4.7 V8 - Head gasket replaced and wont start - JeepForum.com
 
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post #1 of 6 Old 07-13-2017, 12:19 PM Thread Starter
Ice_Mage
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Join Date: Jul 2017
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4.7 V8 - Head gasket replaced and wont start

Hi all,

I have been having a very frustrating issue with my 99 Jeep Grand Cherokee Limited 4.7 v8.

Details:
Replaced both head gaskets
Heads were pressure tested and machined at a machine shop
Put everything back together and engine cranks but wont start
Suspect incorrect timing so pull apart again and replaced valves
Meticulously set timing and it looked perfect as per the manual
Put all back together and the same thing

I have checked for spark from the wires with a noid light (good)
Checked coils for resistance (good)
Checked injector wiring with noid light (good)
Checked compression on all (good except 2 are low)
Tried starter fluid and not even a cough or a splutter
Fuel pump makes noise when ignition on

So I am down to:
Incorrect timing
Spark plugs are bad (possibly coils)
All injectors arent spraying fuel but I would think it would splutter with starter fluid at least.

Any help would be greatly appreciated

Thank you

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post #2 of 6 Old 07-16-2017, 08:44 AM
lovett86
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1990 YJ Wrangler 
 
Join Date: Oct 2011
Location: brantford
Posts: 1,272
I've found its usually something simple that was missed puttiing it back together. Even something as simple as your maf sensor not being plugged in will keep it from starting. I'd go over it again and make sure all your connections are plugged in and tight

its a rusty one

http://www.jeepforum.com/forum/f22/90-yj-frame-swap-build-up-1434246/
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post #3 of 6 Old 07-16-2017, 04:38 PM
toesnthewind
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1979 CJ5 
 
Join Date: Jan 2017
Location: Orlando/Daytona
Posts: 41
Garage
If you sprayed starter fluid into the throttle body and got no sign of it firing, I would look at the spark side as was stated. A harness connector left undone, cps, or something like that. Disconnect a spark plug wire and see if there is spark. I dont think timing or fuel is the issue.

Oh. one more thing. Check your harness very carefully. You may have pinched it at some point in the head change. I have seen people change transmissions and pinch the harness between the trans and engine.
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post #4 of 6 Old 07-16-2017, 07:46 PM Thread Starter
Ice_Mage
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So I ripped off the passenger side head due to the low compression and found 1 rocker arm had come off. The timing still looks perfect according to all the marks.

Spark is fine on all cylinders (tested with a spark plug tester between the coil and plug)

I will see what happens when the head comes back from testing and put back together, hopefully it works
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post #5 of 6 Old 07-16-2017, 08:53 PM Thread Starter
Ice_Mage
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So I ripped off the passenger side head due to the low compression and found 1 rocker arm had come off. The timing still looks perfect according to all the marks.

Spark is fine on all cylinders (tested with a spark plug tester between the coil and plug)

I will see what happens when the head comes back from testing and put back together, hopefully it works
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post #6 of 6 Old 07-17-2017, 02:45 PM Thread Starter
Ice_Mage
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3 of the 4 intake valves were leaking on the passenger side head, I am hoping this was the cause of the no start condition but only time will tell I guess. I will update the thread when I know more
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