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Unread 06-16-2014, 09:28 AM   #1
Gopats
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1991 YJ Wrangler 
 
Join Date: Jul 2009
Location: Boston
Posts: 59
Another 94 YJ that wont start.

After lots of searches and diagnostic posting a new thread for help.

1994 YJ 4.0 will not start. Was running fine with no issues when I parked it but two days later it wont start. It cranks over, has plenty of spark and is getting fuel. No trouble codes except the normal 12,33,and 55. ECU is only 4 months old. New TPS and CPS when I replaced the ECU. Battery and cables are also 4 months old and hold a good charge.

1. check engine light comes on when you turn the key and the fuel pump charges.

2. turn key to run and she just cranks. checked spark, fuel and have good spark and fuel pressure.

3. Changed plugs, and wires, none were fouled but #2 had a crack in the porcelain. still no start.
4. changed distributor cap and rotor. No change
5. changed power pack, No change
6. Fuel pressure is fine and even tried a little starting fluid.

Was looking for a little advise. Everyone knows you start over thinking this stuff and miss the small things. Thanks in advance for your help.

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Unread 06-20-2014, 09:09 PM   #2
laybackman
Bikini Bridge Inspector
 
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1995 YJ Wrangler 
 
Join Date: Dec 2002
Location: Massachusetts
Posts: 6,085
Quote:
Originally Posted by Gopats View Post
After lots of searches and diagnostic posting a new thread for help.

1994 YJ 4.0 will not start. Was running fine with no issues when I parked it but two days later it wont start. It cranks over, has plenty of spark and is getting fuel. No trouble codes except the normal 12,33,and 55. ECU is only 4 months old. New TPS and CPS when I replaced the ECU. Battery and cables are also 4 months old and hold a good charge.

1. check engine light comes on when you turn the key and the fuel pump charges.

2. turn key to run and she just cranks. checked spark, fuel and have good spark and fuel pressure.

3. Changed plugs, and wires, none were fouled but #2 had a crack in the porcelain. still no start.
4. changed distributor cap and rotor. No change
5. changed power pack, No change
6. Fuel pressure is fine and even tried a little starting fluid.

Was looking for a little advise. Everyone knows you start over thinking this stuff and miss the small things. Thanks in advance for your help.
Unplug the VSS sensor from the T-case and see if it start then.

IF it does the VSS sensor is junk and needs to be replaced. Don't buy the el cheapo VSS buy a good one like a Denso or better yet buy an OEM unit.
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Unread 06-26-2014, 12:31 PM   #3
Gopats
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1991 YJ Wrangler 
 
Join Date: Jul 2009
Location: Boston
Posts: 59
the VSS is is cable and a plug. My jeep is a 91 with an engine out of a 94. I didnt think the old style VSS would matter. I will check it out though. Cant hurt at this point.
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Unread 06-26-2014, 12:32 PM   #4
Gopats
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1991 YJ Wrangler 
 
Join Date: Jul 2009
Location: Boston
Posts: 59
I did a valve cover gasket two days before the jeep died. After replacing the gasket I drove the jeep and it seemed fine.
Anyone have any knowledge about the two braided grounds off the engine? As for the braided grounds, I found the one off the firewall attached to the block wasn't even attached. It was just resting on the engine. The second ground off the fender that attaches near the dip stick was also not attached. it was just sitting on the fender.

Will or can this effect the computer or the starting? haven't seen much written up on these grounds and didn't have time to change them since it started raining.
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Unread 06-26-2014, 03:11 PM   #5
laybackman
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1995 YJ Wrangler 
 
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Location: Massachusetts
Posts: 6,085
Quote:
Originally Posted by Gopats View Post
I did a valve cover gasket two days before the jeep died. After replacing the gasket I drove the jeep and it seemed fine.
Anyone have any knowledge about the two braided grounds off the engine? As for the braided grounds, I found the one off the firewall attached to the block wasn't even attached. It was just resting on the engine. The second ground off the fender that attaches near the dip stick was also not attached. it was just sitting on the fender.

Will or can this effect the computer or the starting? haven't seen much written up on these grounds and didn't have time to change them since it started raining.
IIRC they suppress radio noise BUT I have heard of jeeps that will not start because of generally poor ground throughout the system and when these got cleaned and reattached the jeep would then fire up. ALL grounds are important.
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Getting older, I have developed some special skills. I have the ability to cough, sneeze, fart and pee at the same time.

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