When I start cold engine and I start driving emediately, when I press the throtle, it has no power up the hill. Like it's ignoring my throtle pressed. Then in a 2 or three seconds delay It accelerates and car goes fine afterwards. What could couse this ? It is the symptom from last few years, but I decited to get to the bottom of this. Tipo 1.4 i.e.

I have encountered the same symptom a few times when starting with the engine very cold due to low outside temperatures, I have never however given any notice to that as it lasts only for 1-2 seconds.
I believe it has to do with the cold oil and the instant resistance it places to the rotation of the engine. This is why we should' t try to drive at high rev/min when the engine is cold. The important is that if the engine works for a few seconds (10 seconds for example) before starting to roll the symptom doesn't make its appearance.

Yes, the simptom is the same. With addition, if I stop the car before warmed (let's say in first 5 minutes) and leave it in IDLe, RPM drop below 900 and then after few seconds, they raise up to normal "warming up" - 1100. Could this be something else, like lambda heater problem ?

ive had exactly the same proble on a 1.6ie, if i held the throttle consistantly while driving it would appear as if the car was going to stop (no power) momentaraly!! also injector light would come on too...

That rev rising and dropping is a tricky one.... if you have had you battery dis-connected for a period of time or it has run dead flat then the stepper motor needs to be reset, the rev rising and falling is due to the stepper motor not recognising where to idle properly so it does that,,, to reset the stepper refer to your Fiat Tipo hand book which came with the car....

if its not that then it will be your lambda sensor!!!

I wish I know how to reset it .. at least I could try this. My manual is no good, since it is in Italian language and I don't understand a word. Althou I think it is probably lambda problem, becouse I recently boutht new stepper motor, wich was totaly unnecesary

There is something in there about resetting the stepper motor? Can't say I've noticed that before.

So how do you reset it ?

I never heard anything about resetting the stepper motor .
However, it is possible to reset ECU by disconnecting (-) cable from the battery for, say, 30 minutes.

even if you have put a new stepper motor on this will not be programed to your engine and will need resetting i guess, my friend found the info when i sold him my old 1.6ie, he came accross it and to tell you the truth i had never heard of it till he pointed it out either, i will see if i can get the book back or if some one on the forum would be kind enough to share the info....

On the 1.4ie, it uses a Bosch Mono unit. As far as iam aware, the ECU learns the base idle so the stepper motor is always set correctly. All the stepper motor is, is a dc motor which moves a rod by reversing the winding voltage within the motor. Poor cold performance could be a faulty coolant temp sensor. A coolant temp sensor that does not run its full range, will playup. Could be a leak somewhere making the mixture lean[when heated up, leak disappears]. Could be over rich mixture due to a faulty Lamba, but this would show up when hot too. The spacer under the Bosch unit is leaking [common].

Andy.

It's not realy such a big deal. I left the batery disconected for half an hour. And pluged back and no low revs were detected when I stoped driving after 1 minute and left it IDLEing. The tricky thing is, when driving down the hill and the slope ends, and when I press throtle, car hesitates for 1 second and then it pulls. So the problem is delay with pressing throtle. When car warms up, that problem disapeares. I tried changing coolant temp sensor and it's not that. I puted the original one back, since with the new one (made by FACET) car rews were a bit lower in IDLE. And it's not a stepper motor wich is also new. It is not distributor cap either, it is also 1 year old. I'm sory to bug you guys, but I realy wan't to get to the bottom of this. Any more suggestions ? Anyway except this minor "bug" when cold, car is normaly driveable.

death_paladin9 said:

It's not realy such a big deal. I left the batery disconected for half an hour. And pluged back and no low revs were detected when I stoped driving after 1 minute and left it IDLEing. The tricky thing is, when driving down the hill and the slope ends, and when I press throtle, car hesitates for 1 second and then it pulls. So the problem is delay with pressing throtle. When car warms up, that problem disapeares. I tried changing coolant temp sensor and it's not that. I puted the original one back, since with the new one (made by FACET) car rews were a bit lower in IDLE. And it's not a stepper motor wich is also new. It is not distributor cap either, it is also 1 year old. I'm sory to bug you guys, but I realy wan't to get to the bottom of this. Any more suggestions ? Anyway except this minor "bug" when cold, car is normaly driveable.

Click to expand...

When you changed the stepper motor, did you change the spacer between bosch unit and manifold? Have you got a manifold to head leak when cold causing a weak mixture? Have you checked your plugs to see what colour they are?
When you change the coolant temp sensor, ALWAYS use a Fiat item, not an aftermarket one as they are no good. Airflow sensor maybe faulty allowing a lean or over rich mixture[check plugs].

Andy.
Why dont you have the emissions checked and a diagnostic done?

I didn't change spacer. Where is air-flow sensor located ?

death_paladin9 said:

I didn't change spacer. Where is air-flow sensor located ?

Click to expand...

Air Temp sensor is located with the injector and above the stepper motor on the side. Think it is a 4 pin plug.. You will see wires going to it.

Andy.

when you hold the throttle at a constant rpm say 1500 do the revs rise and fall???

Air temperature sensor - item 2.
Bosch Mono Jetronic does not have an airflow sensor.

dazzo666 said:

when you hold the throttle at a constant rpm say 1500 do the revs rise and fall???

Click to expand...

No they don't. As I said that problem was fixed, at least they don't fall anymore, since I unpluged the batery for 1 hour and plug it back on. I think the point is, you must newer unplug and plug back with hot engine. It must be done on cold engine. The only minor bug that remains, is that 1 second throtle delay with cold engine (happening only once in warm up period) and even that is not always present. I hope I better expressed myself this time, what the bug is.

Thanks for all advices in the past and in the advanced

(CZ)enda said:

Air temperature sensor - item 2.
Bosch Mono Jetronic does not have an airflow sensor.

Click to expand...

Do you have full shematics on mono-jetronic sistem on my Tipo? I would realy like to know, how it works. Is that Air temp sensor removable and how much does it cost ?

death_paladin9 said:

Do you have full shematics on mono-jetronic sistem on my Tipo? I would realy like to know, how it works. Is that Air temp sensor removable and how much does it cost ?

Click to expand...

I have an original Bosch documentation for Mono Jetronic, but it is in Czech, thus of no use for you Although it is an interesting reading, I am not an expert on the system as it works OK on my car, and trying to fix the things that work is the fastest highway to hell .

Some details are provided in Haynes manual for Uno, which is using the same system. The manual is available for download e.g. here:
http://www.italiancars.org/fiat/technika/technika.php
Haynes and Porter manuals for Tipo I have are no good for this purpose, but you can still download them from the web - if interested, do some googling as I do not have their sources bookmarked.

If you understand at least a bit Italian, here is an interesting resource:
http://xoomer.alice.it/flmbe/Manualea.htm

Thinking about the delay...
Maybe you should check the vacuum connection (rubber hose) between the inlet manifold and Digiplex 2 ignition module (the finned ECU in your engine compartment, behind the engine). The unit sets the advance according to the vacuum in the manifold and it may be that when the connection is not tight, it sets the advance incorrectly.

BTW, are you sure your fuel and air filters are clean?

(CZ)enda said:

Air temperature sensor - item 2.
Bosch Mono Jetronic does not have an airflow sensor.

Click to expand...

I meant to say air temp sensor which i corrected later in the posts.

Andy.