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5.3 will crank, no start

grevels

Full Member
Joined
Feb 26, 2013
Messages
12
I was driving the other day and pulled in to drop my daughter off at school and truck started running will rough. Shut it off and it would crank over and almost start, but wouldn't. Fuel pressure is 55-60 with key on, did a compression check on cylinder 1 and it was 150. Have spark at the #1 plug. It is not throwing any codes. Any suggestions on what to check next? Thanks.
 
Not much point in checking compression and spark on just one cylinder...
 
Check the fuel pressure with the engine cranking
 
I finally got a chance to look at it a little more. Tried to start it and battery was a little low. Connected the charger up and it actually started up! It run very rough like it is missing on a couple of cylinders. I did get a P0300 error also. I shut it off 3-4 times and it started back up and run, so at least that is better than before. I did have access to an HPTuner and did some log files. It is showing Ethanol Fuel % at 23.9%. Is this too high and could be causing my issue? I have only purchased 87 Octane gas and have never run E85 in it.

Thanks,

Greg
 
What is HPTuners showing your fuel trims at?  Are they maxed out?
 
Spent today pulling plugs and doing a compression check on all cylinders. #7 has 0 psi.  :E:
 
07 with AFM. It has 250k miles on it. I have had the AFM disabled for probably the last 100k.
 
Cam and lifter issues seem to be popular on 2007

 
I just got the valve cover off. Looks like a broken valve spring. Now to find directions on how to properly remove rocker arm.
 
which valve?
dig into more then broken spring.
check those AFM lifters.
 
I don't know which one is exhaust or intake. The one on the left of cylinder 7. So you recommend pulling the head to check the lifters or is there another way?

Thanks
 
There should be color on the stem seal of the valve. Exhaust is reddish brown, intake is black. It doesnt take much strength to take off and put back on the rocker arm.
 
intake is inboard and exhaust is outboard ner exahust manifold.
 
I finally had a chance to pull the head and lifters this weekend. The lifters look fine, but I plan on doing the AFM delete. With 250K+ miles I plan on doing the timing chain and considering valve springs. Is there anything else I should replace like sensors?

Thanks,

Greg
 
I think Knock sensor under intake would be good... since you have access and can do the Silicone DAM to keep water out.
 
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