1998 venture 3.4

[willrc]

A buddy of mine installed a 3.1 lower end on this and now it runs but is very rough. The original engine had spun a bearing after the intake gaskets went.
can the convertor be plugged/ or any help would be greatfull. thanks rich

[IsaacHayes]

If he swapped the whole 3.1, block, then what year 3.1? If it was a 3.1mpfi then it will lack the provision for a cam sensor, and 24x crank sensor....

If he just did the crank/rods/etc then it should be fine, and some sensor or other issue is at work...

[willrc]

the 3.1 was out of a 97 van. 24x crank sensor?

[bszopi]

A 97 van was never available with a 3100. only 3400.

[willrc]

well i thought it was but it was over a year ago

he started the project over a year ago. just trying to get it going

[IsaacHayes]

If he DID get the parts out of the 97 van, it was a 3400. The 3400 will have a crank that says 3.1l on it as it's the same part (stroke).

[willrc]

98

the engine came out of a 95 van. there is a wire at the back of the engine that looks like a early oxygen sensor wire. is this supposed to be hooked up?
Thanks rich

[bszopi]

You will not have good luck running an engine out of a 95 van with the 98 ECM, as from what I remember, the 95 vans still had the old 3.1MPFI engines. This then goes back to what Isaac said in port #2. The engine lacks sensors that the ECM is looking for.

[IsaacHayes]

1995 Lumina had 3.1mpfi from what I gather (120hp).

That means it's a gen2 engine. Means you need custom length pushrods, and that you are lacking a cam sensor, and a 24x crank sensor on the engine....

I would grab the 3400 block, and swap in the 3.1's crank and rods (I think the rods are the same, I KNOW the cranks are).


Bascially the ECM is looking for a CAM position sensor that is NOT there, for fuel timing, and a 24x high resolution Crank sensor for spark and idle control....

Or did he jsut use the guts and not the whole block?