new one here 97 blazer 4.3 w in the last 4 mounths i've got codes p0102 maf low input, p1870 trans coup. slippping, p1361 ic cyl not toggling after enable and one for camshaft sensor low input( don't knwo the number) started cleaning cable connections and maf sensor start the truck runs fine(this thing can stall anytime) Everything ok try to start it 3 days later, big pop , knocked, no start , smoke pouring from under hood, let the smoke clear and i found the upper manifold is cracked between the throttle body and thefuel spider, spider gasket hanging out throttle body lifted off manifold about 1/4 of a inch, no antifreeze in oil, antifreeze level is ok any ideas what might have caused this, thanks

 

Sounds like you had a pretty violent backfire into the intake. If your timing chain has stretched or jumped timing, this can happen. Did the code description read something like CMP/CKP correlation error?

 

i was camshaft sensor low imput, thats all i remember,i'm going to start pulling it apart soon, check the timing too. with all thr blazer problems i thought someone my have see this thanks

 

In all of the 4.3L equiped vehicles I have maintained and worked on for friends, family and co-workers, this is a first I have seen. But a backfire would definitely do it.

The last vehicle that I worked on that had a backfire condition was an '86 Buick LeSabre with the 3.8L v6. It actually bent the throttle shaft and blew the air box to peices! The timing set, more specifically the plastic/aluminum composite cam gear was at fault. Another by product of the back fire was busted rings on one cylinder. Lots of damage can be done.

In your case, the weakest link was the plastic upper plenum. I am betting that your timing chain is at fault. A compression check should confirm/deny this.

 

i'll check it out and report back thanks

 

Could be a faulty fuel pressure regulator. Exploded intakes happen on the GM 3.8L motors.

See this link:

http://www.bonnevilleclub.com/forum/...highlight=fire

 

it was the timing chain, replaced chain gears manifold and fuel pressure reg runs fine! thanks guys your always a big help