2014 SR Viper hard starts cold/ won’t idle

SRXSRULE2 said:
I haven’t pulled the plugs but I know they are going to be wet/ rich as I can tell it’s running rich by the smell of the exhaust and the low idle. Plugs were new last season, I can throw another set in, just didn’t feel the need to foul another new set.

Near the end of last season I swapped the baro and map sensors (same part number) to see if there was a change, ran the same. I used my voltmeter to back probe the readings with the key on engine off, both the baro and map were reading the same as they should. When it’s running, the map sensor changes voltage as it should, also checked it using a vacuum pump.

A couple nights ago I pulled the IAC apart, it was clean and the valve is not binding. When I turn the key on the valve opens up to say 50 % as it should for cold start. When the key is turned off it cycles to the nearly closed position and then slightly open. Interesting part, when I removed the solenoid from the housing part of the IAC and cycled the key a bunch of times, each time the valve would come out a little further (towards the closed position) and would change its rest position key off. I reinstalled the valve and tried it, it idled pretty good around 1750-1800 rpm. Watching the IAC reading on the gauge it was moving around and changing like it should. I let it warm up to operating temp and shut it off. Yesterday I let it sit outside the garage for a few hours, tried it and it stalled. Gauge was showing 120 on the IAC which seems to be the max/ full air bypass.

So without being able to see how this ecu works, I would assume the only inputs to the fuel injection would be the map, baro, intake air temp, coolant temp, crankshaft speed, and throttle position. I have ruled out the map/baro, crankshaft speed is fine. Intake air temp seems to read what my thermostat in the garage reads so I rule that out. Coolant temp reads normally. The throttle position sensor reads 0% and 0.6volts and idle and 98% (can’t remember voltage) at WOT.

If someone can chime in with their TPS readings and IAC values when idling to compare I will have ruled out just about everything.
Click to expand...
Mine is still in apart but another thing to consider is that its losing spark. I remember my Phazer did this right before total failure of the Pickup coil. Chased that for awhile as even gas quality effected it.
 
Tonight it got a used map sensor, baro sensor and IAC to try (throwing darts) and it runs exactly the same. Borrowed a whole throttle body, not going to bother swapping it over. Plugged in the tps to compare readings, reads the same.

Had it running on the stand tonight. With the clutch engaged running 4500-5000 rpm If I let off the throttle slowly to idle, it will idle okay. Let off the throttle quickly it will stall almost every time. I’m assuming these things have a throttle override system. I already previously loosened the cable in case it was too tight, no difference. Is there a way to temporaily disable the system like you could with tors??
 
There must be a way. Never did it though. This one is acting just like one at dealer that had the reluctor ring spin on stubshaft. The one Pickup reads. I believe there is some dots that should be lined up if you decide to look.
 
Bringing this thread back to the top, have had some more time to mess with this machine. I am aware that there is a new flash out, it will be going into the dealer for this. From the feedback I have read, I hope it will solve some of the cold start issues that have plagued these sleds. However I don’t feel it will fix the stalling issues it still has.

I finally got a peak at the shop manual so I could do a little more digging, today I reset the throttle cable adjustment per the manual which I’m not sure about. It asks for a 0.030-0.060” gap between the throttle block and the lever at closed throttle. With the throttle lever at closed throttle there is probably an 0.080-0.100” gap even with the cable slacked off. So instead while killing two birds with one stone I checked the throttle block (TORS if you will) switch and set the cable to where it should be. The switch works as it’s supposed to showing less than 1 ohm with no throttle input and greater than 1000 ohms (mine showed 16xx ohms) with and throttle input. Also checked it on the gauge and set it so it just reads 99% at WOT and 0% at closed throttle. So I have ruled that out for now.

I checked the stator (resistance test) and it is within shop manual specs. From my experience usually when a stator fails, it would fail hot or all together anyway so I have ruled that out.

Shop manual says fuel injection at idle is based off engine coolant temp, throttle input, map readings and intake temperature to determine fuel needed. I have already checked and verified the map and tps readings. It was 15°C in my garage and the intake air temperature on the gauge read 15°C.. bang on right? When I checked the resistance with my fluke meter it is 6380 ohms.. according to the shop manual that would put it in the range of 47°C.. that can’t be right. So I checked the voltage sensor plugged in with the key on and got 3.65v.. checked the chart and that puts it at -13°C? The sled has been sitting in the garage for days at 15°C. I checked the resistance of the wires from the sensor to the ecu, less than 1 ohm. They are not shorted to power, ground or together. I load tested them with a light bulb and they are nice and bright. I checked source power to the ECM, I have battery voltage. Checked the ground, ground is good. Checked reference voltage to the intake sensor, solid 5v reference.

I plan to get a sensor coming for it as it is not that expensive. However if anyone happens to have one handy and would be awesome enough to check the resistance of their sensor and a temperature that would be awesome. It just doesn’t make sense to me why the gauge displays the temperature so accurate even though it has to be way off? As I’m typing this I’m thinking I should probably check the coolant temp sensor to compare it with the chart as well to see where it’s at. Unless the manual is incorrect, I did find a lot of other things that were incorrect in the manual. If the manual is correct, that would explain why it’s running very rich and would definitely explain the low/poor idle.
 
Last edited:
SRXSRULE2 said:
Bringing this thread back to the top, have had some more time to mess with this machine. I am aware that there is a new flash out, it will be going into the dealer for this. From the feedback I have read, I hope it will solve some of the cold start issues that have plagued these sleds. However I don’t feel it will fix the stalling issues it still has.

I finally got a peak at the shop manual so I could do a little more digging, today I reset the throttle cable adjustment per the manual which I’m not sure about. It asks for a 0.030-0.060” gap between the throttle block and the lever at closed throttle. With the throttle lever at closed throttle there is probably an 0.080-0.100” gap even with the cable slacked off. So instead while killing two birds with one stone I checked the throttle block (TORS if you will) switch and set the cable to where it should be. The switch works as it’s supposed to showing less than 1 ohm with no throttle input and greater than 1000 ohms (mine showed 16xx ohms) with and throttle input. Also checked it on the gauge and set it so it just reads 99% at WOT and 0% at closed throttle. So I have ruled that out for now.

I checked the stator (resistance test) and it is within shop manual specs. From my experience usually when a stator fails, it would fail hot or all together anyway so I have ruled that out.

Shop manual says fuel injection at idle is based off engine coolant temp, throttle input, map readings and intake temperature to determine fuel needed. I have already checked and verified the map and tps readings. It was 15°C in my garage and the intake air temperature on the gauge read 15°C.. bang on right? When I checked the resistance with my fluke meter it is 6380 ohms.. according to the shop manual that would put it in the range of 47°C.. that can’t be right. So I checked the voltage sensor plugged in with the key on and got 3.65v.. checked the chart and that puts it at -13°C? The sled has been sitting in the garage for days at 15°C. I checked the resistance of the wires from the sensor to the ecu, less than 1 ohm. They are not shorted to power, ground or together. I load tested them with a light bulb and they are nice and bright. I checked source power to the ECM, I have battery voltage. Checked the ground, ground is good. Checked reference voltage to the intake sensor, solid 5v reference.

I plan to get a sensor coming for it as it is not that expensive. However if anyone happens to have one handy and would be awesome enough to check the resistance of their sensor and a temperature that would be awesome. It just doesn’t make sense to me why the gauge displays the temperature so accurate even though it has to be way off? As I’m typing this I’m thinking I should probably check the coolant temp sensor to compare it with the chart as well to see where it’s at. Unless the manual is incorrect, I did find a lot of other things that were incorrect in the manual. If the manual is correct, that would explain why it’s running very rich and would definitely explain the low/poor idle.
Click to expand...
I would check the coolant tempsensor. They are known to go bad.
 
SRXSRULE2 said:
Just went out to check, 5.58k ohms or 5580 ohms which would put it at 1°C.. compared to 11°C on my thermostat in the garage. So it’s off by 10° as well. Not as out to lunch as the Intake air temp sensor but not great either.
Click to expand...
Studroes had 2 go bad. Trying to get ahold of him for the symptoms.
 
Definitely doesn’t fluctuate like that unfortunately. I don’t ride the sled as it my fathers but the coolant temperature has always been accurate and read smooth with no huge fluctuations. The intake temperature he noticed seemed to be warm when cruising down the trail even in cold temps. I kinda thought it was from heat coming off the radiator and being sucked up by the intake. He never really paid attention to the intake temps before however so I don’t have a baseline for that. If the coolant temp sensor is only $10 I’ll get one to try as well. With how far off the intake temp sensor is with the chart I’m thinking that it’s more likely the culprit.

I’ll add some other things I checked today. I believe this has the 2nd or 3rd flash on it. If the oxygen sensor is unplugged, no codes. Unplug the ignition coils, no codes. Unplug the injectors, codes set. Unplug the intake temp, code set. Checked resistance of the injectors and ignition coils and they checked out fine.

Did the flash eliminate the o2 sensor? I haven’t ruled it out but I would say if it doesn’t set a code being unplugged, the ecm must not be looking at it. In the manual there are codes for the o2 sensor circuit and the ignition coil circuits yet they don’t set codes when disconnected.. It makes no sense to me why they added the oxygen sensor that the nytro never had, yet they aren’t using it. Closed loop mapping would be a lot better for drivability.
 
When my temp sensor went bad it was just screwy readings on the gauge, never went low enough to put it in limp mode and sled never stalled, just had huge changes in temp readings. Sled ran no different than any other day.
 
SRXSRULE2 said:
Definitely doesn’t fluctuate like that unfortunately. I don’t ride the sled as it my fathers but the coolant temperature has always been accurate and read smooth with no huge fluctuations. The intake temperature he noticed seemed to be warm when cruising down the trail even in cold temps. I kinda thought it was from heat coming off the radiator and being sucked up by the intake. He never really paid attention to the intake temps before however so I don’t have a baseline for that. If the coolant temp sensor is only $10 I’ll get one to try as well. With how far off the intake temp sensor is with the chart I’m thinking that it’s more likely the culprit.

I’ll add some other things I checked today. I believe this has the 2nd or 3rd flash on it. If the oxygen sensor is unplugged, no codes. Unplug the ignition coils, no codes. Unplug the injectors, codes set. Unplug the intake temp, code set. Checked resistance of the injectors and ignition coils and they checked out fine.

Did the flash eliminate the o2 sensor? I haven’t ruled it out but I would say if it doesn’t set a code being unplugged, the ecm must not be looking at it. In the manual there are codes for the o2 sensor circuit and the ignition coil circuits yet they don’t set codes when disconnected.. It makes no sense to me why they added the oxygen sensor that the nytro never had, yet they aren’t using it. Closed loop mapping would be a lot better for drivability.
Click to expand...
Yes O2 sensor was eliminated with the flash before current.
 
Let's go back to basics with this thing. Do all 3 plugs look the same? What happens before it stalls if you spray some ether in airbox? What happens if you spray it around boots and hoses. What does your Map sensor read?
 
Last edited:
Air Intake temp has always been much higher than Ambient while riding in all I have seen.
 
You must log in or register to reply here.

Similar threads

DTJ
Won't idle cold without throttle.
Replies
12
Views
6K
cannondale27
cannondale27
P
Idle air control valve
Replies
11
Views
5K
picasso
P
V
Viper won’t start after ecm update
Replies
7
Views
2K
cannondale27
cannondale27
burlyviper
2016 Viper starts but wont stay running
Replies
4
Views
3K
burlyviper
burlyviper
P
Frustrated with Yamaha
4 5 6
Replies
83
Views
13K
Jason.Benjamin
Jason.Benjamin


Back
Top