The Scrapcento

[AndrzejM]

I'll keep my fingers crossed for your engine. And congrats on FE, I'm sure you'll find a way to keep it that way.

[Piwoslaw]

Maczo, how is your engine?

[maczo]

Originally Posted by Piwoslaw

Maczo, how is your engine?

Oh, I wish I knew. The last 2 weeks I've been away on a business trip and haven't heard from the mechanic.

Before I left all I knew was that the core plug was blasted out. I'm going to call the mechanic tomorrow.

[maczo]

Aaand I have the car back. Seems to run, so all is good
It had the head gasket replaced + new oil, coolant etc. I don't know whether plunging into a puddle was the cause, maybe it just speeded up the inevitable.

To celebrate the return of the 'cento, I bought it a ticket to the car wash... a place, where it has been very rarely

[maczo]

Finally I filled up the tank and got record FE, unfortunately it was the wrong end of the spectrum (9.0 lhkm or 26.1 MPG)

On my defence, the scrapcento took part in a rally and had 2 long visits at the mechanics' afterwards, with lots of idling. During the second visit it spit out a core plug again, which had been fitted incorrectly (probably the same plug the first mechanic replaced, but I'm not 100% sure).

As for ecomods, I replaced the coolant temperature sensor (it had most probably failed, leading to the head gasket problems) to one with different characteristics, so that I can use it with a temp gauge (previous one was for overheating warning light). I also got a temp gauge. Only minor issue is that the needle barely shows anything when engine is at operating temp (shows 40 deg C...) so I'm going back to the mechanic once more



The other "ecomod" is a short-shift mechanism and moving the gear lever higher, so that it's near the steering wheel for more convenient P&G

[Pandaf]

Are you sure the thermostat is still working, VDO gauges are generally more reliable than Italian thermostats...

[AndrzejM]

Put the sensor into a boiling water and check your gauge if it's showing 100 degrees. Temp sensors may have different characteristics and only the exact pair of sensor + gauge will show the correct temperature. So maybe you should check your sensor+ gauge pair first before you'll change your thermostat. That's always a good idea to know the exact reading for the boiling point anyway.

[maczo]

Thanks for the input, guys.

First of all, the sensor is in the head, so as far as I understand, thermostat is not a factor here.

Second thing is I'm betting on incorrect wiring by the mechanic. Here's why I think so:

He said he connected the gauge directly to the sensor before mounting, waited for the engine to heat up and the fan to engage, and the readings were OK. Then he proceeded to mount the sensor inside the car, tapping into the wires there. So my guess is he might have tapped into the second temp sensor (both are head-mounted), the one that feeds data to ECU. Then there's resistance and voltage drop on both of them, correct? And neither works correctly, which would explain why the fan wouldn't engage when I let the engine idle for half an hour.

Anyway I'm not sure whether the sensor-to-ECU wire goes through the passenger compartment, so my theory may be totally invalid. If you guys have any more hints on this, I'd love to read them. The car is going to return to the mechanic, but no sooner than in 3 or 4 weeks as I'm going abroad again.

[AndrzejM]

Originally Posted by maczo

First of all, the sensor is in the head, so as far as I understand, thermostat is not a factor here.

Thermostat is always the factor, if it's opening too early engine temperature will drop significantly while driving. And it doesn't matter where temp sensor is placed. Coolant temp is similar in whole system.

He said he connected the gauge directly to the sensor before mounting, waited for the engine to heat up and the fan to engage, and the readings were OK. Then he proceeded to mount the sensor inside the car, tapping into the wires there. So my guess is he might have tapped into the second temp sensor (both are head-mounted), the one that feeds data to ECU. Then there's resistance and voltage drop on both of them, correct? And neither works correctly, which would explain why the fan wouldn't engage when I let the engine idle for half an hour.

That can be the factor.

You can check wiring on your own very quickly, just short a "temp gauge wire" to the mass and gauge should go crazy. You may hook up it through light bulb to not destroy it, but few seconds of pure mass won't be a problem for your gauge. Then you'll know for sure if wiring is correct.

[Viturro]

Good job, i did never seen that car, but i know those engines.
My dad had a Fiat 125 with Fiat ritmo engine 1.7l diesel, and with my dad we reach the 155 km/h that engine have 55 hp, your car should reach the same speed at least.
i remember that in the 125 the hood open from back, then my dad did open it and the hood did rise up like 10 cm, and we get 5 km/h plus. was pretty funny he did try to close it up again at 155 km/h but the hood was to strong .