Holley Engine Management Commander 950

[Timberwolf]

Anyone using it? any success or failure stories?

 

[Timberwolf]

noone?

 

[bruce]

Originally posted by Timberwolf
Anyone using it? any success or failure stories?

So far Holley's been a loser in EFI, IMO.
They bought out Cutler, who's ideas were novel, were poorly executed.
The early TBIs, were just slightly better then comical.
Then they come out with a series of EFI related materials, and ignition stuff, and then cancelled that product line.

So far they're track record is that of failure.

While the Commander might be good, there are just so many others with strong track records, it's hardly worth the gamble in alot of guys eyes to even play with it (or so it seems).

 

[64duece]

I've used it on a bunch of 4, 6 and 8 cyl stuff. As a base box (especially if you run high impedance injectors) it's a hard deal to pass up. A Cmdr950 system w/ WBO2 can be bought new for about $1250 using the Innovate controller.

Feature wise, it has alot of options FAST doesn't. Internal datalogging + 2 analog datalogged inputs, programmable MAP scale, 1 pulse per 2 revs etc (will idle bigger injectors better than a Fast BtoB). I like alot of what the other boxes offer but, this setup gets the job done without giving anything up.

I've made 1600hp running 160lb injectors w/ the Auxillery injector driver. I've not dealt with Holley's older stuff nor, there ignition stuff but, I can say the Cmdr950 is probably the best deal out there for what it offers. Even with the Aux driver, I had less than $1900 into it. My WBO2 comes out to tune anything else I want and the replacement sensor is a whole lot cheaper!

 

[65malibuss]

Is it compatible with Buick GN Ignition?

How is the Commander 950 ECM connected to the Buick ignition system? Is the Buick CCCI compatible with the Commander 950 ECM? Does it all plug together easily? Or does an aftermarket ignition system need to be installed?

 

[RickWI]

Just go here: http://www.chevytalk.org/threads/postlist.php?Cat=&Board=UBB12

Doug is the moderator and the lead guy from Holley on the 950 system. He's a great guy and will answer all your detailed questions on the system. I to think it is a great bang for the buck aftermarket system.

 

[65malibuss]

Use Distributor with GN Engine?

I spoke to Doug (dougflynn@holley.com).
He said that the Holley Commander 950 is not capable of operating the Buick Grand National ignition system.
All of the people I've been able to find that use this system have engines with distributors, including the 4.3L turbo GMC and Chevy trucks.

Maybe it would work if a distributor was used with the 3.8L Grand National engine instead of the cam sensor? Does anyone know if that's possible?

 

[TurboTR]

I wonder why not? We had one on a F*rd TFI system, which is similar. The coil module IS the "distributor" in our case. So the 950 doesn't even have to know what it's driving- it just provides the spark signal at the right time on a single line. Maybe it just does not have the right polarity to drive the EST; in that case maybe a simple inverter could be used to correct that. The TFI crank pulses also occur in the same spot as the Buick pulses.

TurboTR

 

[65malibuss]

Ford TFI

Does the Ford TFI have an actual distributor that rotates?
If so, that may be the reason the C950 will work with it and not with the Buick, since the Buick doesn't have a rotating distributor and I wouldn't have anything to plug the spark plug wires into if I tried to bypass the stock Buick ignition module.

 

[TurboTR]

Yes it does. And the Buick has an electronic version- the coil module. There is only a single EST line in either case, so the ecu has no idea (nor does it matter) how the spark actually gets distributed to each cylinder. That happens downstream of the ecu in this case.

They may also have stated that because the Holley may not have a "Bypass" output like the stock Buick ecu has. That's also probably trivial to get around, assuming the Holley can make sparks happen properly at cranking engine speeds

TurboTR

 

[ijames]

Is the 950 batch or bank-to-bank only? So long as it doesn't try to do sequential injection I would guess that it should work. The stock ignition module takes the cam and crank sensors and does the sync up so the module knows which cylinder to fire with each est signal (just like the mechanical distributor does). Like you said, cranking est handoff might be an issue (but why couldn't you tie the assert line so that the 950 is always in control instead of letting the module handle cranking, and thus avoid the handoff?) and are there any limits on the initial reference angle that would make the 950 not work with the stock Buick 10 degrees btdc (or whatever it actually; I'm feeling too lazy to check that number )? Anyway, just wondering out loud.

 

[65malibuss]

The 950 does not do sequential injection, I believe it fires all 6 cylinders at the same time and there is a choice of once per revolution or once every other revolution. I think the latter allows larger injectors to be used.

The Buick ignition module controls timing while cranking, and when the Buick ECM gets a "good cam sensor signal", the Buick ECM sends a 5 voltage reference signal to the "bypass" wire connected to the Buick ignition module, which tells the Buick ignition module to use the EST signal from the Buick ECM.

The Buick ECM also has high reference and low reference wires.
Does anyone know what these do or how they work?

The 950 actually has a bypass wire also, but I don't know if or how that could work with the Buick ECM.

What I'm wondering now is how often is the EST signal sent from the Buick ECM to the Buick ignition module?
Once per crank revolution?
Or 3 times per crank revolution since the buick crank has 3 "triggers"?

I'm not giving up yet.
Thanks for any advice.

 

[ijames]

I think you will have to look at ref hi and ref lo with a scope to see if the lo is simply the hi inverted to form a differential pair, or if they have different timings. Since the cam signal is not differential my guess is that they do have different timings. They both go to one chip in the ecm that also handles the maf signal, and generates the est and bypass signals that go back to the ignition module, along with a signal for the fuel pump relay trigger circuit and a couple of est signals that go to another chip. Finally, ref lo is also used along with the cam sensor signal cam hi to generate a camsync signal which also goes to the fuel trigger circuit. Using ref lo in that manner means that it is not simply a ground line - maybe for interfacing to an aftermarket ecm it gives a second choice of base timing and signal polarity?

I've always read that the ecm waits until the rpm is over 400 before asserting the bypass line, not just until it gets a cam sensor signal. I understand that this bypass is part of "limp-home" mode, since the module can do a fixed 10 deg BTDC timing to keep the engine running if it loses the bypass input, but what I was suggesting earlier was that if the 950 couldn't do the bypass stuff this input could be hardwired on so the 950 always did the timing even during cranking.

Again, from reading my belief is that the ecm sends 3 est signals per revolution. Besides controlling the timing the est also determines the dwell, how long current builds up in the coil before firing, and this would have to be done for each firing or 3 times per revolution.

If the 950 only does batch firing it does not need a cam sensor since it doesn't care which cylinder is firing next - that's what the distributor handles. Like Todd said, I don't understand yet why the buick dis can't do that.

 

[TurboTR]

So yes, the bypass could be tied off and it should work as long as the ecu can then make sparks happen properly at very low (cranking) speeds. In fact this is how my own FAST setup is currently, since we've used the Bypass line for another output. And yes, the ecu sends out one EST pulse per firing event, so 3 pulses per rev on a v6. Next question, the polarity (and level and drive capability) of the EST signal would also have to be correct to work properly on the Buick application. If I recall, the Buick EST may be an active high signal to start the coil charge or dwell, then when it falls back low the spark happens. But this is opposite to how a generic "points" type trigger output would act, which goes active low to start the dwell, as in when the points would close to start charging the coil primary, then it lets go (back to high) for the spark, as in when the points would open. So there may be a polarity issue between the Holley spark trigger output and the Buick coil module EST input. If I recall, the F*rd TFI system fires the coil on the rise of the SPOUT (SPark OUT, their name for our EST signal). There are 2 versions of TFI module, an early one that does not use CCD (computer controlled dwell), and the later ones that do. I assume the Holley can probably handle CCD, but not sure.

TurboTR

 

[ijames]

The chip that creates the est and bypass signals runs off of +5V, and the est output has a pullup resistor to +5V, so those must be 0-5V and not 0-12V. Seems like a simple 2n3906 npn transistor inverter would take care of the polarity: ground the emitter, go from the collector to +5V (from the tps sensor) with a 1K resistor (that should be low enough output impedance I think) and to the est input on the Buick module, and go from the 950 est or spark trigger output through a 10K resistor to the base of the 2n3906.

Well, without actually holding a 950 -)) or dragging out an oscilloscope I think that's about as far as I can go. Good luck if you actually try this, and post back to let us know how it worked.

 

[TurboTR]

Carl I swear, now you can add circuit design to that already over-achieving resume of yours! lol I might go up on Rb and down on Rc though, depending on how much EST drive current the DIS module takes in the high state

TurboTR

 

[ijames]

Well, remember that I spec'd a lowly 2n3906 so I wanted to keep Ic down in the low 10's of mA since I think the limit is about 100 mA. I just guesstimated that 500 ohms for Rc would allow enough current to flow to pull the est input high while keeping Ic at 10 mA (yeah, I'm assuming a fairly high input impedance but this would work even with standard TTL - are you old enough to have used any of that, or did you go straight to cmos ?), and in case the 950 output was 0-12 V that still limits Ib to 1.1 mA and if hfe is on the low side of the spec (since this is a crude circuit that actually depends on hfe, sigh), say 25 or so, and the 950 out is 5 V so Ib is really only .4 mA then Ic will still be 10 mA and the transistor will just saturate to pull the output all the way down to "0". If you go down on Rc then you go up on Ic, and if you go up on Rb you might not have the base drive to get the Ic you thought you would (I was more worried driving the "0" than the "1"). I always like analog stuff better than digital, but, hey, waddda I know, I just whipped it out this morning during a coffee break .

 

[TurboTR]

Hehe Now we're getting wayyy off topic here (lol), but what concerns me is- if we even draw say 2.5mA through Rc in the EST high state, we have reduced the available voltage out down to half, 2.5v. But to be honest, I don't know how much current the coil module EST input requires in the high state, or even which direction it is (lol), but I see the above scenario as a potential problem. Personally, I was kinda surprised at how much current the Bypass input seemed to want. Anyway...

TurboTR

 

[65malibuss]

Transistor Inverter

So where might I be able to acquire a 2n3906 npn transistor inverter?

 

[ijames]

First you let me scrape the egg off my face for confusing the 2n3906 which is a pnp transistor with the 2n3904 which is the npn transistor I meant, sigh Either the 2n3904 or 2n2222 or pn2222 will work and at least one of them is available at a Radio Shack, along with the 1 kohm and 10 kohm resistors in 1/4 watt or 1/8 watt size and a little piece of perforated board to build it on. The best way would be to get Todd to build it for you If you have never built any electronic circuits, maybe you have a friend who can help out with the circuit and wiring it into the car harness? Unfortunately MD and TX are a bit of a ways from NY. Hmm, also, I was thinking about putting this under the hood next to the ignition module (which is why I suggested the tps as a source of +5 V), but it would be much better to put it next to the ecm inside the car. Does the 950 use an adapter harness to go between the 950 and a stock Buick harness, or does it have its own harness? If it uses an adapter harness, then that's the best place to cut the est wire and insert the inverter, and you can pick off +5 and gnd from the tps wires there as well.