hi_arshard said:

Hey Allan,

Thank you very for the information shared it was very helpful really appreciated.

I have done the test and following are the results.

Mean time I have ordered the cable for the USB FDTI cable for the Rover gauge, will be working on that soon.

Reading from MAF,

Red/Black - ground
Blue/Green - air flow signal

Reading ignition on - 0.22 to 0.24
Idle cold 1.65 to 1.67
Idle hot - 1.58 to 1.62

Idle CO mixture adjustment
Red/Black
Blue/Red
Idle 1.87

As you mentioned the CO adjustment on the MAF, this adjustment is sealed and unable to access the adjustment screw. Is there a way to open this or some comes sealed ?

Also I have black smoke issue, if I press the throttle full I see thick black smoke.

Appreciate your input…

Click to expand...

Hi, few more readings from MAF which I missed in the last post,

Idle CO mixture adjustment
Red/Black
Blue/Red
Idle or with ignition on the reading is same 1.87

Also reading from air flow signal, as switch on the ignition its shoots to 0.64 and settles back to 0.24, does this means that the MAF is bad ?

Yes by factory it’s without catalytic.

I have to fix the black smoke issue as MOT test is scheduled for next week.

As long as the 0.64 drops pretty quick, it might be OK. Settling to .24 may depend on the quality of your meter and leads - that IS fairly close to 0.30 to 0.34 though.

The Coolant temp sensor for the ECU is the one with the square "timer" plug on it, kind of behind the distributor near the thermostat.. Not the round single pin (gauge), nor the big one with two spade teminals (cooling fan). If you unplug the "timer" plug and measure the resistance of the sensor, then heat up the engine and measure the resistance, it should change with the temp (I can't recall the expected readings, but Uncle Google should know). The resitance should decrease as the engine heats up. something like 2K ohms "cold" to a few hundred ohms "hot".

Again, Rovergauge would tell you exactly what the ECU sees there, too (I really like Rovergauge )

It runs it very rich on initial cold start, so maybe check that as they are a some-what common failure item. If its dead, or the wiring in faulty, it tries to run it like a cold engine the whole time.

AllanWorms said:

As long as the 0.64 drops pretty quick, it might be OK. Settling to .24 may depend on the quality of your meter and leads - that IS fairly close to 0.30 to 0.34 though.

The Coolant temp sensor for the ECU is the one with the square "timer" plug on it, kind of behind the distributor near the thermostat.. Not the round single pin (gauge), nor the big one with two spade teminals (cooling fan). If you unplug the "timer" plug and measure the resistance of the sensor, then heat up the engine and measure the resistance, it should change with the temp (I can't recall the expected readings, but Uncle Google should know). The resitance should decrease as the engine heats up. something like 2K ohms "cold" to a few hundred ohms "hot".

Again, Rovergauge would tell you exactly what the ECU sees there, too (I really like Rovergauge )

It runs it very rich on initial cold start, so maybe check that as they are a some-what common failure item. If its dead, or the wiring in faulty, it tries to run it like a cold engine the whole time.

Click to expand...

Cool. Will check that this evening when I back home. Will update soon.

Btw, I have already ordered the USB cable for the rover gauge. Is it a must to install the 400 ohms resistor on the cable to get it work ?

Yes - you need the resistor, but people have used the more common 390 Ohm without trouble, I beleive.

Being a proper nerd, I ordered specific 400 Ohm resistors though

hi_arshard said:

Hi, few more readings from MAF which I missed in the last post,

Idle CO mixture adjustment
Red/Black
Blue/Red
Idle or with ignition on the reading is same 1.87

Also reading from air flow signal, as switch on the ignition its shoots to 0.64 and settles back to 0.24, does this means that the MAF is bad ?

Yes by factory it’s without catalytic.

I have to fix the black smoke issue as MOT test is scheduled for next week.

Click to expand...

Hi guys good day,

I have checked the Engine temp sensor and the fuel rail pressure sensor, following are the reading,

Reading engine temp sensor
Cold without start Eng off 1.58 ohms
Start Eng dash at gauge 30% 0.47Ohms
Start Eng dash gauge 45% 0.30Ohms
Running for few KM’s Viscous fan on 0.22Ohms

Fuel rail pressure sensor
Eng off 0.42ohms
Eng Start 0.56 as throttle rises shoots to 62,65,69,75,Ohms
Shut down the car for 5 min drops to 62ohms
Start engine again rises to 0.80 0.83ohms

Above test done Ohms meter set to 20k


As per the guide for engine temperature sensor it should it shows in ohms in 4 digit attached screen shot, abit confused with that. Any knows the conversion would be appreciated.

Thanks.

That's why I like auto-ranging, like on my Fluke meter

So, very liekly your meter is like most: when set on 20K, the 1.58 mean 1K58 or 1580 Ohms - thats plausible for a temp of around 30-something C? The 0.22 would be right up there, with your Viscous fan locked, very close to 100C - seems fairly plausible too. That actually seems like it might be OK! The other issue though - is the ECU seeing that - a broken wire can affect that (Rovergauge wins here, again )

The other sesnor is Fuel TEMP, too, not pressure - just FYI. It's readings are usually less of an issue, but do influence mixture somewhat.

Have you checked the fuel pressure regulator? Do you have the Evap cannister? Could it be jammed open and sucking fumes from the tank 100% of the time? (Honestly - I think you're richer than that would do anyway!).

It might be worth checking the fuel pressure with a mechanical gauge to see it going up and down, to spec. Idle, with high vacuum tries to suck fuel from the injectors, so pressure it lower at idle, or should be. Do you have a gauge you can use for that? I've rigged up a water pressure gauge before... but obviously you have to be a bit careful with high pressure fuel!!!

This is the point where Roverguage will become more helpful - in case a reading is out of whats expected at the ECU end. A mechanical fuelling issue is still a possibility though!

Also - I just realised: You said your plug was on the MAF the wrong way??? There could be ECU damage, I guess - I don't know if it would do that, but possible). Again, Rovergauge would help (sorry!).

Yes, your readings are way too low, it should be like in the table corroborated by a laser thermometer pointed to the engine head, buy a new sensor and measure that one to compare maybe your multimeter is making tricks... how many digits you see on the screen when you set it to 20k with probes in the air?