Suzuki DF60 2004 Won't go above 3000 rpms No error codes

[go2ski]

So for some reason now it runs fine out of water and when put in the water something is limiting the rpms again. I have recorded the engine service data in and out of water switching gears. I have put timestamps in the video to help explain because there is no audio. I have also recorded audio of the engine the best I could out of the water.
Engine out of water
Engine in water
Engine Audio
Also when the engine was in the water it would sometimes die when switching gears.

[ECU1984]

Is it starving for fuel when wot?
Would fuel pressure gauge tell us?

[go2ski]

ECU1984 In the water it runs as it would if you wanted it around 3000 rpms, out of the water it sounds perfectly fine when in wot.

[redlowrey]

Ok looking at the sds, in the water I can see that at 35 seconds you go to wide open throttle looking at manifold vacuum, injection pulse width12ms, 34mcc, then at 45 seconds injection and vacuum starts to change and at 51 seconds nearly back to idle injection and manifold vacuum, how can that be with a wide open throttle.
Your engine has a hose connected to the map sensor make sure the hose has no restrictions or cracks and make sure the little hole in the manifold is not restricted.

Check the operation of the map sensor it has three wires power, signal and ground, at idle signal voltage around one volt, wide open throttle around four volts.

[redlowrey]

listening to the audio the engine revs evenly to a bout 2500rpm and then back to idle with the throttle in the wide open position, the manifold vacuum is at absolute 29in hg, or 4 volts on the map signal line, it should be still injecting the same amount of fuel as it was at,34 seconds but is doesn't. With the throttle in the wide open position the map sensor signal voltage should be stuck on 4 volts and only change as you change the position of the throttle.

I want you to tell me that you can physically see the throttle plate sitting in the wide open position when you are doing the wide open throttle test, something is not adding up, The map sensor signal voltage will be jumping from 4 volts to 1 volt back to four volts instead of staying at 4 volts with the throttle wide open.

[go2ski]

redlowrey the throttle does indeed open all the way I took off the intake and looked. I’m not sure if I have the proper equipment to test the map sensor I might just replace it tomorrow if it’s cheap enough.

[redlowrey]

Don't replace it yet something does not add up here, on your sds with the engine in the water at for ten second there is plenty of fuel being injected into the engine with the throttle in the wide open position it should have went straight up to the rev limiter. what I can't fathom is how the engine can idle with the throttle wide open.
It is impossible for the manifold vacuum to start heading back to the idle measurements with the throttle in the wide open position.

If the engine was going into fail safe and it was substituting a value for the map sensor that could make the value change even with the throttle wide open, but there are no lights indicating that, disconnect the tacko and try it, then pull the wire off the temp sensor, the computer should bring the light on and substitute a value for it, same with the exhaust temp sensor. Try this also with the engine running and the throttle in the wide open position as it is running spray some carbi cleaner into the throttle plate and the rpm should shoot straight up.

It just sounds like a slower version of a failed neutral switch problem.
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[go2ski]

If the engine was going into fail safe and it was substituting a value for the map sensor that could make the value change even with the throttle wide open, but there are no lights indicating that, disconnect the tacko and try it, then pull the wire off the temp sensor, the computer should bring the light on and substitute a value for it, same with the exhaust temp sensor. Try this also with the engine running and the throttle in the wide open position as it is running spray some carbi cleaner into the throttle plate and the rpm should shoot straight up.

It just sounds like a slower version of a failed neutral switch problem.
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Could you explain this a little further what’s the “tacko” and what’s the purpose of unplugging the sensors. Also what do you mean by the last comment could it still be the neutral switch?

[redlowrey]

Tacko is the rev counter it may be sending over revving data to the computer which is wrong, disconnecting the temp sensor will tell me if the computer is in control, make the check engine light come on and substitute a value for the sensor, I am trying to see if the computer is controlling the rpm stopping it going higher. Now that you have said that you can see that the throttle is wide open I am thinking the the computer is controlling the rpm because there was plenty of fuel injected to make the rpm go to the rev limiter. the computer controls spark as well.

The reason I want you to spray some carbi cleaner into the throttle body is to make sure the engine will go over 4000rpm. I am not saying it could be the neutral switch just a slower version in the changing rpm than the neutral switch normally does when it is faulty, If the rpm shoots up over 4000 rpm when spraying carbi cleaner into the throttle it will tell me that the computer is not controlling the rpm to 3000.

If you had a fuel restriction and the throttle was in the wide open position there is no way it could duplicate that problem of reving to 2500rpm and then back to idle and keep idling impossible. Different story if it was a direct injected engine

[go2ski]

redlowrey the engine will go over 3000 rpms out of water sometimes. The other day it wouldn’t go above 3000rpms out of water now it will but when it goes in the water back to less than 3000 rpms.

[go2ski]

Also when I do these tests should I do them in the water since that’s when my rpms won’t go above 3000 rpms

[redlowrey]

I had a look at the sds out of the water and at 22 seconds it was injecting 7ms and 20mcc of fuel plenty, at 23 seconds it went back to 2.2 ms and 5mcc of fuel with the throttle nearly all the way and over 3.500 rpm. and 8.7 in hg of vacuum something is amiss here. I have never seen a map sensor fail like this the signal voltage will be going 4 volts 1 volt 4 volts 1 volt and so on.

Don't worry about the other tests at the moment, do this one first, remove the map sensor hose from the engine and leave it unplugged, that will leave the map signal voltage at around 4 volts start the engine and as soon as it starts go to wide open throttle. Dou you know how to use a multimeter. Do this out of the water.

[redlowrey]

I should have added connect your sds up when you do this

[go2ski]

When I tested the red wire with the multimeter it gave 4-5v the white wire gave 1-2v with the hose off my software didn’t record the sds for some reason ill do it again but it gave me two errors when I removed the hose one for the hose being removed and one for the air screw

[redlowrey]

With the hose disconnected the voltage should have been around 4 volts and stay at that voltage because there is no vacuum on it to change it, map sensor voltage will vary between 4 volts when the engine is not running no vacuum, to around 1 volt when the engine is idling high gauge vacuum , then vary as the throttle is opening and closing with different loads, to have 1to 2 volts on the white signal wire when the hose is off indicates the sensor has failed.

If you can leave the hose off connect your meter to the signal wire and test the sensor with the key on to see if you can get it to show 4 volts, even if you tap the sensor with something, if you start the engine and go to full throttle, it should rev straight up tp the limiter.