Motronic and PMO ITBs

[draab29]

I am interested in getting the look of carburetors but the reliability of the Motronic system. I currently have a 3.2 Motronic with steve wong chip, bursch headers and M&K exhaust. I am satisfied with the performance level of the motor From the information I have gathered (searching threads and the internet in general) the PMO ITBs seem to be what I am looking for, but all the threads I have read discuss PMO ITBs with aftermarket, fully tunable EFI systems.

Is it possible to run PMO ITBs with the factory Motoronic DME? if so what modifications are needed. Thanks

[mamut]

Can't do., you need speed density sensing, which Motronics does not support.

[James Brown]

Not the end of the world, you can get a 2nd party controller like a Megasquirt unit that controls both spark and fuel and you can pay for it when you sell the Motronics unit and the intake.

[stv951]

bump ! I am also interested in this. You guys suggest PMO ITBs with Megasquirt ?

[James Brown]

yes that's one route. The big sticking points that many have is: you need a new dissy, you cant use the motronic controller, fuel mileage down a little, cool factor way up. Check out Al lkosmal's thread on ITB FI. this was on a 2.7 mule but can be made to work on any engine.

[DUK]

If it's a 3.2, you don't need a new dissy. Just need to lock it down and use the MS to control spark. My fuel mileage is 36 mpg highway, but I don't have ITB's just the 3.2 manifold.

[James Brown]

Woops, your right DUK, thinking of too many things!! You can also use several differant ignition control units that are out there.

[LJ851]

there is no need lock the advance mech down in the distributor, it is there to compensate for the rpm related timing changes so the rotor will better line up with the terminal that is getting spark transferred to. even with stock motronic it has this same function and has nothing to do with altering the engines timing. if i was carbing my motronic engine on a budget, i would keep motronic for ignition and permanently connect the WOT switch . this would give you a situation like a carb distributor without a vacuum advance like most weber setups use (not enough vacuum w/o a common plenum)

[DUK]

Not to say it can't be done that way LJ, but when I did that I had more crossfire than with it locked down. May have to do with my msd but I had to lock mine.

[LJ851]

it would be interesting to cut a viewing hole in the side of the cap to watch the rotor (with a timing light) at various timing advance points, but obviously your setup was proved by experience not theory. how do you like your MS ? ive been thinking about going that route myself...

[DUK]

For the money, it's the best system if you're not afraid to do some leg work. They have nailed down most of the problems out there and have enough good people now to fix the rest. I'm not the most computer savvy person and they have helped walk me thru my problems. You have a good source real close to you: DIY autotune, very helpful group of guys there.