What went wrong...how do i fix it...
08-19-2007, 02:25 PM
#1
What went wrong...how do i fix it... #2 and #4 cylinder dont act like theyre hitting the headers stay cool while all the others run hot... swapped coil packs injectors plugs and wires...any ideas...this all started after heads were pulled due to #7 cylinder with no compression due to bent exhaust valve which was replaced...
08-20-2007, 11:40 AM
#5
well Id think the first thing to do is see if you got spark at the cyl. pull off the plug wires to those two cyl.s and either get a spark tester or you oculd use the screw driver method. if you do have spark, then you need to see if you got inj. fire at those two inj.s. (you did swap back the inj. harness the right way, right?). then do a compression test on those cyl.s compared to a known good cylinder. maybe you got bent pushrods? mabye the valve is burned and not sealing? also look inside the conn. for the ign. coils, Ive seen people plug those in, and bend over one of the terminals.
chris
chris
08-20-2007, 01:31 PM
#7
all new parts dont = good compression necesarily. you need to know if the valve train is haveing an issue or not. if you got good cranking compression in those bad cyl, then you can rule out pushrods, lifters, cam, valves, all kinds of stuff. you NEED to do a compression test. as well as SEE SPARK at the cyl., not just swapping parts. thats a good step AFTER you know you dont have spark to find out why, but it does not tell if you have spark at the cyl.
another possiblity is the inj.'s could be plugged too. leanign out those cyl.s only. pulling the plug will hlep you see that or not. they should be wet if the inj./harness/pcm are workign properly and you just cranked the eng. over. if there too clean/dry, then look at the fuel side.
lots of work to do buddy. sorry.
chris
another possiblity is the inj.'s could be plugged too. leanign out those cyl.s only. pulling the plug will hlep you see that or not. they should be wet if the inj./harness/pcm are workign properly and you just cranked the eng. over. if there too clean/dry, then look at the fuel side.
lots of work to do buddy. sorry.
chris
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08-20-2007, 01:33 PM
#8
Originally Posted by charlie_gonzales
we have tried all of that...getting fuel and spark
or does this mean you DO have spark and fuel inj. pulse and fire into the cyl? whats the cranking compresion on those cyl.s compared to what in the good cyl.s?
yes, the pcm can cause certain cyl.s to drop out, but I have never seen it. the pcm fires each inj. individually so the potential is there to be internal to the pcm. what I have seen is interm. misfire on certain cyl.s due to the inj. wires from the pcm to the inj. being pinched in the harness. the harness was misrouted in the back/pass side behind the head and got pinched everytime you accelerated hard.
chris
08-20-2007, 02:28 PM
#9
it is getting fuel and spark......it acts like it is randomly switching cylinders....it started with just 2 then 4 started then 5 is the last to start.....tsp checked the heads last week and the bottom end was rebuild 20,000 miles ago.....they suggested the pc might be acting up? I will try a compression test next........