trickster555

I am the proud new owner of a k5 blazer and joined this forum for it's incredible wealth of knowledge concerning tbi's. I want to run propane cuz it's cheap here in Montreal but i am running into a problem concerning timing. I bought a used impco kit for a carbed 350 and had to buy a tbi adapter. My problem is with timing. I need to advance it to take full advantage of the propane conversion. I plan on using the truck as a switchable dual fuel vehicule so in essence be able to flick a switch to change fuels. There was a module that piggy backed the ecm in the past but it is now discontinued and I don't want to spend a fortune for a MSD timing adjuster or expensive aftermarket ecm just for a few points of timing. Is there a way to fool the distributor or ecm into doing this? I am well versed in electronics so even hard to accomplish solutions will be appreciated.

Ronny

iTrader: (1)

No need to fool. Just advance timing at the distributor. Disconnect the brown plug so ECU is not in control. Then reconnect. Years back i ran a hyperchip with cold therm and they suggested advancing in that manner I think 2-4d....

trickster555

I also run 87 octane gasoline so 15 degrees of timing is going to give me detonation. That is why I want to have switchable timing on the fly

RBob

iTrader: (1)

The easiest way to do this is via either two PROMs or a larger PROM with a switch. This way you can have a gasoline tune in one PROM/area, and a propane PROM/area to use. A flick of a switch can be used to select which one.

I though that Craig had something like this (www.moates.net), but looked briefly and didn't see it. Best to email with your current set up and ask about a BIN/calibration switcher for it.

Craig just supplies the hardware, IIRC, tuning/PROM-burning is up to you.

RBob.