labsope for pitted valve mopar 3.6

[Dr Dave]

hey guys happy new year almost. Hey I have quite a few chrysler 3.6 jeeps and c-van coming in with misfires codes ,Most you can barley feel but most you can record on a misfire screen.. most are taken care of by a good induction cleaning and a sparkplug replace . But 1 I have wont go away . I hear that chrysler has some pitting valve issues , and I read about ocaional cam or lifter issues, I would like to be able to determine within reason fairly quickly if the misefires are of a mechanical orgine before we take the intake off to replace the plugs or coils.y first thought is realitive compression -but idont know if i want to go there because this is not a dead cylinder.My limited experience with realitive compression is your not going to see small diffences unless maybe one of the pico style bar graph sofware may give indacations?? Then I thought vacum ? I know a bad valve spring or a cam would show on a vacum gauge. But the snapon pressure tranducers are all I have.. would they work???? is there a other sensor that would work? And the big question will any of these really show a minor misfire in the mechanical side of the engine,, and what other ideals can you give me . Or how can I tweak whatI already have to help this cause...... thanks

[Dr Dave]

Ok i,be been doing some research.Seems some say the snapo n predecessors will read vacuum and some don,t or the scale reading is not correct,something about doubling the reading?????? What? Please someone ,anyone reply. I think what I really need is a wave pattern and a good and bad pattern to compare.The thing that really bothers me is how many times I pull a labscop e and the result is inclusive. I ask again can the pressure transducer give me a dishonorable pattern ?? I'm not in a place where I could afford a first look sensor right now so I take back some of my original question .just looking to see if what I have will work or a DIY sensor at minimal cost would work like a MAp sensor?

[Dr Dave]

What about reading the map sensor signal wire would that give me a readable p attern

[greasybob]

Does the data identify which cylinder is misfiring ? A running compression test on that cylinder might give a better indication of the problem than a relative compression test. A relative compression test would just verify that it is a compression problem.

[BMW JEDI]

Originally Posted by Dr Dave

Ok i,be been doing some research.Seems some say the snapo n predecessors will read vacuum and some don,t or the scale reading is not correct,something about doubling the reading?????? What? Please someone ,anyone reply. I think what I really need is a wave pattern and a good and bad pattern to compare.The thing that really bothers me is how many times I pull a labscop e and the result is inclusive. I ask again can the pressure transducer give me a dishonorable pattern ?? I'm not in a place where I could afford a first look sensor right now so I take back some of my original question .just looking to see if what I have will work or a DIY sensor at minimal cost would work like a MAp sensor?

Build your own First Look sensor for literally pennies. I made one and it works great!

[Dr Dave]

So yes #2 is missing randomly. And yes a compression test or leakdown would be best , a running comprerssion is not possible because the intake has to come off to access #2 . So I was looking for a faster way to tell I thought vacum may be able help diag,