88sk

my 88 fuel pump a problem that comes & goes ,I put a new pump on last year & took it out today & cleaned the contacts & it started (pump & pressure OK),1 hour later no start again & no pressure in the rails, last week the scanner code said low fuel pump voltage ,theres a little white plastic box just below the top(sending unit) where 3 small wires go into then the other end to the pump ,the wires are very hard & very very short Im thinkin it might be that, ? is what is that white plastic box on the sending unit/pump assembly& can I eliminate & bypass,dont know what else it can be

Da Mail Man

...i too have an 88....take the fuel pump relay and the maf relay and reverse the two as they are the same and see what happens.....you could have some high resistance in the contacts contained w/in the relays......you can also run power directly to the fuel pump from the aldl and the battery.....

88sk

I got 2 xtra relays Ive switched also took out the pump& jumped it on the battery it runs good,seems like the voltage isnt gettin to the pump,I gotta gauge on the rails & 0 pressure ,dont hear the pump go on when I turn the key to on like normal,what are the readings for voltage at the outer plug for the pump

Da Mail Man

..12vdc should be at the pump...the fuel pump relay (fpr) comes on only when turning on the key and for approx 2 seconds to prime the fuel rail...after that and after the car starts, voltage is attained through the oil pump switch at/near the distributor after the oil pressure hits 4lbs...you must wait approx 15 seconds between turning the key to get the fpr to energize.....

.....i know that you said that you REMOVED the pump and applied power directly to it however, did you apply 12vdc to the aldl to see if the pump runs that way?...i don't recall but, isn't here a fuse for the pump?..if so, pop the fuse out and "reset it" in it's contacts by putting it back in or substituting another in case there is oxidation (bad connection) at the fuse......do you have a helms service manual?.if not and you intend to keep the car, a helms manual is an absolute nesessity.....when you turn the key to "on" do you get pressure at the rails...you could try to temporarily jump the sender unit as mentioned above....

Tom Piper

Possibly, a bad fuel pressure regulator?

There is also a check valve in the pump that may stick.



Tom Piper

rick lambert

Take the fuel pump relay off.....next remove the fuel pump relay plug from the fire wall (the part the relay plugs into). Alot of us have found the insulation on the wires going in has shrunk back exposing bare wires. In my case there were some actually coming into contact with others.

AGENT 86

Check those wires at relay connector.
Sounds like your fuel delivery electrical, needs some attention.
http://members.shaw.ca/agent86/Fuel%...elivery-8A.pdf


http://members.shaw.ca/corvette86/Fu...mDiagnosis.pdf