stumped on a dying issue
#2693279
08/31/19 10:16 PM
08/31/19 10:16 PM
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Joined: Feb 2003
Posts: 8,671
Andrewh
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OP
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Joined: Feb 2003
Posts: 8,671
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1965 coronet. 5.9 magnum out of a 2000 durango. Megasquirt 2 running the stock efi, with a mod to the distributor so it doesn't need a crank sensor. It has a shutter wheel to give it timing.
After driving it for a bit after it gets up to operating temp it starts to stumble, and run rough. eventually dying. It will restart once or twice, also running rough and then won't run again for 15 to 20 min or so. Then it will restart like nothing happened.
I have replaced the coil, the surge tank fuel pump. I rechecked the MS box for the jumpers I put in, in case they might have overheated and melted the solder. one of the wires I used as a jumper had some corrosion on it and I replaced it with a solid wire jumper. but all the solder joints were solid when I took it apart.
The only things left might be temp sensors and the distributor sensor.
feets suggested logging data from the megasquirt, but I am not sure what I should be seeing to decide what sensor died. RPM followed what I felt, and AFR went to 10, which I think means the injectors were still firing. Is there some specific test I should try? how would I tell what isn't working when it is dead? I mean I am pretty sure it is spark now, but how do I find the part causing it?
Last edited by Andrewh; 08/31/19 10:17 PM.
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Re: stumped on a dying issue
[Re: Andrewh]
#2693537
09/01/19 10:20 PM
09/01/19 10:20 PM
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Joined: Nov 2004
Posts: 25,050 Texas
GoodysGotaCuda
5.7L Hemi, 6spd
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5.7L Hemi, 6spd
Joined: Nov 2004
Posts: 25,050
Texas
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Distributor sensor could certainly be it, it could also be it's air gap. How much gap is there from the sensor to the pickup? If it's a VR sensor, it could also be very susceptible to noise/RFI. Instantaneous and wrong high RPM can demand high fueling, it'll show up on a log, but likely not a tach.
You can probably do a tooth trace/high fidelity log and watch each crank tooth, if you see the crank signal just drop out, that'll tell you something for sure.
- What's the rpm log look like?
- Hitting 93kPa with a maximum TPS of 16% seems a little suspect. if the MAP signal isn't accurate, it jumping to 93kpa will just dump fuel [also seeing low/rich AFR]
- Try cutting down on the number of common data names you are using per trace in megalog viewer, PW x PW x VE1 x VE2 isn't very useful. I would scale the TPS chart to show 0-100%, it looks like the scale is showing ~0-20%, which makes 16% look very high. Small tweaks in MLV will help your data start to show a bit clearer story.
- I'd like to see your MAT trace and MAT fuel correction as well. There is a MAT correction curve that, if wrong, can dump a good amount of fuel on top of the base fuel table. There is on my MS3, not sure about MS2.
Last edited by GoodysGotaCuda; 09/01/19 10:29 PM.
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Re: stumped on a dying issue
[Re: GoodysGotaCuda]
#2693550
09/01/19 11:26 PM
09/01/19 11:26 PM
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Joined: Feb 2003
Posts: 8,671
Andrewh
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OP
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I don't know how much gap there is. It is a shutter wheel, so it passes through the sensor. that hasn't changed as far as I know. In that if that were the issue, I would expect it to be all the time. ?
I was just barely on the throttle, so pretty low rpm, and it started to chug like that.
It is the same logging software, I just have to figure out how to set it to show what I need. or maybe I have to pay for the registered version to get all the bells and whistles. All I did was start logging, I didn't see any settings for what to log, so maybe all the data is there, I just can't see it.
I haven't messed with any of the curves or any of the computer stuff since I got it running a few years back. I switched from the prototype painless setup when it started blowing fuses.
Wouldn't a drop in the pickup also stop firing the injectors? or since they are batch, there is enough to keep it running?
and wow canned air is expensive for what it is. lol.
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Re: stumped on a dying issue
[Re: Jim_Lusk]
#2693894
09/03/19 10:54 AM
09/03/19 10:54 AM
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Joined: Jan 2003
Posts: 10,714 North Dakota
6PakBee
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 10,714
North Dakota
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It sounds like a thermal issue. First suspect coil, second suspect distributor pickup, third suspect ECM. If I was a betting man, I'd go with the distributor pickup.
"We live in a time when intelligent people are being silenced so that stupid people won't be offended".
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Re: stumped on a dying issue
[Re: Andrewh]
#2693993
09/03/19 02:49 PM
09/03/19 02:49 PM
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Joined: Oct 2007
Posts: 3,884 Oregon
hooziewhatsit
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master
Joined: Oct 2007
Posts: 3,884
Oregon
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IIRC, that has the Ford 5.0 distributor pickup? I'd look at that for sure. Another friend had the same symptoms, and a new distributor (with a new pickup) fixed it.
If you ever find yourself in a fair fight, your tactics suck.
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