Yamaha f115 efi error code 37

[oceanoblu]

Hi,

my 2009 Yamaha f115 efi (with 909hours) has a problem between 1200 and 1700 RPM: it goes "in fits and starts".

Under 1200 and over 1700 it's perfect and without any issue.

Checking the error code list it says number 37 which should be "Intake passage air leak/incorrect Idle speed control"

If I switch off the engine the problem disappears and it comes again only when I reach approx 1200 RPM (it disappears again after 1700 RPM).

The engine has always been maintained properly: sparks and filters are new.

Any idea?

Thanks from Italy!

Angelo

[rodbolt17]

find and fix the excessive air issue.could be an ISC issue, doubt it, most likely a vacuum line off or a gasket leak.

[oceanoblu]

Thanks for your help!

I took a look and, at a first sight, all the piping seem good.

Today I tried to accelerate when in neutral and the issue is not present. Only when I accelerate over 1200 RPM on gear the issue comes back.

Can be a fault of the intake airpressure sensor?

Is there any other test I can do?

Thanks

[rodbolt17]

do you understand why the ECU looks at MAP sensor feedback?? do you understand why it uses intake air pressure feedback????.

[oceanoblu]

Not exactly let's say engines are not the subject of my doctorate!

Just trying to understand why accelerating in neutral the engine is perfect. If there is a leak I should have the issue also in neutral. Isn't it?

[boscoe99]

do you understand why the ECU looks at MAP sensor feedback?? do you understand why it uses intake air pressure feedback????.

"slain to us how it all works please.

[boscoe99]

Not exactly let's say engines are not the subject of my doctorate!

Just trying to understand why accelerating in neutral the engine is perfect. If there is a leak I should have the issue also in neutral. Isn't it?

buon pomeriggio

A motor being accelerated in neutral has no load applied to it. Little power is being produced.

The difference between a motor having a load applied to it and one with no load applied to it is the difference between night and day.

[oceanoblu]

Ciao

I made another test. With the propeller out of the water and on gear, so with no load, the issue is again there just it appears at 1700 rpm instead of 1200.

[boscoe99]

Leaks into an air intake system can manifest themselves at different times. With different engine loads and engine RPM's.

You got a master mekanik suggesting you find and fix an intake air leak.

You got a fault code that says "intake passage air leak".

Why not inspect the motor for an intake air leak?

Now if you don't know how to do this then my suggestion is to take the motor to a Yamaha mechanic for a repair.

It is beyond my capabilities to inform, via the inner web, as to how to inspect for an air intake leak. The leak does not come from just one places. There are a number of ways air can leak into the intake system.

Do a google search for finding and fixing intake air leaks and maybe that can help you. http://www.aa1car.com/library/vacleak.htm

[pstephens46]

Don't cut your leg off running prop out of water. Just bit a hole in couch when you described doing that.

[boscoe99]

Don't cut your leg off running prop out of water. Just bit a hole in couch when you described doing that.

Ever had to adjust the idle mixture screw on an O-520? It has to be done with the motor running. A whirling six foot diameter propeller blade maybe two feet away from the hands/head? With an exhaust system that has nil mufflers installed beating drums inside the head? It can be a nerve racking experience.

It is a wonder that more people aren't hurt messing around with machinery.

[rodbolt17]

the F115 of that era used a simple speed density open loop efi setup. crankshaft speed inputs are a function of the pulser coils. density is a function of barometric pressure and air temp. at key on the MAP sensor lock baro pressure for that key on cycle. once the engine is running the map is now sensing intake manifold pressure,the inverse of vacuum. so if your getting a code 37 the ECU is seeing a spike in pressure that it considers abnormal. this can be an air leak,a stuck valve a misfire a bad wire or a bad sensor or incorrect map ref voltage.

[oceanoblu]

Hi all,

new summer season but same problem :-) I went through all the suggestions proposed last time, but the issue is still there.

A friend gave me a Yamaha Diagnosis System and you can find the result in attachment. Basically it says the Throttle Valve Opening is at -3.8 (correct range 0-90).

I read the Yamaha Service Manual and I found this:

ADJUSTING THE THROTTLE
POSITION SENSOR
1. Measure:
• Throttle position sensor output
voltage
Out of specification -> Adjust.

Throttle position sensor output
voltage (pink (P) – black (B))
0.732 ± 0.014 V

Measuring steps
(1) Remove the intake silencer. Refer to
“INTAKE ASSEMBLY” on page 4-3.
(2) Disconnect the throttle joint link rod 1
at the throttle body.
(3) Check the throttle valve.
(4) Connect the test harness (3-pin) as
shown.
(5) Connect the digital tester probes to the
test harness (3-pin) as shown.
(6) Turn the engine start switch on.
(7) Measure the output voltage.
(8) Install the intake silencer.
(9) Start the engine and measure the output
voltage again.

Adjustment steps
(1) Loosen the screws 2.
(2) Adjust the position of the throttle position
sensor until the specified output voltage is obtained.
(3) Tighten the screws.
(4) Connect the throttle joint link rod 1.

Do I have to do this? Am I on the right way?

Thanks as usual!