Snowmobile Fanatics banner

1 - 18 of 18 Posts

·
Registered
Joined
·
39 Posts
Discussion Starter #1
I have a few old post's on this topic. for two + years I have been chasing this issue. It is most common after sitting at idle for two min. or more. I have tryed every thing. 99 ZL 600 EFI (eliminating kill switch & key, changing fuel, installed RAD reed valves, shaved cyl. head 0.010, replaced pipe with D&D performance trail pipe, changed out throttle position sensor, I even changed out the computer (ECM) and monitered coolant temp. sensor, I've even took the injectors out and had them rebiult,even though the lab scope patern showed no problems with them,Re-clutched drive clutch, installed doubble helix in driven clutch) At the end of last season I installed a D&D chip.
Alas we ran out of snow so I'm not real sure that it helped the 500 yards of snow I found, it bogged out twice.
I have been told now that the mid westerners are replaceing the stock clutch weights with polaris weights.
IS ANYONE FIGHTING THE SAME PROBLEM?
HAS ANYONE CHANGED OUT CAM ARMS?
 

·
Registered
Joined
·
9,619 Posts
i seemed to have a problem like that on my 99 powder special 600 EFI last year, but not enough snow to really figure nething out, i ran some injector cleaner in the gas, but didnt ride it much after that, so i dunno.....see how it goes this year


 

·
Registered
Joined
·
2,584 Posts
have you called D&D and just asked their opinion? My counsin's 99 ZR 700 was doing the samething, but it is carbed. They called D&D and they helped them a bit. It got better though I am not sure if it totally went away.
 

·
Registered
Joined
·
9,619 Posts
hmmm........all '99's.........


 

·
Registered
Joined
·
2,729 Posts
Well you sound like you have covered everything i would have suggested except for two things. Check all the grounds under the hood. Its possible that A/C didnt remove the paint before screwing the grounds to the chassis thus giving bad readings. And one other thing im not sure if it is relevent or not seeing how i have never worked on an efi cat, but i do work on efi cars alot. Does your machine use an O2 sensor? if so, that could be the cause. In other words it sounds to me like your sled is running rich after it idles for a little while. Now if we think about what determines how much fuel the engine gets you are left with an O2 sensor. The O2 usually has final say on how much fuel you are getting because it is what determines if you are running rich or lean. I will rule out the Injector timing because it only does it at idle and not all the way through the rpm band. So for starters try looking for bad grounds, then with all of the other stuff you have replaced i would look into the O2 sensor next. I hope this makes sense to you, i could explain it much better in person, but i did my best here writing down some thoughts. But it is also much easier to diagnose a sled in person. Give me some feedback and let me know what you think.

Polaris is my way out - Other people just use a door.
 

·
Registered
Joined
·
39 Posts
Discussion Starter #6
Triumph...
Cat's do not use O2 sensors the fuel ratio is determined by the MAP value,
coolant temp and TPS value. All grounds are good I have lab scoped all of these sensors as well as the inectors at connector and at ECU all paterns are very clean and within cat specs.
However I aggree with you I am convinced I'm fighting a fuel related issue.
one other tid bit I forgot is I installed a manual fuel pressure regulator, I regulated pressure from 29 psi to 38 psi the higher pressure's helped a little but I have never have been able to get the bog out since the second winter.
Thanks for the reply! PLEASE pass along any other ideas.

IF IT DOSEN'T SCARE YOU A LITTLE,I'TS TOO SLOW
 

·
Registered
Joined
·
4,617 Posts
I was just browsing another site and saw this Just wondering if you had this checked out
There is a possible problem in the fuel pump so maybe check it out.

http://www.snowmobileworld.com/recalls/arcticcat/recalls/1999-3.shtml

Trees don't make the greatest brakes.
 

·
Registered
Joined
·
3,188 Posts
You say this usually happens after sitting for 2+ minutes. Well, what's one major thing that changes whether or not it sits for 1 minute or 5 minutes..........Temperature!

1.) You know that the coolant temperature sensor plays a role in determining the A/F ratio. Perhaps you are running a bit rich after idling for a few minutes. We all know a waterpump runs slower at lower RPMs and that if the sled is not moving, there is no snow to cool the heat exchangers. With that said, is it possible that the coolant is heating up slightly higher than normal operating temperature, causing a higher coolant temperature reading, and ultimately the ECU creates a rich A/F condition? Is it possible that it may do this ONLY after a few minutes of idling, and then when the throttle is opened, you have a bog from too much fuel? Perhaps it is "loading up".

2.) Or, perhaps this short "rich" condition is caused by excessive radiant heat under the hood from the hot engine/pipe, and the intake is breathing in all hot air after a few minutes of idling, and causing a "rich" condition (bog) until the cold air is once again ingested. And then as soon as the cool air is once again being used, you have full power again. Are any of these possible? Think about it.....the engine can give off radiant temperatures of 200-300 degrees F. and if the outside air is down to 0 degrees, then the ECU is trying very very hard to meet the requirements of such a wide range of temperatures. If it can't keep up, then maybe it just goes into a safer mode or "map" and it may run rich for a short period until you get moving (racing) again.

3.) And since when at idle, your TPS is always in the same position, the ECU has one less indicator of the engines status, thus creating one more reason it may choose to operate "rich" after a predetermined amount of time.

This may happen even if your EFI sled is in perfect operating condition. My first thought would have been to replace or alter your chip, but you did that; however, it too may have a safe margin for error.

These are just my thoughts and opinions, so please correct me if this is incorrect. Keep us updated with your findings.
 

·
Registered
Joined
·
2,729 Posts
Well while i am thinkin about this i have another suggestion, once again im not sure if it is relivant or not but its something relitivly inexpensive to try. I just finished reading an article about exaust pipes and they threw out some interesting ideas. But from what i read, i would try wrapping your exaust pipe to keep it heated up. They are suggesting that when the sled idles the pipe begins to cool down thus losing performance. Exaust pipes are designed to work best when hot so when they cool they cant produce. I think it would be something cheap and easy to try (wrapping your exaust with an insulating material to keep it hot when idleing). I will keep thinkin about this and let ya know what else i come up with.



Polaris is my way out - Other people just use a door.
 

·
Registered
Joined
·
2,729 Posts
Thought of one other thing....you have probably already checked into this, but have you made sure your thottle body is clean? Or is it possible that the throttle blade is closing too far? Or does the sled use an IAC motor? (idle air control) Once again this would be much easier if i could actually get some hands on time with Cats setup, but i will keep thinking.

Polaris is my way out - Other people just use a door.
 

·
Registered
Joined
·
39 Posts
Discussion Starter #11
Trimuph
I thought about wrapping my pipe but, I'm a mountain rider and with
the head shaved and the fuel pressure backed down heat must go some
where. I dont want to risk a lean melt down. I cant afford a new motor right now. The dirty T-body issue was one of the first things I thought of, being a
auto tech. we see the sag at tip-in quite often. almost always caused by coked throttle blade.

Megaman
Great ideas to investigate. I'll have to figure a way hook up my lab scope
and make darn sure it is secure. that has been a big hold back in getting good trail readings I'm scared of loosing my scope off the side of the trail
I dont think UEI warranties snow damage on their scopes. If I lost it playing around with my slead The BOSS wont let me buy another. she wasn't happy about $600 the first time. hehehe
The hot air intake is another great idea I have been playing around with that same idea, my concern with this is altering the air box, not being able to get it back to stock if it disrupts air flow so greatly that I create more or a worse problem.
If any one has modified A cat EFI air box let me know how that turned out.

Hay thanks for all the great input guys please keep it comming

IF IT DOSEN'T SCARE YOU A LITTLE,I'TS TOO SLOW
 

·
Registered
Joined
·
9,619 Posts
i just got around to reading the big clutching article in snogoer, and w/ my powder special i think i will have to look into that, cuz it seems doggy when workin the throttle (hard to explain, but takin moguls and stuff) and im thinkin it could be engagement RPM is to low? or high? i dont remember off hand, but it explained that if it was to low or high it would be boggy. i will have to look into that, and check for bad grounds etc... like u guys suggested.


 

·
Registered
Joined
·
2,729 Posts
Now mega-man has some very good points, but what i am wondering is does EVERY 1999 A/C ZL 600 efi behave this way. If the answer is no then we are looking for something specific to this machine. The coolant temperature and the Air intake box will be the same on all 99 ZL 600 efi machines so unless every one of those sleds has the same symptoms i will rule them out.

As for the TPS reading, when the throttle is closed the sensor is still used, it is telling the computer to idle the machine, or 0% throttle angle. So the computer still uses it to adjust the fuel trim.

Something else i will bring up is the injectors again. Do you know if the Injectors are pulsed or are they constantly on? I previously thought that the timing of them would have been ok, but with the process of elimination we are getting back to that. If they are pulsed look into whatever gives the computer the signal to fire the injectors.

Another thing that i am wondering is how does the computer adjust the idle? Does it have a bypass around the throttle plate or does the computer control a motor that opens the throttle plate slightly? In either case the device should be checked to make sure it responds as it should. What i am suggesting is that the TPS sends the signal to the computer sayin go...and that the idle control device closes as soon as it sees a tps reading above x% when in all actuality it should stay open to help create a smooth airflow.

Once again, Im just throwin out ideas here so i may be offbase, but im a Car Technician by trade and a sled technician by curiosity. Sleds are my love so i try to gather what i can and be helpful to everyone.

Polaris is my way out - Other people just use a door.
 

·
Registered
Joined
·
2,770 Posts
Hey Sledhead,
I think that i have found a solution to you sled woes.
Make sure that the next time you get onto your sled
that this is what you see.........

/snofan/../images/users/500fasEnuf/dash.jpg

Just kidding SH, maybe try changing the windsheild,
sounds like that is the only thing you haven't touched.

I used to ride a rare '81 Trailcat that was always breaking down
and was impossible to get parts for.....so I feel your pain.
K

Ride to ride again.
 

·
Registered
Joined
·
39 Posts
Discussion Starter #15
Trimuph
I figured you were an auto tech. too we 're speking the same lingo.
the T-bodys have no IAC system idle is controlled via throttle blade angel
my wife's is a 2000ZL, that is the machine I've swaped parts with (everything but injectors are the same) The pulse width of inj. are very clean and pretty much the same between sleads as well as current ramp on both inj.
I think what Im going to do is hook up the lab scope and moniter pulse width as it warms up and compare them.
Being a technician this is driving me bat s**t crazy, cuz I know it's not right !!
I'll have the machines at my house in a few weeks, We keep them at my folks place in the mountains. When I get them over here I'll let you know any results.
Untill then any more ideas pass them along

IF IT DOSEN'T SCARE YOU A LITTLE,I'TS TOO SLOW
 

·
Registered
Joined
·
39 Posts
Discussion Starter #16
Injectors timed off of the crank sensor. dual trace shows thay are in sync
crank has good clean square wave too.

IF IT DOSEN'T SCARE YOU A LITTLE,I'TS TOO SLOW
 

·
Registered
Joined
·
2,729 Posts
Have you Pulled the Crank Sensor Just to check it out? Possibly have a metal shaving stuck to the magnet? It would still allow a clean square-wave but might shorten the height of the wave so your computer is having a hard time reading this signal. I see this type of thing with the GM cars and crank sensors after they have warmed up usually causing a stalling/no-start condition though. But of course if your sled uses a hall-effect type sensor this can all be thrown out the window.

Just something else i thought of.


Polaris is my way out - Other people just use a door.
 

·
Registered
Joined
·
2,729 Posts
Forget about the previous post i made....i wasnt thinking when i replyed. You obviously use a hall-effect sensor(switch) if you are getting a square wave. the PM sensor would give you a sine-wave. Sorry bout that.

Polaris is my way out - Other people just use a door.
 
1 - 18 of 18 Posts
Top