Audi s4 V8 won't Start HELPPPP!!!!

[Gary cox]

I've got a audi s4 and the timing guides snapped and a valve broke and broke a piston I've fully rebuild the engine and time it up to piston number one like the audi diagram shows you and it wunt start not got a clue what It could be as I've done everything to the diagram is their any one out their who can help me before I have send it to a specialist thanks gary

[Sump]

A bit more detail on how it doesn't start exactly.

[LukeR94]

As above? Does it crank? Is it deffo getting fuel? Spark?

[Gary cox]

The engine is turning over but won't fire up. It's popping but just no fire.
I've replaced the valves timing guides piston and new head gaskets and timed it all up as per the diagram from audi to Piston one.
I've had it fired up last week but the oil pump sprocket was loose so had to take it back out tighten it up put it all back and now it won't fire.

[Gary cox]

Yes it's getting fuel and sparking just won't fire up for some reason

[joefraser]

Just a guess but probably something to do with or linked to the first thing you did after it worked last.

[Condi]

Gary cox said:

Yes it's getting fuel and sparking just won't fire up for some reason

I suspect the timing is out, as thats the only logical conclusion, although its impossible to tell you how/why over the net.

[Gary cox]

Has anyone ever timed it up to a different piston? Or anyone local to wigan?
I've timed it up to piston one ?

[Jim the Sunderer]

[anonymous-user]

Times like these that a I realise a K series is a joy to work on. Good luck getting it sorted.

[anonymous-user]

Crank sensor?

[Mopar440]

Gary cox said:

Has anyone ever timed it up to a different piston? Or anyone local to wigan?
I've timed it up to piston one ?

Have you got a proper timing tool set, and have everything locked off and set in position as you reassembled and set up?

[Roo]

You've rebuilt the engine yourself but have no idea why it won't start?

[paintman]

Mopar440 said:

Gary cox said:

Has anyone ever timed it up to a different piston? Or anyone local to wigan?
I've timed it up to piston one ?

Have you got a proper timing tool set, and have everything locked off and set in position as you reassembled and set up?

If you have checked that everything is connected up correctly then my vote is for the timing being out as well. I once refitted the dizzy slightly out on Rover V8 & whilst it popped & farted it wouldn't run until I VERY carefully reset the timing.

[Fort Jefferson]

Have you timed it right?

[morgrp]

Not teaching you to suck eggs or anything but have checked that absolutely everything is plugged back in correctly and in the right place - namely have you forgotten to plug in a sensor or similar - happens more often than you'd think. Presumably many ancillary parts have been removed and refitted based on all the work you have done

[mickytruelove]

Like the post above said, check every plug. Then engine to chassis earths, battery to chassis earth. Seen a few mates of mine leave them off and wonder why it would run.

Spark plugs out and check for spark on each one, While they are out and cranking check for fuel in each cyclinder. If answers are yes and yes. Then its timing. Crank sensor maybe got knocked.

[Easternlight]

Hats off to you if you've managed to tear down and rebuild that engine.
How did you set the timing? Full set of timing tools? If so Re check all that, also is it possible you could have set it at TDC on an exhaust stroke instead of compression stroke?

[k20erham]

Hi most very likely that the cam timing is out, I took my drivers side head off my V10 S8 quite a challenge without taking the drive train out but I did it, but interestingly I could not get to where the timing pin goes in to lock the crank so went down the mark the pully after locking the cams (with the proper tools) and interestingly what looked to be a TDC mark on the front cover/pully was not TDC!!! so I made sure number 1 was not on valve overlap locked the cams and took the drivers side head off. number 1 was at TDC (drivers front)but the front pully mark was way off, DONT USE IT
Would not have taken Audi much to put a little more thought into design to enable top end work without pulling the drive train, Oh I had the starter motor and alternator overhauled too whilst I could (see) them, and did the inlet decoke which was horrific to see.