Temperature gauge issue/ and other issue

[Moisesm]

. I have a skoda felicia 1.3 97. I bought around two months ago, at the beginning was working fine, but now it is just giving some troubles like for example.

 

the temperature gauge is not working properly. it works for day  or a few hours  and all of a sudden it drops. the  arrow is indicating 70c, and  just stops working. I changed the temperature sensor, but it did not help. looking for someone who knows how to work with this car it is like needle in haystack. 

 

I was basically forced to installed  the LPG gas, because it was comsuming a lot of gasoline e.g.  13 km per 1 galon. I took it to a carburetor expert  and He cleaned it and changed a few parts and that did not help either. 

 

i got a few more issue, but if you can help get this fixed. i wil really appreate it..

 

thank for your help

[RicardoM]

The most frequent cause of temperature gauge malfunction is a faulty coolant temperature sensor (CTS). But before changing it, we need to find evidence of CTS malfunction. You need an ohmmeter handy. As soon as the needle of thetemperature gauge drops, stop the car then stop the engine. Disconnect the connector of CTS. Measure the resistance between pins 2 and 4 as shown below. On a good CTS you should measure 100-150 Ohms at 90 C (warm engine).

 

[felicia16v]

possibly a faulty thermostat not allowing the engine to warm up properly.

As you have already changed the sensor, maybe drain some coolant and remove the thermostat to check if it's broken or not, as it's only 3 screws .

[RicardoM]

If CTS proves to be good, check the wiring between CTS and gauge.

 

Here is the schematic. I've marked and numbered the points to check for good contact.

 

The correspondence between the numbers on schematic and physical location is shown below.

 

[KenONeill]

Can I ask an "off the wall" sounding question: When the engine has been running for maybe 10 to 15 minutes, do you still get a smell of petrol from the exhaust?

[RicardoM]

I was basically forced to installed  the LPG gas, because it was comsuming a lot of gasoline e.g.  13 km per 1 galon. I took it to a carburetor expert  and He cleaned it and changed a few parts and that did not help either.

Sorry, but a carburetor expert doesn't force the owner of the car to buy a LPG system as last alternative. A carburetor expert repairs it.

[Moisesm]

Thank for the advices.

Frankly, i need to buy or borrow a ohmmeter asap. I will follow you instruction,and let you know what happen.

You are right about the carb expert i think I felt desperate at that time. I took it to more than one technitian and did not see good outcome.

[RicardoM]

You are right about the carb expert i think I felt desperate at that time. I took it to more than one technitian and did not see good outcome.

I posted numerous replies and photos about repairing the carburetor. Search for them.

 

How much did you pay for LPG system?

How many miles you have to drive to recover the investment?

Edited 4 June, 2016 by RicardoM

[Moisesm]

Hi,

 

Man, I do not know where to start.

 

 

How much did you pay for LPG system?

around 200 dollars or 8000 pesos. and 35 kilometer per Galon which i think it is worthy.

 

well, i checked the CTS  it was given 119 ohms at 90

however when it stoped working i  measured again  it shows 285  OHMS (i do not understand)

 

I took out the the dashboard everything looks good. i used  good contact cleaner  to remove any possible moisture. I reinstalled averything back. 

guess what happened. when i turned on the light in evening  the dashboard was off completely. i meant the dashboard´s light did not turn on, on the top of  that, the gas reader,  and speedmeter shut down  and  temperature gauge was all the way to top. meaning the light is controling  the hole dashboard.  please take a look at the picture.

[Moisesm]

i would like to upload some picture, so you can see how this is acting out. the fuse box picture is just make sure everything is laid out well.

Edited 6 June, 2016 by Moisesm

[Moisesm]

chek out  these pi

Edited 6 June, 2016 by Moisesm

[RicardoM]

well, i checked the CTS  it was given 119 ohms at 90

however when it stoped working i  measured again  it shows 285  OHMS (i do not understand)

That is enough evidence to replace the CTS.

 

About messing with the dashboard, I said "If CTS proves to be good, check the wiring between CTS and gauge." You found evidence that CTS was not good, therefore you should've stopped there and let the dashboard alone.

 

I said it many times, the PCB of instrument cluster is bad designed and poorly made. The copper traces are too thin and brittle. Sometimes it is enough to disconnect the back connectors and you end up with a mess...

[RicardoM]

I reinstalled averything back. 

guess what happened. when i turned on the light in evening  the dashboard was off completely. i meant the dashboard´s light did not turn on, on the top of  that, the gas reader,  and speedmeter shut down  and  temperature gauge was all the way to top. meaning the light is controling  the hole dashboard.

I will help you locate the problem in each case. However, you need basic soldering tools and skills to repair the circuits. You must identify where there is a crack in the copper traces of the PCB. You will use a powerful magnifying glass and an ohmmeter set on continuity measurement. In case you feel this job is too difficult, ask any electronics repairman for help.

 

First of all, let's clear some terms. See photo below.

 

The backlight not working - check blue trace

The fuel gauge not working - check magenta trace

The tachometer not working - check green trace

 

The temperature gauge needle stuck up - check magenta traces (see photo below)

[Moisesm]

Hi ricardo,

I found someone who helped me solve the problem. We followed the steps above as you told, and now it is partially up and running. All the board it is working as ussual.

Thank

Now, i got a couple of issues more that i do not know if i should open a new topic

1. Radiator fan is running in high speed when I start the car. I checked others topic with this issue but, i am stuck.

2. Getting too hot when i used A/C 110 C

Edited 14 June, 2016 by Moisesm

[RicardoM]

I need more information. Remember you have full access to your car, I don't.

 

1) Does your car have A/C from factory or did you retrofit the A/C?

2) Are you using coolant or tap water?

3) You've mentioned that the radiator fan starts at full speed right after starting the engine. Are you saying that the coolant temperature still goes to 110 C with fan on high speed???

4) Did you ever flush properly the radiator?

5) What is the status of the thermostat? Are you sure it isn't stuck closed?

 

Do you remember any prior event that could be related to this overheat? Repairs, poor maintenance, mistakes, etc.

 

PS

Always stop the engine immediately if the coolant temperature reaches 100 C.

[Wael78]

On 02/06/2016 at 22:11, RicardoM said:

The most frequent cause of temperature gauge malfunction is a faulty coolant temperature sensor (CTS). But before changing it, we need to find evidence of CTS malfunction. You need an ohmmeter handy. As soon as the needle of thetemperature gauge drops, stop the car then stop the engine. Disconnect the connector of CTS. Measure the resistance between pins 2 and 4 as shown below. On a good CTS you should measure 100-150 Ohms at 90 C (warm engine).

 

How to measure the single pin (CTS) 

[RicardoM]

The second pin is the ground/chassis.

[Wael78]

3 hours ago, RicardoM said:

The second pin is the ground/chassis.

Do you mean I should follow the same steps replacing the second pin with the ground? Did I understand you in a correct way? 

[RicardoM]

I thought that you don't know where is the second pin of the sensor.

I don't have the temperature/resistance characteristic for CTS used on BMM engine cars.

The alternative is to use the VAG-COM scanner to check the temperature with engine cold then with engine warm.

[Wael78]

On 15/09/2020 at 13:41, RicardoM said:

 

 

16 hours ago, RicardoM said:

I thought that you don't know where is the second pin of the sensor.

I don't have the temperature/resistance characteristic for CTS used on BMM engine cars.

The alternative is to use the VAG-COM scanner to check the temperature with engine cold then with engine warm.

Thanks for your reply

I'm talking about the one pin CTS like that