i did a search and could't find anything so here it goes ....
my car was running fine on the way home after work. i parked it and came out 3 hours later and tried to start it, it started but was running on such a low rpm it almost died kinda like it was running out of gas. i shut it off and started it agian and nothing... it seems like it wants to turn over but it just doesn't get that extra oomph! to kick it over..
my question is, is my fuel pump dead since i can't hear it when i turn the key to "ON"?

 

well i'm a bit confused, does the starter spin the engine or not? if you can't hear ther FP with the KOEO you have a problem. i'd look at the fuse and relay. a pump the doesn't develop or maintain preasure with still run. start poking wires with a light if the fuse and relay are good till you find the problem.

 

Yes, the engine does turn over.

 

I was thinking of getting a personal plate that says FA-Q, or maybe even FAHQ, dont know if they would let me.

anyways,

turn the key forward, to run, not start.

do you hear the fuel pump prime? if not, turn the key forward and have a friend put there ear to the gas tank, it should run for a couple seconds when the key is put to run.

if you dont hear the pump, check the FP relay, located on the drivers side firewall, and check the FP fuse, located in the fusebox.

if both are OK, I would say, replace the FP, also, be ready to replace the sending unit as well, as the steel lines tend to rust out and break, the sending unit is proly around 300$$

 

i must be an idiot becous i can't find the fp fuse. i don't even see it in the man. diagram. it's an "in-line" fuse so does that mean its somewhere along the wiring and not under the dash?
i replaced the relay and still nothing. im going nuts trying to find the fuse though. i also did a fuel pressure test on the fuel rails and im not getting any pressure.

 

i recently had a buddy put his hear to the tank and i turn "key on" he said no prime just a small *glug*.
would this be a good indication of a clogged or bad pump?
also i have read somewhere else on this site about the fuel pump fuse being by the battery but this was on the camaro, i can't find it on my bird is it in a similer place?

 

FU-Q, you could always search our V6 tech board, I've got tons of old messages up about how I replaced/diagnosed my fuel pump. Replaced the damn thing twice

The fuel pump fuse also gives the ECM it's power. Look on your passenger side upper main frame rail, near the front of the car (under the hood of course), and you'll see two little black boxes, each with two wires coming from them, held to the upper frame rail with a single 9/32" (or 7mm) screw. (Oops, you might just have one, not too sure about the '90 speed density change.) They're fuse holders. You want to take the cover off the one with a red and orange wire coming from it.

Here's a chart that I typed up a long time ago. All you need is a multimeter to run through it, and it'll tell you what part of the pump's electrical system is shot. If everything tests out okay, you might be replacing the pump. It's really not that bad. (sigh) Like I said, search the V6 board, too. Here's the chart, it's for code 54- even though you're not getting code 54, it'll help you trace all the wires. (Same chart applies for you v8 TPI guys, too.)

-----------------------------------------------
DIAGNOSTIC CHART FOR CODE 54 (2.8L MPFI ENGINE)
---------------------------typed by Tom P------

Preliminary stuff:

Ignition off for ten seconds.
Ignition ON, listen for in-tank fuel pump
Fuel pump should run for 2 seconds after ignition on

Not ok? See "1"
Okay? See "6"



1. Ignition off. Remove the fuel pump relay, but keep the harness connected. This is
____located on the top of firewall, driver's side, on a relay bracket. It's the leftmost
____relay, with a connector that has these wires: Tan/white, black/white, green/white,
____orange, orange.

____With the relay still connected, back-probe terminal "A" (that's tan/white, circuit
____CKT #120) with a test light to ground, make sure you can see the test light from the
____driver's seat. Turn the Ignition to on (don't crank the engine/start the car). The
____light should turn on within 2 seconds.

____Light on? See "1A".
____Light off? See "2".

___1A: Repeat the test on CKT 120 (tan/white) at the rear body connector. You saw this
________connector if you replaced the fuel pump, it's in front of the tank, against the
________top of the underside of the car.

________Light on? Faulty pump ground or pump (ouch!)
________Light off? Fix the open (break) in circuit 120.



2. Disconnect the pump relay. Put the ignition on, engine stopped. Probe the fuel pump
____harness connector, terminal "E" (orange on the edge of the connector, Circuit 340)
____with a test light to ground.

____Light off? See "2A"
____Light on? See "3".

___2A: Repair open in CKT 340, this comes off of both your "computer-and-oil-pressure-
________safety-switch" setup and your "fuel-pump-and-computer-fuse".

________Your fuel pump/ECM fuse is under your hood, screwed down to the upper-frame-rail
________on the passenger side of the car, close to the air cleaner & black fuel-vapor-can.
________You'll see two little black boxes, each with two wires coming out of them, screwed
________down to the upper frame rail by one screw each. One of them has a red wire and an
________ORANGE wire coming out of it- that's your pump/ECM fuse holder. Pop the top off
________to see the fuse. (The holder with red & brown wires is for your 85-89 MAF sensor.)

________Now, two things could happen here. You could have a bad fuel pump fuse- check the
________fuse. If it looks okay, replace it anyway... sometimes a fuse can look good, but
________really be blown. The second possibility- I want you to probe the red wire on the
________fuse holder with a test light to ground. The red wire goes to the positive-
________junction-block on the radiator support- your pump/ECM fuse might not be getting
________any power! If the light doesn't light, check the red wire hookup. However, with
________either case your computer would be acting up, too, and I don't think you could get
________the car to start at all.



3. Connect a test light beteween pump connector pin "B" (black/white wire, CKT450) and
____pin "E" (orange wire from step 2, CKT340).

____Light off? See "3A"
____Light on? See "4"

___3A: Repair open CKT 340. The black/white wire isn't making a good ground. Sorry, I
________don't know where this grounds out to. I'd imagine it goes to a screw on the car.



4. Connect test light between pump connector terminal "C" (dk green/white wire, CKT 465)
____and ground. Ignition to "off" for 10 seconds. Note test light within 2 seconds after
____ignition "on".

____Light on? See "4A"
____Light off? See "5"

___4A: Faulty Relay! Hey that's cool, a $10-$15 part from the GM dealer! But, if you
________replaced that already, something's funny. You might want to do the chart again.
________Check for intermittant connections, possibly caused by dirty connector contacts.
________Note: The manual continues to test the "oil pressure safety switch", I'll put
________that test at the end of this message.



5. Ignition "off". Disconnect ECM A-B connector and check for an open, or a short to
____ground, in circuit 465- that's the dark green/white wire from the relay. It's on
____terminal "A1" of the ECM A-B connector.

____CKT 465 okay? See "5A"
____CKT 465 Bad? See "5B"

___5A: Check resistance across pump relay pins "opposite harness connector terminals B
________and C". Should measure 20 ohms or more to be good.
___________Resistance good? Faulty ECM A-1 connector, or bad ECM
___________Resistance bad? Replace Relay AND ECM.


___5B: Fix CKT 465. If CKT 465 was shorted to ground, re-check for a light "on"
________between harness connector terminal "C" and ground within 2 seconds after ignition
________"on".
___________Get a light? Cool, reconnect your relay
___________No light? Faulty ECM terminal "A1", or bad ECM.



6. Clear codes. Start engine and note service engine soon light. If the light comes
____on, check the code, if it's not 54 or you don't get a light, it's something else
____wrong, or an "intermittant" problem.



7. Backprobe ECM terminal "B2" (that's tan/white, CKT 120) with a test light to ground.
____Ignition off for 10 seconds. Note light within 2 seconds after ignition on.

____Light on? See 7A
____Light off? See 7B

___7A: Faulty ECM terminal "B2" or bad ECM.
___7B: Repair open circuit 120 to ECM terminal "B2".



*** Oil pressure switch test: Our 2.8's have two oil pressure switches. One is for the
gauge panel to control our oil pressure light (or gauge). The other one will keep the fuel
pump running if the relay happens to die while you're driving. I assume the theory was that
if you pull out onto a highway and the relay dies, you don't get killed? Contrary to popular
belief, this switch does NOT turn the pump off if oil pressure goes to zero. That's false,
and can easily be seen by looking at the f-body's wiring diagrams. Anyway...

OP1. Start the engine, get it up to normal operating temperature. If you can, verify that
______the oil pressure is normal. Disconnect fuel pump relay- the motor should keep running.

______Engine stops? Bad oil pressure switch.
______Engine keeps going? See "OP2"

OP2. Reconnect fuel pump relay. Ignition "off". Find the fuel pump test terminal on the
______ALDL (Assembly Line Diagnostic Link, the connector above the driver's feet you used
______to get the error code out), which is terminal "G" -- the bottom leftmost terminal.
______Probe that terminal "G" with a test light to ground.

______Light off? No trouble found! (Doubtful, if you got this far & nothing's wrong...)
______Light on? Bad oil pressure switch. Oh yeah this switch is screwed into your engine
_________________block, right above your oil filter, with an orange and a tan/white wiring
_________________harness on it.



Whew.

-Tom P (Hot rodded 1986 Firebird 2.8l)

 

Oh, and this might help, too. When my first pump died, it went from making a strong "hummm" noise to making a sickly "gurgle" noise. The replacement pump made a nice strong hummmmm noise, until IT died. (F'er left me stranded at the racetrack, just as I lined up to the tree. Talk about embarassing!) But when that 2nd one died, it made a LOUD "nest of angry bees in my gas tank" BUZZZing noise. The thing was almost screaming, it was that loud.

Do some searches for "fuel pump pulsator", too. You don't want to re-use the pulsator. Either buy new or throw it out and replace it with a bit of hose. The messages you dig up with the search will tell you why.

 

You could also try checking the fuel pressure, not sure how it is done exactly don't have the tools to do it myself so we took it down to the dealership to do the diagnoses. 60 bucks and they can pretty much tell you if it is the fuel pump or not, and if it is not the fuel pump maybe they can tell you what it is. They might have a computer scanner thing that can see if any error codes are being returned. I say might cause the dealership we took my GF car to only had the card for the 93+ camaros so it didn't help to much.

Anyway if it is the fuel pump it is fun to replace and if you don't have some fancy after market rear coil springs or shocks you might consider replacing them at the same time. Since replacing the fuel pump entails dropping the exhaust and rear suspension to get the tank out. Me and a friend did the job in about 6 hours first time through. Put a pretty nice dent in the gas tank doing it to. On my Gf camaro there was a piece of the subframe that was blocking the tank from comming all the way down. Finally we just yanked on the tank really hard, hear a loud clunk as the tank suddenly dropped on muffler and found a dent in the side of the tank. Didn't hurt the muffler though Anyway enough of my babbling for now.

 

Only thing is, I don't think he'll gain much by checking fuel pressure if he can't hear the pump turn on, ya know? But a fuel pressure gauge is definately a good idea!! Got mine for $40 from Pep Boys, it's by SunPro (just like my compression tester and injector tester and MAF tester and timing light and ....), make sure you buy the one for fuel injected cars. The gauge has a hose and a fitting, and goes up to 80 PSI. (The low pressure one for carbureted cars is only $15 or so.) I've used that gauge more times than I can count- any time my car won't start, or if it acts up, if I think it's the fuel system, I throw the gauge on it. Right away, when I see the correct pressure, I know I can eliminate the whole fuel system as being a problem!

I'm very lucky to have a car with a bent bolt holding the panhard rod to the body brace (passenger side of the car). The bolt doesn't budge. Gotta back the car so the butt hangs over the grass (so my jackstands are on concrete), dig a hole in the grass, and swing the panhard rod into the hole to get it out of the way of the tank. But I'm just a lucky guy like you were (with that bit of frame getting in the way), most people aren't as lucky as us! (sigh)

 

Hehe fun, you could try drilling out the bolt. Need a pretty heavy duty drill and about 3/4 metal bit. Not to mention a steady arm should come right out after that. Of course you will need a new bolt. And at any rate I suggested the fuel pressure check simply because just because you can't hear don't mean it ain't working you know he could have some creapy really quiet fuel pump that is hard to hear through all that steel. Ya never know

 

thanks TomP,
i found that post on another thread last night. i didn't run through the whole thing, but the discription of where the fuse is help out alot. by the way mine has only one box on that side becouse of the speed density thing.
anyway i just started to do the replacement tonight and am half way done.

 

well it took me a couple days couse i didn't have the right tools at first, but i got it done.
what a bitch it is to do with half a tank!
it fixed the problem, but i just realized that my exaust is hanging a little lower than normal, i'm gonna fix that tomarrow...