Problems with Chrysler 2.2/2.5 mode

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UnaClocker
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Re: Making sure correct injectors are firing

Post by UnaClocker »

UnaClocker wrote:Any luck on this yet, James?
Any luck on this yet? :) I had a peak at the source code for this decoder. Looks like it's simply looking for the second input to be high or low at a specific time. Seems like that could be leading to a lot of the confusion. Engine speed is very erratic during cranking, and with all those teeth, the second sensor could easily be giving the high reading at a time the MS thinks is indicating TDC. Seems like the decoder really needs to be counting teeth from both sensors at the same time. Is that possible? It'd definitely be a much different decoder.
Brian
'84 Dodge Rampage
UnaClocker
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Re: Making sure correct injectors are firing

Post by UnaClocker »

Ok, wow.. 3 or 4 months of fighting with this thing, seems like I try something new to fix the problem each weekend. Last weekend I reflowed all the solder joints on the MS and tried bypassing the relays, with no change. Weekend before was some attempts at going back to single coil/distributor mode, non sequential fuel, etc etc. No luck there. Also tried a simple distributor but found that trigger return setup is a PITA and never did get the car to run more than horrifically after spending an entire day on it. Weekend before that I changed the head and headgasket.. The list goes on.. Needless to say, this is probably the most thoroughly troubleshot MS install I've ever done.
So today I was preparing to wire a factory ECM into this thing and just admit defeat.. For some reason, I changed the "Use Prediction" option, it was on "1st derivitive", changed it to "Off" or "No Prediction", whatever it calls it. Poof, problem is 95% gone. Certainly good enough for me. It had been impossible to even drive this thing around the block without people thinking I was shooting at them (Backfiring). Now I only get the slightest of hickups from time to time.
So what is causing this? Should "Use Prediction" be disabled in Chrysler 2.2/2.5 mode? Is it happening due to the second sensor being 20 degrees off from where James had thought it was (160 degrees instead of 180)?
Also, I still have to crank this thing 3-4 times before it syncs correctly, 50% of the time, it kicks back on the starter because it got the coil phasing wrong. This is most noticeable on a cold start, hot starts are usually perfect on the first crank. Again, probably due to the second sensor being mislocated in code.
Brian
'84 Dodge Rampage
billr
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Re: Problems with Chrysler 2.2/2.5 mode

Post by billr »

Are your crank and cam sensors, and trigger-wheels OEM stock?
UnaClocker
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Re: Problems with Chrysler 2.2/2.5 mode

Post by UnaClocker »

Yeah, I've also provided James with a trigger log file. I've tried two different sensors, one old junkyard one, and one brand new one. Identical results from both. Tried running the sensor at 5v and battery voltage, no difference there either.
Brian
'84 Dodge Rampage
juansh2385
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Re: Problems with Chrysler 2.2/2.5 mode

Post by juansh2385 »

Hey Brian, Sorry to hear you are still having problems I know that probably you want to run this with the stock sensor and all but why haven you try a different trigger wheel let say 36-1 custom in the car. I am pretty sure that this could be a possible solution for your trouble. I know you have try everything else you thought about it but before going stock again I think you should give it a try.
UnaClocker
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Re: Problems with Chrysler 2.2/2.5 mode

Post by UnaClocker »

I see it as helping debug a wheel decoder in the firmware. This thread probably should have been in the development section, rather than the general support section, but it started out with a normal question and evolved into a full blown debugging session. I've been helping James/Ken field test MS firmware since the end of MS1-Extra when they first started development on MS2-Extra. I'm not much for programming, and I can only toss a few bucks their way from time to time, so I contribute by testing out the code, especially experimental new features. I like living on the bleeding edge running the beta and alpha firmware. If I were to just give up on the wheel decoder and run a standard decoder, the next person with this engine that came along would run into these problems instead of me. That may turn them off to MS entirely, or at least leave them with a bad taste in their mouth. This way, I get to find the bugs/glitches, confirm it all works right in the end, and MS3 will be better for it in the long run. The unique factory wheel decoders in MegaSquirt are one of the prime selling points over their competition, who can really only read generic wheels like the 36-1.
Brian
'84 Dodge Rampage
juansh2385
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Re: Problems with Chrysler 2.2/2.5 mode

Post by juansh2385 »

I understand your point. I only mention it because you said you where thinking using a stock computer.
UnaClocker
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Re: Problems with Chrysler 2.2/2.5 mode

Post by UnaClocker »

For the record, and in case anyone comes along wanting to run this decoder on the MS3. It kind of works in 1.0, but spark timing is jittery, and advances with RPM. 1.1 seems to have some kind of overflow issue where RPM will jump dramatically from idle to 25k for half a second, causing the engine to stall suddenly.
Check with James before running this decoder, he should have enough logs to get the problem fixed in a future update.
Brian
'84 Dodge Rampage
Peter Florance
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Re: Problems with Chrysler 2.2/2.5 mode

Post by Peter Florance »

UnaClocker wrote:For the record, and in case anyone comes along wanting to run this decoder on the MS3. It kind of works in 1.0, but spark timing is jittery, and advances with RPM. 1.1 seems to have some kind of overflow issue where RPM will jump dramatically from idle to 25k for half a second, causing the engine to stall suddenly.
Check with James before running this decoder, he should have enough logs to get the problem fixed in a future update.
Does this work in MS2Extra?

Thanks
Peter Florance
PF Tuning
81 BMW Euro 528i ESP Car
60-2 Wheel LS2 Coils, Low Z Inj
Co-Driver 1999 BMW E46 DSP car.
UnaClocker
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Re: Problems with Chrysler 2.2/2.5 mode

Post by UnaClocker »

The MS3 code was a direct port of the MS2 code. So it shouldn't work any better or worse than the MS3 1.0 decoder.
Brian
'84 Dodge Rampage
Peter Florance
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Re: Problems with Chrysler 2.2/2.5 mode

Post by Peter Florance »

UnaClocker wrote:The MS3 code was a direct port of the MS2 code. So it shouldn't work any better or worse than the MS3 1.0 decoder.
Does that mean you feel it is useable or not?
thanks!
Peter Florance
PF Tuning
81 BMW Euro 528i ESP Car
60-2 Wheel LS2 Coils, Low Z Inj
Co-Driver 1999 BMW E46 DSP car.
UnaClocker
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Re: Problems with Chrysler 2.2/2.5 mode

Post by UnaClocker »

I would recommend installing a 36-1 wheel on this motor, and use the distributor with all but one tooth removed as a cam sync signal. Someone should mail James one of these distributors along with the HEP so that he can finally nail down the problem in the code on the bench. If I had a spare, I'd certainly do it. I ended up just going back to factory electronics.
Brian
'84 Dodge Rampage
Peter Florance
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Re: Problems with Chrysler 2.2/2.5 mode

Post by Peter Florance »

UnaClocker wrote:I would recommend installing a 36-1 wheel on this motor, and use the distributor with all but one tooth removed as a cam sync signal. Someone should mail James one of these distributors along with the HEP so that he can finally nail down the problem in the code on the bench. If I had a spare, I'd certainly do it. I ended up just going back to factory electronics.
I think we will put VR distributor in it for now. I'll borrow the TD distributor and get composite logs to send to James.
I think the JimStim pattern isn't that great either; which complicated testing for me.
Peter Florance
PF Tuning
81 BMW Euro 528i ESP Car
60-2 Wheel LS2 Coils, Low Z Inj
Co-Driver 1999 BMW E46 DSP car.
jsmcortina
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Re: Problems with Chrysler 2.2/2.5 mode

Post by jsmcortina »

The problem we were having was pattern distortion due to cranking acceleration and tach input circuits.

These made developing reliable code very difficult and frustrating for both parties.

James
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Peter Florance
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Re: Problems with Chrysler 2.2/2.5 mode

Post by Peter Florance »

jsmcortina wrote:The problem we were having was pattern distortion due to cranking acceleration and tach input circuits.

These made developing reliable code very difficult and frustrating for both parties.

James
Is there anything you need from me on this? I can spin a distributor on the bench to create log, and make mods to input circuit.

When I built this box, I used the VR circuit as one input and the opto as the other to avoid having to build in proto area. Seemed to work well from a hardware standpoint. This car is a long drive away and I was nervous that it wouldn't work well based on feedback I read here.

Having said all this, I'm hearing these engines are getting really old and there are not as many parts available for them. The twin cam motor (NGC wheel?) is supposed to be a drop-in? So maybe we should let this application go away.
Peter Florance
PF Tuning
81 BMW Euro 528i ESP Car
60-2 Wheel LS2 Coils, Low Z Inj
Co-Driver 1999 BMW E46 DSP car.
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