[Scott65]

Maybe find a sheet of rubber and temporarily afix it between the sensor and the pump? I have no idea what it would actually take. I've read if you have a hand held AM radio, you can use it to detect interference. Might be worth a try...

[adynes]

I would just relocate it, even if only temporary. Low pressure fuel lines are cheap and easy enough to rerun, as well as extending the wiring.

Another thing to consider... How closely connected are the 12v/grounds for the pump, and for the crank sensor? Ideally, very far separated from each other. If not, maybe some sort of filtering can be added.

On my setup, I have the battery in the trunk, supplying power directly (through relays) to the in-tank fuel pumps. The computer (MS1-Extra, under-dash) gets it's power through a long length of it's own dedicated wire, and grounds to a cylinder head

[Scott65]

Originally Posted by adynes

I would just relocate it, even if only temporary. Low pressure fuel lines are cheap and easy enough to rerun, as well as extending the wiring.

Another thing to consider... How closely connected are the 12v/grounds for the pump, and for the crank sensor? Ideally, very far separated from each other. If not, maybe some sort of filtering can be added.

On my setup, I have the battery in the trunk, supplying power directly (through relays) to the in-tank fuel pumps. The computer (MS1-Extra, under-dash) gets it's power through a long length of it's own dedicated wire, and grounds to a cylinder head

DITTO THIS... Mine is the same(and trunk mounted as well). Dedicated power for the ecu and engine position sensors. Battery is grounded to the head(00 welding cable), and the ecu grounds there, as well as a ground bus so anything sensitive can go to the head as well.
It may seem overkill, but its not. It's the difference in having major headaches, and not...

[krisr]

Asking because I just had a read through the thread but can't see an MSQ file. Can you share it? I've run into a similar problem in the past where I was on the wrong "Input" edge. Once I changed it and reset the timing offset, the car was fine after that. Even though a hall effect sensor is +12V (or +5v), signal & ground, you still need to get on the right edge. The coil output edge is pretty simple as if you're on the wrong edge, you'll need 8 new coils LOL.

Also can you share a logfile of what the car is doing.

[Scott65]

Kris there's a thread at MSEXTRA running with a log and msq here:
https://www.msextra.com/forums/viewt...?f=131&t=75049
He told me hes tried both edges, but I'm not sure if he has since shielding the signal wire. The symptoms do sound like what you mention. In the log it runs good til 51xx rpm then loses synch. At a little faster rpmdot it loses it 7 times quickly on the way up.
ETA: Kris, the Holley sensor he's using is mentioned by part number in that MS thread. Do you have any experience with it? Is its built in pull up compatible as is?

[FMile Pontiacs]

Originally Posted by Scott65

Kris there's a thread at MSEXTRA running with a log and msq here:
https://www.msextra.com/forums/viewt...?f=131&t=75049
He told me hes tried both edges, but I'm not sure if he has since shielding the signal wire. The symptoms do sound like what you mention. In the log it runs good til 51xx rpm then loses synch. At a little faster rpmdot it loses it 7 times quickly on the way up.

Thanks for posting that link Scott. Please take a look Kriser and see what you think. I appreciate all feedback. I plan to work with it some tonight.

[Scott65]

Originally Posted by FMile Pontiacs

Thanks for posting that link Scott. Please take a look Kriser and see what you think. I appreciate all feedback. I plan to work with it some tonight.

No problem! Kris is very knowledgeable, and is generous with it. He was very helpful to me when I was in the early stages, and its appreciated.

[FMile Pontiacs]

I worked more tonight. I was worried about the fuel pump being an issue. I did a log where I cut the electric fuel pump off and revved and it still had sync loss and misfire for the same code. I did the same with the water pump. I then some filtering with no luck. I put another sensor in that will work with a 5 volt source from the ecu. It may have been some better but still not very good and still lost sync. I also closed the sensor gap as the people I bought the ECU from recommended and it really did not help. I am at a loss. If you want to follow along with my thread on the megasquirt forum, and take a look at my data logs you can go to https://www.msextra.com/forums/viewt...?f=131&t=75049

As bad as I hate to say it I may do away with the Megasquirt and go with a Holley ECU like the Terminator X system. I hate to give up though and would like to figure it out.

[JD]

What voltage electrical system are you using? 12 or 16 volt? I have had issues with the square truck coils with a 16 volt system.

[FMile Pontiacs]

Originally Posted by JD

What voltage electrical system are you using? 12 or 16 volt? I have had issues with the square truck coils with a 16 volt system.

12 volt

[Scott65]

I would encourage you to stick with it and figure it out. Not out of brand loyalty, but because it's likely gonna be noise, or a ground loop issue at least contributing. You'll be fighting those type issues with the Holley too, and have a lighter wallet to show for it, and the same headaches...

[FMile Pontiacs]

Originally Posted by Scott65

I would encourage you to stick with it and figure it out. Not out of brand loyalty, but because it's likely gonna be noise, or a ground loop issue at least contributing. You'll be fighting those type issues with the Holley too, and have a lighter wallet to show for it, and the same headaches...

I know that is very true, but it's hard to not get frustrated. I still have a few more things to try.

[Scott65]

You'll get it. I think you're gonna get some advise from the tooth logs you posted that will get this resolved.

[FMile Pontiacs]

Originally Posted by Scott65

You'll get it. I think you're gonna get some advise from the tooth logs you posted that will get this resolved.

Thanks for the encouragement. I need it. This is driving me crazy.

[johnta1]

Alternator noise?
Fan motor noise?

[FMile Pontiacs]

Originally Posted by johnta1

Alternator noise?
Fan motor noise?

I plan to check both of those this evening after work. It just started getting late last night and shut down out of respect for the neighbors.

[FMile Pontiacs]

Feel like I made some progress today. I have now ruled out fan and alternator as noise sources. I went to resistor plugs and changed the tooth angle from 81 degrees to 40 and it did better. Still recorded a couple of sync losses but definitely better. Even made it to rev limiter once. Any other suggestions?

[johnta1]

Using resistor wires?

[FMile Pontiacs]

Originally Posted by johnta1

Using resistor wires?

Yes. Currently running Accel 8.8 spiral wound RFI suppression wires.

[LATECH]

What kind of balancer are you running?
Does MSQ detect misfire by crankshaft velocity? It could be messing with crank signal. Yes ? No?
Can you get an oscilliscope to see what the true real time crank signal looks like? It would show a velocity problem as a pulse too close to another (problem with even spacing). It would also show how clean the pulses are.
High rpm crankshaft velocity changes can affect crank signal timing ( read frequency - pulse spacing)


I had a Buick last week, that kept setting random misfire (P0300)
Tuned it up.Intake gaskets , still misfired.
Changed the serpentine belt. Problem dissapeared whacked
It was a brand new Vato Zone belt.It had a hard spot in it and every time it went around it wacked the tensioner around.It also caused a velocity change , in the reciprocating mass, which is how a Spuick detects a misfire.
The fact that the belt is no where near the exact length to go around once per revolution of the crank is why the misfires were random.
I know you are not working on Moms Buick here, but I see some similarities


If the crank velocity is getting wacked around by a ****ty balancer it may be missing the pulse because it is happening outside the "window" allowed for detection
I know this sounds far fetched
I am talking out my Butt.
Whatever.
It is just something that came to mind for you to digest.
Stranger crap has happened