Why do I have exhaust blowing from intake

[lwtint]

I have a 86 Buick LeSabre. The other day I drove it to the store and when I came out it would no longer run. Wont start, it's getting fuel to the injectors and good spark. I noticed when I disconnected the air box and tried to start it that the exhaust is apparently blowing back through the intake. It seems as if the engine is trying to run backwards. It is an 86 3.8L fuel injected w/ coil pack. No timing adjustments, all computer controlled. Did a compression test on the front 3 cylinders and got 30,60,30 psi which I know is bad. Anyone have any ideas on what might be going on?

 

[theoldguy]

Gheck the timing !! You might have a timing chain that slipped a tooth or two.

 

[WildKitty]

'86 = timing belt, 30lbs compression, no start = broken timing belt

:angry:

 

[BigRivy]

'86 3.8 has internal timing chain not an external belt!

 

[39CENT]

check the intake and exhaust manifolds, they must come close to each other like EGR etc. and maybe have cracked or blown a gasket, and allow the 2 systems to come together.

 

[bednarick]

I'm new

so I might be doing this wrong but does anyone know where the belt tensioner is on a 89 park ave.,with the 3800?