Rough idle and MAP sensor | GTAMotorcycle.com

Rough idle and MAP sensor

sburns

sburns

Well-known member
So my bike developed a problem idling. It idles rough, sputters, and almost seems to want to stall. Tracking down the issue it seems related to the MAP Sensor (Temperature Manifold Absolute Pressure) on the intake manifold. I've cleaned around this area, removed the sensor and cleaned it as well.

I started up the bike it seemed ok. But I imagine that could be a false sense, as maybe the issue won't reveal itself until it's fully up to running temperature?

HD want's $130 for this part (even the aftermarket price is similar which is kinda surprising)

It looks like a Bosch part, could I just find the same sensor from Bosch?

GTAM guide me!

MAP Sensor.jpg
 
My Triumph can have a similar symptom if 1 of the 2 rubber MAP hoses disconnect ... you have something similar?
 
That's used on Fiats and Jeeps - bosch 261 230 268. $40 new off ebay.
 
Had a bad MAP sensor on my Super Tenere, bike would stall and sputter. Thankfully I had a check engine light to guide me. Does HD have a diagnostic mode? On my Yamaha I was able to see the output reading that the computer was seeing. Could also try disconnecting it (putting the FI system into a default open loop) and seeing if the problem goes away.
 
LBV said:
My Triumph can have a similar symptom if 1 of the 2 rubber MAP hoses disconnect ... you have something similar?
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Not that I can tell. The sensor sits on top of the MF, and that's it.
 
regder said:
Had a bad MAP sensor on my Super Tenere, bike would stall and sputter. Thankfully I had a check engine light to guide me. Does HD have a diagnostic mode? On my Yamaha I was able to see the output reading that the computer was seeing. Could also try disconnecting it (putting the FI system into a default open loop) and seeing if the problem goes away.
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I am sure there is a diagnostic mode, or a method to read codes, just not sure how to do it or if you need a comp to get to the codes. I've heard to you reset the system similar to what you mentioned but I think it's best to replace it.
 
sburns said:
I am sure there is a diagnostic mode, or a method to read codes, just not sure how to do it or if you need a comp to get to the codes. I've heard to you reset the system similar to what you mentioned but I think it's best to replace it.
Click to expand...

100% replace it if faulty, my recommendation of disconnecting it was just to confirm your diagnosis
 
sburns said:
I thought it was kinda general automotive sensor part. Thx!
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Over time MAP sensors can get dirty, when they do you might notice a bit of occasional hesitation, particularly under heavier loads like going uphill or accelerating. They do fail, but just as often they just get dirty. 1100-160,000km is about the time to give them a good cleaning. I just did it with my Jeep, I noticed an occasional misfire under load on the highway.

Maintain vs replace is as hotly debated as oil types -- I clean them, always have. In 20 years I think I've restored MAP function to new a dozen times by cleaning, only recall having to replace 1. Cleaning is easy - blow any loose duct out with air then shoot a little carb cleaner or MAF/MAP sensor cleaner into the sensor - let dry for 10 minutes and you should be ready to go.

If the sensor was really dirty and benefited from a clean, your engine will start easier, give you a few more MPG and lose the cough/sputter under load. If not, you might need to replace it.
 
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sburns said:
I am sure there is a diagnostic mode, or a method to read codes, just not sure how to do it or if you need a comp to get to the codes. I've heard to you reset the system similar to what you mentioned but I think it's best to replace it.
Click to expand...
You can use the trip reset button to cycle through codes in each of the code categories and note the DTC itself. Here are the possible codes and their meanings ( not all codes apply to every model, a service manual for your year and model is helpful).

How to access codes from the dash
  1. Set run/stop switch to RUN
  2. Hold down the trip reset button while turning the key to the ON position
  3. Press and release the TRIP button to cycle through different modules.
  4. When you arrive at the module you want to investigate, hold the TRIP button and it should cycle the module specific parts and codes (I think HD calls them PART NUMBERS). Note that a code doesn't equal a fault -- you need the manual or a good interweb resource to understand codes
The onboard diagnostic system can also display a number that corresponds to the trouble code, and it will allow you to clear the code. This part is tricky without a manual. Try this link for more:

www.uti.edu

Harley Davidson Check Engine Light & Trouble Code List Guide

Learn the basics of Harley-Davidson trouble codes. Get a list of what each DTC on your Harley bike represents. Then, dig deeper with motorcycle tech training!
www.uti.edu
 
Have you checked for a vacuum leak? I don't know what to recommend, but the car guys usually spray throttle body/carb cleaner or brake cleaner around the intake manifold to identify.
 
Hey all thanks for the additional input. Yesterday I took out the sensor and cleaned it and the MF. It was kinda gunky. Put it back together and just came back from a ride to Port Perry. At first it seemed ok but on the return it started sputtering again and at any stops I had to force the idle up a bit.
I found a part on Amazon but I'm second guessing it, and found another supplier in the States which matches the HD part and Bosch parts exactly so I will order that one and cancel the Amazon part. Hopefully it doesn't take to long to get here with good weather finally here!
 
Bit of an update on this. The MAP sensor arrived from AliExpress before the other one did. I tried it and it didn't work or at least the rough idling and almost stalling didn't go away. I looked into this a bit more and there is another sensor, engine temp sensor. Replace that, no change.

Got to thinking about this more, end of last season I replaced my spark plugs with NGK's. I didn't like how they ran, something was off. Beginning of this season I took them out and replaced them with Champion plugs which were suppose to be OEM's. Seemed fine until the idling issue started. I took them out the other day and replaced them with HD's plugs, and at the same time reset the Throttle by wire setting. Took it out for a little run, idle was better, didn't dip like before and didn't feel like it wanted to stall. But still off, or I'm just not remembering how it was before after dealing with this so long. Will test again.

As I've been going down this rabbit hole of figuring this out, it came to my attention this might be related to the fuel filter. I've got the part for that and the regulator. I've never changed the fuel filter so might be worth just doing anyway and rule it out.
 
Mad Mike said:
You can use the trip reset button to cycle through codes in each of the code categories and note the DTC itself. Here are the possible codes and their meanings ( not all codes apply to every model, a service manual for your year and model is helpful).

How to access codes from the dash
  1. Set run/stop switch to RUN
  2. Hold down the trip reset button while turning the key to the ON position
  3. Press and release the TRIP button to cycle through different modules.
  4. When you arrive at the module you want to investigate, hold the TRIP button and it should cycle the module specific parts and codes (I think HD calls them PART NUMBERS). Note that a code doesn't equal a fault -- you need the manual or a good interweb resource to understand codes
The onboard diagnostic system can also display a number that corresponds to the trouble code, and it will allow you to clear the code. This part is tricky without a manual. Try this link for more:

www.uti.edu

Harley Davidson Check Engine Light & Trouble Code List Guide

Learn the basics of Harley-Davidson trouble codes. Get a list of what each DTC on your Harley bike represents. Then, dig deeper with motorcycle tech training!
www.uti.edu
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I fianlly got around to checking this out. Annnd no realy codes found on my bike. Just a couple of ABS codes, nothing related to the engine. I've got another MAP sensor to try as the one from AliExpress didn't do anything or work.
 
I think I finally fixed this. I received the MAP sensor from the States which seemed to work, compared to the cheapo one from AliExpress which didn't. But I also did some other things to help this situation, as the manifold and general area were pretty contaminated with oil.
- Cleaned manifold area
- Lowered crankcase oil level a bit
- Cleaned air filter.

I also removed my USB port just in case, since I added it and around the same time I started to have this problem. But I've since put it back on. So far so good.

But my Garmin GPS just died.... can't win.

Edit, Garmin GPS came back to life... ya! (y)
 
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