Yesterday it seemed better after each start-stop. Crud/ carbon in the motor after sitting 4 years.

But the main fuel pump seemed noisy and then I filled the tank and noticed it was better.

I pulled the in-tank pump again thinking I'd missed a bad pickup. The pump was dead and the lower clamp on the pump was stripped and slightly loose.

I replaced the in-tank pump and it seems fine - easy start, quiet main pump. We'll see when I drive it.

It still doesn't have much power though.

What happened was: I replaced the in-tank and main fuel pumps with units from another car - I'd purchased those units new ~ 2 years ago. The main failed within 10 minutes; the in-tank failed sometime during the 1st 48 hours (50 miles of driving).

"The pump I used is out of a 1986 240. Any chance the 91 pump had an internal check valve - vs the 86 pump which expects a separate in-line valve."

My Bosch catalog lists the same Main pump for all 240's from '86 on.
This pump (GP 299 or 0-580-464-039) uses the replaceable check valve at the pump outlet, see Bentley page 230-5.

I agree with Herb that the check valve's purpose is to prevent vapor lock caused by heat soak.
--
Bruce Young
'93 940-NA (current), 240s (one V8), 140s, 122s, since '63.

jfhojfh,
"hard to start: requires 3-4 attempts before it will catch and stay running." That is the love song of the flywheel sensor. I own a '91 245 and have had similar problems, previous messy repairs, etc., but my problems went away, almost, after replacing that $30.00 part. They are nortorious for their failings, especially if it is the origional one. If you feel a little "kickback" in one of those 3-4 attempts to start, then you know for sure it is the fault.

Len

My '92 had the check valve at the pump outlet-- it doesn't anymore because the Carter pump I bought to replace it has a straight-through fitting in its place, and it uses a different thread on the pump side so I couldn't re-use the old one. Your '91 should have had an external one as well.

Unless your problem is hot restarts, I would look elsewhere-- it seems the check valve is mostly to keep the fuel pressure up when the system is dealing with engine heat soaking. Sounds like you might want to measure your fuel pressure at the rail. It is also worth checking to be sure you didn't kink the plastic line between the pump and the filter. Checking the amp draw on the new pump might be useful as well.

Good luck!