Need MaxxECU base tune

[944m3]

Can someone please share a working base tune file for their MaxxECU. I’m using Race but I think any version would be good.

Totally understand it won’t necessarily work on my car but just want something I can compare with my base tune.

I’m facing the dreaded crank but no start issue. Fully aware it’s a steep learning curve but it’s been fun so far.

[cda951]

Do you still have the stock 951 flywheel with the reference studs and the 133(?)-1-1 tooth pattern?

If so, I can share the same data with VEMS in the hope it might work with your setup.

[944m3]

Do you still have the stock 951 flywheel with the reference studs and the 133(?)-1-1 tooth pattern?

If so, I can share the same data with VEMS in the hope it might work with your setup.

Yes I do. Stock flywheel and reference sensors.

[cda951]

Are there others who use MaxxECU with the stock setup? I know that VEMS is one of the few aftermarket ECUs that plays nice with the early Bosch Moronic system that uses flywheel ring gear teeth as the input for the engine speed sensor. Bosch had a special chip in the DME dedicated to converting this specific analog signal to digital, and is the only component carried over by F9 and others who modernize the 944 DME.

I need to find my old tuning laptop first, then I'll see if I can post some screenshots of the basic setup.

[944m3]

That would be great. Thanks

[cda951]

In the meantime post screenshots of all relevant trigger and and ignition/injection settings in the MaxxECU software, maybe we can catch something.

[944m3]

With the help from vendor, I was able to use the oscilloscope to determine my flywheel trigger signals are very bad. Not a big deal with stock ECU but not good enough for standalone.

Looking into custom bracket and trigger solutions now.

[Tom]

With the help from vendor, I was able to use the oscilloscope to determine my flywheel trigger signals are very bad. Not a big deal with stock ECU but not good enough for standalone.

Looking into custom bracket and trigger solutions now.

What was wrong with your trigger signals? Lots of third party ECUs (i.e., lots of vendor products) have a hard time keeping up with so many teeth on the flywheel, but the signals themselves are fairly typical for variable reluctance sensors.

[944m3]

They appear to be all over the place, not consistent “pattern”.

But I will be honest, taking the vendors word on this but I am trying to learn myself. From what I’ve read, the signal does seem to be “off”. He did suggest ways I could try to clean up the signal such as making sure the sensors are gapped correctly. But the cost of the bracket kits aren’t that much so I rather not try to fix my “old” stuff, will try to do it right.

[Tom]

See my video below showing the sensor signal. Given the spacing of the teeth (or the spacing of the reference pins), there isn't a lot of room for the signal to be 'off' -- other than if they are weak (low amplitude) due to an excessive gap, or have frayed wired inside the connectors, or have internal damage. If you have a crank but no start condition, check for tach bounce. If you have no tach bounce, chances are very good that the connectors are frayed under the rubber boots.

The amount of engineering Bosch put into the Motronic and the results they achieved is super impressive to me, based on the relatively primitive hardware they had available back in the day. You don't see that much anymore, since prodigious computing power is everywhere and helps make bad programmers look good.

That's not to say there's anything wrong with trying a stand-alone with custom trigger wheel, especially if you are into projects like that. Most stand-alone systems have troubles keeping up with the speed and ref signals, despite their marketing claims, so that's reason enough to do a custom trigger wheel if you are otherwise planning a stand-alone. I just wouldn't install a stand-alone due to a simple no-start condition, especially if an ECU-vendor is in your ear about how old and out of date the factory parts are. You'd be trading a simple and fairly inexpensive repair for a more expensive, long-term project, with lots of issues to sort out, and lots of mapping to perfect. If you are up for the challenge and like projects of that nature, go for it. Just don't be talked into thinking it's the easy way out... (It isn't!)

If the vendor isn't able to supply a solid base tune for a stock 951, I'd be inclined to call on someone like @chris white with a proven track record getting stand-alones to work (and work well) on these cars. Chris also has a trigger wheel option what might be of interest.

There are a number of people on Carpokes who have smooth-running cars with stand-alone systems, e.g., @Thom, @Darwin, @cda951 -- might be good to get their take too....