1porschenut

I installed a newlly rebuilt motor in my 84 with a refreshed auto trans started it and it ran ruff than slowly started to run a little smother is that normal or not

928mac

well it is normal on a push rod engine but not on a over head cam engine.
still there could be air in the fuel line, or a stuck injector till it got wet, possible that one of the valves did not completely seal right away.
also with a cold engine and forged pistons the fuel will not atomize right away and the compression may be low I suppose but doubt it.
watch the oil pressure (should be maxed ) watch that the cooling system bleeds and that the engine dose not get to hot.

blown 87

Every 928 engine I have built fired right up and ran right except for lifter noise at first.

I guess it depends on what you are calling a "Rebuilt" engine.
So the answer is that it should run right after few minutes of a short drive.

Jerry Feather

Every time I disconnect and reconnect the battery in my S4 it takes a short while for the computer to sort itself out upon restart and usually not until I drive a mile or so. Jerry Feather

Speedtoys

JF

This always makes me wonder...

Every, EVERY other car ive had, I do that, I get the same result.


ON my 88S4 Auto, if I pull the ground strap under the toolbox in the back for 10min, plug it back in...it'll start and run like it was any other day.

No hint of "I forgot how to do this.." at all. Always wondered if I actually did it right or not.

James Bailey

I have never seen a good explaination of how adaptive the adaptive part of the L H Brain really is.......and then certain functions like wide open throttle may not be adaptive at all

1porschenut

Another question I have is that when you turn the key on but not starting the car all the gauges set at the bottom except the oil gauge is at the top is that normal or not.

dprantl

I believe the main reason for the LH 2.3 adaptation is to compensate for wear of system components. If everything in the engine is working 100% like it did when it left the factory, there will be no adaptation required and the car will run the same whether or not it has just had the battery disconnected. If some parts in the car are worn and you reconnect the battery, it takes a while for the LH to get used to this wear. For example, as MAFs get older, they tend to read a little leaner and LH uses O2 adaptation to compensate for this. It's not a bad thing since the LH was designed to be able to handle this to a certain extent.

It is very easy to observe this adaptation when working with a SharkTuner. Oh, and let me tell you it has a pretty damn big range to adapt. I can set my base map off by 30% and it will still keep the O2 sensor in spec.

Dan
'91 928GT S/C 475hp/460lb.ft

1porschenut

Ok thanks everyone for your answers

RKD in OKC

You got your car back?

1porschenut

No the Trans that I bought and put in does not work I got to drive it but it would not leave the subdivision under its owen power

RKD in OKC

Oh man...bummer. That new job makin enough more $$$$ to get one that works quickly?

1porschenut

I think what we are going to do is put in the old trans that we know that works