mk1 ., 1.2 8v punto. wondering, what is signs of blocked exhaust. would it be revs slightly jumping, and overfueling ?

everything new (used , but known good working condition) from (including) inlet manifold and up (sensors and injector), also vacuum pipes and lambda, new wiring loom, and ecu changed.
all cylinders has 15 bars compression .

no changes.
Would worn tappets cause irregular engine work ?
Possible bend crankshaft or camshaft ?

thanks.

Never use a second hand lambda

Blocked exhaust catalyst causes reduced power when you need it. At low speeds and tickover it feels normal. Take it for a long motorway drive and see if it improves.

The symptoms you have can be caused by various things including:

• lambda sensor
• air leak into inlet manifold
• dirty throttle body
• worn spark plugs.

Go through them starting with the cheapest/easiest and see what changes they make.

Also do a compression test to kelp rule out more expensive problems.

agree blocked exhaust = loss of power. I think compression is ok as he has 15bar on all cylinders. Easy test on exhaust and other power issues with the car is to take the car on a drive and red line it in 2nd, 3rd or even 4th gear. If that is possible your exhaust is fine.

Acceleration in 4th gear will better test the engine's gas flow. In lower gears its not worked so hard unless you drive like you stole it.

Do the cheap/easy stuff until its running as it should. If it comes to it, don't fit a used or cheap lambda - often no better than the old one

WhiteSei said:

Blocked exhaust catalyst causes reduced power when you need it. At low speeds and tickover it feels normal. Take it for a long motorway drive and see if it improves.

The symptoms you have can be caused by various things including:

• lambda sensor
• air leak into inlet manifold
• dirty throttle body
• worn spark plugs.

Go through them starting with the cheapest/easiest and see what changes they make.

Also do a compression test to kelp rule out more expensive problems.

Click to expand...

* lambda changed, no difference.
* cannot be airleak in inlet manifold... done and sealed and checked over number times
* tb looks clean
* sparkplugs are new, specs as per manual.
* vacuum hoses changed, two sets, and different ones... no changes
* two temp sensors changed, no changes,
* timing perfect
* new ignition coils
* new , expensive spark plug leads, no spark leak
* map sensor from good working car
*new wiring (changed over fire... nearly burned down car, while changing injector) with new inlet manifold and everything on top from good working car.
* ecu changed, no difference.


Garage keep saying need to change tappets , as they worn, causing late valve opening and closure, causing irregular engine work.(never hear before that).
Tappety sound on high revs, 3k and over.

Mar4ix said:

Garage keep saying need to change tappets , as they worn, causing late valve opening and closure, causing irregular engine work.(never hear before that).
Tappety sound on high revs, 3k and over.

Click to expand...

Guess us dangerous to do the redline test to rule out the exhaust system.
Blocked exhaust maybe testable with a vacuum gauge.
However, tappety sound about 3k is strange. You cannot change the tappets as they are not hydraulic (no point changing effectively), but you can reshim to remove the noise. However, as it only happens when over 3k I suspect that won't help. I will investigate poor oil delivery to the head, problem with valve springs (weak or even broken), or even damaged camshaft.

if valves are opening and closing and giving good compressions but you are getting misfires above 3000rpm then rather than looking at worn tappets which is non sensickle you want to be looking for worn/broken valve springs