I bought a bmw 320i manual. When new the car had Vanos, the engine it had in when I bought it had a s1 non-vanos engine. It ran perfectly for a couple of months (the guy I bought it from had it 3 years) but it had a water problem, when this was checked out it seemed the engine was on its last legs and had so many crap repairs it was a wonder it went at all. I got a good mechanic to find an exact same engine (S1) from a scrap yard that was running and guaranteed for 6 months.
Once the engine was replaced the mechanic started the car and it started to idle fine but would pop and bang if you hit the throttle.
He continued putting everything back together and when trying to start again the car would not do anything but turn over normally without firing.
The fuel was reaching the injection with a great amount of pressure and the plugs were all sparking fine. The compression for all cylinders was fine.
After checking, testing many parts we took the car to BMW who checked it electronically and said the only errors stored were old and nothing that would stop the car from running.
Unfortunately they said they couldn't explain why the car would not go because the engine in the car was not the original engine but from what they could see there was no reason the car should not go. (What a response).
Someone suggested towing the car in case while the engine was sat for so long there could be no oil for the valves to open correctly and towing it would make sure everything was fine with the hydraulic valves.
We towed it down the road and at about 40mph putting it in gear the engine turned over but no firing at first. When the throttle was full on the floor, the popping and farting started. After a mile or so the engine did start and keeping the rev's over 3000 the engine sounded fantastic as if it was ready from a few laps on the racing track, however as soon as the rev's came under 3000 the engine would cut out. When running you could hear the car trying to suck in air between revving like it had just ran a marathon.
We drove the car back from the dealer and once home, for the third time took the injection off to check, it seemed perfect so it was getting fuel.
Off course the mechanic suggested straight away that the timing is the problem, but as this engine has no vanos it should all be done electronically. The engine this new one replaced was exactly the same, so in a normal world it should have ran perfectly, however not to be.
To top it off when we removed the injection system after getting it home we noticed oil coming from the head, so now we had just knocked out the head gasket. After doing another compression test we saw that one cylinder now had no compression, two were a little low. Luckily when we removed the head, the piston's and rings were still fine but the valves were now leaking.
The valves have now been reseated and the engine is yet again back together and the compression is again 110ish for all cylinders, the petrol still has enough pressure to shoot a jet 30 feet and the plugs are all lighting up.
But the car still wont go?
You can turn the engine over on the key forever and it will not fire. We certainly wont try towing the car again.
The mechanic is convinced the timing is out on the engine, which makes sense but this is setup electronically and was perfect for the old engine, of which the new engine is exactly the same?
That we need help is putting it lightly. BMW could not tell us why the car would not go, and of course the minute they saw the engine had been changed gave them a one line out for not fixing anything (it's because you changed the engine to a non-vanos). The fact a non-vanos engine (S1) had been running perfectly for many years in the car didn't impress them as they said it wasn't possible!
The mechanic to be fair has tried so many different parts he is adamant that mechanically the engine is perfect.
I doubt as strange as this is it has never happened before, and I am sure someone will be able to help? I just need to try and connect the dot's before I loose what's left of my sanity!
Sorry for such a long story.
Friday, July 20th, 2012 AT 11:25 AM