Hello,

I'm helping my neighbor fix her '90 740 B230F w/~180Kmiles. It has a bad roll-on hesitation, and slow starting both warm and cold. The problem sometimes goes away and it runs fine with small hesitations. Other times it gets very bad and can barely be kept running at all.

Fuel pressure is low. Shows just over 20-24psi at the rail, sometimes reaching 30. I've replaced the in-line fuel filter without change. Drawing 0 to "25Hg vacuum on the pressure regulator causes no change in fuel pressure. I've momentarily crimped the return line which also had no visible effect on pressure. Assume a pump problem.

It's a Regina system, and the dealer says this means two pumps. I was going to test current draw on both to see what's happening but can't find the external pump. There are fuses for both the pre and main pumps. (pulling either stalls the engine) However, I can't find anything between the tank and injector rail. Some FAQs mention these have only one pump. Did it vary within the same year?

All suggestions welcome!

Thanks,
Dave