Hi all, Getting a tad desperate on my mk4 Golf now, I'll copy the post I made on ukmkiv's and would really appreciate any help as I am running out of things to test now! * I swapped my turbo back over ko3s back to the ko3 it originally had. Now it turns over but won't fire. No faults in vcds, check the plugs and they are wet with fuel. Getting a very slight spark when I tried with the plug removed on the coil. I have looked everywhere for a plug I may have left undone, but it looks okay. Even did a compression test which was just over 200 psi on all 4. 14bar. What are the symptoms of a faulty ignition amp? It tried to fire once or twice initially. But now it's not even trying. I think it's the amp so want to try another really. I have tried another Ecu and taught in the immobiliser (swapped over from a mapped ecu). If it is an ignition amp are they main dealer only? I'd better spend some pennies unless anyone is near Salisbury who would let me borrow one for an hour? Cheers, Mark.* * Right a little update. I have checked all fuses and fuse links on the battery. All okay, I get a very strong smell of fuel when cranking. Removed the plugs and attached to the coils and turned over with injectors unplugged, a nice bright spark on all four plugs. Checked the engine is drawing air, sucking on intake pipe when cranked. Fuel pump checked, fuel pump only runs for about a second when the ignition is switched on, this spurts out around 100~150ml of fuel and then stops. I have run a 12v feed to fuse 28 which runs the fuel pump all the time, fault is still the same. I remove the plugs and dry then off before cranking over. The fuel pipes are now firm with pressure. I am running out of things to check now, how can I test the ingnition amp? Would I be able to see a difference between a weak spark and a normal one? Everything I have read suggests an ignition amp fault leads to a missfire. Can anyone think of anything I could have inadvertantly knocked, unplugged or caught some wires during the turbo swap? Engine doesn't run with a number of sensors unplugged one at a time. MAF, coolant temp sensor, lambda sensor. I could do with a few things to check if anyone has any ideas? VCDS returned no fault codes when I scanned it before, I will plug it in again to try and monitor some actual values to see if it gives me any clues. Thanks again, Mark* So if anyone can offer any help I would really appreciate it. I am a Merc truck/van mechanic so know my way around a vehicle just not completely clued up on a petrol engine and this one is doing my head it! Thanks all.