HELP! wont fire up, got compression, fuel and spark?

Hi

I have had my 1.8 GTI cab for some time now and never had it running properly. When I brought it, it needed a new engine so I have done that, recon bottom has gone in with a totally stripped and rebuilt head from a different 1.8gti engine. I have set the engine timing up correctly, ensuing at TDC the mark on the inside of cam shaft is inline with the cylinder head and the mark on crank is vertical, lining up with the mark in the transmission bell housing.

I have done a compression test and I am getting about 10 bar from all cylinders, so that?s good isn?t it?

Also I have checked I am getting a spark and that I am getting fuel through, but when I turn it over it still wont fire up. I am wondering if I might be getting too much fuel through, and perhaps flooding it from the start, but I am unsure how to correct this.

Any help or suggestions with this will be gratefully received  

thanks

check the fuel relay. my car wouldnt started yesterday and just hit the fuel relay and it started up. might not be th problem but may be worth a look?

Equal pressure from all cylinders is definitely a good sign, as is the presence of fuel and spark (meaning your relay is working fine).

I would guess that your spark timing is out, especially as you've replaced the bottom end - set the engine to TDC no.1, then  check that the rotor arm is pointing towards one of the connections on the dizzy cap.

From memory I think the rotor arm rotates anti-clockwise (you can check this by turning the engine over with the dizzy cap off), and the firing order is definitely 1-3-4-2, so make sure you've got each HT lead going to the right place.

HTH

Rich

sounds like more timing whoes  :wink:  lol

the top end timing should be the cam pulley inner dot to the top point of the inner cambelt cover otherwise it could be a tooth out

sometimes its quite easy to put the timing 180 degrees out or knock the timing pulley out a couple of teeth  

so…

double check that with everything set at TDC that the rotar arm is pointing to the No.1 HT lead in your dizzy cap (normally around between the 10-11 o'clock but not always) if it isnt, then to save taking the cambelt off again and if you have enough to play with you can twist the dizzy round so its "roughly" where it should be (this is what i mean by 'not always')  :roll:

if the plugs smell of petrol and your getting a soark then i would worry about the fueling or ignition, it sounds like its more than likely a timing issue

hope this helps

damn you mcscrew… damn you!

lol  :roll:

thanks for your replies,

 I feel sure it?s not a tooth out, as I have recently changed it because I thought it was a tooth out before. With the cam in its pervious position, the compression was less than its current location.

Also I have got the rotor arm in line with ht1, followed by 3,4,2 in a clock wise rotation, I have also tried slightly moving the dizzy case to the left and the right whilst some one else is turning the ignition over, but still I am getting nothing.

I have noticed that the plugs are very wet with fuel, and in the attempt of starting the car, I have boar washed it a couple of times in the process.

Try cutting the fuel and using ethyl diether (cold start fluid) alone to start it. If it kinda starts but then stutters and stops, then your original setup was too rich. Sometimes its possible to start a too-rich car by holding your foot part or all the way on the throttle during starting.

Another trick is to temporarily rig up a little circuit/wire so you can fire the 5th injector off a push button. Then you can play around and add more fuel into the engine ad-hoc to figure if its too rich or too lean.

I took your good advice, isolated the fuel, added some cold start, and it did try to fire up, which by your reckoning indicates that?s that the mix is too rich, how would I go about correcting this? Thanks

i'd be very tempted to take your rocker cover off to see whether your cam isnt 180 degrees out

sometimes people can put the pulley on the wrong way round which can cause just that… this means that your car is firing at the end of its exhaust stroke

the other way of checking the top pulley is on the wrong way is that there should be a squared surface on the outside and the inside should have bevelled edge which makes fitting the pulley onto the cam shaft that much easier, so double check the squared surface is bolt/washer side

dude, easy start will get any car started even with bent valves, busted rings, blown head gasket and all sorts… its not really proving anything other than it can fire, ur not proving its rich or lean or whether the cam timings out… or anything thinking about it

i really wouldnt recommend using "cold start"/ easy start - as its not good for petrol engines (it can blow piston rings and head gaskets!) and all it'll do is prove that your car is firing but wont actually prove/dis-prove anything (its designed for starting stubborn diesel engines which can take the high energy it creates!)

you say you've never had it running properly, but when it has ran what has been the problem? bad idle? running lean/rich? lacking in power? miss fire?

its usually something overlooked, such as breathers, air leaks (split hoses) weak spark, miss timed, damaged/cracked dizzy cap, faulty air mass meter

but seriously, dont keep using "cold start"…

All cold start does is helps eliminate/diagnose fuelling issues. (If you have an ignition fault, then cold start wont make it start).

So, now that it starts (of sorts), it proves the timing is good enough to get it running (might need a tweak on the ignition timing once running).

To adjust the mixture, turn the mixture adjustment screw (anticlockwise = leaner). There's a guide with pics in the technical section on the left menu bar.

i'll let this thread be, i agree it'll tell you if its firing but you already know he has a spark… it'll fire even if the ignition timing is 180 degrees out, and even if the cams 180 out… if this is the case your gonna do more harm than good using it

but i would go through everything else before playing with the mixture since it should still run even if its miles out (unless its lean to the point of no fuel getting through… ) and you need to get it running 1st

to diagnose this issue you need to describe it in a little more detail, does it fire then die? does it sound like its tripping over itself when your turning it over? does it start, run rough then die? does it just turn over with seamingly no attempt to fire (at the right time)? does it start but then idles really badly and wont rev up? does it try to start better when you give it a little throttle? does your exhause pipe smell of unburnt petrol? when its firing/running (a few minutes) does the exhaust smell rich (if your eye's start to water then its definatly rich!) lol

all of this helps no end in diagnosing the problem especially when you havent got the car infront of you!  :wink:

if you have an extra pair of hands its well worth getting them to turn the engine over while you twist the dizzy around a little to see if it starts to run (disconnect the vacuum advance pipe 1st)… if you advance it (anti clockwise)  and the car is running rich then it'll help burn off the extra fuel if there is anyway… if you do get it idling then you can play around to get it right (timing light would help no ends here), once the timings sorted then you can play with the fuel

if that fails to help in any way, double check all the breathers, even a faulty injector seal or it not being seated properly can cause this issue (see rossirvines posts about this almost exact problem) you'll see there 2 marks on the cam pulley, one inside the other outside, if the pulley is on the wrong way the cam will be out 180 degrees

its a long read but thats my bidding, so if that doesnt help then its all yours