Pajero junior cranks but not starting after cylinder head swap

[dani_kk]

Remember wrong timing pe engine never cranks freely. It takes load & tries squeezing valves with Pistons.

One more thing pulse wire of injector if it is broken engine doesn't starts. And if firing order is incorrect it gives spark but doesn't starts or throws bangs from tail pipe. Describe your problem more clearly so we all can help you with pinpoint accuracy.

[margallar]

the sensors should be fine if the car was previously running.

1. Check all wiring connectors.
2. bleed the petrol pipe, remove the pipe from engine and put it into a bottle, give turn on ignition, turn it off, turn ignition on again and then shut off ignition. reconnect the pipe. Now try starting again
   3.check the timing

[Xulfiqar]

They have three wires, 12v positive and negative and one output

The output is basically a 5v signal from ecu which the sensor pulls to zero v when it activates, you can check with a dmm and slowly turning the engine.

Easy for anyone who knows basic signalling etc.

[pwuser151870858523]

the injectors have pulse and we cheaked them if they have pulse. and how can i fix the fireing order? as the valves were also touched by the mechanic

[Xulfiqar]

Are the coils sparking?

Is the fuel pump running?

The timing is checked from front of engine, the cam and crank pulleys have timing marks.

[pwuser151870858523]

the the coils spark and the fuel pump runs

[pwuser151870858523]

the we set the timeing from the front of the engine just like the manual

[Xulfiqar]

Good,

Have you verified that the fuel pump is actually pushing pressure and not just dead humming.

Try squirting some fuel in throttle and see if the engine fires.

If it doesnt fire and you have spark then you have a mechanical issue like leaking valves

[pwuser151870858523]

yes i cheaked if the fueline has pressure and it does have a pressure i realy dont understand whats going on

[SER_GTR]

If Sensors Are OK. You Prolly Had Leaking Valve Or Very Low Compression's...If Timing Is Correct...

Recheck Everything...You Are Missing Something...Its right There Just Not Getting Caught...

[pwuser151870858523]

yes we i know we are missing someting but even with low compressions the engine should start but stumble?

[Xulfiqar]

wrong timing can cause the valves to bend - when that happens the engine has zero compression and wont start.

OR

the valves were leaking before install of the new head, use proper test equipment to test compression pressure, fuel pressure, injector pulse etc.

dont just rely on thumb covering the fuel line and Rs 20/- test lamp to test injectors.

[pwuser151870858523]

new update ...we did the injector test as you said and they seem okay . but what i want to ask you is the if the piston is at the top dead center the valves should be closed right?

[Xulfiqar]

Piston comes to tdc twice in a cycle, on compression tdc, all valves should be closed.

[pwuser151870858523]

i guess the mechanic didnt cheak that i think he is has a little knowldege ... when i cheaked the pistons at the tdc and the timing mark showing at the first cylinder and blow through the spark plug hole it doesnt have compression the air just comes out from exhaust valves i guess

[pwuser151870858523]

and how can i correct no1 cylinder to fire

[Xulfiqar]

What you are seeing is piston at exhaust stroke tdc,

Whnn piston 1 is at tdc, the crank timing marks line up, if the cam marks line up this means the cyl head is also at fire position. If they are upside down meaning cam is 180 degrees off, the cyl is at exhaust.

Rotate engine crank 360 degrees so cam moves 180 degrees, in this position the cyl should show tdc at fire position.

It maybe possible your cam pulley is installed wrong or is wrong pulley. Use a wire to find tdc of piston and then check cam lobes, they should not be depressing or even start to depressing any valve.

Check timing marks at this position. If you found them incorrect, remove head and check valves as they would be bent.

[pwuser151870858523]

ok i will do that and cheak with you later with images

[dani_kk]

No bad compression engine doesn't starts.

[dani_kk]

Yes i believe if this is this case, valves would be bent.