90 YJ Got spark, got fuel. No start - JeepForum.com
 
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post #1 of 5 Old 06-18-2011, 05:28 PM Thread Starter
Plyj
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1990 YJ Wrangler 
 
Join Date: Feb 2010
Location: Plymouth, MA
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90 YJ Got spark, got fuel. No start

Okay... this is frustrating. Installed new 4.0L head (new valves, springs, retainers, headers, rocker arms, etc.) on my 4.2L block.
Got TDC on compression stroke (the way I checked this was by watching the valves open while manually turning engine... last valve open before TDC mark hit 0 was intake valve). Have GM HEI which ran great before head transplant.
In fact, everything ran great before transplant.

I'm getting spark (hung light off #1 & cranked engine). I'm getting fuel (looked down throat of Weber & see gas going in when I move throttle).

This should be simple... I've got spark, I've got fuel, and I'm on TDC.

Time to pull timing chain cover??? This thing has me baffled... help!

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post #2 of 5 Old 06-18-2011, 05:51 PM
giggityjeeper
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1990 YJ Wrangler 
 
Join Date: May 2007
Location: British Columbia
Posts: 4,022
bad vac leak somewhere, taht would keep it from firing, if it was bad enough....

ground not hooked up somewhere...

dont know man frustrating fro sure this kind of ****

Started with some rust repairs ended in a SOA...

http://www.jeepforum.com/forum/f12/h...-jeep-1050879/

family roll bar swap/upgrade..

http://www.jeepforum.com/forum/f12/f...grade-1054753/

1990 YJ. SOA, OME 36R 3.5" lift springs, OME 5/8 greasable shackles, OTT high steer, Custom cage, team Rush, Posi, 33 TSL swampers
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post #3 of 5 Old 06-18-2011, 08:46 PM
laybackman
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2010 JK Wrangler 
 
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Quote:
Originally Posted by Plyj View Post
Okay... this is frustrating. Installed new 4.0L head (new valves, springs, retainers, headers, rocker arms, etc.) on my 4.2L block.
Got TDC on compression stroke (the way I checked this was by watching the valves open while manually turning engine... last valve open before TDC mark hit 0 was intake valve). Have GM HEI which ran great before head transplant.
In fact, everything ran great before transplant.

I'm getting spark (hung light off #1 & cranked engine). I'm getting fuel (looked down throat of Weber & see gas going in when I move throttle).

This should be simple... I've got spark, I've got fuel, and I'm on TDC.

Time to pull timing chain cover??? This thing has me baffled... help!
That intake valve should have been closed (fuel air charge has to be in the cylinder before the compression stroke begins) as you were coming up on TDC of the compression stroke.

Do you know what was good about the good old days? I wasn't good, And I wasn't old!

Senators and Congressman should wear uniforms like NASCAR drivers so we could identify their corporate sponsors....
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post #4 of 5 Old 06-18-2011, 09:07 PM
Noltz
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YJ Wrangler 
 
Join Date: Oct 2010
Location: Hamilton
Posts: 742
^^ beat me too it. Your last valve to open before TDC, and it should close as you approach TDC. If there's a bit of overlap in the cam you might have both valves moving at the same time, @ TDC.

Sounds like you're 180 out.

-Noltz
'91 Frankenheep YJ. 4.0, 4" BDS, Richmond 8.8, Titan 12k, 35" KM2's, rust.
'88 YJ, 4.2/4.0 head, +4" & shackles, BFG 33's (sold)
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post #5 of 5 Old 06-18-2011, 09:30 PM
laybackman
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Location: Massachusetts
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Pull #1 plug...stick finger in plug hole. Have a buddy bump engine until the compression wants to push your finger out of the #1 plug hole. Use breaker bar and large socket to findish bringing this engine up to TDC by sticking long thin stick in #1 hole to watch #1 piston come up to TDC checked against your timing marks. Once TDC on the compression stroke is attained, pull the distributer cap and check rotor position. Move rotor to just before #1 plug tower position on said disrtibuter. Enjoy!

Do you know what was good about the good old days? I wasn't good, And I wasn't old!

Senators and Congressman should wear uniforms like NASCAR drivers so we could identify their corporate sponsors....
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