This is on my bosses project car that I have been tinkering with at work, essentially a stripped 1.6 chasssis harness running a relatively stock BP 1.8L with a SLIGHT over bore. Obviously running 1.6 ignitor/coils and at the moment 1.6 throttle body with no IAC, and no AFM, stock flowed tan top injectors. I made a rough base map off of the DIYautotune 1.6 base map adding the correct values for the 1.8, and set req fuel to 12.9 for now. I can get the car to run but it is RICH (<10:1), and everything including MS -> PC communication intermittently cuts out regardless of RPM. I am not sure what the status LEDs inside the MSPnP are for so I am hoping someone on here knows. Three of them shut off when the ECU cuts out which I show in the video. Battery voltage is sufficient (>12v). I should also note that when the stock (1.6) ecu is plugged in it runs smooth without cutting out (despite being stupid rich) so I can't imagine it is a wiring issue on the car. I also noticed that the MAP sensor doesn't seem to be reading accurately, with engine off it is showing 95kpa which I am assuming is absolute, so shouldn't that be 101-103kpa? Any ideas? I haven't had my hands on MS in a few years so I feel like a !

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LEDs are Spark A, Warmup, and Spark B. post your msq.

A bad misfire can cause a processor reset, but that looks more like along the lines of a loose power or ground connection somewhere.

It is definitely acting like the MS is losing power but at the same time the issue disappears if I run off the factory ECU. I attached the .msq that I have been using. Req fuel is probably off (1840cc/4cyl/255cc/14.7afr), couldn't remember what AFR to input. Regardless it should still run fine as it sits now unless if I am missing something. Thanks for the input so far, it is MUCH appreciated.

Attached Files

megasquirt201109220941.msq (35.0 KB, 22 views)

Does your MSPNP have variable TPS mods?

If not, I'd still suspect a wiring fault. The factory ECU may simply have larger capacitors, or may be able to run off the keep alive power input for short lengths of time.

The MSPNP is untouched, no mods. While looking at the wiring diagrams for the chassis, I am seeing that the "circuit opening relay" on the chassis has a wire that used to go to the "st sign" fuse in the factory fuse block that is supposed to be removed on the MSPNP9093. I believe that wire was wired to receive power as if the fuse block was still installed. Could that have anything to do with it? I was under the impression that if the fuse wasn't removed it would fry a resistor on the board, but going off the wiring diagrams it looks like that wire needs to maintain its power (off the starter circuit if I am remembering correctly) for certain engine components to receive power. Is there something else on the "st sign" circuit that would cause damage to the MSPNP?

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the owmecu can run without the fuse; it's just allows temporary power to prime the pump at first key on.

but without it being removed it overloads the driver on the MS.

So if the car was wired with that circuit still active and the MSPNP was used would it absolutely damage the driver? Could that be my issue?

it would only damage the driver that runs the fuel pump. so the car wouldnt run at all, since there would be nothing turning on the fuel pump.

Fuel pump is wired independently so if I am understanding correctly even though the wiring may have damaged the driver I wouldn't even know since I am not using that driver?

I disconnected the mentioned relay and as of right now its idling fine (considering tune) and not cutting out!

Spoke too soon. It ran fine, I adjusted timing and shut the engine off to adjust the throttle stop, and the issue is back upon restart.

Sounds like you have a loose connection to track down.

Still no luck.. Verified that power and ground wasn't losing connection, even redid the grounds to be 100%. The power LED on the MSPNP stays on the entire time. Half the time it seems to run normal, the other half it cant even make it to 4K before losing communication and cutting out momentarily. Even if there was a failing component on the car like CAS it would still have communication when it cut out.

I did notice that loading any .msq shows 1 error, but trying to open the audit log in MegaTune gives me another error message "Couldn't edit C:/..../audit.og, ShellExecute error code 31." I've attached the audit.log if anyone has time to take a peek.

Attached Files

audit.rar (2.9 KB, 11 views)

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