Technical No compression on 2 cylinders after rebuild. 1.4L Multiair

[Sean0402]

Hello all,

I have recently rebuilt my fiat 500x 1.4L Multiair Engine after finding that Cylinder 3 had very low compression and would stall on idle.

After finding the issue, I rebuilt the engine & now I have 0 compression on Cylinder 2 & 3 (The needle won't budge at all) . Cylinder 1 & 4 are perfectly fine reading around 140psi. The vehicle will start but stall almost instantly after struggling.

I have installed the following:
new piston rings on cylinder 2 & 3.
head gasket,
water pump + belt,
new intake + exhaust valves on cylinder 3,
new valve stems seals on every valve.
new spark plugs
new coil pack,
new knock sensor,
new crankshaft sensor,
new camshaft sensor,
new battery,
new multiair filter + oil filter.

I'm at a bit of a stand still as to why this is not working. My only assumption would be the piston rings as these are the only 2 things which Cylinder 2 + 3 have in common.

I have confirmed I do have spark + fuel. Also getting 0 error codes. Multiair brick seems to be operating as normal as oil is seen to be circulating through the oil cap.

 

[PuntoHowTo]

Did you have the head skimmed ? Given it’s the centre two cylinders an obvious suggestion might be a warped head.

The fact that it is so dramatically failing to provide any compression at all suggests that it should be something quite obvious? The camshaft isn’t out of phase or the valves not seating properly?

 

[Sean0402]

Did you have the head skimmed ? Given it’s the centre two cylinders an obvious suggestion might be a warped head.

The fact that it is so dramatically failing to provide any compression at all suggests that it should be something quite obvious? The camshaft isn’t out of phase or the valves not seating properly?

I have not had it skimmed. I may be inclined to take it apart and pop it into a machine shop and see what they think. The surface didn't originally look too bad but perhaps I misjudged that and looked past it. As for the timing, I have tripled checked that and it all lines up every time.

 

[s130]

Have you correctly bled the multi-air unit? There is a bleed valve inside the rocker cover directly below the oil filler aperture. This is one of those ball bearing type valves. You need to depress it whilst cranking / running the engine. Not sure for how long but suggest till no bubbles and a continuous flow emerges.

 

[bugsymike]

Have you correctly bled the multi-air unit? There is a bleed valve inside the rocker cover directly below the oil filler aperture. This is one of those ball bearing type valves. You need to depress it whilst cranking / running the engine. Not sure for how long but suggest till no bubbles and a continuous flow emerges.

Never worked on one , but reading up a bit that would be where I would start checking.
Generally speaking, any piston/ring/bore issue will still give a little compression even if bad, but if a valve is not working then instant no compression.
As the valves are hydraulically controlled , if air in system the valves cannot work as @s130 says bleeding.

 

[Sean0402]

Have you correctly bled the multi-air unit? There is a bleed valve inside the rocker cover directly below the oil filler aperture. This is one of those ball bearing type valves. You need to depress it whilst cranking / running the engine. Not sure for how long but suggest till no bubbles and a continuous flow emerges.

Never worked on one , but reading up a bit that would be where I would start checking.
Generally speaking, any piston/ring/bore issue will still give a little compression even if bad, but if a valve is not working then instant no compression.
As the valves are hydraulically controlled , if air in system the valves cannot work as @s130 says bleeding.

I’ll give this a go! Thank you!

 

[s130]

Please report back.

Unlike you I have never rebuilt a multi-air cylinder head.

I've seen videos of fancy tools to hold & secure the multi-air actuator assembly etc. and compared to my old school experience "things have changed a little"

 

[ZaphodB]

I'm so glad I didn't buy a multi-air fiat

They look like so much fun

 

[s130]

I'm so glad I didn't buy a multi-air fiat

They look like so much fun

When they work they are better than pretty good.

I have a 1000kg caravan that I have towed with a Tipo 1.6ix, Stilo Abarth 2.4, Croma 16V 2L and now a 500X Multiair 1.4L Turbo.

I can honestly say the 1.4L multiair turbo is astonishingly excellent at torque for towing and power for balls out driving.

That said when technology diverges from traditional (e.g. steam engine with huge torque but no real power) every change comes with plusses and minuses.

If you want to get more basic the old points, coil, distributor and individual plug leads whilst not up to modern ECU control incantations these old systems just work and when they go wrong are easily diagnosed and fixed.

If all else fails buy a horse and cart, shovel and hay deliveries If nothing else no road tax, no MOT, no ......

 

[348azeus]

Did you use the correct tool to lock down the Multiair unit ? If you don’t you can bend the valves. I did 4 or 5 without bending a valve but after bending two valves I now always use the tool.

 

[Sean0402]

Did you use the correct tool to lock down the Multiair unit ? If you don’t you can bend the valves. I did 4 or 5 without bending a valve but after bending two valves I now always use the tool.

I do have the special tool but I’ll have to double check the valves in the morning if this has happened :/

 

[Sean0402]

To update this thread:

I have attempted to prime the multiair brick, I now have oil flowing through the ball valve on top which is a good sign. The engine now turns over with 0 compression in any cylinders which I would assume is normal until the brick can operate the valves. I will attempt to give this more of a go tomorrow and attempt to inject oil into the valve to prime some more. I have done some research and it seems some people have had to crank is for a very long time over the course of an hour before it would even get compression.. :/

 

[bugsymike]

To update this thread:

I have attempted to prime the multiair brick, I now have oil flowing through the ball valve on top which is a good sign. The engine now turns over with 0 compression in any cylinders which I would assume is normal until the brick can operate the valves. I will attempt to give this more of a go tomorrow and attempt to inject oil into the valve to prime some more. I have done some research and it seems some people have had to crank is for a very long time over the course of an hour before it would even get compression.. :/

Make sure you rest the starter and battery a lot when doing this or you will have another bill.
As I understood it once bled correctly it would start to operate with compression, but I confess not an engine I have had any desire to buy or work on, inspite of any performance benefits. It just seems over complicated for a vehicle that you want to be simple and reliable over many thousands of miles, without having to have dealer maintenance.
I sometimes think manufacturers are deliberately making fancy engines for government emmission regulations which when new are great but once warranty expires and a few years down the line people are pushed towards EVs as a "reliable" alternative at even greater expense, with even less chance of DIY repairs or even many garages.

 

[s130]

Rest assured DIY repairs are rapidly ceasing to be viable. Neither are dealer repairs due to cost. Despite all the EU/World ECO *rap cars are becoming expensive throw away items when out of warranty. Good warranties are up to 5 or 7 years. Cars for family (especially EVs) are now £30K. Over 5 years with no running or repair costs that is a potential £5K to £6K per year depreciation. After warranty a simple repair cost like a new un-repairable DCT transmission is going to cost another arm and a leg.

Sadly there is little we can do. Older cars now cost £350 road tax. !0 years and that is £3.5K on top of all the other costs.

At this rate running a horse and cart will be cheaper, more ECO friendly, cause less road deaths, no speeding tickets. Plus no number plates, no MOT, Insurance advisable but not compulsory, park where you like and the horse will be pissed off when the parking ticket is stuck to it's nose.

I think I have a cunning plan

 

[bugsymike]

Rest assured DIY repairs are rapidly ceasing to be viable. Neither are dealer repairs due to cost. Despite all the EU/World ECO *rap cars are becoming expensive throw away items when out of warranty. Good warranties are up to 5 or 7 years. Cars for family (especially EVs) are now £30K. Over 5 years with no running or repair costs that is a potential £5K to £6K per year depreciation. After warranty a simple repair cost like a new un-repairable DCT transmission is going to cost another arm and a leg.

Sadly there is little we can do. Older cars now cost £350 road tax. !0 years and that is £3.5K on top of all the other costs.

At this rate running a horse and cart will be cheaper, more ECO friendly, cause less road deaths, no speeding tickets. Plus no number plates, no MOT, Insurance advisable but not compulsory, park where you like and the horse will be pissed off when the parking ticket is stuck to it's nose.

I think I have a cunning plan

I have often thought we will become a Third World Country with a bullock pulling the family along in an old dead car, not quite sure where the EV plug goes though.

 

[ZaphodB]

Sadly there is little we can do. Older cars now cost £350 road tax. !0 years and that is £3.5K on top of all the other costs.

I'm not sure where you've got this generalisation:

As far as I read it (and corect me if I'm wrong) there are three age categories:

Cars and light goods vehicles registered before 1 March 2001​

The rate of vehicle tax is based on engine size.

Private or light goods (TC11)​

Engine size (cc)	Single 12 month payment	Single 12 month payment by Direct Debit	Total of 12 monthly instalments by Direct Debit	Single 6 month payment	Single 6 month payment by Direct Debit
Not over 1549	£220	£220	£231	£121	£115.50
Over 1549	£360	£360	£378	£198	£189

Cars registered between 1 March 2001 and 31 March 2017​

The rate of vehicle tax is based on fuel type and CO2 emissions.
CO2 emission details are shown on the car’s V5C registration certificate, or you can find emissio
n details online.

Petrol car (TC48), diesel car (TC49), alternative fuel (59) and zero emission cars​

Band and CO2 emission	Single 12 month payment	Single 12 month payment by Direct Debit	Total of 12 monthly instalments by Direct Debit	Single 6 month payment	Single 6 month payment by Direct Debit
A: Up to 100g/km	£20	£20	£21	N/A	N/A
B: 101 to 110g/km	£20	£20	£21	N/A	N/A
C: 111 to 120g/km	£35	£35	£36.75	N/A	N/A
D: 121 to 130g/km	£165	£165	£173.25	£90.75	£86.63
E: 131 to 140g/km	£195	£195	£204.75	£107.25	£102.38
F: 141 to 150g/km	£215	£215	£225.75	£118.25	£112.88
G: 151 to 165g/km	£265	£265	£278.25	£145.75	£139.13
H: 166 to 175g/km	£315	£315	£330.75	£173.25	£165.38
I: 176 to 185g/km	£345	£345	£362.25	£189.75	£181.13
J: 186 to 200g/km	£395	£395	£414.75	£217.25	£207.38
K*: 201 to 225g/km	£430	£430	£451.50	£236.50	£225.75
L: 226 to 255g/km	£735	£735	£771.75	£404.25	£385.88
M: Over 255g/km	£760	£760	£798	£418	£399

*Includes cars with a CO2 figure over 225g/km but were registered before 23 March 2006.


and finally:

Cars registered on or after 1 April 2017​

You need to pay tax when the vehicle is first registered, this covers the vehicle for 12 months.
You’ll then pay vehicle tax every 6 or 12 months at a different rate.
This guide is also available in Welsh (Cymraeg).

First tax payment when you register the vehicle​

You’ll pay a rate based on a vehicle’s CO2 emissions the first time it’s registered.
This also applies to some motorhomes.
You have to pay a higher rate for diesel cars that do not meet the Real Driving Emissions 2 (RDE2) standard for nitrogen oxide emissions. You can ask your car’s manufacturer if your car meets the RDE2 standard.

CO2 emissions	Diesel cars (TC49) that meet the RDE2 standard, petrol cars (TC48), Alternative fuel and zero emission cars	All other diesel cars (TC49)
0g/km	£10	£10
1 to 50g/km	£110	£130
51 to 75g/km	£130	£270
76 to 90g/km	£270	£350
91 to 100g/km	£350	£390
101 to 110g/km	£390	£440
111 to 130g/km	£440	£540
131 to 150g/km	£540	£1,360
151 to 170g/km	£1,360	£2,190
171 to 190g/km	£2,190	£3,300
191 to 225g/km	£3,300	£4,680
226 to 255g/km	£4,680	£5,490
Over 255g/km	£5,490	£5,490

This payment covers your vehicle for 12 months.

Rates for second tax payment onwards​

	Petrol or diesel, Electric & Alternative Fuel
Single 12 month payment	£195
Single 12 month payment by Direct Debit	£195
Total of 12 monthly payments by Direct Debit	£204.75
Single 6 month payment	£107.25
Single 6 month payment by Direct Debit	£102.38

So cars manufactured before 2001 are two rates £220 (up to 1549cc) or £360 (1549cc and above)

But a 2001 to 2017 vehicle can be anything from £20 to £1760

and after 2017 they are all £195

I think I have a cunning plan

No you can't strap a number plate to a horse and cart

 

[s130]

I'm not sure where you've got this generalisation:

As far as I read it (and corect me if I'm wrong) there are three age categories:

Cars and light goods vehicles registered before 1 March 2001​

The rate of vehicle tax is based on engine size.

Private or light goods (TC11)​

Engine size (cc)	Single 12 month payment	Single 12 month payment by Direct Debit	Total of 12 monthly instalments by Direct Debit	Single 6 month payment	Single 6 month payment by Direct Debit
Not over 1549	£220	£220	£231	£121	£115.50
Over 1549	£360	£360	£378	£198	£189

Cars registered between 1 March 2001 and 31 March 2017​

The rate of vehicle tax is based on fuel type and CO2 emissions.
CO2 emission details are shown on the car’s V5C registration certificate, or you can find emissio
n details online.

Petrol car (TC48), diesel car (TC49), alternative fuel (59) and zero emission cars​

Band and CO2 emission	Single 12 month payment	Single 12 month payment by Direct Debit	Total of 12 monthly instalments by Direct Debit	Single 6 month payment	Single 6 month payment by Direct Debit
A: Up to 100g/km	£20	£20	£21	N/A	N/A
B: 101 to 110g/km	£20	£20	£21	N/A	N/A
C: 111 to 120g/km	£35	£35	£36.75	N/A	N/A
D: 121 to 130g/km	£165	£165	£173.25	£90.75	£86.63
E: 131 to 140g/km	£195	£195	£204.75	£107.25	£102.38
F: 141 to 150g/km	£215	£215	£225.75	£118.25	£112.88
G: 151 to 165g/km	£265	£265	£278.25	£145.75	£139.13
H: 166 to 175g/km	£315	£315	£330.75	£173.25	£165.38
I: 176 to 185g/km	£345	£345	£362.25	£189.75	£181.13
J: 186 to 200g/km	£395	£395	£414.75	£217.25	£207.38
K*: 201 to 225g/km	£430	£430	£451.50	£236.50	£225.75
L: 226 to 255g/km	£735	£735	£771.75	£404.25	£385.88
M: Over 255g/km	£760	£760	£798	£418	£399

*Includes cars with a CO2 figure over 225g/km but were registered before 23 March 2006.


and finally:

Cars registered on or after 1 April 2017​

You need to pay tax when the vehicle is first registered, this covers the vehicle for 12 months.
You’ll then pay vehicle tax every 6 or 12 months at a different rate.
This guide is also available in Welsh (Cymraeg).

First tax payment when you register the vehicle​

You’ll pay a rate based on a vehicle’s CO2 emissions the first time it’s registered.
This also applies to some motorhomes.
You have to pay a higher rate for diesel cars that do not meet the Real Driving Emissions 2 (RDE2) standard for nitrogen oxide emissions. You can ask your car’s manufacturer if your car meets the RDE2 standard.

CO2 emissions	Diesel cars (TC49) that meet the RDE2 standard, petrol cars (TC48), Alternative fuel and zero emission cars	All other diesel cars (TC49)
0g/km	£10	£10
1 to 50g/km	£110	£130
51 to 75g/km	£130	£270
76 to 90g/km	£270	£350
91 to 100g/km	£350	£390
101 to 110g/km	£390	£440
111 to 130g/km	£440	£540
131 to 150g/km	£540	£1,360
151 to 170g/km	£1,360	£2,190
171 to 190g/km	£2,190	£3,300
191 to 225g/km	£3,300	£4,680
226 to 255g/km	£4,680	£5,490
Over 255g/km	£5,490	£5,490

This payment covers your vehicle for 12 months.

Rates for second tax payment onwards​

	Petrol or diesel, Electric & Alternative Fuel
Single 12 month payment	£195
Single 12 month payment by Direct Debit	£195
Total of 12 monthly payments by Direct Debit	£204.75
Single 6 month payment	£107.25
Single 6 month payment by Direct Debit	£102.38

So cars manufactured before 2001 are two rates £220 (up to 1549cc) or £360 (1549cc and above)

But a 2001 to 2017 vehicle can be anything from £20 to £1760

and after 2017 they are all £195



No you can't strap a number plate to a horse and cart

I could have quoted exact instead of generalised but a 1980s over 1600cc car (e.g. Fiat Strada Abarth) now costs £360 in road tax. A Barchetta 1.8 at £335.

My generalised £350 is not far off the mark and IMHO near enough to make a generalised point.

As for EV owners .... your time is coming as we now see their fees rising.

Rest assured many many modern vehicles will not reach the current UK 40 year classic exemption criteria. And if or when those that do increase in numbers then they too will get clobbered. I won't comment on the Gov officials and politicians who get their free, fully insured, this year models, maintained, etc. free rides.

 

[ZaphodB]

Rest assured many many modern vehicles will not reach the current UK 40 year classic exemption criteria.

I totally agree there ... the classic ICE cars are just gonna get older and older and there'll be a huge gap for this era ... and I wonder how many electric cars will get anywhere near 40 years

 

[bugsymike]

I totally agree there ... the classic ICE cars are just gonna get older and older and there'll be a huge gap for this era ... and I wonder how many electric cars will get anywhere near 40 years

They will, as there will not be enough charging points and electrical capacity to supply them, even if they only run during the day, from the windmills and chinese solar farms, so never wear out.

 

[s130]

Nasty thieves used to steal CATs off ICE cars. Those electric motors full of copper, aluminium and rare earth magnets, not even counting lovely lithium batteries make lovely prime targets.