I was wondering if anyone knew what the timing should be at idle on my 97 discovery. When I watch it with my scan tool it is about 25 degrees. When I snap the throttle it jumps to about 50. I did not know if that was normal. Not having a dist I dont know if it can be adjusted or if my chain is streched. I have also seen some topics about adjusting the maf. Can this be done? I live in colorado and would like to tune it a little better for the mountains. Any thoughts would be helpfull.

 

The timing is determined by each cylinder by the ECU, with help from the knock sensors. So you can have 8 different advances all at the same time. But I'll do the same throttle blip on mine and report back. Don't think the MAF offers much adjustment, but cleaning it cold with MAF cleaner, and cleaning the PCV system and doing a Sea Foam treatment can't hurt.

 

Just cranked mine up in 40F outside, fast idle about 950 RPM 32 advance shown on scanner. Moved to 2000 rpm, advance went to 42 degrees. Blipped throttle and saw some change in advance, but hard to see with update times of scanner. 183,000 less than cared for miles on the motor.

 

You cant adjust the timing on a electronic ignition engine.
The ECU will adjust the idle based on conditions like air density, it can only do so much so keeping the engine in good tune is paramount.

 

Thanks for the replies. I have done a BG induction service. I had read that the test book could adjust timing but did'nt want to take it in and waste the money if it was not possible. I sometimes find it hard to belive that there is no way to tune this V8. I have seen the double throttle plate plenuims before but dont know where to get one. has anyone heard of adjusting the throttle plate?

 

I did not know you meant adjusting the timing with a re-map, yes you can do that, but if you tune it for your elevation when you travel somewhere else it will run rough.
Without a complete ECU re-map and complete rebuilding of the engine there is nothing you can do, its a 4500lbs offroad brick, its not meant to go fast, its meant to go anywhere slow.

 

What would i need to do to have that done? Where is a good place for that. I assume it would have to sent the computer out, unless there is another way.

 

The dealer can do it, or you can have the ECU sent to a tune shop but its going to cost you almost as much as you paid for the whole truck and you will gain nothing because you are not rebuilding the engine and putting in a hotter cam, lifters, etc.

 

Ok. I will call my local dealer and find out details. Thanks for all the help.