Alternating or simultaneous?

[q4_fre]

Hello all!

I have an MS2 3.57 up and running on an Alfa Romeo 2.7l V6, 60-2, distributor, single coil controlled by bosch ignition module, 384cc injectors, Turbonetics T04E-46 with T3 .63 turbo.

The car has now been driven approximately 20000km. All seem to be fine, except one thing. The last times I have driven the car I see that the AFR is changing from before. Since it is now getting warmer, I have tried to adjust the correction for fuel vs intake air temp, the only problem is that sometimes the AFR at idle is 14.5, then when I start the car 2 minutes later it can sometimes be 12.5 - 17.5. The engine is warmed up - so no warmup programs running... This is strange.... In the winter it was much more "correct" all the time - and consistant, the same AFRs at the same load, now it seems to "slip-away". I need to readjust all the time...

I now use alternating / 2 squirts. Is this the optimal for this engine? -I have tried to read about this, but I cant understand it completely..

I have coupled injectors for cyl 1-2-3 on inj1 and 4-5-6 on inj2. The firing order for the engine is 1-4-2-5-3-6..

Some help / suggestions on this would be great!

Fredrik

[devastator]

How does the AFR look during driving? I get some funky AFR numbers during idle occasionally, but as long as it does idle I'm happy. I know we have different engines, but I switched my 4 cyl. to simultaneous w/4 inj./cycle, the engine ran a whole lot better. I also played with the Injection Timing Delay settings and the engine idles much better than when it was set to zero. I'd suggest that you try changing from alternating to simultaneous and see what happens, knowing that you might have to change the req_fuel settings a little. Just be sure you save your MSQ so you can return to where you were if you need to. That's one of the cool things about MS, you can mess with it based on new theories, but always return to where you started if things don't go the way you hoped.

[q4_fre]

Sorry it took so long for an answer...

Regarding the AFR it was sometime too lean - sometimes too rich.. Lets say 2 - 3 AFR up/down.. When driving normally it is a little annoying to see the 12.5, when I want around 14.5 - 15.. But have not seen any big differences during full throttle, just during cruise/idle.
I have both an LM1 and an LC1 with each own sensors, they both follow the same pattern, just that the LC1 seems a bit more "all over the place" than the LM1.

But I have now just figured out that one of the pushers for the exhaust valve on one bank has been too worn, so one exhaust valve have not opened completely - maybe this have been playing with my AFR readings.. It have now resulted in that the engine sounds like it is running on 5cyl....

Regarding the injection, simultaneous/alternating.. Tried some changes - but only 2-alternating seems to work, but I did not put too much work into adjusting the ve table..

Still, when the engine is firing 1-4-2-5-3-6, and I have injectors 1-2-3 on inj1 and 4-5-6 on inj2, someone would be able to understand if this is the best solution I suppose? 1-4-2 inj1 & 5-3-6 inj2 maybe? And nr of squirts, is this no way to calculate - just test and see?
-But, any combination I do that is "allowed", will not result in some cylinder not getting fuel and melted pistons as an result, as far as I can feel that the engine is doing ok ofcourse, running smooth??
I have driven 20000km with 2-alternating, so it cant be that wrong now...

This days the 2.7l v6 is taken out from the car and an completely overhauled 2l v6 is put in its place, so it will be interesting to readjust the MS for that engine! This engine should suite the turbo more, so more hp should be gained

BTW, how will MS respond to more boost than the mapsensor can take? If I boost 2bar on an 1.5bar capable sensor, it will just read it as 1.5 and use the 1.5bar values, or will it sense it and cut somehow?

The v3.57 box I have had v2.687 software in it, so I just used that. Is there any reason I might want to upgrade the software? Better accuracy or something??

[devastator]

It does seem like that your engine AFR problems are related to that "tired" engine and valvetrain. I wouldn't upgrade the code any until you get everything running. You should definitely change map sensors though. Boost pressure fuel enrichment is something not to be played with. I don't know what the lower rated MAP sensor would do, but I'm sure it won't work for higher boost pressure.

[q4_fre]

Quote from the megamanual:
"Note that the MegaSquirt® EFI controller is a bank fire injection system, you connect half the injectors to the driver for one bank (pins 32/33), the other half to the other driver (34/35) [4 are shown]. See: the FAQ. You can connect them in any order. For troubleshooting ease, having each bank on a separate driver might help. However, you might want to separate them into alternates in the firing order, which some people have claimed is theoretically slightly beneficial. As an example, on V8s with bank fire systems, manufacturers typically run one bank off one driver, regardless of the firing order. The advantage of doing it that way is it makes troubleshooting easier."

Where it says theoretical slightly better, alternate in firing order, when I have inj1 1-2-3, inj2 4-5-6, that is not in the firing order is it? When my firing order is 1-4-2-5-3-6, which ones go together on inj1 & 2?

[AR 67202]

Where it says theoretical slightly better, alternate in firing order, when I have inj1 1-2-3, inj2 4-5-6, that is not in the firing order is it? When my firing order is 1-4-2-5-3-6, which ones go together on inj1 & 2?

I'd put inj 1-2-3 on channel one, 4-5-6 on channel two, and depending on the engine this will also be bank 1 one channel1 and bank 2 on channel 2...

[q4_fre]

Ok, that is what I have been running with until now, so OK then I think..

[Dariocc]

I have the same question, is it the same to put "cilinders 1 and 2 conected to driver 1 and cilynders 3 and 4 to driver 2" than "1and 3 to Driver 1 and 4 and 2 to Driver 2" with alternating( my car is 4 cylinders firing order 1-3-4-2)

[devastator]

I experimented with the firing order and bank 1 and bank 2 on my 4cyl. You can hook it up as you wrote, and just experiment with it after you get it running. I ended up with 1 and 3 on 1 bank and 2 and 4 on the other, injecting simultaneously.

[Dariocc]

I experimented with the firing order and bank 1 and bank 2 on my 4cyl. You can hook it up as you wrote, and just experiment with it after you get it running. I ended up with 1 and 3 on 1 bank and 2 and 4 on the other, injecting simultaneously.

but if you inject simultaneously it doesnt matters which pair of injector you hook it up....
I was thinking to, that if im not going to control the ignition it doesnt matters the pair of inyectors that i hook up because de MS doesnt know which is the first cilinder....i dont know if you understand me (sorry my english)

[devastator]

Remember that MS is a batch injection system anyway. In theory, the injectors should fire in the same order as the firing order of the engine. I spread out the injectors to alternate between banks to "ease" the load on the drivers as my firing order is 1-4-3-2. (1 and 3 on one bank and 2&4 on the other). I noticed, however, that changing the injector leads from injector to injector, had very little effect. Switching from "alternating" to "simultaneous" made a world of difference on my start-up, idle, and throttle response. My point is that you can always switch things around at any time to see what works best for you.
BTW- MS does know which injector is #1 because it requires the ignition signal from this event in order to work, even if you are not controlling your timing with it.

[Dariocc]

yeap i understand your case.....but the question in my case is...if i dont manage the ignition whith MS, I only take the (-) coil to get the tach input to MS. Here is the thing...how does MS know when the spark is on cilinders 1 ...3...etc...

[66fb]

MS II has no way of determining when #1 cyl is on the compression stroke. You need input from a cam sensor for that.

The input from a crank trigger wheel will indicate when #1 is on compression AND exhaust -that's why EDIS (Ford) is a wasted spark system, it sparks in #1 cyl and its complement cylinder one of which will be on compression stroke.

[Dariocc]

Yes you are right, but in my first try I dont want to use de 60-2 wheel, i just want to pick up de tach input from (-) side of the coil. I think that is possible isnt it? (im using a conventional distributor)

[devastator]

i just want to pick up de tach input from (-) side of the coil. I think that is possible isnt it? (im using a conventional distributor)

Yes, that is how I'm set-up and it works great.