Delete Distributor on TBI?

[nvrenuf]

I know Howell offers a tbi kit with the option of "no iginition" so you can run what you want, is this possible on an OE tbi set up? I've got a fairly complete factory set up but want to use my MSD dist & box instead of the OE unit. I would need a custom chip anyway due to the camshaft so can this be accomplished thru the chip as well?

 

[dave w]

I know Howell offers a tbi kit with the option of "no iginition" so you can run what you want, is this possible on an OE tbi set up? I've got a fairly complete factory set up but want to use my MSD dist & box instead of the OE unit. I would need a custom chip anyway due to the camshaft so can this be accomplished thru the chip as well?

You can run the Howell system described above without the factory HEI. The Electronic Spark Control will need to be by-passed in the PROM custom chip. The MSD system must be able to trigger the ECM with a square wave pulse for the distributor reference signal, so once you have the MSD set to provide an ECM reference pulse your good to go.

What I don't know is if the ECM will be able to operate in "Closed Loop" without the factory HEI? It's not very likely the fuel only Howell system will operate "Closed Loop" but check with Howell to find out.

I think having the ECM being able to control both fuel and spark is one of the best benefits TBI offers over the old school carburetor and vacuum advance distributor. With a carburetor and distributor I was always tweaking a carburetor jet size or changing distributor weights and vacuum advance canisters.

With good data logging software and modified ECM hardware I can change the fuel map or timing advance with a laptop while I drive.

dave w

 

[nvrenuf]

... is this possible on an OE tbi set up? ...

I know Howell can do it, I'm curious about a factory set up that I have from a '90 "V" series truck. I have a fair amount of money invested in MSD parts (distributor, 6al, coil, fancy wires) and would like to utilize them after making the swap to tbi.

 

[dave w]

I really like my 1993 E6 TBI. Both E6 and OE have real VE tables and timing table with 289 cell in 5 KPA increments! I'm sure the OE TBI is better than the E6 TBI because the OE is used for the 4L80E! Curious, when I asked Howell about a VSS for my E6 ... they sent me to Jags that Run http://www.jagsthatrun.com/SpeedSensors_Order.html

The timing tables for OE are AWESOME, for both Off Idle and Near Idle! IMHO ... NOT using the factory distributor with OE definition file would be a HUGE step BACKWARDS ... like a dinosaur stepping into a tar pit.

dave w

 

[4X4HIGH]

If your MSD distributor was for a carbed vehicle it won't work with FI.

 

[dave w]

The MSD 6AL Ignition controller will correctly trigger the ECM, so the GM ignition module can be eliminated. I used a 6AL on a non-GM engine EFI conversion. I was really disappointed with my non-GM EFI conversion, until I converted the non-GM engine to a modified distributor using an externally mounted GM ignition module. Personal experience teaches many things about EFI!

dave w

 

[nvrenuf]

I know the box can be connected to the tbi, I'm wanting to eliminate the integrated ignition from the factory tbi. Since I will need a custom chip for the camshaft I'm curious if I can bypass the ignition. This way I could have tbi and all of my MSD ignition.

Howell offers this feature with their kits, since they use mostly GM components it would seem it should be possible with my parts.

 

[dave w]

I would change the PROM programming to disable Error Code 43 (ESC Diagnostics).

dave w

 

[bigblock72]

Lock out the advance from the MSD distributor and wire it to a TBI ignition module. Just connect your current orange and purple wires to the terminals on the ignition module that were originally connected to the TBI distributor's pick up coil, make sure to observe polarity. The coil output of the ignition module will then run the MSD box and coil. I have done this exact setup an several TBI transplants and it works flawlessly just make sure the ignition module is mounted to a piece of aluminum heat sink or the module may burn up. PM me if you want.

If you still want to do a fuel only setup (which is silly IMO) you'll need to get a filter of some sort to clean up the tach signal enough for the computer to work properly. Contact Howell or one of the TBI conversion companies for the proper filter.