Technical 1.1 i.e. timing belt/cambelt and poor mixture (idle fault)

[andre79ge]

Hello!
It' s not the first time that I write on this forum for a problem on my Uno, this is a problem of a bad idling of engine (is a 1.1 with lambda and mono jetronic fuel injection). I did never solved the problem and some months ago i stopped to write on forum because my grandfather crashed the car (Not a big crash fortunately). But car was repaired for crash problems (anterior light and other stuff) and I'm trying to solve idle problems another time.
The problem appears some minutes after engine start (when it starts to warm up and idle rpm is decremented by ecu as soon as temperature rises up). I tried to check basilar stuff (sparks, air leaks, vacuum advance, lambda sensor, air temp and water temp sensors and similar) without finding any fault and without success in solving problem. Idle is bad and bad as soon as external temperature is low. THen it is better when engine is completely hot.
However it sounds as a poor mixture problem (engine looses rpm at idle and it cuts out or looses power if i rapidly push gas). Sometimes it cuts out also soon after I start it: rpm is at approx 1300 (it is incremented by ecu when cold) then it dies. It remembers me old carburettor engines: they died if started without mixture enricher when cold).
So I tried all that came in my mind...
After a lot of time and after trying to change sensors, sparks, testing etc... i tried to change timing on cambelt (!) (because i had a suspect that the machanich who changed timing belt could regulated it in retard). SO I advanced cambelt position respect to timing belt of only one unit (I can't say it in English: timing belt and pulleys are divided in units, relases, and I advanced of one of it).
Then... problem desappeared (not at 100% but probably now it is good at 80%)!
But I have questions:
Now idle is good but engine loosed power at full throttle/high RPM (for example on highway in 5 gear and 80 - 90 mph). It's not a big loss of power, but it is noticeable.
So... I can't say if this is the correct position (good low rpm and idle but a little less high rpm) or if it was correct on the other position. Does only one unit change cause all this differences? (Note that I also compensate advance by retarding it on the distributor because it is mounted on cambelt. I retarded it in order to maintain the correct advance).
I can't check the correspondence between signs on pulleys and engine because I'd have to dismantle alternator pulley and I thing it's hard to refit-retension its belt!
Does someone has an idea?
Thanks and sorry for the long long post!!! And also sorry for my bad bad English!!!

 

[Luke]

Have you checked your engine timing to be correct now - since you changed the cam timing?

Also when you have done your timing check, make sure you did it when the engine was warm and block the vaccuum advance unit pipe..

I dont know the timing for yours but mine was 2 degrees BTDC (before top dead centre). If you have a haynes manual it should say there.

 

[Louie Bee]

Hi andre79ge,

Welcome back! I missed your posts the other week. Back in December, I Posted this:-

I am guessing but I think your [vacuum advance] hose is rooted wrong. It could have had bad parts cut out in the past. Perhaps then it was rerouted taking a shorter path. If so, the chances are the pipe will have perished more. If you have disturbed the air cleaner (eg. when looking at injector jet) it may now be squashing and blocking the pipe preventing the vacuum advance functioning correctly (as would bigger nicks and holes). It might be worth trying the pressure at the other end of pipe. (With engine off), unplug pipe from the throttle body and free it from anything else enroot to Vac` advance. Try pressure by sucking and blowing down pipe. If pipe OK and no signs of pipe collapsing inwards see if it can SAFELY reach round engine (anti clockwise) to the throttle body. I am 90% sure your root incorrect if you have a white distributor cap, but FIAT do change things. Let us know if your current root is correct with a different connection point to throttle body for 1.1 IE, or how she idols from cold with new (Correct?) configuration.

Did you get round to checking this pipe?

Also, it might be Fuel breather problem? See https://www.fiatforum.com/attachment...tachmentid=3016

And explination on

https://www.fiatforum.com/showthread.php?t=24351

Kind Regards,

 

[andre79ge]

Hello! And thanks a lot for your attenction to my post!!!
I'll try to reply both to Louie Bee (happy to read from you another time!) and to Alex1985. In particular, after moving cambelt respect to timing belt, I also moved distributor in order to maintain the correct spark advance (I did not performed this operation with strobo, I only did it by retarding it a little in order to avoid "engine head bumps"). However my idle problem is not very sensitive to advance (it's clear that if I retard it, engine can't work good, and I tried to reach an intermediate position between "head bumps" and bad performance).
I also checked vacuum hose and it' s good without air leaks!!!
But I did not understand the other part of message about "root incorrect": I can't get a good translation of "root" because, in my English knowledge, the word "root" means tree's or grass' link to heart... so I can't understand the correct sense of the phrase.

However, the strange fact is that idle is better by anticipating cambelt. But I think that this new configuration is not correct (because of the slight lack of performance at high rpm). Probably it's only a way which cause to the engine to suck a little rich mixture which permits to work better. Do you know if it's easy to dismantle (and refit) alternator belt in order to dismantle the dragging pulley? After this pulley there is a mark for regulate cambelt with respect to camshaft! But I'm not sure of the difficulty of the tightening alternator belt. It musn't slit!!!

Very thanks a lot to all of you!

 

[Louie Bee]

Rubber Feet?

... I did not understand the other part of message about "root incorrect": I can't get a good translation of "root" because, in my English knowledge, the word "root" means tree's or grass' link to heart...

Try "wrong way" or "incorrect direction" the pipe should go from Vacuum advance (on distributor), Counter clockwise, to the back of throttle body. Not under the air filter.

This pipe might be getting squashed or trapped, stopping the advance from functioning?

The timing should be set with a strobe. You will only ware out the piston rings faster with wrong timing.

I advise you to get a strobe as you will save cash in the log run... they are quite cheep these days...

Kind Regards,

PS Andre, see Air Filter box “Rubber Feet”? I thought of you before I fitted these a while ago - lol.

 

[Morty Mort]

Hei.

I don't remember if I answered last time, but:

1: Check if the idle plunger is depressed when throttle is released. It is located on the back of the throttle body. A little rubber thing. This halvens the amount of petrol let into the engine when idling. Due to a too tight accelerator cable, this one was never depressed on my Uno 1.1 i.e.S. This led to problems when starting, and when I "gave gas" it could die. Also when I let my foot off the pedal (red lights etc.) the engine died.

2: Clean the throttle body with some oily tissue paper. Try to not lose anything major into the intake A box of WD-40 should be mandatory to any Uno sold, and should have it's own place somewhere in the car with a warning sign on the instrument panel telling the amount left. This would let the fuel flow more freely into the intake. Due to bad air filter box (that lets through much dirt) and the oil deposits from the oil breather, the whole throttle body looks contaminated.

3: The fuel filter!!! Maybe it is clogged? It picks up enormous amounts of rust and dirt from the petrol tank. At least on my car. I get surprised each time I cange it - usaually every spring. It is on the left side of the engine bay when looking into it, and has the size of a 25 cl beer / coke can. Don't worry about de-pressuring system etc. I've disconnected these hoses a dozen times, and never de-pressurized anything...

Morten.

Morten.

 

[andre79ge]

Hello!
Thanks for your considerations!
I'll try to check for a timing spark "object" (of course it's my problem with english... I mean strobe or similar... however it's the instrument which permits to check advance!).
I' also check fuel filter: I never checked or changed it.
However I think its good because engine works good in all situations except idle. Also at full throttle and full rpm, when fuel request from engine is maximum! If fuel filter'd rusted or bloked, I think engine 'd not go well at full throttle before than at idle!!!

I also checked idle plunger (also by a continuity test on its electrical wires) and it's OK.

I'll let you know if something changes!
Thanks a lot,
Andrea.

 

[Louie Bee]

Fuel filter

...Don't worry about de-pressuring system etc. I've disconnected these hoses a dozen times, and never de-pressurized anything...
Morten.

HI Morten,

I have just changed my Fuel filter - this time by my self (on 1.0 IE)

You’re right about the absence of a large Jet of fuel! I had loads of rags ready just in case.

Now I’ve fitted the new one, I'm a bit worried I have over or under tightened it

Any tips would be helpful,

Kind Regards,