383 Dodge MS3x build. Cant keep running.

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Black_Bee
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383 Dodge MS3x build. Cant keep running.

Post by Black_Bee »

Hey guys!

I've been at this for close to a week worth of evenings and weekends now and I am getting pretty frustrated with myself due to my lack of progress... I thought that maybe if somebody could take a look at my MSQ file to see if I'm completely out to lunch somewhere or have missed something that is staring me in the face... I apologize if this question/post seems all over the place.

I am working on adding MS3x (built for me by DIYautotune) to my '69 Dodge Super Bee's 383 V8. I am attempting to go full sequential fuel and spark with cam sensor and 8 LS2 coils. This has been a running and driving engine previous to the MS install for 10+ years with carb and distributor.

I am using a 36-1 trigger wheel for crankshaft and half moon for cam. I placed the crank sensor (Jeep hall effect) 5 teeth before the missing tooth (4 before tooth #1).

At #1 TDC compression, the half moon cam sensor (Jeep hall effect) is off the moon part of the sensor (.05 Volts) , and on the moon part (4.95V) on exhaust TDC. Instructions tell me to set "Level for Phase 1" to High, but I have read elsewhere that this means you need to add 360 degrees to your tooth#1 angle.

It seems like a pretty typical MS build... GM sensors everywhere (except for those Jeep cam and crank sensor). Accufab 4150 throttle body w/ GM 4 wire IAC. Every MS ground has been grounded to the engine, and all sensors to sensor return.


The car will only sometimes start and when it does, it idles extremely poorly, like RPMs rapidly jumping between 0 and 400 RPM, and then dies.

Putting a timing light on shows that timing is at least in the ballpark while cranking and running (I have tried 0-15* crank and 0-20* fixed advance)... certainly enough to keep it going.

If I move the throttle while idling, it wants to die, but I can occasionally keep the car alive for a short time pedalling the throttle. Usually it just dies, or backfires and dies.

Is it typical for a car to take a long time to get running? Reading most posts it seems like even if your settings are way off, you should at least be able to use the throttle to keep it alive long enough to warm up. My experience with a carb and distributor tells me that an engine will sun with super rich or super lean AF, and ignition from 0 degrees and above.

I have attached my MSQ, but keep in mind that some of the tuning settings are all over the place while I attempt to have any kind of impact.

Thanks for any tips and advice!
grom_e30
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Re: 383 Dodge MS3x build. Cant keep running.

Post by grom_e30 »

have you got any data logs to go with?
1990 bmw 320i daily driver with m20b25 ms3 sequential fuel, 380cc injectors, d585 coil near plug, home made cam sync, launch control, fan control, vss, homebrew egt logging what's next????
Black_Bee
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Re: 383 Dodge MS3x build. Cant keep running.

Post by Black_Bee »

I'm currently waiting for the battery to charge before I can try to get any logs. What logs should I capture to be most useful?

Thanks!
grom_e30
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Re: 383 Dodge MS3x build. Cant keep running.

Post by grom_e30 »

grab a composite log, tooth log and a normal data log.
1990 bmw 320i daily driver with m20b25 ms3 sequential fuel, 380cc injectors, d585 coil near plug, home made cam sync, launch control, fan control, vss, homebrew egt logging what's next????
Black_Bee
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Re: 383 Dodge MS3x build. Cant keep running.

Post by Black_Bee »

Here are some datalogs... I ran them all until the engine died. Please let me know if anything else would be helpful here.

Thank you very much for your help!
grom_e30
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Re: 383 Dodge MS3x build. Cant keep running.

Post by grom_e30 »

if you click on data logging at the top then 'start logging' do a few start attempts then click stop then post that, that will record all the sensor reading and so on. the logs you posted are a bit hard to follow, the composite log looks like it sync's up with the crank and cam signals but does lose sync towards the end, but the tooth log just looks bad but it was a really short log and could just look bad because the engine was stalling.
1990 bmw 320i daily driver with m20b25 ms3 sequential fuel, 380cc injectors, d585 coil near plug, home made cam sync, launch control, fan control, vss, homebrew egt logging what's next????
Black_Bee
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Re: 383 Dodge MS3x build. Cant keep running.

Post by Black_Bee »

OK, sorry... I hadn't used that datalogging feature before.

Attached is a log of a few start cycles. I cant tell if it loses sync because its running so rough, or its running so rough because it loses sync.

Thanks again!
billr
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Re: 383 Dodge MS3x build. Cant keep running.

Post by billr »

I think it is rough because of the sync loss. I can make my engine run pretty crappy without sync loss.
Matt Cramer
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Re: 383 Dodge MS3x build. Cant keep running.

Post by Matt Cramer »

Agreed - I think the sync loss is driving the rough running. Check the crank sensor gap - with the crank turned to four separate points 90 degrees apart, in case you have a runout issue.
Matt Cramer -1966 Dodge Dart slant six running on MS3X
Black_Bee
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Re: 383 Dodge MS3x build. Cant keep running.

Post by Black_Bee »

billr wrote:I think it is rough because of the sync loss. I can make my engine run pretty crappy without sync loss.
Matt Cramer wrote:Agreed - I think the sync loss is driving the rough running. Check the crank sensor gap - with the crank turned to four separate points 90 degrees apart, in case you have a runout issue.
I am not going to have a chance to do anything for a couple of days, but what would be an acceptable amount of runout? I believe that I set the gap to the crank trigger wheel to about 1mm. Should I tighten that up maybe, or would increasing it possibly help?

I cant believe that it didn't occur to me that the sync loss wasn't just a side effect of running poorly, but was actually the cause of the poor running!

Thanks guys, I really do appreciate this help!
Matt Cramer
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Re: 383 Dodge MS3x build. Cant keep running.

Post by Matt Cramer »

Not sure what this sensor's limits are on runout, sorry.
Matt Cramer -1966 Dodge Dart slant six running on MS3X
Black_Bee
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Re: 383 Dodge MS3x build. Cant keep running.

Post by Black_Bee »

I still haven't had a chance to check my runout, but I am trying to research other things that can cause sync loss (so I have a few things to try tonight).

I haven't touched the VR trim pots on my MS. Should I have done anything with those when using hall effect sensors for cam and crank? Looking at http://www.diyautotune.com/tech_article ... _index.htm I'm not clear on whether or not these need to be set when not using VR sensors.

Thanks!
grom_e30
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Re: 383 Dodge MS3x build. Cant keep running.

Post by grom_e30 »

http://www.msextra.com/doc/pdf/html/MS3 ... e-1.4.html

http://www.msextra.com/doc/pdf/html/MS3 ... e-1.4.html

tells you how to set up for hall sensors, the trim pots could be the issue.
1990 bmw 320i daily driver with m20b25 ms3 sequential fuel, 380cc injectors, d585 coil near plug, home made cam sync, launch control, fan control, vss, homebrew egt logging what's next????
redmist
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Re: 383 Dodge MS3x build. Cant keep running.

Post by redmist »

Your fuel VE Map has a funky ramp in the lower RPM's that looks like what some folks do for timing. Looks like it would be flooding itself trying to stay on that peak at idle.

I would smooth the map, or use the generator for a base map.
1968 Dodge Charger, 446ci 513HP/542ftlbs,Full sequential fuel/Spark using MS3X. Jeep CPS, Ford Crank sensor, 36-1 wheel, Coil near plug with D-585 ls2 coil packs. Edelbrock pro-flo intake, 600cc injectors, GM MAP, TPS, IACV, CTS, MAT. 92mm Throttle Body.
Black_Bee
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Re: 383 Dodge MS3x build. Cant keep running.

Post by Black_Bee »

Hey guys

OK, I pulled the MS out and adjusted the VR pots for the crank and cam to how I believe that the instructions say. CCW 7 turns, and then adjust R65 and R11 CW until 2.5V. I couldnt get R11 to adjust higher than 2.4V, but I am going to assume that is close enough.

Anyway, it fired up right away after this change, and now idles very smooth without losing sync!!!

It still seems to be losing sync if I rev it up past 1000 RPM or so, so I am going to check the crank sensor gap runout. I did a single point check and its 0.024" which I think might be a bit tight for this Jeep crank sensor (I have read that it should be at 0.030")

Anyway, I am ecstatic with having it idle so nicely!

Thanks for your help guys!
Black_Bee
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Re: 383 Dodge MS3x build. Cant keep running.

Post by Black_Bee »

Hey guys!

So, now that it is idling really nicely, I am attempting to figure out why It wont rev off of idle without losing sync.

I checked runout on my hall cam sensor. Its about .022" difference between the lowest (.018) gap and highest (.040) gap. I guess without knowing the spec for acceptable runout of my sensor, these values are uselessm but it sure doesnt seem like much. I thought that the gap was a bit tight, so I opened it up to 0.040 where it was tightest, but that had no effect.

I have attached a log file, just in case there is some info in there that might point me in another direction!

Thanks!
Black_Bee
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Re: 383 Dodge MS3x build. Cant keep running.

Post by Black_Bee »

Might as well attach a composite log too.
Matt Cramer
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Re: 383 Dodge MS3x build. Cant keep running.

Post by Matt Cramer »

Can you get a tooth log? They're a bit easier to use for loss of sync issues on 36-1 wheels.
Matt Cramer -1966 Dodge Dart slant six running on MS3X
Black_Bee
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Re: 383 Dodge MS3x build. Cant keep running.

Post by Black_Bee »

Matt Cramer wrote:Can you get a tooth log? They're a bit easier to use for loss of sync issues on 36-1 wheels.
Thank you so much for your help here! Attached is a tooth log. This is just after a first fire up, but it does the same thing when it warms up to temp.

Thanks again!
billr
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Re: 383 Dodge MS3x build. Cant keep running.

Post by billr »

.022" TIR run-out is rather a lot, I would try to get that wheel centered better. I can't claim run-out is your whole problem, but it sure isn't going to help. I think .003-.010" TIR is realistic.
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