Quote:
Originally Posted by gabedrummin
I connected the durametric and it shows cylinder 4 with misfire's . I do have to admit I don't know what I'm looking at . I'm not a professional mechanic and I don't understand what I am seeing when using the durametrics software .There is a box for each cylinder .I put a check in each box at the left for each cylinder ,on the right side of the page is a box and for each cylinder and for cylinder 4 I see the number counting up .So I assume there is a problem with cylinder 4 . I don't think I used my words right to explain the problem . When I try to accelerate the engine runs choppy its not revving cleanly .What I said was a bog is the engine not having that snappy response when you hit the gas . I hit the pedal fast the motor cant rev fast because its back fires thru the intake as the engine rpm increase and once it gets above 2 thousand rpm I don't notice it running bad .When I press the gas slowly the motor has time to accelerate . And I don't hear backfires. So I guess you are all right its either a bad injector or I have a dead cylinder . I guess I could change the coil pack to another cylinder But I doubt the miss fire will follow the coil .I don't think its timing or it should show one or both banks with a problem ? Porsche dealer had said multiple cylinders were misfiring but I don't see that . I see one. If this was a fuel pump problem I think all cylinders should have an issue .When I had the heads off the car all the cylinders looked great no scuffing no scoring a nice even colored wall . I have been a tool maker for 35 years and understand making parts and the walls were not worn . I so do appreciate all your help and patience helping me .Thank you all
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A backfire thru the intake can only happen from:
Bad ignition timing
Bad intake valve timing
intake valve sticking open
collapsed intake lifter
weak or broken intake spring
something that allows the burning fuel/air to leak past an intake valve.
Something that prevents the intake valve from sealing properly at the correct time during the combustion of the fuel/air mixture.
any one of these things could cause a misfire.
If you have backfires into the intake you have one or more intake valves not fully sealing or not sealing at the correct time.
A vacuum test should show a ticking needle every time that cyl. comes on the intake stroke.
If you have multiple valves out of time or not sealing you will have low vacuum possibly with a steady needle or possibly with a drifting or ticking needle.
A compression test should also show lower compression for that cyl. or cyls if the intake valve-valves are not sealing or are out of time.
So at this point I think a vacuum test and a compression test on all cylinders is very important to try and pin down your issues.
Until we know that you have proper vacuum which relates to proper compression, we are going to chase our tails.
When a cylinder does not fill properly with the fuel/air mixture at the correct time,or burn at the correct time it can look like many many other issues.
I think cylinder 4 misfires are caused by an intake valve issue the fuel air/mixture is not burning correctly leading to the raw gas smell.
Which is leading us to think you have injector problems.
Is cylinder 4 one of the plugs that smell like gas??????
So you could have more then one issue.
Intake valve issues on at least number 4 cyl. and possibly fuel injector issues.