MX5_PSI

All of a sudden having an issue with MS "resetting" as it starts to build boost. Never did it before. Only started after replacing the brake booster hose with an oem one with a check valve, and set the "fan on" temp to 180f. Thought maybe the crappy ebay slim fans were causing electrical noise when on, so I set the temp back to 203f and it is still "resetting" when I roll on the throttle and the boost starts to build. I don't think the brake booster hose would cause it, even though it did fix a large boost leak. I wouldn't think fixing a boost leak would cause the ecu to reset though. Car is stock 1.8 with sr20 t25, stock fuel system, MS2PNP. Any ideas where to look next? Ill try putting the old brake booster hose on tomorrow, just to rule it out.

MX5_PSI

Well I went ahead and put the old brake booster hose back on, just to rule it out. First little pull was smooth, and had no issues. ( about 315sec. into the log) I was starting to think somehow the hose was causing the issue. Tried it again a little later ( 523sec. into the log) and it reset again. I noticed this time that when the "reset" happened, the digital odometer on the dash went out for a second and came back on, and the air bag light flashed a couple times. Almost like I had quickly turned the key off and back on. Im not really sure where to look next. Everything is back to the way it was before the problem. Anybody have any ideas? Anything in the logs jump out as weird to someone with experience?

Ted75zcar

iTrader: (2)

If you have the older version of the MS2PNP with the TO package components this could be your problem:

https://www.miataturbo.net/mspnp-55/...2/#post1149065

MX5_PSI

I don't believe I have the older version. I just ordered it from DIYautotune a couple months ago. I'm going to put the oem brake booster hose back on since that doesn't seem to be effecting anything, and its nice to not have a rock solid brake pedal after boosting. When I originally installed the ecu and wideband gauge, I cleaned up the grounding location on the intake manifold before tightening them down. Ill take them off and get it down to nice clean bare metal again, just to confirm its not a bad ecu ground.

MX5_PSI

Well I think I may have figured it out. Took the car out a little while ago and on the way back home it did its "reset" and actually shut completely off this time. No power at all to anything. Pulled to the side of the road, and started troubleshooting what I could. Started thinking maybe a battery cable had popped off or something, so when I opened the trunk I noticed the battery had shifted back, and the edge of the hold down bracket slipped under the little rubber positive terminal cover, and was likely shorting out. Pushed the battery forward so that the bracket wasn't making contact, and surprise surprise I had power again. tried starting the car, and it barely turned over twice before clicking. Called a buddy nearby to give me a hand either push starting or jump starting the car. After 20 minutes or so he showed up, and before pushing the car I decided to give it one last try. It turned over a bit better, and actually fired up. My guess is that the shorting battery overheated, and once it cooled back down it had enough juice to crank. Im willing to bet this was the cause of the resetting in boost. The force of the acceleration would push the battery back and was shorting out on the hold down bracket. I feel like such a noob! I was just messing with the battery a few days ago, making sure connections were tight, and the battery was mounted solid! not sure what caused it to come loose all of a sudden, but im going to dig into it and make sure it stays firmly in place in the future!