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91 Buick Century - Spark no Fuel

schwj1000 schwj1000
New User | Posts: 1 | Joined: 10/13
Posted: 10/07/13
06:42 PM

Like the title says, I have a 91 Buick Century 3.3L V6 that I've been having some issues with lately.  The car stalls, mainly during hard acceleration but sometimes while driving at a steady speed.  After it stalls it is difficult to re-start.

So far I've checked:
-Fuel Filter (put a new one in)
-MAF Sensor (unplugged it, car still behaves in the same manner)
-TPS (checked it with a DMM)

I had the car in the shop a few weeks ago when it first started giving me problems, they cleaned the MAF and fixed a vacuum leak, car idles better now but still stalls.  They also said that they checked the fuel pressure and it looked OK.

Despite the good fuel pressure, I'm still thinking its the fuel pump but I'm not sure.  Are there any other components I need to rule out?  I was going to check the CPK but the car stalled today and wouldn't restart, so I sprayed some starting fluid into the intake and it fired/ran for a little bit, so wouldn't that rule out the CPK (isn't it primarily for spark timing?)  So long story short I've got spark but no fuel.  Does anyone know if theres a valve I can open on this model to see if I have fuel coming to the rail?  Shouldn't there also be a fuel pressure regulator somewhere?  Sorry if these are stupid questions, but I haven't worked with fuel injection systems very much before.  The dang thing is stuck about 2 miles from my house now and won't start.  Thanks in advance for any help.

And to add, the check engine light has not been coming on during all of this...  

wayne712222 wayne712222
Guru | Posts: 1856 | Joined: 03/13
Posted: 10/07/13
08:35 PM

first thing...

see if you can get codes out of the computer...

write them down and post them here..  or google them..

first step.. how are the battery terminals.. i have found a LOT of these cars with cables that are not tight.. where the side terminal bolt hole in the battery is not deep enough to allow you to pinch the battery cable ring terminal down..

i have fixed this in several ways..  grind some of the threads off the end of the bolt.. put a 3/8 lock washer under the head of the battery bolt..

please also check the negative battery cable connections that go to the transmission bellhousing mounting stud..

the first place i always start with these intermittents is the ground connection...

battery neg to the engine

battery neg to the body

engine to firewall.

fuel pump ground connection to the inner trunk.. or to the buss bar in the rear door sill..  

wayne712222 wayne712222
Guru | Posts: 1856 | Joined: 03/13
Posted: 10/07/13
08:49 PM

fuel pump is controlled by the computer.. via a fuel pump relay..

turn the key on.. without  cranking. you should get 2 seconds of fuel pump run ..

the fuel pump should again run when you are cranking..

you can use your owners manual to locate the fuel pump relay in one of the relay boxes.. remove it..

gently pry the cover off and see  if the fuel pump runs when you have the contacts closed with your fingers..

if you get NO fuel pump operation when the key is turned on.. for 2 seconds.. find a friend.. you beat on the bottom of the fuel tank medium hard while your friend is cranking the engine..  this will usually get the fuel pump to restart as you are bouncing the brushes..    i spend an hour under one minivan that had been filled to the top with fuel.. and there was a roll over ball in the filler neck.. so the only way was to extend the fuel pump relay circuit with a momentary push button and beat the drums on the bottom of the fuel tank  i don't like spilling fuel all over the shop floor or parking lot..

a few questions..

what do you have in the way of diagnostic tools..

a digital volt meter

a test light..

an OBD1 scan tool to check codes and read the live data from the computer..

the proper wiring diagram for this model??  

wayne712222 wayne712222
Guru | Posts: 1856 | Joined: 03/13
Posted: 10/07/13
08:58 PM

there are 4 sources of repair info..

autozone dot com has some on their site when you join and lot in at the extreme upper right corner of their web page..

autozone also owns alldata.. so you can get onto the alldatadiy dot com web site and access their professional data..

mitchell has it also a eautorepair dot net..

i can probably talk you thru this...

there is one more trouble issue.. once in a while an ignition switch goes bad..  looses contact..but i would have to examine the wiring diagram first..  

wayne712222 wayne712222
Guru | Posts: 1856 | Joined: 03/13
Posted: 10/08/13
03:42 AM

here is the proper wiring diagram for you engine control system.

note that the fuel pump control circuit is shown on the right side..

1990 91 3 3L VIN N Zps533a8b6e  

wayne712222 wayne712222
Guru | Posts: 1856 | Joined: 03/13
Posted: 10/08/13
03:54 AM

the reason i want you to clean and check the grounds up front.. is the fuel pump is supplied with electrons via the body of the car..

if the battery negative to body connections at the front of the car are dirty or missing. there will be no energy for the various parts to operate..

you could also.. have a clogged fuel filter..

or a burned out electric fuel pump..

pounding on the bottom of the tank while cranking will usually get the car started one more time.

you could also have a burned out fuel pump relay.. or burned out 3 wire oil pressure sending unit..

fuel pump relays i usually pry the lid off so i can see the contacts.. or just install a new fuel pump relay.... but you can test the oil pressure switch to see i its working..   get the engine running and pull the fuel pump relay out of its socket..

this switches all the load of the fuel pump to the oil pressure switch contacts..  if the engine dies when you pull the relay. time to change the 3 wire oil pressure sending unit..

sorry.. i keep falling asleep at the keyboard..  

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