change bad fuel pump in the tank, or just get an inline pump?

Man all the crap you must rewmove to drop the tank to replace the fuel pump, not to mention my exhust system is welded.

Anyone here ever say just screw the tank pump and put on an after market inline fuel pump.


will an inline pump be able to pull gas through the bad pump in the tank? well the one in the tank works but it has low voltage code.


This would save me lots of work, I can installed an inline pump in a hr. it is gonna take days to drop my tank, espically if my exhaust does no drop far enough.

 

Supposedly you can, I remember one guy wrote about doing it on the main Technical board. His pump pulled fuel thru the "dead" in-tank pump. Is your fuel pump really shot?

Lowering the exhaust isn't the big deal; it's lowering the axle and raising the car up high enough. Don't do this job inside, you don't want to get killed from gas fumes sitting and collecting, waiting for a spark!

I bought 1' x 1' blocks of concrete, and used them to put the back of the car up on jackstands on my gravel section of the driveway.

 

no my pump is not completly gone, it has had a low voltage error ever since I got the car in 99 but it ran great so I ignored it.

It still works but if I am too quick with my pedal movments it will studder for a sec and then take off.

problem was I ran two tanks of cheap 7-11 gas through it being lazy.

I do not know if Sunoco gas has anything special in it but it made my pump work great since 99, two tanks of cheap gas and its now acting up.

 

You gotta slap a fuel pressure gauge on there, man... seriously... why wait until you get stranded? Do they not sell them by you? When my pump died, it was putting out only 23-25 PSI. I'm lucky I made it home.

 

Did you know that error code could just be a bad relay?
I got the same error code with my RS, 10 minutes later and $25 for a fuel pump relay and it was normal.

 

Simple fact is my car ran fine until I got them two tanks of 7-11 crap gas.

so it almost has to be the pump, what else could gas screw up like that in a short peroid of time?

I am thinking that Sunoco must use something to lubs pumps and/or 7-11 gas has super cleaning stuff.

I am going with the gas as the problem, what could it have screwed with???

The store is just too far away, if I go and buy a gauge I might as well buy parts too. so somewhere I am going to waste 30-40 bucks. Just gotta have in mind what I need.

what is a pump relay, I do not see that listed in the book. does it have another name?

 

ok i found the relay, good chance that has been bad this whole time yea, but after getting them two tanks ofcheap 7-11 gas something else went wrong. makes sence that it is the pump the way it acts, but relay couls still be bad also.

I do get the code for the fuel pump twice now, when before i only got it once, at the end it does the 12 then the pump code again, so it has two error codes for the pump in computer.

It has has 1 error code for the pump since i bought the car.

 

I have my tank out. And I will say shes alot harder going back in then coming out. Right now it is sitting under my car in postion. I am just to busy with school and 200 km away from it yo finish the project.

I would say drop the tank. You don't need to drop the axel and all that. You just need to remove a few braces, and the muffler. and be very good at manouver where there is no room.

Check Fuel pump relay first. It will make you feel alot better if its that vs the latter.
Good luck

 

So bring it to a garage and have them put their fuel pressure gauge on it! You're making this out to be harder than it is, no offense intended... I don't know why you don't want to put a gauge on it, but if you don't, I won't mention it again. I hope it's just your relay, but a bad relay wouldn't cause your driveability problem, only a long cranking before the engine starts.

 

ohh the gauge is a good idea and I had no problem with that, i just wanted to explore more options before i drove 20-30 mins for parts or a gauge. just a pain in the but driving all the time, even to get food. no runnin to bking, food is cold by time u get back.

well I did fangel the garage down the road to check it. psi ok,

I took back my tank pump, got a relay.

Ok well now I have no more codes, the check engine light is now off. but it still runs like crap, studders as i hit the gas but then quickly smooths out.

we did also get lots of rain during that peroid that it went nuts.

 

Have you tried some of that Gas Dry stuff that you pour into to your gas tank ? It's suposed to have alcohol or something in it that combines with water and lets you burn it out, cleans ur injectors too.

To answer you're original question - I had a friend who had an '80 Monza / 350, Holly dp. 1/4cam; he had 3 fuel pumps on that car - the one in the tank, an inline electric, and the mechanical one on the motor. He could run it on any one of them or all 3. (awesome Car)

 

Glad to hear the PSI is okay!

 

I will go get some gas dry today.

"Glad to hear the PSI is okay!"

do you have any other idea's tom?????

This is so strange, and baffling.

none of the clues point in the right direction.

maybe I can sue 7-11, get a life time of free slurpies.

 

The QUALITY of gas plays a big part on how the car runs... Again it goes back to "you get what you pay for." Theres Wal-Marts aroun here selling gas... 1.05... then again theres also been 5 people that have had their engine blow from detonation from that 1.05 gas... I knew one of the peopl and they showed me 2 pistons from their durango with less then 7500 miles that you could put 4 fingers through easily. Wal-Mart has never been known for "quality", and neither has 7-11.

Get 3 bottles of dri gas, octane booster and hopefully your car will recover. If not get some av-gas(avation fuel) 130 Oct and put 2-3 gallons of that in. But Hold The F*ck on cause its gonna RUN...

 

Well besides the gas, I have had most of them codes the whole time i have owned the car and it ran great. So i ignored them.

Now i have replaced all those parts and it did not help, and i noticed that at then end of every error code it says " or bad ECM"

would a bad ECM make a car run like that, just studder all of a sudden for a sec or two then keep reving fine? till you shift and start reving again?


so strange.


I did fill the tank full of new 93 gas and 2 bottles of gas dry.

 

another Q, would a coolant temp sensor also do this?

I am lost, and about read to just put on the car cover and park her for a while.

I need a new set of carbs for my bike, and this is cutting into my goodie budget.

 

so if i siphoned the gas outta my car and ran av fuel it would run ok and stuff and it would be fast? i know its gotta be expensive but i mean would the car run normal?

 

Ok forget allot of what I have said so just, that intinal code 12 is so fast i allways thought it was a code 33, changed my MAF once then just ignored that code.

I have had the code 54 the whole time, so last 3-4 years I have had a code 54, got two tanks of 7-11 gas and it starts acting funny.

I got good fuel psi, new TPS, fuel filter, pump relay.

Under code 54 is also says oil pressure switch, so I guess i will change that too.

Also it could be a bad connection or open short, or like at the end of every code bad ECM.

would the oil pressur switch affect it like that??? befor i go buy one.

 

you could even add a gal or 2 of av gas right into the tank. that alone will even remove some water.

 

Code 54 wouldn't be for an oil pressure switch for an '86 2.8. Do you know how to work a multimeter?


(And for anyone reading this, the nitwit below me is wrong- the oil pressure safety switch does NOT shut the fuel pump off if there is no oil pressure! The wiring diagram for the 2.8 MPFI motor shows this as CLEAR as DAY. It's not a "kill switch for the car"- it's a BACKUP for the fuel pump relay. Don't believe me? Unplug the oil pressure safety switch while the car is running- if your fuel pump relay is fine, your car will keep reading. Camaro_hunter_d has no clue what he's talking about, and loves giving out mis-information. And I posted this because of the code 54.)

-----------------------------------------------
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 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.
________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. But you get the code, so I shouldn't have
____even bothered typing this.



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? 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)
..................................................................

Now, the car acts up all the time, hot or cold? What did you adjust the TPS for at idle?

 

Before you wasted your time with all that you should read that his fuel PSI is fine. meaning relay is OK.
Oil pressure switch, mainly operates as a kill switch for the car. Supposedly when it drops too low(and its working right) its supposed to kill the ignition. It also has to read pressure before starting the car, AGAIN if everything is working right.

 

The O/P switch as I stated above is one of many sensors that have to read pressure before the car is "allowed" to start by the ECM. If your car is/was running fine chances are the ECM's fine. Just a bad sensor somewhere. Thats chasin wires for ya. the sensor I believe is a cheap one, 15-19 bucks. Easy R/R(repair/replace) should only take a few minutes. Nothing else after you get the new one in and reset the codes and it did not work, take it back. Say it did not fit right or somethin. I went through 4 IAC's and none of them fixed the prob. And the IAC was sticking, a good long hard highway run fixed that though.

 

so where could i pick up some av fuel at? would i have to go to the airport?

 

yup. And be REALLY NICE...

 

RECAP:

The code 33 I thought the car had the last 3-4 years was really a code 12, the default code when getting codes. it just goes so fast.

the code 54 also 3-4 years but never any ill effects, screw it.


got 7-11 gas, we gots lot of rain for two days, car wents nuts.

got codes, and besides the normal, [33]12-54 I had the TPS code, so it was a bad tps.

Now I will be honest here and open up myself for flames, even though I should have paid more attention, but I swear I read the book a 4-5 time and some how missed that the TPS had to be set.

even before I went to the store to get a new TPS I losened the old one to change it in the parking lot. the car didnt run any worse so it had to be bad, being out of adjustment.


I got a new TPS and just threw it on, the TPS code went away but the car still runs goofy.

hmmmm I wonder why



but lets see what happens, its allways the little details that hang you up.