Hey Guys,

My 1989 Trans AM has an issue.

The fuel pump does not prime when turning the key 1/2 a turn like it normally does.. checked all fuses, and possible bad connections/wires.. none spotted.

However, the relay that clicks wildly when removing/replacing the fuse for the fuel pump.
I removed the relay..checked to see if it was damaged or if the wires were corroded.. but it
was filthy of that grease. Other than that, it appeared to be normal at the connection and
the relay itself.

Sound like a bad relay? or possible issue
in wiring/pump? Also, The car ran and started
fine until today ..

Any suggestions/expierences would be great

 

So you already identified the fuel pump relay on the firewall? Good. Now put 12V on the tan/white wire on it. If the fuel pump primes, it's the wiring or relay. If it doesn't, you might need a new fuel pump (mine died on my overnight too).

Lou

 

Thanks for the advice, I did what you instructed.. But to no avail the pump did not even make a sound. The noise just jumped to the next relay.. that also contains a tan/white wire.

Ive never had a prime or pump problem with this car ..

This is very concerning, Because I cant find
any bad/broken wires protruding from the relay
or any of the connections.

If I can manage to start the car with some carb cleaner.. Will the pump operate with the motor ??

If its just a pre-ignition prime problem it must be electrical, right??

I had been scheduled for my custom exhaust
to be welded, Its 85yds down the street.. and I wont be able to get it there if I doesnt start.

I was hoping for a quick fix, but if I can
band-aid it till after the welding is complete..
ill be a happy man !!

 

First to answer your question on will the pump operate if you get her started.I think the answer is no but some of the cars have a secondary wiring thru the oil pressure switch/sensor.The grease you speaking of is it a yellowish/white in color?That would be dilectric grease.It's used to provide a barrier against moisture.The pump relay coil may not be holding or the contacts may be burnt.I had a similar problem on my '95 Jimmy(thankfully it wasn't the pump itself).Hope this helps but like Biglou states fuel pumps go out without warning.

 

Thanks again for the input,

Im not going to try to start it, Id rather fix
this problem right away. I did some searching
and found a guy with a similar problem.. his pump wouldnt prime, replaced the relay and it was
back up and running.

But, going back to Lou's directions, feeding it
12V's just clicked the another relay.. so I dont
know what to think.

Its a inexpensive attempt, rather than go for a
new a fuel pump just because of a $12.00 relay,
Its worth the attempt.

Also, The grease I mentioned probally used
to be yellowish/grey in color but not anymore.
Its grimed up pretty good of whatever it is,
I can tell its not healthy looking, Darkish in
color grease.. Ill replace it for good measure.

Thanks again for the responses

 

Alright, let's see.
When you applied 12V to the tan/white wire and your fuel pump did NOT turn on, something is wrong with the pump or the wire going to it. The click you heard was probably the MAF relay because it is activated when the fuel pump runs (which is what you were trying to simulate).

Since you don't have exhaust yet (I'm guessing), you could easily put in a new pump. Because otherwise you'd have to cut the exhaust out to pull the gas tank.

But before you start dropping the fuel tank, jack up the rear end and unplug the fuel pump connector that's on the wall just behind the seats. Apply 12V to the black and tan/wht wires and listen for a whine again. If THAT doesn't work, the fuel pump is gone.

HOWEVER, there might be a temporary fix. If your pump is just stuck, like mine was (I guess the bearings dry out and seize occasionally), you can "jump start" it. Open the hood and pull the connector off the fuel pump relay. Get another battery and connect the negative terminal to the tan/wht wire on the connector. Then take 12V off the positive terminal and MOMENTARILY (i.e. for half a second) put it on the orange wire on the connector. This will give the fuel pump 24 volts and might jump start it (worked for me!) but as I mentioned, do it ONLY for a split second, not more than one second at a time. Plug the relay back in and turn the key, you might get lucky and the fuel pump is spinning free again. At least for a few days.

Lou

 

What you said above makes sense, I had just
done a new motor swap over the summer .. So
the car itself sat for a couple months with no
way of starting. The pump could have dried up
or something happen within that period.

Which is why I think the pump could of got "stuck".
I was praying last night that it was just a stuck/shot
relay causing this mess.. and I could rectify it within
an hour (yea right..)

*EDIT* The MAF burn-off/fuel pump relay was
the squarish in shape relay to the far-left on
the relay rack mount, right ??

The other relay that clicked as I applied 12V's
to the fuel pump relay was the middle-relay
kind of cyclindrical in shape.

My car, 1989 should be the square relay for
the fuel pump, correct ??

-Thanks Again guys, A big help!

 

The fuel pump relay is the one with the following 5 wires: red, orange, tan/white, black/white, green/white. That is the fuel pump relay.

The relays don't have a set position on the firewall. Sure, they could have come out of the factory with the relays organized in a certain way but anybody can swap them around. You should never try to locate an electrical component only by its supposed position. The wires will tell you which one is which.

Lou

 

Another way to jump start a fuel pump is to connect power to the tan/white wire a jumper from the orange wire will work. And then tap on the tank with a rubber mallat. The reason that the pumps will stop working over night has to do with the brushes in the pump going bad. When the pump is spinning it will keep running past the bad spots. But once it stops completly randomly in the bad spot the pump won't restart. A little shake will powering the pump will usally get it restarted. I have had them restart after a ride on the tow truck. Mike

 

Very encouraging post, Im optimistic I can get the pump
moving freely again.. If I have to do a fuel pump swap later,
So be it.. But ill at least attempt the "jump-start" method.

I have a good feeling it could just be stuck, its the
original pump from the factory, and Ive never had
a fuel pressure problem before.

Hopefully Ill have some luck tonight, Ill let you
guys know the results.

In addition to Lou's post, A very true statement..
From now on, I will not presume a components
type by its location, regardless who's car it is.


Great advice, Thanks

 

As I mentioned earlier, if you need a new fuel pump, it would be good to do BEFORE you put the exhaust system in. It takes maybe 4 hours to drop the tank, put the new pump in and install the tank. And that's a "newb" labor time. You will need a buddy or two to help you wrestle the tank out of the car, especially because the filler neck will catch on the subframe.

Once you put the exhaust in, you won't be able to drop the tank without cutting the exhaust out of the car. That's why I'm pointing this out.

Lou

 

Yea Im debating that right now whether to just go for a new pump and not have to worry about it for
a long time.

How much do our Fuel Pumps run?? that would be
the litigating factor in starting the project..

If Its inexpensive, I will consider just doing a pump swap.

Lou, you are the man !!

 

Our pumps are definitely below $100. Mine was a little more expensive than the regular stock replacements because I bought the Bosch pump with lifetime warranty. I'm not 100% sure on the price but it might have been around $80. The cheaper pumps run around $50 or so.

Lou

 

Wow, thats surprising..

I did a fuel pump swap on a 2001 Dodge Stratus, and that
unit was $300.00, hahaha.

Im about to try to "jumpstart" the pump in 15mins, Ill post
results.. I have a feeling its going to come down buying a
new pump.

I thank you for your responses, as I am not as panicky
as I was yesterday

 

Some pumps might be more, depending on year, make, model. Some aftermarket hi-flo pumps are even more expensive than that. It all depends.

Good luck with the jumpstart!
Lou

 

Ok, No luck .. I couldnt get it to actuate.

I bought a new relay, and with the same result, it clicked.
Tommarow I will jack the rear-end up and try to actuate
the pump with a external power source, If it does actuate
with a outside source then my problem is uptop somewhere.

I noticed minimal gas in the tank while tapping it, Though I
think I was tapping the shroud making the hollowed noise.
I do not know if the gauge is correct because of the engine
swap.. But I remember the pump sounding faint or funny a
few days before It had problems, maybe no gas or..?

The car is not on the road, so It hasnt seen a gas station
in a few months, But it always ran previously.

The pump might have burned up, we will find out tommarow.

A buddy asked If you could run a "remote" electric
fuel pump from topside, drawing fuel off the fuel lines
on the driver side. I wanted to ask If that is a plausible
idea and If anybody hasdone it with results..
Id like to explore all ideas.

The idea made sense, Completely eliminating the
trouble of replacing the in-tank pump.. but I dont know
what to think

Any opinions will help, Thanks

 

Electric fuel pumps push fuel better than they suck fuel so you usally mount them as close to the tank as possible if not in the tank. They also don't like obstructions on the inlet side such as a stock intank fuel pump. If you do want to use an external fuel pump replacing the sending unit with a Carb. sender would work. Mike

 

Hey thanks 83z,

I chose to replace the internal pump.

I un-bolted the shroud, and the tank is visible. I have
the fuel pump wires visible.. its the 3-prong connector
thats mounted behind the seats right before the tank.

I tried sending 12V to the actuating wire and the pump
didnt make a sound. I see the wires vanish at to the top
of the tank, So im sure those are the wires I need to test.

I also tried feeding 12V to the ALDL connector
(bottom-left) and the same relay clicked, that indicates
a bad pump, right?

I also tried hitting the tank with a rubber mallet while
trying to jump-start the pump with external power,
nothing came of it.

Ive almost concluded that the problem is nothing
electrical, but the pump..I will find out for sure tonight.

The connector at the bottom that is visible seems
to go into the car, behind the seats.

Should I check to see if power is going back to the
connector? and If it has power, then it is the pump
correct?

 

A new discovery I didnt notice.

I went to add 4-5gallons of gas in the tank
for good measure and noticed the gas gauge
is also pinged to "F" or Full. I know for a fact
its not full of gas.

I disconnected the battery, and also checked
my grounds to the back of the heads. nothing
looked bad. I left the grounds undone for the
moment and proceeded to the cab of the car.

The gauge is still pinged at "F" with no battery
and Ive tapped the gauge window numeriously
to help it fall, nothing. it remained firm far past
the "F" ..I reconnected the grounds and put the battery back in and the gas gauge is still pinged to "F"

Does that have anything to do with bad pump/sender? Or am I looking at another problem ?

 

You can check your gauge easily.
Turn the ignition. Have somebody watch the fuel gauge. You climb under the rear end and ground the center pin on the connector on the wall (C313 - the side that goes into the car).
If the gauge reads empty, it's good. Then it should go back to full.

Next test you can do is, at the same connector, connect pins A and B (the A is the one with the black wire). The gauge should read empty again. If it doesn't, you have a bad ground G304. Remove back seats and peel the carpet back and trace the wire loom and find the ground where it's connected. I seriously don't know. But I'll try to find out for you.

One more test I can think of: take the C313 hanging from the fuel tank and measure resistance between the black and purple wires (A and B). If it reads more than 90 Ohms, the sender has gone bad.

Hope this helps!
Lou

 

Is that connector under the rearend also the power to
the fuel pump and/sender?

I know exactly what connector you speak of, it flows
through the sheet-metal behind the seats then looms
into the car.

and its has 3 plastic prongs, the wires are a tad
discolored Id have to clean them up to identify them
properly, I had to remove to tank shroud to see it.

I just want to make sure I got the right component.

Thanks for the tips, Ill find out tonight.

 

Yes, that's the C313. It supplies ground and 12V to the fuel pump and brings back the fuel gauge signal (against the ground). The pins are A, B, C. They mean: ground, fuel gauge signal, fuel pump power. The ground is definitely black.

Lou

 

Thanks so much, Im going to get on it right away.
Ill post up results after I rectify the problem.

Again Lou, the support has been outstanding
It is greatly appreaciated.

 

You did remember to plug the fuel pump connector back in when checking the gauge. Mike

 

I double checked the connector at the rear and it was
plugged in. I also checked the multiple grounds to the back
of the heads and through-out the car, didnt spot anything..

And still with the same result, the gas gauge is
pinged "F" and the pump doesnt prime or actuate..

When I first turn the key, 5-8 seconds will pass and
then the relay responds with a click.. as if the system
was sending the pump power, but doesnt respond..
hence the click, 5 to 8 seconds after the fact.

Any thoughts ?

 

On thing that I noticed after having the exact same fuel pump-related issue, be careful when jumping accross the relay connector. After confirming that the relay clicked, it was removed and we performed the jumper test which proceeded to blow "something" netting a relay that no longer clicks (when reattached) and an SES light that no longer functions. Any ideas???