s4bill

My car has been sitting for a couple years and I have decided to get it running.

I have set off a chain of events.

There was nothing majorly mechanically wrong with it. It had a bad battery, ac wasnt working properly and a window with a bad guide or roller.

I decided that I would disconnect a plug wire to keep the engine from starting so that I could crank it over and move some oil through the engine. I had a young man helping me and he took the he-man approach to removing a wire and broke it.

So I decided that I would remove the fuel pump relay so that I could roll the window down and look at it to see how it moves. I tried removing it by hand and pulled the cover to the relay completely off the relay.

So I decided I might as well disconnect the fuel line after the fuel pump and connect it to a hose and pump the stale fuel into a fuel container.

I turned the key to the on or run position and the fuel pump does not run.

(On a side note I noticed that my tank is nearly empty - the reserve light is on. A little bit of fuel drained out of the filter when I disconnected the line from it so once I get the pump running I wonder if or how much I am really dealing with)

I want to check for voltage at the pump and I noticed that the electrical connections on the fuel pump are covered by a rubber or plastic boot.

How do these wires connect to the fuel pump? Are they round wire connections with nuts? Do they snap on? Do you slide the boot down the wire to expose the connection?

I think I have terrorized myself and want to be cautious in what I do.

pcar928fan

Should have just started the damn thing every couple of months since you would have had to put a new battery in to do your "crank it over to move oil through the engine" anyway...

No idea where you should start with this...new battery if obvious, probably a new set of plug wires, maybe a relay puller and a new fuel pump relay...you ultimately may need a new fuel pump too and might as well replace the filter while you are screwing with that.

Always hate to hear stories like this...

76FJ55

wires at pump are attached with ring terminals and nut. you will need to pull the boot back fron the pump to expose the connectors.
If you have the cover off the relay you should be able to manually close the contacts to see if the pump runs. by the way the pump will not run with the ignition in the on position and engine stopped, it needs an ignition pulse to the compter in order for the computer to turn the pump on. However the ignition in the crank position should send a signal to the fuel pump relay to turn the pump on during cranking.

s4bill

"If you have the cover off the relay you should be able to manually close the contacts to see if the pump runs. "

Shoud I use something non conductive or simply fingers to close this with the key in the on position and this should set off the pump? should it be in the on position when doing this?

"by the way the pump will not run with the ignition in the on position and engine stopped,..."

Does this mean that the fuel pump relay will not close on the on position if it working properly. The reason I ask is with the cover off the relay, I turned the key and was looking for the relay to move. No such luck.

" it needs an ignition pulse to the compter in order for the computer to turn the pump on. However the ignition in the crank position should send a signal to the fuel pump relay to turn the pump on during cranking. "

If I turn it to crank and the relay closes, it would appear that the relay is not the issue?

Thanks for your help

pcar928fan

Maybe a completely gummed up fuel pump...it did sit with fuel in it for YEARS w/o being turned I guess. Doubt Stabil was put in before it was parked and it probably would not have helped after that amount of time anyway...

VehiGAZ

You have my sympathy for your series of false starts!

Reserve light on my car comes on when 50 miles of range remain, which translates to about 2 - 2.5 gallons in the computer's mind. You can guesstimate from there how much fuel might be left.

As an aside, I am assuming your forum alias means "S4 Bill" instead of "S for Bill" so your remaining range should be about the same. But that brings up another point... ALWAYS GIVE MODEL YEAR INFO WHEN SOLICITING REPAIR ADVICE!!!

Now back to the basics... You are reviving a mostly-dead car. One step at a time. Screw the window and the a/c... you should get it running first so keep focused on that issue for now.

Good luck!

s4bill

Yes an s4. I have an 89 S4.

I have to order wires and hood struts. I was hoping to order the window parts at the same time. Hopefully I wont have to order much more.

dr bob

The good news is that he only broke one plug wire. Other news is that pulling one plug wire doesn't keep the car from running. One broken plug wire won't keep it from running either, it just knocks out ignition to that one cylinder. More good news is that if you didn't crank the engine with the broken plug wire, you didn't risk damage to the ignition system. Lots of news!


Depending on what year your car happens to be, you may be lucky and have a LH controller that uses a very common relay for the fuel pump. Pre-1980 US cars have an RPM-sensing relay that's a bit more (OK, a LOT more) expensive.

To remove the old one, disconnect the battery ground strap at the rear apron, normally hidden by the tool tray. That cuts down on the accidental welding when you pry the remains of the relay out. I use a pair of paint-can openers, the ones that look like a beer-bottle opener at one end and a bent-over screwdriver blade at the other. Home Depot paint department stuff. The bent-blade end tucks under the relay base, one on each side. Rock the tool and it will pry the relay base out.

The fuel pump only runs when the engine is running. It's a safety feature so it doesn't feed the fire following a crash. Early cars may run the pump for a few seconds on initial key-on, but generally the pump only runs when the relay or LH controller detects ignition pulses.

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jon928se

Just use a finger. With ignition on pump should run if you close the relay contacts by hand.

Fuel pump relay will only be activated (close contacts) by the LH (fuel ecu) if the LH ecu receives pulses from the crank postion sensor - ie engine has to be turning.

Correct - and because you can activate the relay by hand you also have the ability to check that the pump will run. and the car may start - with enough gas in the tank and the plug wires connected.

Mrmerlin

warning if your working on the fuel pump then reconnect the fuel lines .
dont try to do any jumpering or connecting wires at the pump with the fuel line disconnected as you can create a spark that will catch your car on fire.
If the pump is in fact frozen a good possibility, then remove it from the car and work on it away from the car

WallyP

1) Reconnect the fuel lines.
2) The plug wire can probably be reattached to the resistor/plug connector. Look at it carefully. Re-attach it if possible.
3) Install and charge a new battery. Clean every connector on the battery - all are critical. Clean the ground strap connection.
4) The old fuel is in the system, including the injectors. If you want to drain the tank, remove the acorn-shaped cap on the forward end of the passenger-side fuel rail. Be certain to counter-hold the rail, and be careful to avoid losing the small steel ball that is inside the nut. Attach a rubber line to the fuel rail, insert it into a large suitable fuel container, turn the ignition switch on and press the relay contacts. Do this outside, have a helper watching, have no ignition sources, and have an extinguisher handy.
5) Replace the acorn cap and ball, counter-holding the fuel rail.
6) Add a few gallons of fresh fuel, and add a large bottle of Stabil - in addition to keeping the fuel fresh, a heavier dosage is an excellent fuel system cleaner.
7) Hold the relay contacts closed, or move the defroster, blower or horn relay to the fuel pump position. Try to start the engine.

Good luck!

s4bill

I am finally getting to the car.

I know. The last response was 2010.

I closed the relay for the fuel pump by hand. I saw a small spark at the relay. I assume that is normal and indicates that a contact was made. The ignition was turned to the on position and I squeezed the relay. I had someone at the fuel pump and they said it did not turn on. Gas did not come out as well.

Was I supposed to do this with fuel pump relay. I believe it is relay XX?

Does the LH relay need to be closed/activated?

If I am using the corect relay and the pump is not running. What are my next steps?

Should I check for voltage at the pump?
IF so where exactly should I check?

I have done as Wally suggested and removed the Acorn nut and have a hose. I am ready to go. Just want to do this right.

I read on another thread that I shouldnt try to start the car with it sitting for a few years?

dr bob

Is there a battery connected? Pump won't run without one. Pumps get gummed up with old gas crud an varnish, so it's still possible that you have voltage at the pump but no run. If you can get the pump relay out, you can add a simple jumper in the socket between terminals 30 and 87. Make it easy on yourself and put a switch in the jumper so you can turn the pump on and off. Battery installed, LH and fuel pump supply wire connected at the battery positive terminal (one of several smaller red wires at the battery positive terminal), that jumper/switch should put power at the pump itself regardless of the position of the key switch or other relays.

Be aware that there are TWO fuel pumps in most US S4 cars. One is in the tank, other on the tank. Power supply is common. Internal pumps fail from age and intermediate hose failure inside the tank, and from trying to eat disintegrated suction strainer screens plus dirt. Given the long lay-up, it would be prudent to finish draining the tank, then pull both pumps. Plan on replacing the tank strainer and the connecting hose at minimum. Pumps would be replacement candidates too if it were my car or my customer's car. Then new fuel lines stem to stern are also in order as you set one foot over the edge of the slippery slope.

The fuel pump relay is XX for 1987-1989 US cars. For later S4 cars 1990-1991 it is relay XXVI. I would have to search just one wiring and relay diagram if you would put the year of your car in your posts. Next time all references might be to 1977-early 1978 production since they are the first diagrams in the stack.

WallyP

"If I am using the correct relay and the pump is not running. What are my next steps?"

The next step is a careful examination of Fuse #42, the fuel pump fuse, and its connectors. The Central Electric Panel is in an area that is susceptible to damage from moisture, and corrosion of the fuse connectors is the most common problem.

First, check Fuse #42 and ensure that it is not blown. There should be a fuse checker built into one of the relays. Remove #42 and plug it into that checker. If the green light glows, the fuse is OK.

Closely examine the legs of the fuse for corrosion. Remove any corrosion with a fine wire brush or similar tool.

Closely examine the fuse connectors - each leg should fit snugly into the connectors. If not, carefully twist each connector a few degrees to improve the contact.

Your next steps require a couple of tools, one of which you buy, and one of which you make.

Go to a good auto parts store and buy a twelve-volt test light. This will resemble an old-fashioned ice-pick with a transparent handle. There will be a light bulb inside the handle, and a wire from the handle, with an alligator clip (crocodile clip for those from the Old Country) on the end. When the tip is firmly touched to a 12-volt source, and the alligator clip is firmly attached to a good ground (earth) surface, the light will glow. (Of course, sometimes it is necessary to use it the other way, with the alligator clip on a 12-volt supply, and the tip checking for ground.) A good one should be around $10.

While you are there, buy:
- A SPST (Single-Throw, Single-Pole) toggle switch. Get one that has "OFF" and "ON" clearly marked.
- An in-line fuse holder and a couple of matching 15-Amp fuses.
- Suitable connectors. You will probably need wire splices for the fuse holder (18-gage); female 1/4" flat spade connectors for the switch, and two flat 1/4" male spade connectors for the other end of the relay jumper that you will be making.

Go to Home Depot, Lowes, Menards, or a good hardware store and buy three feet of lamp cord or zip cord. This is the two-conductor wire that is used to connect a table lamp to the wall socket.

Put the two male connectors on one end of the wire, the in-line fuse holder in one of the wires near that end, and the toggle switch on the other end. Tape any exposed wires or connections.

Remove Relay XX. Use the diagram on the relay to locate Terminals 15 (ignition power) and 87 (feed to the fuel pump) in the relay socket.

Connect the alligator clip of the test light to one of the ground connections (bolt with a bunch of brown wires) above the CEL (the fuse/relay panel). Turn the ignition switch on, and touch the connectors on Terminal 15 with the tip of the tester. The light should glow.

Turn both the ignition switch and the toggle switch of the relay jumper that you have built OFF. Insert the two flat male connectors of the jumper into Terminals 15 and 87. Turn the ignition switch and the toggle switch ON.

Go to the rear of the car and kneel by the license plate. Listen for a buzz or hum from the fuel pump.

If there is no buzz or hum, turn both switches OFF.

Remove the panel under the bumper to expose the fuel pump. Find the power lead. Hook the alligator clip of the test light to a good meal ground. Turn the ignition switch and jumper switch ON. Touch the power connector - the light should glow.

Report the results so far. Be precise and verbose.

s4bill

Well I am definitely going to do as you suggest because I drove myself crazy working on it. I was able to climb under the car while having someone cliose the relay and did hear the humming sound from the pump. No gas pumped when the relay was depressed.

I had already disconnected the filter from the pump and had a hose attached there. If I saw fuel there when I ran the pump, I was going to reconnect the fuel filter and pump the fuel through the lines as you suggest. I have already removed the acorn nut on the fuel rail and have a suitable hose that will connect to that fitting.

However, when no fuel woud come out, I drained the gas from the car. About 2 gallon or so as someone suggested. I then removed the pump from the car. With it off the car, I spayed carburetor cleaner to the intake side of the pump and let it sit and then used MMO. I have even let it sit overnight on 2 different days. This is where I am wondering if I made a mistake. I put some air to the intake side of the pump to blow the cleaner and MMO through the pump. Was this a huge mistake?

I have attached power from a batter charger to the pump. I am guessing this isn't brightest idea as well. When I would attach power, I would hear a humming sound but I am not sure if it was the pump or the charger. Was it not enough amps? So my questions now are:

1) Did I possibly damage the pump by putting air to it?
2) Do I need to be concerned with how much amperage goes to the pump? Can I connect it directly to a car battery?
3) When powered is applied should I see the pump spinning inside? Should I feel air moving?
4) Does the pump need to have liquid to work (its had its share of cleaner and MMO run though it)?

I have both the test light and an multimeter. I will test for power even though it seemed like it because the pump hummed when relay was depressed.