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Old 07-29-2004, 08:35 AM
jhanson jhanson is offline
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Location: Eagan, MN
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Hey ya'll, I just put a mechanical fuel pump on the wag, in addition to the electric pump (long story) and all the sudden have no oil pressure after driving 15 - 20 (not sure how many) miles. I had to drive it home about 3 miles that way. Had already checked the oil level and it seemed to high. I suspected it to be gas in the oil even though it didn't smell 'gassy'. Terrible valve clatter on the way home. I was supposed to pick up the wife and kids (wifes van had broken cyl. head and rocker arm shaft), so I changed the oil and then had pressure again (took a while for the valve clatter to go away). All was well, picked up the family, took them to MOA for the afternoon and went back to work (this was on a lunch break - a long one!!) Picked up family after work, went out to dinner and went home to put the van back together, all the while the oil pressure was good.

Today I took wag to work and all was fine. Went home for lunch, no friggin' oil pressure!!! Drive the 3 miles left to get home, changed oil (too much and seemed thin, still not a real 'gassy' smell). Started wag, still no oil pressure...

Do you suppose I trashed something (bearings or such) and now need a rebuild? certainly can't afford that, (maybe someone in MPLS area has a replacement). Seems to me that the mech pump (brand new from NAPA) is bad, it should self regulate the pressure right?

Currently it is plumbed like this:

tank to mech pump to tee to filter to Holley electric pump to filter to throttle body, throttle body return to tee before the electric pump.

I have yet to install a Surge Tank which would change plumbing to :

tank to mech pump to surge tank return to tank and surge tank to filter to Holley electric pump to filter to throttle body, throttle body return to surge tank

Could it be that there is nothing wrong with the mech pump, but because it goes direct to the electric pump, gas is being forced past the diaphram and into the oil. If so, could all be right with the world when the surge tank is installed? But then what about no oil pressure now, after changing the oil?

At least the van runs now, too bad the motorcycle is in several pieces in the garage!
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89 GW, 360, MegaSquirt Fuel Injection, Edelbrock manifold, TFI,Mallory HyFire VIA ignition module, Rusty\'s 4\" lift,Rancho RS9000\'s, RS9700 remote now installed (still leaks, but setting now lasts longer), 31 x 10.5 Hi-Tech Re-Treads, Bulldog remote start and keyless entry
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Old 07-29-2004, 12:44 PM
JeepsAndGuns's Avatar
JeepsAndGuns JeepsAndGuns is offline
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Why are you using two fuel pumps? If you have fuel injection I would use only the electric one.
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79 Cherokee Chief 401/T18/D20, MPFI fuel injection, hydroboost, otherwise stock.
Future mods: Caddy 500/NV4500/NP205, HP D60 front D60 smooth botom rear, 5.13 gears, 35x12.50's on H1 beadlock wheels. Warn M12000 winch.
93 Wrangler 4.6 stroker/AX15/NP231,SYE,CV, OME 2.5 lift, front hub conversion/big brakes, 31X10.50's Warn M10000 winch.
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Old 08-05-2004, 12:21 AM
jhanson jhanson is offline
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external electric doesn't suck fuel out of the tank worth a darn, especially after replacing the sending unit, the new one only has 5/16 pickup instead of 3/8. mechanical pump now fills the surge tank, and the electric pump now fuels the tbi, using the surge tank as its supply.
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89 GW, 360, MegaSquirt Fuel Injection, Edelbrock manifold, TFI,Mallory HyFire VIA ignition module, Rusty\'s 4\" lift,Rancho RS9000\'s, RS9700 remote now installed (still leaks, but setting now lasts longer), 31 x 10.5 Hi-Tech Re-Treads, Bulldog remote start and keyless entry
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Old 08-07-2004, 06:16 AM
jhanson jhanson is offline
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Update - had oil pressure after taking pump apart, packing with vasaline and putting it back together. Worked fine for several days. Then all of a sudden, no oil pressure again. On the way home, just a mile away it stopped running. It still turns over, but slowly and with a squeak. I thought that maybe the pump gears were bad, but without the oil pump gears, it still turns slowly, and squeaks.

So, how much of a rebuild do you suppose is necessary? Complete rebuild I'd guess. Don't have the time for that. Now I guess I need something else, as our lifestyle does not work with one vehicle.

Saw a 1989 Volvo 740 Turbo, 177,000 miles for $750 does that sound resonable? Anyone know what to look for in something like that?
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89 GW, 360, MegaSquirt Fuel Injection, Edelbrock manifold, TFI,Mallory HyFire VIA ignition module, Rusty\'s 4\" lift,Rancho RS9000\'s, RS9700 remote now installed (still leaks, but setting now lasts longer), 31 x 10.5 Hi-Tech Re-Treads, Bulldog remote start and keyless entry
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