Rovergauge soft ware
Discussion
blitzracing said:
You need to install the driver software for the FDTI chipset that the USB cable uses, or it wont appear in device manager.
Ok, I am back, I have now got the system working.These are the Fault codes after a run when the engine got really hot! Fan on stuck in traffic, The revs ran up and down 2000 to 0 then bounced back up again. If I put my foot on the throttle I could stabilize the revs at a fast tick over 1100 rpm. When I got clear of the traffic the temp dropped,the car seemed to run ok but if I did a slow gear change the revs dropped right down past tick over possibly 200 revs.
I canceled all the fault codes to try again.
This is the engine running cold just started up.
This is the engine hot. Running fan. Still just ticking over.
This is what it came up with for fault codes. This was all static running in the garage.
So the implication is low fuel pressure?
blitzracing said:
Its likely both lambda probes have dropped to 0 volts for a period, so the ECU picks up a "lean" mixture that could be low fuel pressure, but a low lambda voltage can also be a bad misfire and the ECU cant tell the difference.
I have looked at the plugs again, they all seem to be about the same grey/fawn in color for the electrode and the tip but the outer ring of the plug has soft black soot as though it is running rich at low revs. I do have a misfire sometimes that you can drive through seem to be 2200 to 2400 rpm. I have not checked the fuel pressure yet I understand that is supposed to be 36psi but is that static or with the engine running at a number of revs?Fuel pressure is difficult, as by its nature it can change depending on engine demand. In an ideal world its 36PSI with no inlet vacuum , full throttle and with the engine at peak power when you need maximum fuel delivery. This is very difficult to measure in real terms unless you have rigged up a pressure gauge you can read in the cabin, whilst driving flat out! A basic static fuel pressure reading is done by turning on the ignition, and then turn on the fuel pump with RoverGauge and you will see 36PSI or so. It will drop sharply as you start the engine as the inlet vacuum cause the pressure regulator to drop the rail pressure, but this only tests the regulator is working, not if the fuel delivery system is up to the job.
To add to the unknowns the ECU can only pick up fuel pressure issues below 3400 rpm or 2/3 throttle , whilst the engine is in closed loop and monitoring the exhaust gas, so something in this region is making the lambda probes output fall to 0 volts. Problem also is un burnt mixture looks like a lean mixture, so the ECU fault code could be completely wrong, as the ECU is not that smart. Plug readings have there limitations as at say idle the mixture is fine, so you get one plug colour, yet if it run leans at 3000 rpm you will get another. To get any real results, you need clean plugs, then you have to run at a fixed load and RPM and then kill the engine with the ignition and coast to a stop, then look at the plug colour. Not easy or that accurate.
By far the most accurate method for any fuel issues is to read the lambda outputs directly with a test meter. The output normally cycles between 0 volts and about 1.2 volts at varying speeds (typically 1 to 4 times a second) as the short term trim cycles between the black (output) and white (ground) wires. This will cycle up to 3400 rpm, and above that will go to about 1.2 volts if all is well. In you case id expect to see it drop to 0 volts for a period when the issue occurs, that would be flagged up as low fuel pressure. Im making an assumption that to get low fuel pressure both lambda outputs are dropping to zero at the same time , as apposed to a misfire on one bank when only one probe would stop switching. In terms of getting the reading, you would need to extend the wires from the lambda probes back into the cabin, so a passenger can read the voltages on a test meter as you drive. Ive covered it here- about 1/3 of the way down the page.
http://www.g33.co.uk/pages/technical-fuel-injectio...
Before you get too entrenched with such though, make sure the ignition system is all in good condition and you have a decent spark. Also check the inlet pipe to the AFM has not become kinked or crushed as this throws up a low fuel pressure.
To add to the unknowns the ECU can only pick up fuel pressure issues below 3400 rpm or 2/3 throttle , whilst the engine is in closed loop and monitoring the exhaust gas, so something in this region is making the lambda probes output fall to 0 volts. Problem also is un burnt mixture looks like a lean mixture, so the ECU fault code could be completely wrong, as the ECU is not that smart. Plug readings have there limitations as at say idle the mixture is fine, so you get one plug colour, yet if it run leans at 3000 rpm you will get another. To get any real results, you need clean plugs, then you have to run at a fixed load and RPM and then kill the engine with the ignition and coast to a stop, then look at the plug colour. Not easy or that accurate.
By far the most accurate method for any fuel issues is to read the lambda outputs directly with a test meter. The output normally cycles between 0 volts and about 1.2 volts at varying speeds (typically 1 to 4 times a second) as the short term trim cycles between the black (output) and white (ground) wires. This will cycle up to 3400 rpm, and above that will go to about 1.2 volts if all is well. In you case id expect to see it drop to 0 volts for a period when the issue occurs, that would be flagged up as low fuel pressure. Im making an assumption that to get low fuel pressure both lambda outputs are dropping to zero at the same time , as apposed to a misfire on one bank when only one probe would stop switching. In terms of getting the reading, you would need to extend the wires from the lambda probes back into the cabin, so a passenger can read the voltages on a test meter as you drive. Ive covered it here- about 1/3 of the way down the page.
http://www.g33.co.uk/pages/technical-fuel-injectio...
Before you get too entrenched with such though, make sure the ignition system is all in good condition and you have a decent spark. Also check the inlet pipe to the AFM has not become kinked or crushed as this throws up a low fuel pressure.
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