TESTING FUEL PRESSURE 97 Lesabre

hello,& thanks for info
im working on 97 Lesabre 3800 w/80k
i suspected it had low fuel pressure in checking w/cold engine turn key
to on gauge reads 20psi i no its low should be 47-55psi
if i reprime no change.when running 25-30psi
when i left gauge on (key off) to check leak gauge reads 40-45psi after 5-10 min. fuel reg seems fine(no gas in vac hose) my question is do
i have a weak pump? other than a rough idle at start up(lack of fuel)
which clears in 30-60 sec & a P0171 P0300 lean & miss fire the cars
runs very good.its my sons car & dont want to guess.could it be some
thing else like a leaking intake or from the readings im getting do
you think its a pump for sure
Thanks again mike

The pump is bad or the filter is clogged.

If the pressure rises over time, I'd be looking at the filter. Definitely the right place to start as it is a much cheaper and easier fix.
Smitty's Buick

thanks guys, i was going to put in a new filter tomarrow i'll let you no
filter was suposably new before he got it 6mths ago.but it doesnt look new

ok filter in, brought pressure up to 38psi(it was clogged) guess im pulling tank
thanks again
mike

You can either pull the tank and clean it or keep changing filters The on danger is that the sediment in the tank can clog the pump inlet strainer (sock) or damage the pump.

ok if i go the ''keep changing filters'' way what can i exspect
over time i'll clean out the tank but still need the pump??
over time the cleaning will/may increase the pump pressure??
or am i just buying time & the pump will still need replacing.
after taking the old filter off & seeing its condition i feally thought
that was the problem.now i wonder what the sock looks like
no ck engine on so far but still stumbles at cold start if its not not going to get any better i'd rather replace the pump now as its still warm outside & thats where i'll be doing the work
Thanks again guys mike

About the only way to diagnose this is by testing pump pressure and flow. Pressure should build to a minimum of 43 PSIG with no vacuum at the regulator, and the pump should be able to move a minimum of 1.5 pints (24 ounces) in 15 seconds at 43 PSIG. Less than that can indicate a restriction in either the pump or filter (or, less likely, the lines).

The pump should have a 100-120 mesh strainer (about 150 microns) on its inlet. It is a turbine type pump so a little sediment will pass through with no real damage but a lot of sediment can eventually wear the impeller and volute, causing a drop in pump performance.

ok was going to replace fuel pump but both carter & delphi brands
would'nt work??after replacing the f/p connector(included w/delphi)
the insulator @ bottom of pump would.nt go on enough to install strainer(sock)
ck & carter is the same.do you replace sender & all or pump only?? in
the past i've replaced the hole unit.this was the 1st time a pump was offered
by itself
thanks mike

heck i'd go ahead to and put new fuel pump ,sock,screen and be done with it and if you get it at adanced or autozone there lifetime as long as you own the car. if you put new pump you wont have to drop the tank again if sock pluggs up again.

ok was going to replace fuel pump but both carter & delphi brands
would'nt work??after replacing the f/p connector(included w/delphi)
the insulator @ bottom of pump would.nt go on enough to install strainer(sock)
ck & carter is the same.do you replace sender & all or pump only?? in
the past i've replaced the hole unit.this was the 1st time a pump was offered
by itself
thanks mike

I'd agree about replacing the whole unit including the sender and the pipes. Some have had leaks in the metal pressure pipe from the tank to the rubber hose that goes on to the fuel filter due to corrosion. I had that on my 98 due to salt or the brine solution they put on the streets and roads here in W. Ohio.

I also know the mechanic I had do it would not put on any brand other than the Delco brand which I assume is what you're getting as Delphi. He said they had too many failures with other brands for GMs where they have to replace them at their cost within a year or whatever was the warranty period for his work. I do know they had trouble getting the right gasket for the flange on top of the tank and had to reorder through the local GM dealer to get the right one for my 98 leSabre.

thanks for info
waiting on parts house never had a problem but
may need a dealer part
thanks again

ok no luck w/parts house.contacted dealer they do not sell the unit
as a complete assembly.you buy the pump or sender separately
im having them pick one up dont no if it will be the same as
the delphi ? cant believe no one else has run into this
i'll post back

ok no luck w/parts house.contacted dealer they do not sell the unit
as a complete assembly.you buy the pump or sender separately
im having them pick one up dont no if it will be the same as
the delphi ? cant believe no one else has run into this
i'll post back

did you try carquest or nappa?

ok got it figured out dealer pump was the same as delphi
the difference was the strainer (delco)it has a longer connector
on it about 1/2 vs 1/4 to install it on pump
pumps in, pressure back 50-52
need to no where i can get new quick disconnect seals
can'nt find without buying the fuel flex line(dealer)
thanks again ev 1
mike

ok got it figured out dealer pump was the same as delphi
the difference was the strainer (delco)it has a longer connector
on it about 1/2 vs 1/4 to install it on pump
pumps in, pressure back 50-52
need to no where i can get new quick disconnect seals
can'nt find without buying the fuel flex line(dealer)
thanks again ev 1
mike
I bought my line at NAPA for about $18. I think the dealer wanted $65. I was going to add if you went the change the filter rute, figure in having to buy a line (the plastic thing on the end).

Chris.

you try autozone,advanced,and i hate to say this pepboys? or is it a dealer item?

thanks happydog,napa does sell the quick disconnect plastic ends
both sizes so i should be good to go .2.50 a bag 5pcs ea.
thanks again mike

ok still looking for quick disconnect for the smallest line
let me verify im right.there are 3 lines(fuel)coming off the tank
1= fuel pressure line to fiter
2= fuel return line
3= fuel gases purged from evap??
im i correct w/#3 is it for fuel vapors(i need the Q/D for this line)
i'll call dealer tomorrow (monday)to see what i need to buy
let you know
mike