99 XJ cranks but no start after head swap
10-06-2017, 08:25 PM
#1
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99 XJ cranks but no start after head swap
hello all,
i apologize if if there is already a thread on this topic, but I have surfed a lot of them
and tried the suggestions to no avail.
Here it goes,
it it started out with a coolant leak someplace on the
back of head, or head gasket (couldn't get back there to see where exactly it was coming from). So i set out and did some research and found that the 7120 head allows for more airflow and would preform better than the 0630 the hero came with. Since I already had the 7120 it was decided that we would use that head in place of the 0630.
We took took the head to the machine shop and had it pressure tested, resurfaced and a valve job done on it. It passed the pressure test. So we proceeded with the head swap. We used the gaskets for the 7120. We made sure that all gasket material was scrapped off the mating surfaces.
since we already had the thermostat housing and thermostat out we went ahead and replaced it. Same with the water pump and the hoses.
After we we got all that done, we started to fill it with coolant.
We we couldn't get the capacity so we wanted to start it and get the coolant throughout the system and add what we needed too. But Low and behold we could not get it to start. All it does is crank until the battery dies. We double checked the spark plug order, we got it right. Checked for fuel rail pressure, it has pressure.
Found on other threads of similar issues that they changed the battery cables and the problem was fixed. Tried resetting the pcm. Swapped out the battery for one we knew was good. Rechecked the firing order.
After all all of this was done we got to where we are now, stuck and have no clue where to start to try to fix the issue.
Thank you you for your time and hopefully as a community we figure this out incase someone else has the same problem I am having.
i apologize if if there is already a thread on this topic, but I have surfed a lot of them
and tried the suggestions to no avail.
Here it goes,
it it started out with a coolant leak someplace on the
back of head, or head gasket (couldn't get back there to see where exactly it was coming from). So i set out and did some research and found that the 7120 head allows for more airflow and would preform better than the 0630 the hero came with. Since I already had the 7120 it was decided that we would use that head in place of the 0630.
We took took the head to the machine shop and had it pressure tested, resurfaced and a valve job done on it. It passed the pressure test. So we proceeded with the head swap. We used the gaskets for the 7120. We made sure that all gasket material was scrapped off the mating surfaces.
since we already had the thermostat housing and thermostat out we went ahead and replaced it. Same with the water pump and the hoses.
After we we got all that done, we started to fill it with coolant.
We we couldn't get the capacity so we wanted to start it and get the coolant throughout the system and add what we needed too. But Low and behold we could not get it to start. All it does is crank until the battery dies. We double checked the spark plug order, we got it right. Checked for fuel rail pressure, it has pressure.
Found on other threads of similar issues that they changed the battery cables and the problem was fixed. Tried resetting the pcm. Swapped out the battery for one we knew was good. Rechecked the firing order.
After all all of this was done we got to where we are now, stuck and have no clue where to start to try to fix the issue.
Thank you you for your time and hopefully as a community we figure this out incase someone else has the same problem I am having.
10-06-2017, 10:37 PM
#2
CF Veteran
Many people have had, and are probably currently having this problem. It is called a "crank-no-start". The steps to figuring it out are generally the same, regardless of what might have taken place prior.
1. Check for presence of spark
2. Check for fuel delivery (both pressure (with a gauge) and injector pulse, or by using starter fluid in the throttle body to see if any combustion occurs).
3. Check for air delivery
There are a few other things to check for, but 95% of the time your next diagnostic steps will be determined by doing those 3 things first. One of them will typically be missing.
Your post didn't mention checking for the presence of spark, only that you checked/rechecked firing order.
1. Check for presence of spark
2. Check for fuel delivery (both pressure (with a gauge) and injector pulse, or by using starter fluid in the throttle body to see if any combustion occurs).
3. Check for air delivery
There are a few other things to check for, but 95% of the time your next diagnostic steps will be determined by doing those 3 things first. One of them will typically be missing.
Your post didn't mention checking for the presence of spark, only that you checked/rechecked firing order.
10-07-2017, 04:57 PM
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Figured it out. The book had the distributor cap markings in the wrong place.
Runs now now but runs rough at idle and when you drive. Unless you keep RPM over 2k. I'm thinking it's time for a plug and wire and cap and rotor change.
Runs now now but runs rough at idle and when you drive. Unless you keep RPM over 2k. I'm thinking it's time for a plug and wire and cap and rotor change.
10-08-2017, 01:25 AM
#6
No, I don't lick fish.
Was it running rough before you did the head swap? If it wasn't, there's probably another issue some where. Worn cap and rotor will not "all of a sudden" cause a rough idle. Check your spark plug gap and inspect the condition of the plugs as well as the cap and rotor before buying replacements and getting the same results. Also inspect the coil to see if there is any cracks in it.
I had a misfire that was driving me nuts until one night when I had the hood up and noticed an intermitten "flash". Turned out my spark plug wires were up against something metal and grounding out THROUGH the insulation. The wire would glow blue right where the wire was touching the metal object. Couldn't see it with any lights on.
I had a misfire that was driving me nuts until one night when I had the hood up and noticed an intermitten "flash". Turned out my spark plug wires were up against something metal and grounding out THROUGH the insulation. The wire would glow blue right where the wire was touching the metal object. Couldn't see it with any lights on.
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Glad you got it figured out!
10-09-2017, 08:49 PM
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Small other problem changed plugs and wires and it’s saying there’s a misfire in cylinder 6. Now I gotta get a compression tester and test that. Wish I knew all this could happen before the head job.