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93 Won't Start

30K views 27 replies 11 participants last post by  louieg1979 
#1 ·
93 2.5 cranks but fuel pump isn't running, doesn't do any thing with gas dumped in throttle body. checked all fuses including the ones by the battery. swapped out fuel pump relay. also when turning key to run the only dash indicator I get is the seatbelt one.
 
#4 ·
check your harness to the computer and ensure it is seated good. The symptoms are just like the computer problems I had and a replacement fixed all of 'em...

One key sign that the computer is bad is if you turn the key on and wait. Sometimes up to twenty minutes, but after a random amount of time, the check engine light will come on at the exact time as the fuel pump growls up. Then, it would run ok until you shut it off again. If she sits with the key on, and does this, your computer is shot.

Based on your symptoms and tests, you are not getting any gas or spark. Interesting, usually its one or the other.
 
#7 ·
You check the codes by doing this: Turn the key to On, Off, On, Off. On and then wait a small amount of time. The check engine light will flash in sequence quickly to indicate the first number of a code. It will then pause for a slightly longer period of time, and then blink again quickly in sequence. This gives the second number in the code, which can then be looked up. Code 55 is "End of Code Sequence", meaning there are no other codes listed.
 
#8 ·
Does the fuel pump prime?
If not, have you checked the fuel pump ground on the parking brake?
This contact often corrodes or even gets knocked off.
I can't remember which does it, but it's either the CKS (crank position sensor) or the CMS (cam position sensor) that controls the fuel...the other controls the spark.
 
#13 ·
Thanks for all the ideas guys I thought I had checked all the fuses but in any event my jeep doesn't have dome lights any ways so I never gave that fuse a second thought until it was mentioned. Went out yesterday and sure enough fuse was blown replaced it and jeep fired right up. Jmo but the wiring diagram in the haynes manual leaves a lot to be desired. Thanks again
 
#14 ·
Check this out for complete wiring diagrams for everything on your jeep. Not sure why I can't make the link work, just copy and paste into your browser and it should work or go to my profile and look at threads I've started and check out the just trying to help one the link should work there.

Jeep 1995 YJ - FSM Wiring Diagrams
 
#16 ·
Can't take the credit for that one. My brother found it. Owns his own shop and teaches auto repair for ASE and other outfits. To make a long story short, my 93 wrangler was given to me because of the same reason. sat in a garage for 12 years owner replaced every electronic part you can name and it never would fire. when he passed away his widow gave it to me because it would not run. took my brother 45 minutes to get it running.
sometimes its the simple things we tend to overlook.

Troy
 
#17 ·
I seem to have this same problem on my 1993 Wrangler. Last night I was really low on gas and then seemed to have run out of gas. Had to pay $10 for a stupid 1 gallon can. Put that in and still no start. Put a bottle of fuel injector cleaner in. It turned over for a second, it seemed, then died. Got another gallon of gas, put it in, still no luck. Put another bottle of fuel injector cleaner in, and for a second thought it was starting, but no. Checked all the fuses under the dash and also the ones in the box by the battery. All test ok for continuity. Then I realized I wasn't hearing the "buzz" sound of the fuel pump? when turning the key to On. Bled the test port valve on the fuel rail, VERY tiny bit of air came out. Tried to start, sound same as when i had put the bottles of injector cleaner in, no luck. I then noticed a small plastic air? hose, near the fuel rail, completely severed. One end goes into the top, rear of the cylinder head, 6 inches behind the oil cap. And the other end goes to a sensor. Looking in the book, it seems to be the sensor next to the Manifold Air Temperature Sensor. Tapped it up best I could, but still no start. After 6 hours in the parking lot, exhausted, I left it on the street and trekked home.

I will check the fuel pump ground by the emergency brake. But where is that? By the brake pedal? or where the emergency brake goes into the rear drum?? I can't seem to find the fuel pump either? On my old (87) YJ, it was in the engine compartment. Where is it on my 93? Also can't see to see where the book tells me the name of the sensor that severed air hose goes to?
 
#19 ·
So my Jeep still won't start. I've tried replacing the fuses under the dash. I tested all the fuses (except the square block type) in the box by the battery for continuity and they are good. I noticed the block fuse labeled "horn" and the one next to it labeled "fuel pump" were identical. So I swapped them. The horn still worked, but still no buzz/prime sound from the fuel pump when I turn the key to On. And it still does not start. I put about 5 more gallons of gas in and turned the key to On, leaving it there for like 1 or 2 mins, hoping maybe the fuel pump would pull the fuel. But nothing. I am at a loss. I did take down the error code message numbers(after doing the thing where you turn the key to On, then Off, then back on..about 7 times). And the series of numbers for the code is: 1 2 3 3 5 5. How do I find out what error this code represents? And any other ideas for things for me to try? Help? =o/
 
#20 ·
I think you got codes 12, 33 and 55. If memory serves me, 12 is power was cut to ECM, this happens if battery is disconnected etc, 33 is the AC and if you don't have it ignore this one and 55 is end of code sequence. The ecm controls the fuel pump and the ignition. check this out http://www.jeepforum.com/forum/f12/cr...rs-ecu-492597/
 
#21 ·
Thanks for the reply. I just found this for the codes.. Hello, I have a 1993 Jeep Wrangler 4.0L HO manua... - JustAnswer

The "expert" there says the 12 is the start of the string. And the 55 is the end of the string. And the 33 is the error code. I DO have AC. SO does this mean I should replace the 02 sensor? The "check engine" light has always turned on for like I don;t even know how many years. Yet after doing the On/Off/On/Off etc key turn test to get the codes, the check engine light doesn't come on anymore.

Just read the first page of that thread for replacing the capacitors on the ECU. Looks easy enough. But yeah, not yet sure that is the source of my problem.
 
#22 ·
So, I still don't know what to do. My Jeep is still stranded on the street, like 2 miles away from home =o( Is there a test to determine if it is the ECU? Aside from pulling the ECU out and replacing those capacitors and then trying it again?
 
#23 ·
Lol, your story sounds like mine. After 6 hours or more diagnosing without tools, I did not want to spend the $90 for a new crank sensor located on the upper bellhousing cover....I had a good idea this was it. I towed it home, where I bought a used one, and it started and ran fine.
 
#25 ·
there is a test explained here...Jeep GC 93' 4.0 no start, cranking but no fuel pressure! - JeepForum.com

I am having a similar issue with my 2.5 to 4.0 swap. Everything was working (fuel pump, ecu, etc on 4 banger) but I am gettting some fire but no run, so I am thinking its the fuel pump now since this swap has been a slow (get to it when I can) swap. I hear the fuel pump come on pressureize after two key cycles, try to start it and it fires kinda but does not run. Or the injectors, dunno, yet.
 
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