For my Sins

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T

Trystan

Member
Posts
17
Location
Cape Town
For my sins I sold a series and bought a Freelander. Sadly Price dictated the purchase so I will have many posts here..
Today I was hunting why the temp gauge doesn't budge at all. Part of the process was checking fuses - me pulling each individual fuse out and inspecting it.

Long story short, the vehicle now runs terribly - missing almost and not accelerating...even backfiring on deceleration. I'm guessing that by unplugging the fuses a data set has been lost / uncalibrated somewhere?

‘98 1.8l K

How do I cnt-z ?
 
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Pulling a fues won't upset anything. All Freelander ECUs store all programmes in non volatile memory. This doesn't need power to be maintained to keep the memory safe.
Running issues on a 98 1.8 are normally confined to HT problems. So things like disy cap, rotor arm, HT leads and plugs are normally at fault. The fuel filter can also clog which will cause similar running issues to HT faults.
 
The only other thing I did was re-lug the wires on the temperature sensor (which I believe is used to sense cold start?) as the lug was broken.
This did not help the poor cold start incidentally
 
Trystan said:
The only other thing I did was re-lug the wires on the temperature sensor (which I believe is used to sense cold start?) as the lug was broken.
This did not help the poor cold start incidentally
Click to expand...

Fuel mixture control is based on information from many sensors, the CTS being just one. There are two coolant sensors on the 98 1.8. One is for the engine ECU. The other is just for the dash gauge. They are different and so aren't interchangeable. They are cheap enough to change out to see if it makes a difference. Jast make sure you get the correct sensor for the job it does.
Also check the vac pipe that connects to the ECU. If it's split it will cause running issues.
 
Thanks guys!
Today's development is that if I disconnect the ECU coolant sensor, she runs better and if i reconnect just one of the wires then she runs marginally better. However connecting the second wire results in return to very poor running. To elaborate on the situation, this vehicle is 3 days old in my life, the engine has been overhauled (likely a result of head gasket), but it has also been manhandled by a wannabee electrician so i cannot say, for certain, that the wires connected to some items are correct).
So my questions are:

1: what is the sensor sending to the ECU
1.1: is there a difference in the terminals and what info they are sending. I.E can the wires be inter-changed (remember that the plastic lug was damaged and thus i put new lugs on)
1.2: The original problem was a poor cold start. This was possibly a result of the one connector not making contact with the terminal...which is why I re-lugged them.

Sooo. Could it be (remember that I come from a series background so a air-mixture change was done with a screw driver not a computer) that when the engine was put back, the ECU was set up (mapped?) with one of the wires not making contact and thus now when i connect it, it runs rough?

2: How do I trace what wire is meant for what? I.E does someone have a ECU - Wiring diagram map?
3: What is the easiest way to re-map the ECU (yes I could send it in to a mechanic...but then I learn nothing).

Lastly, and slightly off topic here, my Temp guage STILL does not budge. Ideas on trouble shooting that?
 
Trystan said:
Thanks guys!
Today's development is that if I disconnect the ECU coolant sensor, she runs better and if i reconnect just one of the wires then she runs marginally better. However connecting the second wire results in return to very poor running. To elaborate on the situation, this vehicle is 3 days old in my life, the engine has been overhauled (likely a result of head gasket), but it has also been manhandled by a wannabee electrician so i cannot say, for certain, that the wires connected to some items are correct).
So my questions are:

1: what is the sensor sending to the ECU
1.1: is there a difference in the terminals and what info they are sending. I.E can the wires be inter-changed (remember that the plastic lug was damaged and thus i put new lugs on)
1.2: The original problem was a poor cold start. This was possibly a result of the one connector not making contact with the terminal...which is why I re-lugged them.

Sooo. Could it be (remember that I come from a series background so a air-mixture change was done with a screw driver not a computer) that when the engine was put back, the ECU was set up (mapped?) with one of the wires not making contact and thus now when i connect it, it runs rough?

2: How do I trace what wire is meant for what? I.E does someone have a ECU - Wiring diagram map?
3: What is the easiest way to re-map the ECU (yes I could send it in to a mechanic...but then I learn nothing).

Lastly, and slightly off topic here, my Temp guage STILL does not budge. Ideas on trouble shooting that?
Click to expand...

The engine ECU is programmed to run the engine with a sensor or sensors not giving plausible data. So if the coolant sensor is damaged, the ECU simply substitutes a fixed value for it. This value is for an warm engine (40°C rings a bell). So starting would be less than perfect, but otherwise it should run OK.
The engine ECU is programmed to learn various running parameters, so it can compensate for engine wear and slight sensor differences (known as adaptation). This generally keeps the engine running as well as it can. Sometimes however, a bad sensor can be logged as a valid value. This can cause issues in running if it's then corrected. I've not seen it with a coolant sensor, as the parameters are quite specific. I have seen a split manifold pipe to the ECU cause a running issue, once it was repaird. This was due to the split slowly getting larger over time. The adapted values assumed a gradual loss of MAP signal, as would happen as the engine wears. This wrong MAP value was then stored as a valid value, so the engine ran pretty well. However when the pipe was fixed, the ECU suddenly saw a huge increase in the MAP signal, it got all confused and ran the engine like a bag of bolts. It took over 1000 Miles for the ECU to re-adapte to the correct MAP signal.

Have you checked the HT system, plugs, leads, cap and rotor arm? It's not uncommon for those to cause running issues, even id they look serviceable. Personally I always replace the whole HT system as a matter of course when bad running is evident. It's also a good idea to check the fuel pressure, as the fuel filter is never changed and so clogs solid.

There are actually 2 temperature sensors on the pre-2001 K series. One is for the engine ECU (brown in colour iirc) and one for the gauge ( blue in colour iirc). They won't work the wrong way round, so need to be connected to the corresponding colour plug. Hopefully I've got the colours correct. It's a long time since I've seen under the bonnet of an early K series Freelander.
 
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Thanks @Nodge this is pretty helpful!

Yes i'm aware of the two sensors - at some point I will trace the temp-guage wiring to see wether its correct - no temp guage seriously sucks...i'm trying to fit a direct guage but its not as straightforward as on a series...there's no way through the firewall :)

What is confounding is the second wire connection. My gut feel is that the plug was sufficiently damaged that in the recent short term the ECU has "learned" to run with that wire not returning a value (as it was, effectively, disconnected). Do I connect it and try to drive it so that the ECU "learns" the new value?
 
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