holy driver

While tuning my VE map tonight I found that MegaTune kept reporting that it would lose communication while trying to write "Page 13" to my MSPNP. It would happen repeatedly right after I heard the fuel pump prime (which I hear every time the MS starts up). It seems to repeatedly take 3 or more tries to get the MSQ to program without MegaTune complaining. Has anybody seen anything like this before?

For what it's worth, the car was totally warm as I'd been driving and tuning a lot. I'm running an MSPNP94/95 in my '95 with a GT2554, RX-7 460cc injectors, and an Innovate LC-1. I'm using saboteur's MSPNP 10G Hi-Res firmware image. Also, this problem only started tonight; I've loaded tens of maps before without any problems.

Oh, and if anybody has a setup close to mine, I'd appreciate any maps or .msqs you want to share.

My .msq is attached, but I doubt it's the problem. This feels like some kind of hardware issue. I almost want to just chalk it up to heat or something, but it's pretty troubling.

paul

iTrader: (21)

Had a simliar problem, kept getting "battery too low to successfully burn". It would come up randomly. I got into the habit of uploading new MSQ's while the car wasn't running for a while. Now I don't get the error any more even while uploading while driving. No idea what was causing it so I guess this thread wasn't very helpful.

I do run a 2554 with rx7 460's though on a 94. Here is the timing map I run

Matt Cramer

Are you using a serial port or a USB adapter?

holy driver

Paul: thanks for the map, I actually based my AFR map off of the one you posted in this thread: https://www.miataturbo.net/forum/sho...ht=afr+targets

I'm using a regular com port (no usb adapter) but I also have a usb adapter I could try.

My working theory is that the battery voltage is dipping low during the fuel pump prime when the car is hot (and the fan is on). I figure that while the car is hot the fans plus the added resistance in the wires from the heat is enough to lower the voltage enough that the MS restarts or something? I will try turning off the fuel pump prime tonight and see if that has any effect. For that matter, the stock ECU never used to prime the pump whenever I turned the car on like this so I assume it's unnecessary? I will also try measuring the battery voltage during programming.

Oh, I should also point out that I have a secondary fuel pump in line with the stock one (I think it's either a Walboro a Pierburg) which is left over from when I was running a BEGi AFPR. I haven't taken it out because I figured it was benign, but maybe I should just pull it now.

Matt Cramer

Pulling that second pump may not be a bad idea; too low voltage can prevent it from loading MSQs and that pump can pull the voltage down.

We've found it makes for easier starting if the fuel pump primes the system.

ScottFW

iTrader: (4)

I had the same problem last night, loading new .msq on a warm car. First I got a battery too low warning, then on a subsequent attempt I got a page 13 error. In both cases it happened right when the fuel pump primes. FWIW, I only have the one stock fuel pump. I did have the stim with me, so I just powered the MS off that to load the new .msq.

holy driver

Interesting... It's good to know that I'm not the only one then.

I didn't get to do my diagnostics last night because I've been kind of sick, but I'll try to take a look tonight.

holy driver

I haven't changed anything in my setup and I haven't been able to reproduce the problem anymore. I'm not sure whether to be happy or not.