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

[redlowrey]

Or you disconnect the plug from the computer and the map sensor and do an ohms test on the signal wire at the computer to the map sensor plug to see if there is high resistance in the wiring.

[redlowrey]

I had a gut feeling it would not fix it, see if you can borrow a computer, something has failed internally keeping the signal low.

[go2ski]

I used another map sensor I borrowed same type from same engine and it gave me relatively same voltages when testing it with the hose off and didn’t change anything.

[redlowrey]

Ok I have miss read the voltage and that reading is fine, forget about running the jumper, I would have removed the sensor and checked it on the work bench to be 100 percent sure , you haven’t got that luxury.
There are a couple of things that just don’t add up but definitely the low signal voltage is wrong with key on engine off, put a sensor in it and we will find out.

[go2ski]

It was 1.8 mv

[redlowrey]

So is it 1.8 volts or 1.8 mv if it is 1.8 mv forget about the jumper wire I have miss read the reading.

[redlowrey]

Hang on I just read your post again, did you change the voltage scale when when you went from the five volts on the red wire to checking the ground. Voltage.

[redlowrey]

Don’t waste 300$ on a map sensor till you fix the sensor ground problem first, it probably won’t be needed. Make a temporary wire with an alligator clip on one end and solder a thin needle on the other end and connect the clip to battery neg, and slide the thin needle beside the sensor ground terminal on the map sensor and see if the signal wire white goes to 4 volts with the key on and start the engine and try it.

You may be lucky and there is only some corrosion on map sensor ground at the terminal block, multiple sensors use signal ground and it terminates I think on pin 11 at the computer

[go2ski]

Okay I’ll look at the wires and also find a new map sensor. Also if the connection is bad and messing with it doesn’t help, would I have to replace the whole harness or could I replace that wire.

[redlowrey]

That’s right, that ground wire should have zero volts or no more than 40 mv just to make you feel good I tested a map sensor on a df 140, key on engine off red wire 5volts white wire 4 volts black and white ground zero volts.

Map sensor disconnected key on red wire 5 volts white wire 1.4 volts ground zero volts.
You have a bad sensor ground, follow the black and white wire it will go to a terminal block with other black and white wires then to the computer.

I knew that there was some other problem if you had of replaced the map sensor you still would have had the same problem.

[go2ski]

So the sensor is not working for sure?

[redlowrey]

Progress, there should be zero volts on the ground black,

[go2ski]

I am using a craftsman digital mutlimeter the red wire is 4.98v the black wire is 1.8 on the 200mv DC mode and the white wire is 1.83v. The hose is unplugged when I’m testing this.

[redlowrey]

You are using a digital multimeter when you are doing these checks aren’t you, because if you are using an old analog meter with a moving needle, the meter will consume more current than the circuit you are testing pulling the voltage low.

Something just does not add up, you have a voltage that has 1.7 volts on it that should have 4 volts on it, key on engine off, the voltage won’t change which should have switched the check engine light on and I have seen the manifold vacuum changing on the sds you put up first.

[redlowrey]

I just had a thought, if the white signal wire was broken where it enters the map sensor you will only see the bias voltage, just unplug the the connector and test the voltage on the pin it should be the same with the key on.