45 miles on 3 cylinders

[Canyonero]

I was going to have a mini-vacation soaking at a hot springs resort about 100 miles away, and I thought, I'LL DRIVE MY TROOPER! Trooper has MegaSquirt and that is a nice road to do some tuning on. And everything was working great. The hills were perfect for holding the engine at various loads to let the megasquirt auto-tune do it's thing. But then I started losing power. My megasquirt was on fire. First thing? Take a picture.



I plugged the factory ECU back in hoping to complete my trip on that, however the truck didn't want to start, and when it did it was very weak and sounded strange. I shut it off since obviously something besides the ECU had failed. Looked around under the hood, nothing seemed amiss. Started the engine again and checked the injectors - one wasn't spraying. I was running on 2-4-6. I unplugged injector #1 to avoid ruining my stock ECU.

Looks like an injector failed and over-currented the board in a catastrophic way.



So, I turned around and drove home. Three cylinders drove me at 55 MPH most of the way. No relaxing in a natural hot spring fed pool for me. Sad.

[pocket-rocket]

That sucks... At least you made it home ok.

Sent from my HTC One X using Tapatalk

[young gun]

My megasquirt was on fire. First thing? Take a picture.

[ATTACH=CONFIG]7919[/ATTACH][ATTACH=CONFIG]7920[/ATTACH]

Quick thinking!

Man good thing you had noticed! Could of been alot worse!

[Canyonero]

Quick thinking!

Man good thing you had noticed! Could of been alot worse!

I do carry a fire extinguisher just in case. I'm still out $219 worth of Megasquirt. I have to buy a new MS1 kit and I'll just drop my MS2 daughtercard into it. :/

This is in my Trooper which has 4wd and manual hubs, so I stuck it in low-range with the hubs open to get 2wd-low and started down the road. But once I was cruising at the top of low range (35MPH-ish), I figured I could probably be in high-range. Turns out I could hold 55MPH in 4th gear most of the way. Not too shabby for a medium-size SUV with half an engine.

[carbon]

It's an interesting sound, isn't it? Don't ask me how I know...

[Canyonero]

It's an interesting sound, isn't it? Don't ask me how I know...

Oh but I must.

[carbon]

It involves a Fiero... and fire.

When I first got the thing, I put new plug wires on it, but I couldn't find a specific set, so I bought the generic GM V6 set. The wires were waaaayyy too long.

So... I was cruisin' along one day and I smelled something burning when I came to a stop. Nothing showing in the rear view, went away when I moved... must have been someone else.

Back to cruisin' along and I start to notice a weird vibration when I step on the gas... goes away when I let off. (Cyl #1 is gone) Come to a stop again, and there's that smell again, now I'm worried. I take off again and suddenly it gets much worse! (Cyl #3&5 both drop) And I am in traffic... and now there smoke coming out of the deck vents. I floor it (dat sound...) and pull off into a mall parking lot where it stalled.

I popped the decklid and found that the #1 plug wire fell down onto the exhaust manifold where it smoldered for a while and then lit up like a metal wicked candle. It in turn then burned through the wires for #3 and #5 and melted the connectors/wiring for my temp gauge sender and tach filter. It finally stalled when the fire got to the short wire from the coil to the cap.

It was still burning when I saw it, like a couple of slow bomb fuses, so I reached in and yanked the unburning ends out and called a flat bed. No fire extinguisher, I was lucky.

[Guest]

You could get away with just buying a circuit board and transfer over your existing components, and the couple new components to replace the failed ones. At least that's what I would do.

[Canyonero]

Well, I figured out what the problem was. It was a combination of things. I had the MegaSquirt built to run low impedance injectors, but I had the PWM and current limiting settings in the software configured for high impedance injectors. So, too much current was running through the injector circuit. Combine that with the the stock wiring supplying injector power right off the main relay with no protection aside from the main fuse-link... That's a lot of current allowed (commanded through the incorrect software settings) to flow through the injector driver over an essentially un-fused circuit, hence the fire.

Had the software been set up correctly, everything should have worked fine.

I found another set of TBI injectors while I was gathering my MPFI gear together last night. Popped those in and I'm running on 6 cylinders again, with a stock ECU.