hi

i have a problem with my felicia 1.3 mpi

when i start the engine in the morning it makes explosions in the air filter

i have a short movie maybe someone knows what is wrong...

any help will be appreciated.

thanks !

Edited 29 August, 201213 yr by andreafree

By the way it sounds, it looks to be an ignition timing issue or a too rich mixture.

I would have a look at oxygen sensor, heating check included.

You say it's an MPi, which excludes my first thoughts of fuel stand-off and/or mechanical distributor timing, since those will only apply to carburetor cars.

So what could emulate those problems with fuel injection and electronic ignition?

Start by checking the valve clearances since an open inlet valve will allow blow-back of burning gases.

Next check the Top Dead Centre missing tooth position and operation of the TDC sensor.

Finally, check if any of the injectors are leaking, since this could simulate carburetor fuel stand-off.

i checked my compression on every piston and it was between 10 and 11 so i think that if any valve would remain opened the compression should drop to 0... so i think the problem its not on the valves...

the injectors are not leaking... all i have to do is check the other 2 suggestions from you

thank you !

inlet manifold gasket has broken. when it is idling spray some wd40 or similar around the joint between the inlet manifold and the head on cylinders 1+2,

usually the gasket splits in half and allows air in when on light throttle.

i will change tommorow the distribution chain kit ... its a bit noisy and i think that it has one tooth broken, maybe this is it...

It's unlikely that you'd break a tooth on a timing chain drive sprocket, but a loose chain could mess up your dynamic valve timing, giving you bad running, but still good compression so that fits both my thoughts and your compression test data.

i changed the timing chain.... it was way too loose... but the problem did not disappeared... i don't know what else to check...

i have good compression, new throttle valve, new temperature sensor, new timing chain....

i found out something else when i changed the rear bearings ...one of my rear wheel was partialy blocked... but this has nothing to do with the engine...

so .. anyone new ideas ?

I would scan for OBD errors. There should be a lot of them. Note them down, then erase them all, then do a new engine start, let it switch to closed loop, stop it, do a new error scan. Tell us what you got.

I would also check engine parameters while it's running, hook the OBD to USB interface to a laptop that runs VAG-COM Release 311 or 409. There must be something obvious that's wrong, like crank sensor, timing, air leak, lambda sensor etc.

As a rule of thumb, be more methodical. Find the cause first, and only then change parts or make adjustments.

i scanned with the obd and there are no errors... now i can only think at the fuel pump or the induction coil...

does anyone knows how to check if the fuel pump works ok ?

To check the fuel pump and pressure regulator you will need a pressure gauge plumbed into the fuel line which leads from the pump to the rail. It should be at 3bar, IIRC.

Have you done what Felicia 16v said? He's not wrong often (in fact, I can't remember when he was about anything Felicia related!)

inlet manifold gasket has broken. when it is idling spray some wd40 or similar around the joint between the inlet manifold and the head on cylinders 1+2,

usually the gasket splits in half and allows air in when on light throttle.

nothing happens , i sprayed wd 40 , starting spray, nothing happens... so it must be something else.....

i checked my compression and i have almost 11 psi on all pistons.... what value should it be ?

Sounds like a vacuum leak at the intake manifold to me... sounds like the timing chain is slack in that video too.

i checked my compression and i have almost 11 psi on all pistons.... what value should it be ?

I'd have expected more like 165psi; are you sure the compression tester is calibrated in PSI and not bar? Bar, in this context, is another word for atmosphere, and 15PSI = 1 bar, near enough.

i checked my compression and i have almost 11 psi on all pistons.... what value should it be ?

You obviously didn't pay attention when you read compression gauge.

It is not 11 PSI, it is 11 BAR. A new engine should have 15-16 bar. Your engine has equal, but low compression.

A low compression value reveals a failure of piston rings, an incorrect valve clearance or the valves/valve seats are worn respectively.

Top up a bit of engine oil into the spark plug holes to achieve a better seal of pistons into the cylinders. Measure all cylinders compression again. If there is clearly a higher compression measured, you can tell that the rings are worn. If the measurement results are the same as before, then the valves are faulty.

Edited 22 January, 201313 yr by adurer

You obviously didn't pay attention when you read compression gauge.

It is not 11 PSI, it is 11 BAR. A new engine should have 15-16 bar. Your engine has equal, but low compression.

A low compression value reveals a failure of piston rings, an incorrect valve clearance or the valves/valve seats are worn respectively.

Top up a bit of engine oil into the spark plug holes to achieve a better seal of pistons into the cylinders. Measure all cylinders compression again. If there is clearly a higher compression measured, you can tell that the rings are worn. If the measurement results are the same as before, then the valves are faulty.

You are right, it was 11 BAR , my bad... anyway i will do this check again and i will be more carrefull at that gauge...

Here is some fresh information.

I checked yesterday a very 'tired' 1.3 LX Felicia (179.000 km - 111,000 miles) for cylinder compression. The car has a 135 type engine, so smaller compression ratio than your engine, yet I measured 14 bar on all cylinders.

- here is another video from inside the car...

i was thinking that this problem could also be caused by the fuel pump ... is this possible ?