I bought a 97 v3 sti with a knocking engine, the guy i bought it from had already taken the engine out so i couldnt hear it run an knock, ive rebuilt the engine with a new block and when it started it didnt sound right, i put this down to a 12'' hole along the seem of the exhaust so got that welded up an tryed again, turns out it was running on 3 cylinders and now will only run on 1, ive done a compression test an each one all came up just under 11 bar so theres compression, i got new plugs and swapped the leads from my other v3 sti still no luck and when i take the leads off the coil all 4 points give a good spark when turning the engine over, the timing is right ive checked an rechecked, i put a new fuel filter in an checked the pump is working, i can hear the injectors ticking away, am stuck any ideas?

 

Hmm... For the engine to run you need 3 things (amongst others) Fuel, Air/compression & spark. If you have all those things then you will have a nice mix of fuel & air in the combustion chamber, then when ignited at the right time it has no option but to work. There are many things that influence these states however- ignition timing, cylinder head valves, fuel pump, spark plugs, coil packs, injectors, piston rings, inlet manifold to name just a few... I could go on.... So there has to be something up with one of them.

When its running disconnect the leads one by one to work our which cylinders are not working. What do the plugs look like on the ones that arn't working?

My initial thoughts are because you can confirm you have equal compression on each cylinder, that pretty much confirms your timing is ok, and you probably dont have sticking valves. So you need to look at fuel & spark. Confirm you have a good spark at each plug by connecting them to the leads one by one, earth them then turn it over. Did you gap them correctly? If each one is giving a good spark then your left with fuel. Double check you have your fuel in/return lines on the correct way, your regulator is ok and your injectors are sealed correctly and each plug has a good connection.

 

Stale fuel if its been stood a while ??

 

The engine is only running on the 1 cylinder the front drivers side and the plugs are black, i pulled the leads out an put plugs in an turned over the engine all 4 leads are sending spark to the plugs whether its a strong enough spark i dont know, the plugs are new NGK laser platinum PFR6B 3500 and were gapped at 0.7mm which i think is right, I didnt take the engine out so had to copy the fuel pipes on my other impreza which is the same model, i didnt touch the injectors i unbolted the inlet and disconnected any wires to remove an replaced on the new block, i thought the fuel might be a problem so i put 15lts of fresh fuel in but didnt help i might just drain the tank completely and put more fresh fuel in

 

Wiring fault to injectors or ECU. Are you sure the injectors are spraying fuel.

 

How do i check the injectors are spraying fuel?

 

Could be a faulty MAF, try new plugs as yours may now be fouled & see how it runs with the MAF unplugged temporary. If you need one let me know I may be able to help.

 

Hope the camshafts have been fitted back in their respective/correct places.

Mick

 

Take your plugs out & get someone to crank it over while you watch to see if fuel is misting out of all cylinders. Disconnect your coil & ensure no sources of ign are near the plug holes.

 

Ye i'm sure i put the cams in right its not the first time ive done them, they have 'in' and 'ex' on them, i could try the MAF off my other car, what should happen when i temporary unplug the MAF

 

If it's faulty it will run better but if you have a good one on your other car try that instead, but you may need new plugs mow aswell.

 

Cheers will check the morro nite for fuel misting out of the spark plug holes, swap the MAF an try new plugs

 

Took the plugs out, fuel is misting out of the holes so its fueling and injectors working, i didnt get new plugs yet

Just tried the same test as i did yesterday to check if the coil was working i lined up the 4 leads with another set of plugs in an turned the engine over and all 4 plugs sparked away, why when i tried this with the brand new plugs did they not spark at all even when i put them close to metal to earth?

 

Try plugs & MAF next.

 

Check you have the injector plugs on the right way round. I.E. The correct injectors

 

I didnt touch injectors but i think ive maybe found the problem, yesterday i lined up the leads with a set of plugs i had lying bout and all 4 sparked when i turned the engine over, since i had the brand new plugs out to check if the petrol was misting in the cylinders i did the same thing lined up the leads with new plugs an not one sparked, so will find out the morro when i get new plugs but how can brand new plugs fail?

 

New plugs and the engines running now

 

If your MAF is faulty it could over fuel & foul the plugs.