I opened up a can of worms yesterday

[user-23911]

You should never trust any of the marketing BS associated with anything.


Measure, measure and measure.

[Belgian1979]

errors are more caused by ground related issues. The 14point7 system has a neat way of dealing with that.

.

Really?


But how would you know?

Do you doubt the calibration of Bosch at 14.7 stoich ?
I'm pretty sure they are up to par considering those sensors are integrated into OEM systems. At least a whole lot better than any chech I could make.

For the voltages in the rich and poor areas (linear relation) you have to make sure there are no ground offsets, which is why you have to calibrate based on the 2 initial readings you see in your user interface and what it's supposed to be.

But like I said, this isn't going to be a difference of 1 AFR point.

And as for MS and ground wiring : this is usually the fault of the end user and not of the system.

[mk e]

And as for MS and ground wiring : this is usually the fault of the end user and not of the system.

Probably so, mostly. OEMs put a lot of effort into both designing a good harness and grounding system as well as hardening the system to ground faults. The MS systems have basically nothing on-board or in the code that I'm aware of so it's critical the harness is good where some other systems seem to be more tolerant....which to your point doesn't matter at all if you have a good harness to begin with.

[Belgian1979]

And as for MS and ground wiring : this is usually the fault of the end user and not of the system.

Probably so, mostly. OEMs put a lot of effort into both designing a good harness and grounding system as well as hardening the system to ground faults. The MS systems have basically nothing on-board or in the code that I'm aware of so it's critical the harness is good where some other systems seem to be more tolerant....which to your point doesn't matter at all if you have a good harness to begin with.

I've got the impression you don't understand MS. It is a DIY system. Which means that you have to make either your own harness or make a harness with some of the more generic products available. That's where most make the fault, although the instructions are clear on the subject and if followed correctly don't give an issue.

Anyway, this thread is not about MS or ground issues. It's about multiple WB's.

[mk e]

And as for MS and ground wiring : this is usually the fault of the end user and not of the system.

Probably so, mostly. OEMs put a lot of effort into both designing a good harness and grounding system as well as hardening the system to ground faults. The MS systems have basically nothing on-board or in the code that I'm aware of so it's critical the harness is good where some other systems seem to be more tolerant....which to your point doesn't matter at all if you have a good harness to begin with.

I've got the impression you don't understand MS. It is a DIY system. Which means that you have to make either your own harness or make a harness with some of the more generic products available. That's where most make the fault, although the instructions are clear on the subject and if followed correctly don't give an issue.

Anyway, this thread is not about MS or ground issues. It's about multiple WB's.

I understand MS quite well...which is why I don't use them

That aside, I'm agreeing with you!
When people are having problems it's normally something they did poorly during install not the system. The 14.7 ground offset probably helps, but mis-matched grounds are very rarely consistently mismatched (light on/off and such can change things, a LOT) so I'm not sure how much I'd trust that vs correcting the harness if you're seeing significant mismatches.

or better yet just swap the high and low senors(including wiring if you can) and you'll probably be able to eliminate senor error as a possible cause.

At low loads like the data you have the most common causes are injector mismatches which you shouldn't have with the setup you have and air flow mismatches which could fix or at least hide with TB adjustment if yours were not on common shafts but they are so your left with trimming the fuel to match the airflow you have....and trimming the fuel is the easiest anyway.

You will almost certainly find that trims at low power are not the same as the trims at high power so just watch out for that and you should be good now that you've eliminated the air box and once you do the high/low sensor swap to eliminated sensor error questions.

It sounds like you're pretty close to done with the project. Well done!

[Belgian1979]

Not really done, now comes the part of using everything correctly.

[mk e]

Not really done, now comes the part of using everything correctly.

Done is a tough word when you're talking about what's really a toy. It will will be "done" the day you sell it

The phase has now changed though, now it works! and you're worried about how well you can get it working. Before you were creating, now you're tuning.

[Belgian1979]

Some progress.

I found out that my iac is causing some of the imbalances. This is probably due to the configuration and inlet position of the vacuum chamber (underneath runners + inlet is at the rar where the distributor normally is).
Added to that is that I was using too little ignition advance at idle and cruise. This lead to some cyls running leaner and even misfiring. So far I've been too conservative with regards to ignition timing in idle, cruise, low rpm and decel. I've now added consecutive 2° of timing in each row downward in load.
This stabilized the misfires a lot and made the engine more comfortable to drive in low rpm, cruising conditions. The engine also ran a lot cooler in those areas (to the tune of 5° F) I hope I do not have any knock there.

Added to that, the individual fuel trim is virtually worthless if the main fuel table is not optimal.

I'm also thinking that fouled plugs show up as individual misfires. I'm going to change the plugs next.

Overall I'm very positive on the multiple WB's and tuning. There definately is a learning curve, but the engine seems to like the ecu correcting individual differences and the reward is a much more stable, balanced engine running and more power.

Oh, and meanwhile I received my last LSU 4.9 sensors, so I changed out the remaining 4.2's that were still in there. As for behavior this didn't make any difference or at least a very minimal difference.