Do any of you guys know how I could possibly hook up 2 TBI's to one ECU? I am scheming up a different Ford 300 setup, where I will be using a Clifford dual 4bbl intake, 2 GM TBI's from 3.1l engines, and hopefully one ECU (GM#1227747). Is there a way to maybe "piggyback" 2 ECU's or where can I get an inexpensive flyback board for use on one ECU? I have tried Megasquirt with hardly any success. The farthest I drove my E-150 with it was 6 feet, never ran good enough for me to drive it around comfortably. I was running an MS2 PCB 3.0 from a kit, so maybe if I bought all pre-assembled stuff from DIYAutotune it would solve my problems. Then I know I would be able to run 2 TBI's, but I just have had bad luck with my MS. Anybody else have good success with an MS?
GM TBI question
- Thread starter 84FordVan
- Start date
My guess would be IF you could get the driver circuit to survive driving 4 injectors you may still have problems getting the rest of the ECU tuned to operate the way you want. I did not get really deep into the GM programing. It looked to be sort of a pain with chip burning and all and people in general did not seem real excited to share the knowledge. My guess is the adjustment range in the factory computers is not that great. Remember most of the design was done in the early 80's so by computer standards they are stone age. The MS2 is a super computer compared to most of the TBI stuff.
Other than a learning curve on the programing and install (stupid mistakes because I did not read carefully) I have not had any issues with my MS project. I did loose some use time on mine because of a sized oil pump but after I finally got that fixed the MS worked fine. I think I had a cam timing problem on my original engine because there were always odd things I could not tune around. After I tore it down to fix the oil pump carnage I apparently got the cam timed correctly and things just fell into place.
If you have no other options and are not in a hurry I would be willing to have a look at your MS board. My car is in winter storage so I dont have anything to plug it into but I do have the stim. I have plenty of projects going so it may take a while to get to it but if its just collecting dust now....
Other than a learning curve on the programing and install (stupid mistakes because I did not read carefully) I have not had any issues with my MS project. I did loose some use time on mine because of a sized oil pump but after I finally got that fixed the MS worked fine. I think I had a cam timing problem on my original engine because there were always odd things I could not tune around. After I tore it down to fix the oil pump carnage I apparently got the cam timed correctly and things just fell into place.
If you have no other options and are not in a hurry I would be willing to have a look at your MS board. My car is in winter storage so I dont have anything to plug it into but I do have the stim. I have plenty of projects going so it may take a while to get to it but if its just collecting dust now....
Hey is it a possibility that my timing for my MS2 is not in sync? I never messed with the timing offset while programming it. I am running about 30 degrees advance at idle, due to the engine being worn out. It otherwise won't run right with much less. I can run it all the way up to about 45 degrees and it still doesn't predetonate audibly. Maybe I need to get my new engine done next month and try it again.
Are you using a stock DS2 with mechanical and vacuum advance? Are you using a HEI or Duraspark module? Or are you using the MS2 to direct control the coil so you just have the purple and orange dizzy wires going direct to the MS? If you are doing direct coil control you need to lock down the mechanical and vacuum advance in the dizzy. You then need to 'index' the dizzy and get that offset correct. The offset is the timing between when the pickup coil in the dizzy sends a signal to the MS and where the base TDC is on the engine. The MS then adds what ever curve from the advance table to that and in theory the timing is correct. If that offset is wrong (and you still have the mechanical advance) the dizzy signal may be say at 30* from TDC and the tables are adding another 30*. That would obviously cause troubles. The indexing is getting the terminals on the cap aligned with the rotor when the system fires. You have to get the offset and timing in the ball park for this. Easiest way is to hack up an old cap. Pick any terminal and hack out as much plastic around it so you can get a good look at the rotor as it comes by. You then use a timing light hooked to that terminal and see where the rotor is in relation to the terminal when it fires. You may find that its sort of between terminals so its a random shot if it goes to the correct one or the next one or it may just not fire because its not close to either one. To fix this with MS is pretty easy. You just rotate the dizzy the proper direction to get the terminal closer to where the rotor is. Rotating the dizzy will also move the pickup coil and change the timing but with MS you can then change the offset to get the timing back on. If you could not adjust the offset you would have to be able to move the pickup coil inside the dizzy to keep the timing reference correct. I have seen it done with modified parts from the vacuum advance.
Hope I was able to explain this correctly. It can be sort of difficult to grasp at first but once you got sort get it its really pretty simple to understand.
Hope I was able to explain this correctly. It can be sort of difficult to grasp at first but once you got sort get it its really pretty simple to understand.
Yep offset is for direct coil and also likely important for sequential multiport. Your current setup should be fine. You are doing what I am doing on my caddy. Im running a 2bbl TBI which a stock HEI dizzy which is functionally and feature wise the same as a duraspark. I have an electronically controlled dizzy to fit my motor and its on my to do list but its a fairly long list so I dont know when I am going to get to it. I rig is running pretty good as is but I bet I could get just a bit more performance if I could really get in there and tweak the timing curve.
