Technical Fiat Tipo 1.6 i.e Idle switch, RPM sensor, Air temperature, O2 sensor shorts ?

[Zlatandrajer]

Hello, i own Fiat Tipo 1.6 i.e 55 kw year 1995. I hooked it up to multiecuscan and saw these errors with shorts on ground for Idle switch, RPM sensor, Air temperature sensor and O2 sensor showed open loop/circuit. When i hooked it up to delphi it showed the same errors except for Air temperature sensor. O2 sensor on delphi showed different mixture each second rich/poor.
My questions are:
If anyone has ever met with these issues ?
If so, what kind of O2 sensor should i buy for this car so the Voltage stays normal, and my mixture will be ok ?
What brand of Idle switch should i buy ? I will look at the cables to find the short, but any suggestions for brand of idle switch ?
The same question for RPM sensor.
Anyway, the issues that these errors do are - RPMs are constantly higher between 1100-1400, or sometimes when i'm driving the RPMs fly to 3000 and won't go down. The gas pedal seems "laggy" i would say. Like i press on it and the car reacts almost after a second, it's not instantaneous.
I would love to repair my beloved car, so if anybody has ever met with these problems, feel free to write me in this thread or as a PM.
P.S. I'm sorry if there already is a thread on this, but i'm really desperate.
THX and long live old classic cars !

 

[jonti]

THX and long live old classic cars !

Welcome to the forum. Post a picture of your car and hopefully stick around. We in Tipo land are a bit thin on the ground. The RPM sensor always comes up on the scan, it doesn't necessarily mean there is a defect with it. If I were you, I would lift the air box off, 3 screws, 2 clips and the air pipe, to see what is happening on the throttle body, which will then be visible. Then get a person to sit in the car. Is the idle motor (black oblong) plunger acting on the throttle lever e.g. pushing it a little when cold (backing off as it warms) or if you have air con, pushing the throttle when it's switched on. Is the inside of the throttle body cleanish - the butterfly flap? I didn't think we had an external temp sensor :-O The issues I had are with the throttle position sensor. My original was worn, causing driveability issues. It then has to be positioned on the throttle body precisely. Using a multimeter and youtube videos, I tested the ground, negative and positive connections to the TPS, then it's position. I mention this, because adjusting the position, in line with my findings has caused the revs to hang slightly now, although now running correctly. Check the cable to the throttle for free movement. Although TPS ground fault came up as my error (along with the RPM sensor), the RPM and ground were fine and youtube shows how to test ground. I believe the o2 sensor can be damaged over time if the car is running rich. All aftermarket sensors worked fine. Also, look for any air leaks the throttle body sits on a paper gasket and another gasket on to the manifold.

 

[Zlatandrajer]

Welcome to the forum. Post a picture of your car and hopefully stick around. We in Tipo land are a bit thin on the ground. The RPM sensor always comes up on the scan, it doesn't necessarily mean there is a defect with it. If I were you, I would lift the air box off, 3 screws, 2 clips and the air pipe, to see what is happening on the throttle body, which will then be visible. Then get a person to sit in the car. Is the idle motor (black oblong) plunger acting on the throttle lever e.g. pushing it a little when cold (backing off as it warms) or if you have air con, pushing the throttle when it's switched on. Is the inside of the throttle body cleanish - the butterfly flap? I didn't think we had an external temp sensor :-O The issues I had are with the throttle position sensor. My original was worn, causing driveability issues. It then has to be positioned on the throttle body precisely. Using a multimeter and youtube videos, I tested the ground, negative and positive connections to the TPS, then it's position. I mention this, because adjusting the position, in line with my findings has caused the revs to hang slightly now, although now running correctly. Check the cable to the throttle for free movement. Although TPS ground fault came up as my error (along with the RPM sensor), the RPM and ground were fine and youtube shows how to test ground. I believe the o2 sensor can be damaged over time if the car is running rich. All aftermarket sensors worked fine. Also, look for any air leaks the throttle body sits on a paper gasket and another gasket on to the manifold.

Thanks, man. I'm gonna look at all of this you mentioned on friday. I tried my luck and bought TPS from aliexpress for 8€. I couldn't find it anywhere in my country, so we will see. It's supposed to come around 20th of july.
I'm planning to look at all the cable stuff on friday-sunday with my dad, he has some experience with old cars, so i will keep this thread updated.
So you mentioned the TPS... what issues did it do to you ?
Anyway i bought the RPM sensor from BOSCH, so i will plug it also on friday, to see what will the multiecuscan show afterwards.
About the ext. temp. sensor. It's situated on the top of the throttle body. just as you mentioned- when you lift the whole air box off you see the monoinjection unit and on top of it sits small circular "thing" with cables coming from it. That's the Air Temp. sensor.

Yeah and this is my Fiat Tipo 1.6 i.e. I bought the Borbet B discs after 5 years of owning it, bcs i couldn't find them anywhere on the market. I wanted to post more pics, but all of them are from the side i dunno why

 

[jonti]

my Fiat Tipo 1.6 i.e.

Nice one. That's great. Teapot was a fine looking car in white. Your defect sounds as though it should be likely able to be fixed. I was new to petrol with my i.e. but I am learning its not too complicated. Didn't know about the air sensor, now you mention it . If the throttle unit is faulty in some way, that would be less good. Not sure if you can get a spare, as there are none here. The TPS has a mechanical track from the throttle plate, so it wears eventually. At 65,000 miles it was causing hesitation. I put a new TPS on but still the engine light came on at times however. I googled 'adjusting a TPS sensor' or similar, there were tips on how to calibrate the position and test the feed. Only fractionally repositioned, but the values are better and the engine light has gone. BTW my idle tends to wander up and down a bit, I have no idea what causes this.

 

[Tipo19GR]

Welcome to the forum, that is a nice Tipo you have there.

The rpm sensor always shows up on the scan as Jonti says. It is explained in the error description so can often be ignored. When accompanied by starting issues, however, more investigation is warranted.

The idle control motor is in my view more likely to be a culprit, rather than tps or air temperature sensor. They can be had relatively cheap. I drove 400.000km plus in my previous Tipo and never had any issues with the throttle body components, the idle control motor however seems to be a weaker point.

I personally stick to the exact right Bosch O2 sensor. When the O2 sensor fails, it seems to cause the injection light to glow on the dashboard and lead to power loss. But that may not be 100 percent always the case.

Hope you find a solution soon, be sure to let the forum know

 

[Zlatandrajer]

So today we worked with dad on tipo. We checked on + cables leading to idle control, we unplugged everything, cleaned every contact put everything back together. We've done the same to the electrical ground which is on gearbox.
The problem persisted.
We also checked for fuse of O2 sensor, and it was okay. Thx for mentioning original O2sensor is BOSCH, i will replace it when i will have money and time.
We also checked the resistance of TPS sensor between the contacts, and every single one had the right values of resistance (ohms).
I bought one from aliexpress, but i'm afraid to plug it in. Does anyone have any experience with aliexpress products ? I bought injector once, but i forgot where i've put it.
The throttle body is absolutely crystal clear, so i don't think that's the issue.
Do your RPMs wander from 800 to around 1200 sometimes even more ?

 

[Tipo19GR]

Well done checking all the cable connections. In my experience the idle does not fluctuate, it is a steady 850 rpm except for when the engine is still cold, then it is a few hundred more rpm.

I would not touch the tps unless I had good reason to believe it was broken. Have you considered an air leak? As Jonti said, the gaskets between the throttle body and the inlet manifold tend to leak. One of them is still available at Fiat, the other you will need to cut from gasket paper yourself. Maybe check first by spraying carb cleaner or starter fluid around the gaskets to see if it changes rpm.

 

[Tipo19GR]

One thing that comes to mind, because you get these four errors together in the MES, could it be that the earth connection on the back of the inlet manifold is bad/dirty?

 

[jonti]

One thing that comes to mind, because you get these four errors together in the MES, could it be that the earth connection on the back of the inlet manifold is bad/dirty?

Yes. Seems likely several codes at once could stem from a single cause. Although 'ground fault' was alleged in my case it wasn't anything to do with ground, this sounds like a good idea. As it seems you've tested single items such as the TPS position & connections. The circumstances immediately before the poor running started might be a clue also. I think you will have already checked the accelerator cable for free movement and that the floor mat isn't interfering with pedal travel (this sounds ridiculous but surprising how often this causes issues).

 

[Zlatandrajer]

Unfortunately Tipo all of a sudden stopped working. Gonna check on the air leaks when i will have time. But first i have to find a way to get Tipo started. When i turn the key, the starter just keeps on spinning, but the engine doesn't kick on.

Tipo19GR where exactly is the ground behind intake manifold ? me and my dad could find only the ground from battery which is on a nut on gearbox i think. Do you have a photo ?
Jonti you mentioned circumstances before the problem with idle happened. The problem is we got the car in 2014 with this issue already, i'm the first one to get it fixed.
The accelerator cable is a little loose... Should it be absolutely tight ?

 

[Zlatandrajer]

I also have a book for repairs for Tipo in german it's So wird's gemacht Fiat Tipo (i have it in czech), but some of my problems are not even mentioned in this book . But the basics are quite helpful.
I also found out that if you write the issues in portuguese in youtube you get a lot of solutions since a lot of brazilians own fiat tipo lol.
Except for the problem which i have now, that i cannot start.

 

[Zlatandrajer]

So today we replaced RPM sensor, the car still didn't want to start. We sprayed starting spray on air filter and the engine kicked on, but the exact second we stopped spraying the engine died. We troubleshooted the fuel pump by taking out the fuel hoses out and flipped the key to the first position which didn't spray any gasoline, so we will replace the fuel pump on tuesday. Will keep the thread updated.

 

[jonti]

So today we replaced RPM sensor, the car still didn't want to start. We sprayed starting spray on air filter and the engine kicked on, but the exact second we stopped spraying the engine died. We troubleshooted the fuel pump by taking out the fuel hoses out and flipped the key to the first position which didn't spray any gasoline, so we will replace the fuel pump on tuesday. Will keep the thread updated.

That sounds encouraging Keep trying things

 

[Zlatandrajer]

So yesterday we changed the fuel pump and voila, the car is running again. However i still get the occasional RPM bump, where they go to 3000 and then they go down. However i noticed the car acts calmer on idle. When the engine is cold RPMs around 1000, then they go down to 850-900.
Antoher issue which i have is that the engine sometimes cuts out. This issue is persistent since we have Tipo. I noticed that it usually happens when the engine is hot, like it gets to the 100-110°C when the fan should start rotating ,but instead the car just dies.
Is it normal for the coolant to have this temperature, or should the fan start rotating just as it hits 90°C?
In two weeks we're planning to replace coolant also with sensor and also the fuel filter. Gonna check also for false air and check the ground behind manifold. Does anyone know what is this ground for ?
Thx.

 

[jonti]

So yesterday we changed the fuel pump and voila, the car is running again. However i still get the occasional RPM bump, where they go to 3000 and then they go down. However i noticed the car acts calmer on idle. When the engine is cold RPMs around 1000, then they go down to 850-900.
Antoher issue which i have is that the engine sometimes cuts out. This issue is persistent since we have Tipo. I noticed that it usually happens when the engine is hot, like it gets to the 100-110°C when the fan should start rotating ,but instead the car just dies.
Is it normal for the coolant to have this temperature, or should the fan start rotating just as it hits 90°C?
In two weeks we're planning to replace coolant also with sensor and also the fuel filter. Gonna check also for false air and check the ground behind manifold. Does anyone know what is this ground for ?
Thx.

That's good news. Yes i believe the idle control motor acts on the throttle on starting it at higher revs. I think my fan cuts in just over the middle of the gauge, running intermittently. However it's not always obvious it's on until the engine is turned off and the motor can be heard, operating after the ignition is turned off. The fan seems to use a lot of power, so is the action of the fan trying to come on tripping your electrics, so to speak, killing your spark. I really don't know if this could happen.

 

[Zlatandrajer]

So today we worked on tipo again. We changed fuel filter, coolant, thermostat and also cleaned the ground contacts behind manifold.
Thermostat solved the problem with the fan, or with holding the temperature below 100°C. Hopefully during driving the engine will not cut out.
Hooked the car to MES, started it up, and only one error code - LAMBDA PROBE SENSOR (O2 sensor), short circuit. In the live data paramaters the probe is giving signal, but the loop is listed as OPEN LOOP, not closed, which indicates, the o2 sensor is not working as it should, i think this is the main culprit behind my big issue with RPMs. The car just doesn't know what to do and the fuel mixture is either rich or poor and keeps adjusting
I dont know which one to buy, since there are 5 different codes under which to find the O2 sensor. These codes are listed for Fiat Tipo 1.6 i.e 55kw (1993-1995).
7668286
7619303
46423798
46423987
46444284
I'd be glad if anyone could recommend under which code to search for if you had this car with the same engine.
I saw Tipo19GR said BOSCH, but i can't find one.
Thanks a lot.

 

[Zlatandrajer]

So today we worked on tipo again. We changed fuel filter, coolant, thermostat and also cleaned the ground contacts behind manifold.
Thermostat solved the problem with the fan, or with holding the temperature below 100°C. Hopefully during driving the engine will not cut out.
Hooked the car to MES, started it up, and only one error code - LAMBDA PROBE SENSOR (O2 sensor), short circuit. In the live data paramaters the probe is giving signal, but the loop is listed as OPEN LOOP, not closed, which indicates, the o2 sensor is not working as it should, i think this is the main culprit behind my big issue with RPMs. The car just doesn't know what to do and the fuel mixture is either rich or poor and keeps adjusting
I dont know which one to buy, since there are 5 different codes under which to find the O2 sensor. These codes are listed for Fiat Tipo 1.6 i.e 55kw (1993-1995).
7668286
7619303
46423798
46423987
46444284
I'd be glad if anyone could recommend under which code to search for if you had this car with the same engine.
I saw Tipo19GR said BOSCH, but i can't find one.
Thanks a lot.

Also i think that cleaning the ground contacts behind manifold solved the short circuit for idle valve.

 

[jonti]

7668286
7619303
46423798
46423987
46444284

Good progress, I think those beginning with 4 are the new numbering system and may duplicate the ones beginning with 7. I would have thought only one or two of these would actually be available now. Find an image of any still available. If it looks the same as on your car, buy it

 

[Tipo19GR]

I have previously from Amazon bought Bosch 0258003772 which corresponds to 46444284 and works perfectly for my 1.4 I.e. from 1996.

 

[Zlatandrajer]

Now what bothers me is this. The whole mechanism is "laggy" and i don't where the problem could be TPS sensor ? False air ? Or maybe the mechanism is set up wrongly? Have you ever met with an issue like this ?