Due to a thrown rod in the original 1990 740 turbo engine I have replaced it with one from an 89 240 non turbo. No problem hooking it up since the engines are almost identical, however, it doesn't want to run over about 15 to 30 minutes at a time. It also requires priming with fuel prior to starting each time indicating that the cold start valve is not working.

I have placed a pressure gauge on the fuel rail and it will hold fuel pressure for well over a week if untouched, so I consider that to not be the problem. The injectors are obviously firing as the raw fuel charge would not last 20 to 30 minutes otherwise. A noid on the injectors indicate that they are working.

If it is getting fuel and fire then why is it not working. Though I have changed the computer it is still out of another 740. I also changed the EZL controller, but it will only work with the original.

I am not new to oddball engine swaps having installed a straight eight Buick engine into a 1942 Dodge convertible, and a 3.8 V6 into a Chevrolet Monza with an original 4-cyl. But all of those were carbureted engines. I have owned and repaired Volvos from the 122S to the 1800S, to the present 740/240 situation.

Has anyone run into this problem before? What is the secret of success? I would like to exhaust all possibilities before pulling that 240 engine out and replacing it with something else.