89 Tbi 5.9l?

[whistlin']

Working on a friend's 89 conversion van w/5.9L TBI. First I'll give the symptoms. The van runs great and starts good when cold. After driving around for awhile then park it and shut off, it has trouble starting. If starting it immediately after shutting off, it starts fine. 20 minutes after shutting off, it takes a lot of cranking to start. 1 hour after shutting off, it starts fine. If it was carburetted I would say the symptoms are like boiling over. He took it to a shop and they told him it was the fuel pump. I changed the pump for him even though I didn't think it was bad. My first thought was a leaky injector. I shut it off and looked down the throttle body and didn't see any fuel leaking.
I then checked fuel pressure. 15-17psi. Funny thing is, as soon as I shut it off the pressure dropped to 0. I pinched off the return line and tried again, 17 psi until shutting off then 0. I took the van for a drive with the dog house off and watched the pressure, stayed right at 17 regardless of driving technique. I disconnected the vacuum line to the regulator, no change. I would assume the regulator was bad but I couldn't feel any vacuum from the line going to the regulator.
When I returned home I connected a vacuum line to the regulator and applied vacuum(sucked):lol: The pressure then dropped to about 5 psi, I could just about shut the motor off by doing this.
So.... is the vacuum line going to the regulator supposed to provide manifold vacuum? If so, any reasons why this one isn't?
And does the fuel pump have a bypass built into it? Wondering why I didn't get a pressure spike when pinching return line. Any help would be appreciated.

[turbovanman²]

Sounds like you have a reg issue or a bad pump. The reg line should have manifold vacuum to it so something is wrong there.

Basically it goes like this, turn the engine off, pressure should stay-No, then pinch the return line, if it holds, then the pump is bad, if it still drops, then the reg is bad. I haven't touched a TBI dodge in a while but usually, the fuel pressure doesn't change much from what I remember on GM's.

[Charger R/T]

I didn't think they TBIed 5.9's in 89. I thought they were still only doing the 5.2.

When you changed the pump did you replace the pump in the sender unit or the whole assembly? Check fuel pressure while cranking it. There should be a one way check valve built into the sender assemble to hold pressure in the line while the engine is off. If the check valve is bad and you changed just the pump the problem will still be there. Pinching the feed line while shutting the engine off it should hold pressure if the injectors and regulator are not leaking. Also if its in the won't start with out cranking the hell out of it mode. Jump the fuel relay and get the pump working before cranking and see if it fires up quickly.

Second thought does the distributer have 2 pick ups? If so one is for start and one is for run. I think a relay switches them when cranking the engine. I have seen many go bad. If the start one goes bad it will crank and crank and crank and sometimes when you let the key go and it switches pickups it will catch and run. When the run goes bad it fires up right away and stalls when you stop cranking.
Tim