Snowmobile Forum banner

94 ZR580 EFI warm start problems

6K views 31 replies 4 participants last post by  kccats 
#1 ·
Greetings from the foothills of the Wind River range and a noobie.

I recently acquired a 94 ZR580 EFI from my father-in-law. He has had this issue with it for a few years so he sent it home with me to get a little use out of it. Sled starts great even in very cold temps and runs great too......until you shut it off. Then you have to wait until it cools down (like WAY down) before it will start again. It's the craziest thing and very frustrating as we can't go anywhere with it except around the pasture.
Exactly what happens is this:

- Starts on 1st or second pull every time
- sometimes sits and idles no problems and sometimes need a little throttle feathering to keep it going
- runs GREAT
- You shut it off or let it die after running for awhile
- go to pull start it it and it sputters and tries to start to give you false hope
- you pull and pull and pull until you're worn out and it will not start
- after several hours over night you repeat the above steps starting with firing right up after one or two pulls

I'm thinking some sort of ECM issue? Do these even have ECM's?
I have quite a bit of experience with vehicles both gas and diesel but zero experience with snow mobiles or even 2 cycle stuff. My father-in-law is a sled head and a hill climb pioneer from Logan, UT but is not a mechanic and has had very little time for the last few winters to do anything about it.

Where could I start?

TIA
 
See less See more
#2 ·
When it won't start, are the plugs wet or dry?

I would verify fuel pressure. Often, the pressure regulator gets old and stiff and may be giving too high of fuel pressure so the injectors may be making it too rich for starting when hot. KCCats has an adjustable regulator that can help that problem.
 
#3 ·
Yep here is what I have found, as the Cat efi grows older the rubber in the diaphragm stiffens and fuel pressure goes up!
And at about 40psi it wont run!
Try this, get a foot or two of 1/4" fuel hose a 1/4" T and a 0-60 gauge and add a hose barb fitting (Ace)
Take the inlet off the fuel rail (clutch side) and add the T the a small piece of fuel line back to the rail!
Then bring the rest of the hose up and out of the engine compartment and put the gauge where you can see it!
Report back!
 
#6 ·
I build an adjustable fuel pressure regulator complete with Gauge to tell exactly where you are!
That being said, you have to understand how to Jet an engine!
Read that as to know the difference between lean and rich!
I have found this to be the BEST way to fine tune the Cat EFI system(older)!
$225
And if you are close I would let you use my T and gauge set up?
 
#7 ·
Also, the battery used in these units must be in good condition (read well charged and capable of holding it) or there will be running issues.
That being said, as previously posted, if it is over pressured it will run very rich.
When starting warm if you hold the throttle wide open when cranking, the ecu will over ride and produce less fuel.

You should also check and see if there are any trouble codes showing,
Any of them can also cause the ecu to run rich.
Air temp.sensor, coolant temp sensor, or having a pressure regulator in need of replacement.
 
#9 ·
On the side of the ECU there is a red LED light. Usual operation is one blink. If there are more blinks, count the number and duration... that will give you a code. Then look at the chart to tell you which sensor is misbehaving. You may not be throwing codes when the pressure gets too high. The sled thinks it's operating just fine.
 
#12 ·
The light will flash once when the ECU is initialized.
Any more than that is a trouble code.
It will blink in long and short durations [example; 1-3, 2-1].
So if you see anything like this write it down and let us know what it is.
 
#15 ·
Probably not my starting problem then. The fuel pressure gauge should be here by Wed.
Between wrestling and work and sub zero temps I won't be riding much anyhow.
 
#18 ·
That fault causes the ECU to pump more fuel into the cylinder to try to cool it down thereby flooding the engine.
The Sensor should be right near the top of the engine on the coolant manifold, usually right by the pressure cap.
It will have a single wire attached and that could be corroded/broken/ or the sensor itself will need to be replaced.
 
#20 · (Edited)
I got an afternoon to go out in some fairly fresh powder in the pasture with the wife and baby and I got nothing but a bunch of strained muscles! I pulled and pulled and got a 2 second sputter several times but no run. Maybe that diaphragm completely kicked the bucket or the sensor has totally kicked the bucket? If I feathered the throttle a little I got the best results but never got it to run for more than 2 seconds. (I know EFI isn't supposed to have the throttle played with but it seemed to help momentarily.) It appears I have fuel coming from a leaky gasket around one of the cylinders as well as fuel finding a little leak in the muffler. All of this would point to way too much fuel - like what you all were saying. I know I have good spark but now I'm going to pull the plugs and pull until I'm worn out again to try and dry the fuel up a little.

Where is a good place to find a sensors/parts? And which model do I have?!?! The hood says ZR 580 and behind the seat says mountain cat. It is definitely EFI but whichever parts website I look at there are options for Mountain Cat, or ZR, or EFI, but none of them are together.

Nate
 
#22 ·
To dry it out quickly, remove plugs and pull it over about a dozen times.
Put plugs into the caps and place them into the holes.
With the key on and throttle held wide open, pull it over.
It will ignite any remaining fuel (with a loud bang).
You may have to do this a couple of times.
If you are not going to run it at this time, leave the plugs out and any remaining fuel will evaporate.
 
#23 ·
I see on the Arctic Cat Parts, Snowmobile Parts, Atv's at Alpha Sports Center, Arctic Cat ATV, Arctic Cat Snowmobile Arctic Cat OEM Parts web site that Arctic Cat had a 1994 EXT EFI 580 Mountain Cat and a 1994 Wildcat EFI 580. If you have a longer tracked sled, it's not a ZR and someone has switched the hood. It doesn't show a 1994 EFI ZR580, the first year for that was 1995.

The site shows the EXT and the Wildcat use the same water temperature sensor. Spendy little guy at $38.16.

To test the sensor, (From the 1995 ZR 580 EFI Factory Repair Manual)

1. Disconnect the main wiring harness connecctor from the water temperature sensor.

2. Connect a multimeter between the sensor terminal and any convenient chassis ground (or any brown wire). The mulitmeter must read less than 20 ohms of resistance with the water temperature above 230 degF. The multimeter must read OPEN (Infinite resistance) with the water temperature below 190 degF.

NOTE: It may be easier to remove the sensor from the water manifold for testing purposes. Immerse the sensor body (only up to the threads) in automatic transmission fluid and slowly heat the fluid. The multimeter must indicate the above resistances when connected between the sensor terminal and the sensor body/chassis
 
#29 ·
I see on the Arctic Cat Parts, Snowmobile Parts, Atv's at Alpha Sports Center, Arctic Cat ATV, Arctic Cat Snowmobile Arctic Cat OEM Parts web site that Arctic Cat had a 1994 EXT EFI 580 Mountain Cat and a 1994 Wildcat EFI 580. If you have a longer tracked sled, it's not a ZR and someone has switched the hood. It doesn't show a 1994 EFI ZR580, the first year for that was 1995.

The site shows the EXT and the Wildcat use the same water temperature sensor. Spendy little guy at $38.16.
Which sensor would it be - the one wire or two wire? Looking at that site it has a coolant temp sensor for $129 as well. (1995 ZR580EFI Part# 3004-059)
 
#24 ·
I was looking at used ones on ebay for around $32 so a new one would be a better bet. One of the sellers also told me that with a manufacture date of 6 or 8 of 94 that it is actually a 95 model. Is that correct? The VIN is gone from the tag but the manufacture date can still mostly be seen.
 

Attachments

This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top