911 Engine trouble
 

I have just fitted a 911 engine into a VW camper. It’s a 2.2 1971 fuel injection engine. It runs well in 1st goes to 5000rpm 2nd 4500 rpm 3rd 3500, and 4th 3000. It will not go over 60 mph in 4th gear and seems to misfire as a friend followed me and said their was a small flame coming out the right exhaust. It has 2 cherry bombs.

The acceleration through the gears up to these revs is great and the engine revs to 7000 rpm when it’s not moving fine. I am using MSD and a blaster coil, with silicone ht leads.

Any ideas things to try would be greatly appreciated.

redbull760,
Is your engine a 2.2 911E or 911S? Was it running properly prior to your installation? Do you have the fuel system plumbed as original in a 911?

There are many issues. Search this form on MFI. Download the CMA instructions.
The engine needs a stock OEM muffler to fine tune the running but that seems to not be your immediate problem.

Best,
Grady

fuel pressure, just a guess, but I'd look there

Its a 911 E. I saw the engine running before I bought it but was unable to drive it. So it seamed fine. The fuel system is as it would be in a 911. A camper fuel tank has no return pipe so I have added one to the top of the tank. It also has no breather. I have drilled a hole in the fuel filler cap and also tried running it with no filler cap to let more air in. But still the same problem.

Is it a secondary break dwn????? (under hard load miss fire -let up on the pedel and runs better??) if so it is coil/ignwire/plugs that cause this.

Does anybody know what pressure the fuel should pump at? It does not say in the book.

measure your fuel pressure, It seems like the engine is fuel starved. You could run the same route again, then pull a plug and examine it.

my guess is dizzy timing.. assuming you have fuel psi.

that would be my second step once fuel pressure is sorted, if the timing doesnt advance correctly it'll feel at like as discribed above.

The engine runs great at 50 mph in 4th gear if you go to 60 mph it wants to go but does'nt and thats when the misfire happens.

misfire? I missed that part, did you mention that before? well, then I would still check my fuel pressure and then make sure that timing was set and functioning correctly. I had a problem like this on a car once and it was a faulty distributer.

Its a sort of misfire, it feels like fuel stavation, but not sure. I have replaced the distributor cap and the rotor arm, although the one i replaced it with is out of a 2.4. The one that was with my engine had a crack in the insulation. Could this cause a problem?

I still think it is the secondary break dwn.......

retarted timing could cause a coughing type syndrome.. leading to hooping cough if the rpm and load is sustained.. and the load is sometimes not necessary. that's different than an ignition miss.

only a guess

What kind of fuel pump are you using??? Is it a Bosch 0.580.970.001 for a 911 with MFI???

The nominal operating pressure is 1 atm or 15 psi ... the volume output is supposed to be 900 cc to 1000 cc in 30 seconds!

Similar symptoms occur when the MFI pump timing is off.

So ... what fuel pump are you using???

Did you test and confirm 1 liter output in 30 seconds???

If the rotor seats properly on the camshaft, it is probably OK ... though they are shaped differently ... the timing setrting would probably be affected. The caps are the same part number, so it isn't a matter of 'reach' ...

Whats your voltage on the battery when its running? Sounds like something electrical.

Thanks for all your help.

I have now found the problem, i wired the fuel filter in as the Haynes manual sujested. On 69-70 engines the manual is wrong and had the fuel pump pumping fuel into the return part of the filter. Swopped them arround and the problems sorted, and it runs great.

Thanks again to all who posted:D