Check engine light sort of problem

[FJRoss]

I am thinking that the goo is coming from the MAP sensor itself - either some sort of assembly lube which agglomerates after a few hundred heat cycles OR some sort of protective gel on the diaphragm of the sensor. (Seems to me I read something about that when doing some background reading on MAP sensors) The goo in the line or in the sensor housing doesn't hurt anything until it blocks the line and prevents the diaphragm from reacting to pressure changes. On mine, the goo did not appear in a low spot and there was absolutely no evidence of anything anywhere else except the one short piece of hose between the sensor and the plastic Tee that joins it to the rest of the system. All the other associated hoses were clean and dry.

[0face]

Can we get a picture of the MAP sensor or at least a part schematic so I can check mine? I've had a similar issue that I though might be related to my power commander...

[BikerGeek]

Can we get a picture of the MAP sensor or at least a part schematic so I can check mine? I've had a similar issue that I though might be related to my power commander...

Marty - try this link: https://www.bikebandit.com/oem-parts/20 ... #sch645195

#17 - SENSOR, PRESSURE 5JW-82380-00-00

[John d]

^^^Google that part number and you'll see lots of photos of it. There is one vacuum tube to it, and that tube splits to four, one to the top of each throttle body. The sensor is right on top, once you pull off the insulation panel.

[0face]

^^^Google that part number and you'll see lots of photos of it. There is one vacuum tube to it, and that tube splits to four, one to the top of each throttle body. The sensor is right on top, once you pull off the insulation panel.

Thanks... so your vacuum tube had the gunk in it?

[John d]

^^^Google that part number and you'll see lots of photos of it. There is one vacuum tube to it, and that tube splits to four, one to the top of each throttle body. The sensor is right on top, once you pull off the insulation panel.

Thanks... so your vacuum tube had the gunk in it?

From a previous post;
"It is the same problem, in that the vacuum lines to the MAP sensor, again had goo in them, but this time a drop of goo was also visible in the inlet port of the MAP sensor. So I cleaned it all up, and guess what? The bike runs perfect again."

[ionbeam]

...It ran like crap until it got fully warmed up..I cleaned out the vacuum lines to the MAP sensor per advice from raYzerman, then it ran like new...
It is the same problem, in that the vacuum lines to the MAP sensor, again had goo in them, but this time a drop of goo was also visible in the inlet port of the MAP sensor. So I cleaned it all up...

1. There could be a low spot in the vacuum lines where this goo can accumulate...rearrange the vacuum lines, so there is positive drainage back to the throttle bodies (no low spots.)...

2. The goo has to come from somewhere, right? It may, theoretically, be unatomized fuel backing up into the vacuum lines due to an injector not working 100%...

The MAP sensor is made of four primary elements -- the housing, a silicon diaphragm a four pole resistor network on the silicon diaphragm and a reference pressure under the diaphragm.

There are three wires going to the sensor -- a +5VDC sensor voltage from the ECU, a 0 volt ground reference from the ECU (may not be the same ground as the battery so you can't use the frame or battery for the ground when using a DMM) and an output voltage to the ECU.

As the intake vacuum changes the silicon diaphragm bulges causing the resistor value to change in a linear fashion. All the complexity of MAP sensing is software in the ECU processing the signal voltage. All ‘critical’ engine sensor wires like the MAP go directly from the sensor to the ECU and do not pass through a connector along the way.

Goo on the diaphragm will cause the resistor to not respond correctly to changing intake vacuum. A hole, no matter how tiny in the diaphragm will cause the sensor to not respond correctly. Sticking something in the sensor vacuum hole or spraying cleaner in the hole is likely to kill the sensor. Sometimes bad things can happen to a wire where it chafes or gets pinched. The sensor is generally like a light switch, it’s Good or Bad, hardly ever sort of good or sort of bad.

The FSM says that with +5 VDC on the Light Blue wire and GND on the Black/Blue wire the sensor should have 3.57 VDC to 3.71 VDC on the Pink/White wire. If you read this voltage it confirms the resistor element is good. In the diAG mode the FSM says to go to Actuator Code 03 to test the MAP sensor. At diAG code 03 -- Set the engine stop switch to RUN, then push the start switch. If the display value changes, the performance is OK. This confirms the diaphragm works.

If you have a hand held vacuum pump you can do an additional test. First check your vacuum pump by plugging the hose, draw a small vacuum and wait 30 seconds to a minute to verify the pump did not bleed down. Passing this test, put the hose on the sensor and draw a small vacuum and wait 30 seconds to verify it does not bleed down.

You should be able to simply unplug the sensor and ride the bike letting the ECU use a look-up table. If the operational abnormalities go away the problem is the sensor or the wires to/from the sensor. My Gen I let me do this, I would expect the Gen II to be the same.

The goo is almost certainly from back streaming. When operating the engine the diaphragm bulges out from the vacuum, then when the engine is shut off the diaphragm makes a tiny sucking which can draw any residual fumes into the sensor hose. Over a lot of time it can plug the hose. In engines with a ‘wet manifold’ or positive pressure intakes such as a supercharger they use a sump or trap in the MAP hose to prevent this from happening. I suspect an enterprising feller could find a small in-line fuel filter from a lawn or garden engine and put it in-line between the intake manifold and the sensor. An even better fellow would run this setup for a year or so, then autopsy the filter and post the finding to this forum I used a small motorcycle fuel filter from a carbureted engine between the intake manifold and the diaphragm of my cruise control servo to prevent the solenoids in the servo block from gumming up and sticking.

And yes I did see "...The bike runs perfect again." Congratulations for finding a simple problem with a simple fix.

[John d]

Mr. Ionbeam,

Without the help of the people on forum such as yourself, the simple problem would be extremely hard to find, diagnose, and fix.

[FJRoss]

The goo is almost certainly from back streaming. ...

I'm not convinced that the goo is from back streaming. The diaphragms on at least some MAP sensors are covered with a protective silicone gel. My guess is that this flows a bit over time and makes its way to the rubber hose where is eventually agglomerates and blocks the line. When I had mine apart to fix error code 14 a few years ago, there was absolutely no evidence of any contamination in anything other than the short piece that runs from the sensor.

This has shown up in a fair number of earlier Gen II bikes. If it happens with my current (2011) bike, I will make a point of saving the material analyzing it to see if composition is a clue to origin. I can certainly tell the difference between silicone gel, hydrocarbon-based assembly lube and back streaming goo.

Whatever the source, it has shown up enough times to be something to look for in case of poor operation - especially at low throttle openings. Often accompanied with a 14 error code.

[wheatonFJR]

I'd just like to add that Marty and Jason have been backstreaming all summer, so I don't doubt that that is part of Marty's issue.Never mind.

[raYzerman]

IIRC, the MAP sensor tube is the only one that does not have flow through to somewhere else, i.e., the MAP sensor is a plug at the end of the hose.... thus the others stay clean?
It is rare to have a MAP sensor failure on an FJR....

[John d]

IIRC, the MAP sensor tube is the only one that does not have flow through to somewhere else, i.e., the MAP sensor is a plug at the end of the hose.... thus the others stay clean?

I believe you are correct Ray. I just looked at a picture I took of the tubing before I took all the tubes out for cleaning, and it clearly shows that the final tube to the sensor is situated below the others where they connect, thus creating the perfect trap for all the goo.

[Iris]

By “running badly”, does that mean that it sputters and spurts and feels like it’s losing power as you’re riding it?
Mine has no check engine light, but it has lately been momentarily loosing power. And then later it runs like normal.


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[Hppants]

Not related to any problem that I'm having, but I'm wondering how a goo'd up map sensor and/or vacuum lines doesn't cause any running problems when the engine warms up? Shouldn't the ECU be monitoring air flow at running temp too?

[raYzerman]

This is really called the Intake Air Pressure sensor (MAP = manifold air pressure). It is constantly monitoring vacuum in the intake system, which constantly changes with throttle input/engine load/altitude, etc. The voltage signal thus varies to the ECU which then constantly tweaks the fuel system. If there is restricted vacuum flow, then those changes may not occur on time or not at all, thus poor idling and performance. A worn/failing TPS sensor can cause similar symptoms, but best rule out everthing else before going the TPS replacement route, and then best go through Ionbeam's TPS analysis procedure. There are other inputs the ECU uses, intake air/coolant temperature related, etc. but mostly those have been trouble free.
Also good to rule out ethanol phase separation/water in the fuel first with a little Seafoam if the bike has been sitting a couple of weeks or more.

[John d]

By “running badly”, does that mean that it sputters and spurts and feels like it’s losing power as you’re riding it?
Mine has no check engine light, but it has lately been momentarily loosing power. And then later it runs like normal.


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If yours is an intermittent problem while fully warmed up, then you have a different problem. Sorry, can't help.

[Bounce]

MAP and MAF. Here I thought it was Mass Air Pressure/Flow.