GM OBDII ECU crazy garage fitment thread

well now that the V8-S10 is up and running I have focused back on my fairlane (has been sitting for over a year pretty much) I am looking to turbo the CrossFlow 250 I have at some point in time (already have the turbo and wastegate) but need a better controller for the EFI then the factory EEC4 setup.

I have been brainstorming about using a GM OBDII box as used in the Vortec Gen 1 trucks and vans (since I have a pile of them laying around from my truck build along withthe tuning software/hardware and misc bits)

The way the system works is there is a 3 tooth reluctor on the crank that fires the coil and provides the timing input to the ECU. this wheel mounts between the balancer and the tiing set (balancer must be trimmed down the thickness of the reluctor to maintain accessory alignment) The cam sensor is a "1" tooth reluctor setup that simply provides the needed info for firing order (IE first 3 cyls or last 3 in the two rev cycle) It uses a basic common GM temp sensor and MAP sensor along with TPS and all that. The MAF is used for idle mixture and some of the closed loop operation. it can be tuned out for a speed density tune but you then loose the ability for the ECU to follow a good set of tables if you change anything.

It may be possible to convert a EEC4 distributor to work with this (as they both use a similar Hall Effect sensor) which would make this much simpler. The stock GM unit is a plastic body with crap style cap and remote coil that is fired off a coil driver of its own.

So the plan right now is to see about fitting the crank reluctor to the XFlow motor and timing cover and then blending two distributors into one (IE a ford shaft and bas with a chevy top half and shaft) the big issue I am seeing is fitting the crank sensor behind the stock balancer as there is not alot of room there the way ford packaged everything. I have a spare XFlow block I will be mocking this all up on. so far it looks like the reluctor will fit the crank ok but I need to find out the location of the keyway (IE are the both straight up at TBC?) so I can figure out where to locat the sensor. I might have to cut a new keyway on the reluctor and rotate it around so I cna mount the sensor in the top of the timing cover (it is just a sleeve and hold down bolt....Hello JBWeld)
 
Kstang and myself are working on a similar track to you. I have some sensor samples coming in from the Phillipines, but I swear they are taking a clipper ship around Cape Horn to get here. I mean, honestly, how long does it take to send about 4 oz's of sensors?

While initially the system will be for the 200/250 US blocks, I do have a xflow 250 in my garage now (looking for a car to shove it in) that I will be making the system for as well, once I get the 200/250 kinks worked out. System is 99% done, just need those damn sensor samples to arrive so we can test the one unknown. Everything else is designed, priced, waiting for confirmation that the sensor will work as I was told they would.

Once we get the prototypes working, and running the ignition, time to move to the EFI manifolds for the OZ heads.

However, we are still heading to the MS2/MS3x for the ECU. The GM ecu is a nice, simple, and from I've seen a fairly easy system to modify and adjust (as opposed to the ford systems). Nice stable platform. However, why would you want to go speed density if you are going to have a MAF as well (not being sarcastic, honest question)? At least IMO (uninformed as it may be) MAF is a superior system since the adjustability is far greater. Though, guess you still need the MAP if you are going with a turbo. Does the GM ECU have the ability to control a wastegate? Or are you going to go with a wastegate controlled directly from the manifold pressure instead of the ECU?

I haven't had a chance to dig into my xflow yet, but do you know how different the dizzy is? Particularly, the shaft/oil pump drive? Still a hex drive at the bottom?
 
the MAF sesnors aren't a big fan of being blown through. it is a total option to run one or not....I most likely would but it is just a matter of checking a box in the software to enable/disable it.

I haven't opened the XFlow EEC4 dizzy but it looks more like a points cap then a tall ford style eec4 cap.

the GM sensor is nice since it mounts flat to the bottom of the housing with two screws and two dowels. putting one into a gutted points body might be doable. The GM cap is a crab style and the big killer will be the fact the firing order is split on it (even and odds for each bank) being an inline you will have to cross the wires back over again.

another reason for the GM stuff is it is all proven. with MS you are kinda on your own a little. I can always get a backup ecu from a parts store and flash it if I have to. all my sensors will be GM off the shelf parts I have piles of laying around here from some parts motors and JY trips. Also for me it will be nice to only have to learn one software package for my fairlane and my s10.

My wastegate will have to be controlled by manifold pressure but that kinda falls into the KISS column. tuning for boost is a 10 minute job.

I would love to try MS but I kinda see it as Linux.....people might have a linux box running but it is not the daily driver and just something to play with. I think being able to plug a scanner into the OBDII port in any shop and troubleshoot will be nice too. beats havng to drag a laptop and cable with me everywhere (granted I will still need to do that if it is a tune issue) I can grab ECU's at the pick n pull for $25 a pop. for another $75 or so for the credits to flash it I can have a spare backup ECU on hand.

I am playing just the same as you guys are. right now I am debating skipping the cam sensor and just running in batch fire mode so I will only need the 3 tooth crank wheel (might just mount it external to the motor) right now I am focusing more on getting my front suspension and brakes back together so I cna drop the crossflow back in the car and get it running on the stock ford junk for now. I haven't driven this car since Tokoyo Drift came out.
 
Put the MAF upstream of the turbo. Then it doesn't matter. That's how my volvos are. That way it meters the true air flowing into the engine and the pressure won't matter.

Yeah, the GM stuff is nice and I like that idea.
 
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