89 2.5 yj that cranks, but doesn't start. When i turn the key, the fuel pump kicks on and is sending fuel to the rail and cranks, but doesn't actually start. It'll crank all day if i let it.

This tells me its not a fuel problem because i have fuel. Not an ecm problem because the fuel pump kicks on. Is this correct?

I have brand new spark plugs. I can spray starting fluid in the air box and it sounds like its going to start for 1/2 second, but then goes back to just cranking.

Any thoughts on what might be going on or what to check next?

**EDIT**
I've also checked fuses under the dash-- they all look good.

Thanks,
Jeremy

__________________
1989 YJ: 2.5, ax5, 4" lift, 33" MTs
In the middle of a frame-off-- build thread to come
Parts in waiting: 1" bl, new tank, corbeau xrs seats, family-style roll bar swap, and whatever odds and ends need tending to.
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Unread 08-29-2014, 01:38 PM   #2
mike134
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1989 YJ Wrangler 
 
Join Date: Aug 2014
Location: Cleveland, OH
Posts: 789
you may not have enough fuel pressure even though the fuel pump is pumping. Go to autozone and borrow the fuel pressure gauge, its free but you have to leave a deposit. Plug it into the shrader valve and report back here with the pressure.
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Unread 08-29-2014, 07:16 PM   #3
jjs89yj
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1989 YJ Wrangler 
 
Join Date: Jul 2010
Location: Austin
Posts: 76
thanks- i just picked up the pressure gauge, but cannot for the life of me find the valve or a picture of the valve in a 2.5. Where's it at?
__________________
1989 YJ: 2.5, ax5, 4" lift, 33" MTs
In the middle of a frame-off-- build thread to come
Parts in waiting: 1" bl, new tank, corbeau xrs seats, family-style roll bar swap, and whatever odds and ends need tending to.
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Unread 08-29-2014, 07:54 PM   #4
mike134
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1989 YJ Wrangler 
 
Join Date: Aug 2014
Location: Cleveland, OH
Posts: 789
It should be on the throttle body on your 89 2.5L. I think you should have 15 psi with the pump running. Your TBI should have a pressure adjustment screw on the pressure regulator which you screw inward to increase pressure and outward to decrease pressure.
25l-tbi.jpg

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Unread 08-29-2014, 08:37 PM   #5
jjs89yj
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1989 YJ Wrangler 
 
Join Date: Jul 2010
Location: Austin
Posts: 76
thanks mike, that picture really helps. I threw the pressure gauge on it and it holds right at 15 psi. Does this indicate that its not a fuel issue?
__________________
1989 YJ: 2.5, ax5, 4" lift, 33" MTs
In the middle of a frame-off-- build thread to come
Parts in waiting: 1" bl, new tank, corbeau xrs seats, family-style roll bar swap, and whatever odds and ends need tending to.
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Unread 08-29-2014, 08:44 PM   #6
mike134
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1989 YJ Wrangler 
 
Join Date: Aug 2014
Location: Cleveland, OH
Posts: 789
yeah, its very likely that the fuel system is working well.

Whats the history of the vehicle? Did you just get it, or have you had it for a while? Was it running before you replaced the spark plugs?

I would definitely take a plug back out and check the gap. Are they copper core or platinum? If the new ones are platinum then put the old ones back in and see if it starts up again.
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Unread 08-29-2014, 08:51 PM   #7
jjs89yj
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1989 YJ Wrangler 
 
Join Date: Jul 2010
Location: Austin
Posts: 76
The engine has maybe 3000 miles on it, but its been parked for two years because i took the body off to take care of some frame stuff. Didn't touch the engine though during that time. Right before it was parked, I drained fluids. Before i tried starting it, i put brand new fluids in it and new copper plugs. I haven't replaced wires though. Should i throw the old plugs back in it to see if it'll fire?
__________________
1989 YJ: 2.5, ax5, 4" lift, 33" MTs
In the middle of a frame-off-- build thread to come
Parts in waiting: 1" bl, new tank, corbeau xrs seats, family-style roll bar swap, and whatever odds and ends need tending to.
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Unread 08-29-2014, 09:08 PM   #8
mike134
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1989 YJ Wrangler 
 
Join Date: Aug 2014
Location: Cleveland, OH
Posts: 789
The new plugs should be ok, but you should still check to see if the gap is the same as the old ones. I have gotten the wrong plug gap from the parts store before.

You should check for power to the spark plugs:
Unplug the ignition coil wire from the distributor cap, hold it a half inch from the cylinder head and have someone crank the engine. See if a spark arcs across.
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Unread 08-30-2014, 04:01 PM   #9
jjs89yj
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1989 YJ Wrangler 
 
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Location: Austin
Posts: 76
Checked the gap and they're alright. There is no spark coming from the ignition cool wire. Should I replace distributor cap and wires next? Or is there something else I can check before that?
__________________
1989 YJ: 2.5, ax5, 4" lift, 33" MTs
In the middle of a frame-off-- build thread to come
Parts in waiting: 1" bl, new tank, corbeau xrs seats, family-style roll bar swap, and whatever odds and ends need tending to.
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Unread 08-30-2014, 04:26 PM   #10
mike134
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1989 YJ Wrangler 
 
Join Date: Aug 2014
Location: Cleveland, OH
Posts: 789
if there is no spark from the ignition coil wire then replacing the cap and wires probably won't help.

Since the car was sitting, did you replace the battery? Try adding booster cables connected to another vehicle and see if it starts up. If the battery is old and not supplying enough voltage, sometimes the coil won't even fire.

Also, try leaving the key in the ON position for a few minutes, then try starting it up. This will allow the ECU capacitors to charge up if they are going bad.
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Unread 08-30-2014, 04:31 PM   #11
jjs89yj
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1989 YJ Wrangler 
 
Join Date: Jul 2010
Location: Austin
Posts: 76
The battery is about two weeks old and fully charged. Would a bad capacitor in the ecm cause this issue?
__________________
1989 YJ: 2.5, ax5, 4" lift, 33" MTs
In the middle of a frame-off-- build thread to come
Parts in waiting: 1" bl, new tank, corbeau xrs seats, family-style roll bar swap, and whatever odds and ends need tending to.
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Unread 08-30-2014, 04:34 PM   #12
mike134
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1989 YJ Wrangler 
 
Join Date: Aug 2014
Location: Cleveland, OH
Posts: 789
Do you have the check engine light come on when you turn the key to ON? Check out the following article if it doesn't come on.

http://www.jeepforum.com/forum/f12/c...rs-ecu-492597/
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Unread 08-30-2014, 08:51 PM   #13
jjs89yj
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1989 YJ Wrangler 
 
Join Date: Jul 2010
Location: Austin
Posts: 76
Do the 89 2.5s have check engine lights? I thought these didn't come along until OBD1?

Would a crankshaft position sensor cause the issues i'm having?
__________________
1989 YJ: 2.5, ax5, 4" lift, 33" MTs
In the middle of a frame-off-- build thread to come
Parts in waiting: 1" bl, new tank, corbeau xrs seats, family-style roll bar swap, and whatever odds and ends need tending to.
jjs89yj is offline   Reply With Quote Quick reply to this message
Unread 08-30-2014, 09:01 PM   #14
bharris68
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1989 YJ Wrangler 
 
Join Date: Jun 2006
Location: Issaquah, Washington
Posts: 763
89's don't have many lights I'm thinking it's the CPS and possibly pinched or unplugged wiring if you pulled the body off and then put it back on If you've got fuel but not spark then I'd check the CPS for sure next.


I have a little '89 2.5 with 220,000 miles on it and it still sounds like a little sewing machine when it's running.
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Unread 08-30-2014, 09:53 PM   #15
jjs89yj
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1989 YJ Wrangler 
 
Join Date: Jul 2010
Location: Austin
Posts: 76
I'll try that in the morning and check back in. Thanks!
__________________
1989 YJ: 2.5, ax5, 4" lift, 33" MTs
In the middle of a frame-off-- build thread to come
Parts in waiting: 1" bl, new tank, corbeau xrs seats, family-style roll bar swap, and whatever odds and ends need tending to.
jjs89yj is offline   Reply With Quote Quick reply to this message
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