I have done somewhat of a rebuild on a 2.8l v6 I know I have the timing right, I never took the distributor out, however i changed the timing chain, gears, and guide. I have a feeling my valves are not adjusted right, ive adjusted twice, first time by the book, wich was way wrong, the second time, I did it the way a mechanic told me too. I have done valves many times before and never had this problem. My question is: Could this be caused by bad plugs and wires, or a simple vacuum leak? Any advise will be appreciated...

 

are you sure you have the firing order right you didnt cross a plug wire check that first.

 

Yes I'm Sure the firing order is right, ive went over it 20 times, and its actualy one of the easiest ive ran across, I'm gona try some diferent plugs and wires in the morning, see what happens, also think I may have a leak in the decelerator valve

 

timing is probly off,just because you didnt remove the dist doesnt mean its still right,putting a new chain in removes all the slack the old one had and depending on how bad it was could throw the timing off a bit

 

I appreciate the thought but I know for a fact the timing is correct I spent alot of time ond research on this engine, If i didnt take the distributor out then it never left the cam or distributors position. If anything it shud have improved the timing. On the other hand it stil has the same plugs in it, and like i said in my initial thread the valves may stil not be right but I do Appreciate the advice I will check the timing again to make sure its right. It shud have rotated with every movement I made with the cam and crank gears, I am pretty sure its correct its not a bad backfire and only does it when you get on it otherwise runs better than it did before I started

 

just ajust it a little it may only be off like 4 degrees take it for a wot run see if the back fire is still there.from experiance ive learned engines want there own timing.

 

could be carbon tracking in the cap but sounds a lot like a timing issue, im going to go with affliction1 on this one try moving the dis. a little and see what happens couldnt hurt.

 

well if any one knows any thing about cars at all will know that when in pops out the intake its out of time weather its dist or timeing it self on the chain or belt . but if its out the tail pipe we all know better if you know anything about cars.

 

Havnt had a chance to mess with it yet but im gona go with affliction diagnosis and try the dist I hope hes right dont wana have to tear this thing down a third time...

Just after I wrote this first part I went outside turned the distributor and bingo! Runs perfect Thanks So Much Affliction I didnt figure it wud be off the little bit wud cause it to backfire like that, I now have faith in you. Thanks again!

 

glad you got it gion like i said earlyer timeing weather its the dist or timeing it self will always pop out the intake glad its running now!

 

Thanks Bro! Im real happy myself after 9 months of not having a way to get it done and not having the time to do what I wanted with it. Ive got an engine and trani built that shud last me a good deal of time now, Full engine gasket kit, new push rods, valves, valve seals, timing chain and gears, timing guide, all new freeze plugs, and a junk yard trani my black beauty is ready for the road again. I feel I made a good choice by stayong with this website and using the forums for advice! Thanks to all that gave there advice!

 

ya i know ive known of this site for a very long time now its grea t but ive never joined but ya love it love cars esp pontiacs and gm

 

no problem,glad to help