Nice to meet you at the desert this weekend. I think I saw 4 rzr's all weekend.

 

Great meeting you also, I glad you had a safe trip. hope to see you again on another trip. and thanks for the beer on the trail there at Randsburg,

 

Is the idle smooth or does it oscillate?
What level is the fuel tank when the problem occurs?
Does it accelerate well? It if does try checking the basic first.

Restriction in the fuel supply (what's your fuel pressure at the fuel rail?)
Low Compression (I assume it's O.K. because it starts off good and gets worse as time goes on).
Crank Case Breather is Plugged.
Spark Plug-Has it been changed lately?
Check all connectors at engine management, TPS etc.
Plugged Air Filter
Leaking Injector
Has anybody messed with the throttle stop screw?

More information please.

 

Check your plugs, too. Polaris set the idle mixture very rich so if you're doing lots of low speed puttering on your trips maybe your plugs are loading up. The Rzr will idle pretty decent on 1 cylinder--a little rough of course but if you're not looking for it you might not notice.

 

We were out Saturday and 3 out of 3 rzrs did this verry thing.. outside temp was approx. mid 80s, trail conditions verry dusty, one stock and the other 2 are piped and uni-ed. Filters at the end of the day were beyond dirty.....And throttle body has traces of dust.....And by the way my machine is 20 days out warranty....

 

pull out your fuel pump, it is only six screws. Check the screen on the bottom of the pump. I had similiar problem.

 

Dirt collecting under your throttle valve causing TPS to back down the Idle..Your sucking too much dirt...Pull your Throttle body off and check the back side of throttle valve..You"ll be shocked...

 

I would check your filter, if it's not getting good air flow, it will not idle worth a damn. Also, are you running a lot of accessories, if so, check your battery.

 

Sorry about that, just noticed you said you filter was clean.

 

dirt has collected between the the trottle plate and the trottle body thus not allowing it to idle or mix fuel with air.... I think i am going to build a dual filter set up.

 

the dealer replaced my tbap runs good now

 

Actually that is the t map sensor, thats an eighty dollar part. I hope Polaris paid for it and not you. Also, it can be affected by dust that gets past your filter, that never happens, right. If the dust coats the sensor
you may start having problems. It is located in (on) the throttle body boot which is attached to the back of the air box, an area that is supposed to stay very clean, just ask Polaris.

Glad your all fixed up.

 

Actually that is the t map sensor...

Parts diagrams call it T-MAP but the service manual calls it T-BAP.
Temperature-Barometric Air Pressure vs. Manifold Air Pressure I assume. Since it's on the atmospheric pressure side of the throttle body I'd stick with T-BAP.

Just splitting hairs and picking nits...LOL

 

Temperature-Barometric Air Pressure tbap - thats what i said

 

I had this happened to mine Saturday too. But I had gone from about 9000ft to 11,500 ft, then back down to about 5000ft. It ran find till we got done low, then it wouldn't idle. I check my filter, it didn't look too bad. The next day it ran fine?

 

I'm going to be taking a ride next month that is going to transition from a few 100' to over 6000' in elevation. Has anyone done similar with no problems? Or should I be expecting problems at the top or at the bottom when I get back down?

 

I have heard that you can relocate the tbap to another like behind your seat and put in a nice air tight encloser to keep clean. I heard turbo guys do that. For fun I removed mine from my boot and just let set out and it did not make a diff in the way engine ran. I don't understand how it is affecting the way other peoples engines are running. Can someone please explain this sensor and its function. I believe it to be a baro sensor to tell computer elevation and a intake air temp sensor to let computer know iput air temp. I don't know please help me out.

 

Yep I mounted mine behind the driver seat like you described. It has the green O-ring:

Here is the other side of the firewall:

It is my understanding that it measures the barometric pressure and air temperature.

 

So if it is behind seat in the elements how in the world does it make someones rzr start running good? I mean it can not get any dirtier than behind your seat like that. I would think it is impossible to mess with the way the engine runs. On a different note Do you like your MCX turbo set up? I am getting ready to install a turbo on mine. Mine will not be as easy to install as yours. I am going to try and make my own kit. It will probably suck pretty bad. I foresee problems with getting fuel mixture correct in the end. I do have a programable ECU that will help me in my quest. It is Rev, Fuel and Timing adjustable. So I should be able to get it pretty close.

 

We're actually running a 3rd injector in ours to get enough fuel under max boost.

Jason

 

It stays pretty clean behind the seat... but I only run in the sand dunes...
The turbo is great. building your own will be tough...
The silver MCX computer you see in the picture senses the manifold air pressure and adds fuel (via third injector) based on the amount of boost being created by the turbo (in basic terms)...

 

My buddy has two of these with the Aerocharger set ups. It has the 3rd injector as well. My plan was to piggy back a third injector onto one of the others. From what I have seen this motor fires both plugs and injectors at the same time. If that is true a third injector piggy backed in should do the trick. It will be the map that will be fun to make. I was just going to use a spring to set up my boost. The Aerochargers use springs,so i can steal some of my buddy's springs to get set at correct pressure. The pluming is not to bad, I have intercooler, pluming and turbo setting here. I just need to work on the fuel part. I am sure it will be tons of fun once it is going.

 

... From what I have seen this motor fires both plugs and injectors at the same time....

Is that true? I know that both pistons move up at the same time, but I thought that while one is compressing and firing the other was exhausting and intaking... Can anyone confirm if both pistons fire at the same time or if they alternate?

 

in my new dynatek coil box instructions it said to hook up coil to either plug it did not matter. I know on cars the system is usually called waste spark. It fires plugs on two cylinders at the same time. It will only ignite the cylinder with compression. I can personally say that I tried it on my rzr with work on either coil tower.

 

the pistons move together and the plugs fire every rotation. it's called wasted spark..
the engine runs as an even firing twin, meaning that the pistons move together but they alternate which one is on the compression stroke..

harley davidson engines run the same way, they are proud of the wasted spark as it gives their bikes that distictive harley sound.



the term t-bap and t-map are interchangable as far as the sensor goes.. if it's on the outside of the throttle blade it is a t-bap set up where the sensor only provides temprature and barometric pressure..
for the systems that use the t-map, the sensor is on the manifold side (feeling engine vacuum) in this case it provides a rudamentary method of giving the ecu an idea of what the air demand is..(it's a cheap and easy way to simulate a mass air flow sensor) vacuum drops so it knows that your throttles are open, high vaccum means their closed.. the term t-bap and t-map actually relate to how the ecu processes the signal from the sensor.

if your t-bap sensor is jacked up or disconnected the ecu uses a limp home value. i believe it is equivalant to 600ft and 62 degrees(if i remember right)

in rustys case he was at 3000 ft, if his t-bap was plugged it was reading 300ft (home altitude) if it was bad the value for the ecu was 600 ft in either case he was getting too much fuel at idle, which would answer the question of "i unplugged mine and nothing changed, how could that make his run bad)
also if the tbap was messed up it could have given a false reading of who knows what altitude..
altitude in the tbap is calculated by reading the drop voltage on the back side of the sensor, multiply that voltage by 25 and it gives you pressure in kpa. as an example, at 300 ft 60 degrees, the atmospheric pressure is roughly 105.6 kpa, at sea level the same temp the pressure is roughly 94.8 as you can see it only takes 1.11 volts to change what the ecu sees in elevation by 3000 feet, so any kind of contamination or manufacture defect, or power fluctuations can really screw up what this sensor is telling the ecu.

nothing like a good brain dump at 1:00 am
m²

 

Makes perfect sense to me. I had same feeling about T-bap. I knew it was not reading map pressure on mine because it was not on manifold side. I am also at around 400 ft. I am not running stock computer either. I have a prototype programable procom computer. I was being a test dummy for procom. I could change the fuel, and timing anywhere I wanted. I also have a 02 sensor in mine to let me know what fuel is doing. If my sensor would have say stuck on 3000 ft I would see a problem in o2 readings.

On a different note I did figure out alot of what was going on with mine. A couple of things actually. First the TP sensor was still not at correct idle voltage. I don't know how it was not, but I let plate snap back pretty hard a couple of times and sensor was reading around .62 volts and reset to .8 and that fixed my off idle dieing. So you can understand my situation I recieved 4 test computers ECU's from procom. I had 2 box A's and 2 box B's. I put them on two RZR's and tested both boxes. I found very quick in testing Box A was a good box and box B sucked.

My brother and I were both running box A and all was good until mine took a dump and started acting up. Last night he brought his over to me to start stealing parts and I took his Box A and put on my rzr and it fixed about 90 percent of my dead spot problems. On his rzr it was perfect. I then put my stock box back on and mine then ran perfect. No dead spots, absolutly perfect. It was a bit on lean side and had stock timing, but no dead spots. So I am thinking that when I was in woods my prototype ECU took a dump and started giving me fits. While trying to get it out of woods I imagine I fouled my spark plugs. Once out of woods I put I Prototype Box B on with fouled plugs making me chase my tail on lots of wierd things caused by poor ECU program. Either way I know 2 of my 3 problems now. Just have voltage thing to look at now. I am putting a big battery in and relocating my vr and going to retest on that.

 

Inadvertently screwed up my TPS adjustment, Wouldn't idle. Maybe adjust it for high(er) altitude? Just a suggestion. Seems to be very sensitive to starting/idle dynamics.