Sick

[Keith Nuttle]

When driving in the mountains it is not necessarily the elevation but the grade. Given elevation effects the fuel ratios as the air is thinner.

[dpb]

On 5/10/2012 7:25 PM, Leon wrote: ...

Indeed; I can't believe I wrote that; certainly wasn't what was intended.

I've not found any reference to dealer-swap PROMs for curing altitude sickness which makes me think it isn't/wasn't the common cure.

I recall working on some of the GM MC6809 firmware while still at uni for the SAE competition and there were some data tables already stored in there that were switchable if need be by a software machination but no PROM switch. That was clear back in the late 60s; can't imagine it didn't get much more sophisticated than that very quickly and leave the actual need to swap anything out behind ages ago...

Carbs may have had jets changed out if mixture couldn't compensate enough...

--

[Ed Pawlowski]

Just put it on my "to do" list. I do want to get out that way and this just adds to the reasons to go.

[Leon]

Well to give you some credit, when switching out jets it is not much much more effort to adjust the idle while you have the sir cleaner off.

I am/was refering to the early to mid 80's when computers were first widely used in most all GM vehicles. I was the parts manager and later the service sales manager for an Olds dealer in the 80's, prom swaps was not at all uncommon. There was basically no reprogramming going on in the dealerships other than changing the prom and or resetting the ECM. There were location specific factory bulletins that indicated a prom swap if the vehicle was not normally operated in a location that it was originally shipped to.

[Max]

The 4.3L V6 that GM produces won't get 18-19 MPG even if it's downhill all the way.

Just my personal experience.

[Max]

On US-550 over Red Mountain pass pulling a 27' travel trailer with a

2009 Ford F250 Super Duty.

[clare]

Somebody else is getting better mileage on a PT with the pedal to the metal than in easy cruising!!! Everbody said I was crazy when I reported 35+ MPG on 2 tanks chasing the tail off the thing through the hills of new brunswick and maine/vermont while getting less than 20 at the speed limit coasting out the 401 from Toronto to Montreal.

[clare]

Just adjusting the idle MIXTURE could often get you by - it richens the bottom end enough to make the engine run and resond better, but does not get the full power back at higher speeds.

Pulled 17 foot Bonair to the west coast with 3.0 liter Aerostar, never below 50mph even on 4th of july pass, or is it called independence pass - can't remember. LONG STEEP SUCKER!!!!

[Keith Nuttle]

The gas mileage depends on the rear end ratio. I believe the same transmission is in all of the Astro/GMC Safari Vans with the same gear ratios. The standard Rear axle ratio, was 3.42 but there was an optional 3.73 ratio. Makes a difference in gas mileage.

[Max]

Did I ever tell you about the 14.5 lb. brook trout I caught?

[Keith Nuttle]

Glad to hear about it ;-)