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Full on flood of fuel

VB242

VB242

I.M. Weasel
Joined
Sep 21, 2011
Location
Driving the No Malarkey Bus
When I say flooded I mean there was literally a puddle of gas 2 ft. in diameter under car where one of the loose V-band let it out and a fog of gas vapor, probably lucky it didn't end up in a fireball. When I unplug the resistor pack it will clear out and run on the gas remaining in the engine, this indicates to me something is wrong electrically with the microsquirt. The failure occurred at WOT throttle and 6K rpms at the finish of an autocross run. I'm running Siemens 788cc/min low z injectors with the regular Volvo resistor packs. I had my phone plugged in running MSdroid for datalogging, I will see if I can link the datalog but I don't think it will show anything unusual since there doesn't seem to be any changes to the Currenttune file when I hooked it up to the laptop. I'm thinking the injector driver is cooked or more hopefully something is wrong with the firmware. I can't seem to find the right link to the firmware downloader also if someone could help with that. I'm going to step back for tonight it took the tow truck almost 3 hours to pick me and the old girl up.
 
check the resistance across the injectors to the ms including the resistors, make sure the grouping isn't doing something silly. There is an output test mode, you can test the injector driver without running the fuel pump (unless you're powering things from the fuel pump relay)

It does sound a little bit like smoked drivers though.
 
This might not be totally related but...I did a Micro install on a car for a friend, and after about 10 minutes of idling/driving, it runs like ass. I've pulled injector connectors off while running, and sure enough, it looks like one/two of them aren't firing anymore. I thought it was a fluke and was going to try another one. I've been installing standalone EFI since 2000, and have a routine down that helps keep errors to a minimum, but I was second guessing myself after this incident.

Maybe I'll swap his micro for a plain-Jane MS2 and see what happens.
 
Broke4speed said:
This might not be totally related but...I did a Micro install on a car for a friend, and after about 10 minutes of idling/driving, it runs like ass. I've pulled injector connectors off while running, and sure enough, it looks like one/two of them aren't firing anymore. I thought it was a fluke...
Click to expand...
The connections inside the connector like to slide out of place and make weak and intermittent connections, you can pull the rubber boots back and see that it's slid out.
 
I did check some things last night but I ran out of time. There's no voltage at the injectors with the key on motor off. I checked injector resistance to ground at the resistor pack connection, 42.8 ohms for all 4 injectors. I couldn't find my noid lights. I tried to check the wiring from the injectors to the microsquirt connector but was trying to check ign1 because I'm f'n retreaded. I will try again tonight and see about checking more things through tuner studio.
 
you should be measuring resistance across the injector wiring harness, not to ground.. i.e the pin on the micro to the power lead at the resistor box (if that's how you wired them)
 
linuxman51 said:
you should be measuring resistance across the injector wiring harness, not to ground.. i.e the pin on the micro to the power lead at the resistor box (if that's how you wired them)
Click to expand...

That's what I was trying to do but picked the ign1 pin because....I don't know, it was my birthday so I guess a senior moment.
 
I looked at your logs briefly and the only thing I noticed that was a little weird was that the log had several 1 to 4 second gaps (turn on "Fill Time Gaps" and look for the vertical yellow lines across the whole screen). I see this sometimes on my Windows laptop when it get's busy doing other things. Was everything running well until it died?

I also saw your note on ms forums that you're running all 4 injectors off a single injector driver. This is probably overloading it, but it's borderline -- rough numbers are:
~2.5 ohm low-z injectors and ~6.5 ohm volvo resistors = 9 ohm load per injector
13volts / 9ohms = 1.4 Amps/injector
4 * 1.4Amps = 5.6 Amps total

If you test everything and don't find a wiring or resistor issue, you could temporarily change to INJ2 and see if it runs OK again.
 
VB242 said:
That's what I was trying to do but picked the ign1 pin because....I don't know, it was my birthday so I guess a senior moment.
Click to expand...

it happens. can't tell ya how many times I was damn positive I was checking what I thought I was, only to discover that I was, in fact, not. lol
 
So yeah I must have cooked the driver, I assumed the Volvo resistors would be enough. I got it running on inj2 and added another resistor pack I had in line by combining the 4 outputs into one. This didn't have the estimated effect of doubling the resistance but I understand why now it only added 1/4 the resistance after measuring it. The wiring with resistors now measures 7.8 ohms on 2 of the legs and 7.9 on 2 of the legs combined with 2.4 ohms per injector I figure it's requiring 5.06 amps at 13v. Will that .06 amps cook my remaining injector driver?
 
it could over time, I would probably get it repaired and split the load across both drivers if you can.
 
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