580 EXT EFI Injectors Going Bonkers - ArcticChat.com - Arctic Cat Forum

LinkBack Thread Tools Display Modes
post #1 of 17 Old 01-10-2017, 05:27 PM Thread Starter
Junior Member
Junior Member
Join Date: Jan 2017
Location: Liberty, UT
Posts: 5
Thanks: 0
Thanked 1 Time in 1 Post
580 EXT EFI Injectors Going Bonkers

HHEEELLLPPP, please for the love of god someone help. Long time reader and fixer, first time I haven't been able to find any solutions through other peoples pain. I have a 1995 580 EXT EFI that has been giving me more than a run for my money. Short of the long is the injectors are being held open and flooding the engine like crazy. There is 12.62 volts at both injector connectors, battery voltage is 12.82 even with the key and kill switch off. If i disconnect the injectors I can start the sled, plug them back in and ride all day, plugs come out the most delicious mocha tan color, runs perfect, idles great, reaches max RPM, gets decent fuel economy. Shut the sled down, come out the next morning and it's a bear to pull, flooded to the gills and generally takes four grown men 30 min. to get it going. Unplug the injectors, pull the plugs, leave it sit for a few days and it acts like nothing ever happened and laughs at me.

A few details and checks so far:
Battery: brand new, holds charge, even recharges during riding to proper voltage
Injectors: Pulled, cleaned, flowed, bench checked -work great
Stator: Resistance within serviceable limits (almost dead nuts actually)
ECU: No codes, injectors still have voltage with both connectors off
Compression: A cool 120 each cylinder with 2 different gauges (one of which is actually checked and calibrated every 6 months - how's that for legit?!
Drop resistor: each black to white gives 5.9~6.0 ohms, black to black is 12.0. With that disconnected the injector power is finally cut off
Injector and Ignition triggers checked good
TSS circuit bypassed or not makes no difference
Found one loose ground on the back of the ECU - no change.
I tried fiddling a little bit with the throttle position sensor without any luck.
Fuel pressure builds to about 36 PSI and holds when the injectors are unplugged, when they're plugged in it drops quick and fills the engine with fuel.

I couldn't find any obviously damaged wires or harnesses although I have not completely torn the sled down, I tried shooting wires to ground but unfortunately even with Arctic Cat's glorious shop service manual there just isn't a comprehensive wiring diagram for the EFI system which serves to annoy the ever loving christ out of me and I have no idea what should be grounded and what should not.

So I'm at wits end, this is my 10 year old son's first sled that Santa brought him this year (Santa doesn't deal dope so he ain't rich) and so far after getting towed out twice and watching his dear old dad's eye twitch and get his hand caught in the secondary clutch he isn't so impressed with owning a machine.

Sorry to write a novel but that's the way she goes.

Last edited by tadschude; 01-10-2017 at 06:03 PM.
tadschude is offline  
Sponsored Links
post #2 of 17 Old 01-10-2017, 05:55 PM Thread Starter
Junior Member
Junior Member
Join Date: Jan 2017
Location: Liberty, UT
Posts: 5
Thanks: 0
Thanked 1 Time in 1 Post
Update to that first post: there is continuity between the injector ground pins on the small ECU connector and the injector leads, no continuity to ground veering me away from the possibility of a wild ground in between. There is NOT power to the injectors when the small ECU connector is pulled. I pulled the ECU cover and nothing appears to be physically burned or loose, not saying that something else might not be wonky in there though.
tadschude is offline  
post #3 of 17 Old 01-10-2017, 07:40 PM
Senior Member
Patrickmccaherty's Avatar
Senior Member
Join Date: Jan 2013
Location: Jacksonville Il
Posts: 721
Thanks: 42
Thanked 66 Times in 63 Posts
Sled: 04 f7 plus 3 others
06-07 Mileage: 650
ATV: 95 Polaris 400
This may be a dumb ? But do the injector colors match the ecu?
Patrickmccaherty is offline  
Sponsored Links
post #4 of 17 Old 01-10-2017, 07:57 PM
Super Moderator
1995acext580's Avatar
ArcticChat.com Moderator
Super Moderator
Join Date: Dec 2010
Location: Grasston, MN
Posts: 4,190
Thanks: 128
Thanked 349 Times in 315 Posts
Sled: 05 F7, 98 ZR600, 95 EXT580
07-08 Mileage: 896
06-07 Mileage: 1354
ATV: 96 Polaris magnum 425
I have no input on the injector issue but I would like to hear how dad got his hand stuck in the secondary clutch

Sent from my XT1585 using Tapatalk

2005 Firecat F7
1998 ZR 600 EFI-needs engine
1997 ZRT 600 Sold!

1995 EXT 580
TSL 136" skid

Welcome to the mad house. Don't mind the rubber walls. Drugs are served an hour before breakfast and and hour after dinner.
Don't drool on the furniture
, keep your feet off the table, and don't make the guys in white coats mad.
1995acext580 is offline  
The Following User Says Thank You to 1995acext580 For This Useful Post:
Patrickmccaherty (01-11-2017)
post #5 of 17 Old 01-10-2017, 08:17 PM
Senior Member
Senior Member
Join Date: Nov 2007
Location: Wi.
Posts: 1,524
Thanks: 25
Thanked 214 Times in 202 Posts
Sled: king cat
07-08 Mileage: 500
06-07 Mileage: 700
Next time you shut it down for the day pull the injectors out but leave them hooked up to the fuel lines or just pull the throttle body out of the boots. Check the next day to see if any fuel has leaked past a injector, the fuel line should hold around 40 psi in the fuel lines for a while after shut down, could be a injector is letting the fuel seep into the throttle bodies.
diggerdown is offline  
post #6 of 17 Old 01-10-2017, 09:21 PM
Senior Member
660catman's Avatar
Senior Member
Join Date: Jan 2014
Location: SE Manitoba, Canada
Posts: 4,955
Thanks: 338
Thanked 636 Times in 590 Posts
Sled: 16 Bearcat XT, 06 T660 TT, 05 S/Cat 600
ATV: 03 400 4x4 auto FIS, 05 300 4x4
Do you have power at injectors if ignition switch is unplugged. Something is putting power to injectors when it shouldn't be there.

Current Sled rides
2005 Sabercat 600 EFI LX
2006 T660 Turbo Touring
2016 Bearcat 2000XT

Past Sled rides
1993 Pantera 550 EFI
1980 El Tigre 6000

Current ATV rides
2005 A/C 300 manual 4x4
RTR Bushings & shock bushings

2003 A/C 400 auto 4x4 FIS
RTR Steerlites & Shock Bushings
Motobatt battery
26" Kenda Bearclaw HTR's

Past ATV rides
2003 A/C 400 manual ACT 4x4
RTR Shock Bushings
Rebuild Project started Mar 15 / 2017
Completed April 8 / 2017

Sold May 16 / 2017
660catman is offline  
post #7 of 17 Old 01-10-2017, 10:39 PM
Join Date: Oct 2016
Location: ojibwe gichigami
Posts: 308
Thanks: 17
Thanked 29 Times in 26 Posts
What year is your EXT? Early battery and late batteryless were different systems. One year was even a bastard child year I think, different from the others.
SevenBlizzardsRoad is offline  
post #8 of 17 Old 01-11-2017, 09:13 AM Thread Starter
Junior Member
Junior Member
Join Date: Jan 2017
Location: Liberty, UT
Posts: 5
Thanks: 0
Thanked 1 Time in 1 Post
As far as the color codes everything is red, even verified the PROM chip matched. I pulled the injectors, put then on the bench overnight with about 35 lbs of dyed fuel behind them, not a drop on the napkin, put power to them and sprayed good. I don't have a spare ecu to slave in and interest in buying parts for this is waning. at this point I'm leaning towards wiring a switch into the injector leads to manually shut them off.

As far as the hand clutching goes.... well let's just say that in the heat of the moment when you're not thinking and grab a belt to pull some tension off it while it's got a little load on it..... well stuff happens and then your son sees you scream like a bitch in front of your friends. not my brightest moment by any means
tadschude is offline  
post #9 of 17 Old 01-11-2017, 11:17 AM
Senior Member
Senior Member
Join Date: Oct 2003
Location: Blairmorganville
Posts: 3,802
Thanks: 4
Thanked 95 Times in 95 Posts
Sled: 94 ZR 580
I'll second Diggerdown's suggestion before you throw any parts at it. That should confirm if there is power to the injectors, with the ignition off, that is holding them open.

94ZR580 is offline  
post #10 of 17 Old 01-11-2017, 12:17 PM Thread Starter
Junior Member
Junior Member
Join Date: Jan 2017
Location: Liberty, UT
Posts: 5
Thanks: 0
Thanked 1 Time in 1 Post
That's pretty much what it's doing, leave them plugged in and the crank gets filled with fuel especially with a near full tank of fuel, it just seems to siphon it through unplug them electrically and not a drop gets through until they're plugged back in. if they're plugged in when the fuel pump primes up it just sprays fuel like crazy, if i unplug them, let the pump prime and begin starting (I found that plugging them in after the first pull is best practice) It starts after 1 or 2 pulls, idles out, warms up and rides all day. This thing is driving me off a cliff. if it didn't run so good after it was going there would be bullet holes all over it. does anybody have any other wiring resouces?? i.e. a breakdown of the ecu board, ecu/efi wire harness, anything?? I would love to just pin out the ecu connectors and find a short to ground if I could only....... $h!+..... just found a picture. more meter chasing to follow after work today.

This is a 95 battery powered efi btw
tadschude is offline  
The Following User Says Thank You to tadschude For This Useful Post:
SevenBlizzardsRoad (01-15-2017)

  Lower Navigation
Go Back   ArcticChat.com - Arctic Cat Forum > Snowmobiles > Arctic Cat Snowmobiles > Z/ZL/ZR/ZRT/Tcat/EXT/jag/cougar

Quick Reply

Register Now

In order to be able to post messages on the ArcticChat.com - Arctic Cat Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome