Technical Rough running after head gasket change

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Technical Rough running after head gasket change

gabster

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1.2 8V. Had head off, skimmed, valves reseated and seals replaced by specialist. Car has had new MAP sensor and coils. I set the timing by lining up the mark on the flywheel with 0 on the gearbox casing and set the cam using mark (cams on No 1 cylinder were both pointing up slightly from horizontal.
The car is idling rough and is very hesitant under acceleration. Lack of top end power. Shaky on idle. I have 2&3 plugs firing on front coil and 1&4 on back one.
Does anyone have any idea what I need to check/do please? The plugs are sooty and so is the newish lambda sensor (top one) which suggests it's running rich. Is it a case of adjusting the timing and if so by how much? Ta
 
According to Haynes book probably most reliable setting the timing is to determinate the TDC (on the first piston) using proper tool, and camshaft slot from coil side should be horizontal (parallel to engine).
 
According to Haynes book probably most reliable setting the timing is to determinate the TDC (on the first piston) using proper tool, and camshaft slot from coil side should be horizontal (parallel to engine).

Utter, total, horlicks. (And I assume we're talking 8v here.)

For the "proper" procedure, see either the factory manual or you can use the Seicento Technical Manual (factory manual) free in the Downloads section.

But it's an almost stupidly simple engine -- no reason to over complicate things. It's also a bit risky to use any tool down the spark plug hole on the 8v engines as the plug isn't central, and anything could easily get bent or even ingested.
 
This morning I replaced the Fiat plugs with some new Bosch ones and fitted a set of the plug lights. Lights are indicating that ignition system is good.
Car started first time with no accelerator but it will stall as soon as you open the throttle. I'm going to try and clean the injectors. Because it started easily and seems to idle OK, I'm sure the timing must be about right, else it would be banging like my next door neighbours Tom cat???
Carb looks clean and opens smoothly.
 
Bizarre! One of the injectors had a small blob of jelly like stuff in it - bit like wallpaper paste! WTF? On the injector end it was brown - like rust. Call me Sherlock but I presume that could be a duff one?!
 
Bizarre! One of the injectors had a small blob of jelly like stuff in it - bit like wallpaper paste! WTF? On the injector end it was brown - like rust. Call me Sherlock but I presume that could be a duff one?!

No idea what that could be. However:

a. You do not have a carb
b. Injector failures are rare
c. Dirty injectors usually cause engines to run over-rich (they stay open too long, rather than close).
d. None of your symptoms tie in with an injector issue.

My best long distance guess -- the timing is out. Why not just check it? It takes about 5 minutes.
 
Utter, total, horlicks. (And I assume we're talking 8v here.)

For the "proper" procedure, see either the factory manual or you can use the Seicento Technical Manual (factory manual) free in the Downloads section.

But it's an almost stupidly simple engine -- no reason to over complicate things. It's also a bit risky to use any tool down the spark plug hole on the 8v engines as the plug isn't central, and anything could easily get bent or even ingested.

just put pencil if you cannot use any tool
:bang:
 
just put pencil if you cannot use any tool
:bang:

Why would you want a broken pencil?

Seriously, where the piston is in relation to the valves depends on the timing belt/chain/gear.

This is why FIAT, in their inscrutable Italian wisdom (and wishing to ensure that the 8v FIRE engine can be maintained at the roadside by Italian shop girls) put timing marks on the cam pulley and the crank pulley and on the cases. If those marks are lined up, and checked by turning the engine through a couple of revolutions in a clockwise direction, then the timing belt will be in the right position.

Sei_timing_-_crank.jpg


Sei_timing_cam.jpg


This is how FIAT describe doing it, in their documentation. Note the complete lack of references to TDC and pencils.
 
Why would you want a broken pencil?



This is how FIAT describe doing it, in their documentation. Note the complete lack of references to TDC and pencils.


yes it is the right the way to do it if you have got those marks
(probably most of engines have)

in Haynes book there are 2 methods are mentioned,
1 is based on marks and 1 is based on TDC and camshaft slot (on coil side)

Also there are Fiat tools for setting the timing even for 8v fire engines, so "marks method" is only the guide but not professional way to do it.
 
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You certainly need the tools for the later (faux VVT) engine.

Petrol-Setting-Locking-Tool-Kit-for-FIAT-MG50372-.jpg


No reason they can't be used on the 1.2 8v (indeed, a very, very few Brazilian made engines have, it is said, no false woodruff keys, so need a tool of some description, but I've never seen one).

Still, those tools are made in China -- not by FIAT -- and the correct methods for non VVT 8v engines are as described by FIAT in FIAT's technical documentation, not Ali Baba's.
 
Have marks on the camshaft pulley but nothing on the crank pulley. I set the crank by using the mark on the flywheel and the 0 on the transmission housing.
I'll leave it as is until my replacement injector arrives. With new plugs, the car starts on the key without hesitation, idles ok but stalls as soon as you open the throttle. Old plugs and Lambda sensor were very sooty so maybe it was a fuel mix problem - possibly from a gummy injector? Will let you all know when it's fitted. I'm sure the timing isn't too far out - if at all.
 
You certainly need the tools for the later (faux VVT) engine.

Petrol-Setting-Locking-Tool-Kit-for-FIAT-MG50372-.jpg


No reason they can't be used on the 1.2 8v (indeed, a very, very few Brazilian made engines have, it is said, no false woodruff keys, so need a tool of some description, but I've never seen one).

Still, those tools are made in China -- not by FIAT -- and the correct methods for non VVT 8v engines are as described by FIAT in FIAT's technical documentation, not Ali Baba's.

Those above tools maybe are made in China, however Fiat have got tools for setting 8V Fire engines. Those "lines" or "marks" mentioned before are not reliable enough and not on all of engines are good visible or even existed.
 
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My guess is that it is not timing - it is a leak in a hose on the intake side.
Buy a spray can of ether and spray it on the hoses while the engine is idling.


/John
 
Those above tools maybe are made in China, however Fiat have got tools for setting 8V Fire engines. Those "lines" or "marks" mentioned before are not reliable enough and not on all of engines are good visible or even existed.

So why do FIAT tell you to use them in their technical documentation?

It's true that the mark on the cases for the crank pulley can be difficult to discern: it's actually a change in depth of the rib. Still.............
 
So why do FIAT tell you to use them in their technical documentation?

It's true that the mark on the cases for the crank pulley can be difficult to discern: it's actually a change in depth of the rib. Still.............

It is in documentation, because it might be useful way to set the timing,
when you haven't special tools, or the easiest way, but not necessarily the best way always.
 
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