fuel pump relay help

[talincolnlsc]

why dont you check for fuel at the fuel relief on the fuel rail(the thing that looks like a valve stem to fill your tires with air). that will tell you right away if you have fuel or not. i ussually hook up a gauge but if you dont have one then you can also push in the stem and have your buddy prime the pump. the pump puts out 35 p.s.i so i would hold a rag in front of it so it doesnt spray everywhere. i had a fuel problem with mine. replaced the pump and still didnt work. it ended up being the wires on the top of the sending unit inside the tank got corroded so i soldered them and its been fine since. if no spark is your problem i would first check fuses then check your coil. the hayes manual says how to do it but i just cant recall how i did. by the way when checking spark hold the spark plus to something thats a ground (alternator bolt, intake bolt etc) and you should see a fat blue spark if you have to struggle to see it its not there or weak then you have something to go from.

 

[marragtop]

Another way to rule out spark is to CAREFULLY spray some starting fluid into the intake while someone cranks it. If it fires up for a short time, then your problem is probably fuel delivery related.

 

[jammin636]

the fuel pump should prime when the key is tuirned to the on position, this means it runs for a few seconds, not clicks

If it does not and its a new pump then the issue is in the wiring to the pump.
I suspect first the plugs that relay attaches to, it is common for them to get corroded, so look deeper then just plugging in a new relay.

Also are you sure you replaced the correct relay?
I would check your fuse, relay, then trace the wiring....
if the fuel pump is not priming then that is the first thing to fix, dont move on to spark just yet.

thats what i thought, but he said that it was just clicking. it is a brand new pump. why is it even clicking in the first place? also i replaced the relay with the green plug(grey one-they are the same correct?) and the black relay. if the wiring does look sketchy where do you find new wiring harnesses etc?

i can also hear lots of clicking coming from the engine when i put it to the start position. and ddoes anyone know why im smelling gas?

 

[410Fortune]

okay
the clicking you hear is the relays turning on and off, this is normal

there are two types of relays, 4 prong and 5 prong.
I would replace with new

If the wiring harness in the box itself is damaged or corroded then you have to take it apart and rebuild it
I would not swap relays I would replace them

If you smell gas it is likely your pump is working fine and the problem is elsewhere.
But do like they suggested and check for fuel pressure at the fuel rail FIRST.

You smell gas when? when you try to crank it?
Are there any gas leaks?

You can also check the vacuum line going to teh fuel pressure regulator, make sure there is no gas in there. Again a fuel pressure test will tell you if the fuel pump is working

 

[jammin636]

okay
the clicking you hear is the relays turning on and off, this is normal

there are two types of relays, 4 prong and 5 prong.
I would replace with new

If the wiring harness in the box itself is damaged or corroded then you have to take it apart and rebuild it
I would not swap relays I would replace them

If you smell gas it is likely your pump is working fine and the problem is elsewhere.
But do like they suggested and check for fuel pressure at the fuel rail FIRST.

You smell gas when? when you try to crank it?
Are there any gas leaks?

You can also check the vacuum line going to teh fuel pressure regulator, make sure there is no gas in there. Again a fuel pressure test will tell you if the fuel pump is working

i replaced the fuel relay and the other black just for the hell of it. not sure if their 5 prong ill have to check but they are new.
i will also find the fuel rail and try and check for pressure. its just hard cause its just me right now. Where is the fuel pressure regulator???

im smelling gas after i try and crank the engine a couple times. no leaks i can see. and their shouldnt be, new fuel lines. ill go check what the wiring looks like now.

 

[410Fortune]

if you smell gas then its likely because you are cranking and cranking with no spark
that tells me you are getting fuel pressure, but if the regualtor is shot then it could be too much fuel or too little.

You need to use the search button for thsi stuff, the fuel rail pressure test and pressure regulator are covered on this site often, with pictures even!!

If you determine youhave fuel pressure (you likely do) then I would turn my attention to checking for spark

also was there a check engine light?

 

[jammin636]

yea i am getting a check engine light. i pulled a code awhile back for fuel fump faulty secondary circuit or somehting like that. if that matters i dont know.

 

[410Fortune]

the code you get is VERY important
you MUST pull the correct code (read it properly) and get the correct definition for it.

that is ALWAYS step 1
is the code still there with the new fuel pump/relay/etc?

if so then please double check the code and post it here

 

[jammin636]

got it!! 542 Test condition O,C Fuel pump secondary circuit fault

 

[shamaal]

Not to jump in on 410's assistance but it's been a while. Guy's gotta eat sometime

When you turn the key, you energize the PCM Relay and supplies power for the Fuel Pump Relay. The PCM supplies the ground to energize the fuel pump relay for a short time and senses the fuel pump relay has closed (pin 8 of the PCM). See figure 19 from post #11.

This code indicates the PCM is not reading the voltage from the fuel pump relay. This could be a bad fuse 16, or faulty wiring. Please note that this is a step backward from your post #13; so consider some previous action you took. My guess the fuse blew, a bent relay pin or a dirty connection. Until the 542 code is fixed any troubleshooting past the relay is not meaningful.

Let us know how it goes.

 

[jammin636]

so where should i start looking, the wiring to the fuel pump relay? i took the relay off and looked at the harness, the green one, and it almost looks brand new, very clean. so from that would i got downwards on the wiring? then it merges into i big bundle of wires. where do i go from there?

so should i get this code all sorted even before i check for fuel pressure like was said in above posts? i was about to do that. needed another hand though.

 

[shamaal]

Yes sir, the codes going to have to be cleared before anything will work. The computer thinks the relay didn't close and there is no fuel available.

Looking at the diagram, remove the relay and with the key turned on, check the voltage at the following pins corresponding to the wires indicated, use a paperclip or similar to ensure you have good contact:

1. Black/Yellow wire - +12 volts - if not fuse 16 is bad or wiring in between

2. Red Wire - +12 volts - if not the wiring to the PCM relay is bad. That the PCM works means the relay is working.

Turn off key, insert relay, turn on key and back probe wire on back of relay

1.

 

[jammin636]

Yes sir, the codes going to have to be cleared before anything will work. The computer thinks the relay didn't close and there is no fuel available.

Looking at the diagram, remove the relay and with the key turned on, check the voltage at the following pins corresponding to the wires indicated, use a paperclip or similar to ensure you have good contact:

1. Black/Yellow wire - +12 volts - if not fuse 16 is bad or wiring in between

2. Red Wire - +12 volts - if not the wiring to the PCM relay is bad. That the PCM works means the relay is working.

Turn off key, insert relay, turn on key and back probe wire on back of relay

1.

so if im not getting 12 at one of these or both pins i should back probe the wires till i get to the point where i do get 12? i think i understand what i need to do know lol. just answer my one question to make it clear. thanks for all this help. i really appreciate it. if thats what you mean ill get on this tomarrow and let you all know.

 

[shamaal]

Yes, you should have +12 volts at those points with the key on. Look at the diagram. I wasn't paying attention and hit the reply button. This is the full message:

Yes sir, the codes going to have to be cleared before anything will work. The computer thinks the relay didn't close and there is no fuel available. Disconnect your battery for a couple minutes to clear code. If intermittent it may clear up during troubleshooting.

Looking at the diagram, remove the relay and with the key turned on, check the voltage at the following pins corresponding to the wires indicated, use a paperclip or similar wire to ensure you have good contact:

1. Black/Yellow wire - +12 volts - if not fuse 16 is bad or wiring in between

2. Red Wire - +12 volts - if not the wiring to the PCM relay is bad. That the PCM works means the relay is working.

Turn off key, insert relay, and have assistant turn on key on demand and back probe wire on back of relay

1. Lt Blu/Org - should be +12 volts - when key is turned on it will drop to zero for 3 seconds, relay will klick then go back to +12 - If not, something is wrong with signal from computer - further troubleshooting required.

2. DkGrn/Yel - should be near zero (3.6 volts from post #13) - when key turned on should go to +12 volts, relay should klick for three, then return to near zero. If not relay is bad.

Consult the diagram, the troubleshooting procedure is logical, ask questions if not sure. All this is based upon the code 542 is valid and your fuel pump does not whine for approx three seconds. Disconnect the battery for a couple minutes to clear codes.

Let us know what you find.

 

[jammin636]

thanks shamall ill let ya know

 

[jammin636]

ok i went and did some testing and here is what i found. hopefully you guys can make some sense of this cause i have no clue.

black/yellow wire had 12v
red wire 11.9v

lt lbue/ orange when the key was turned on it went to zero for a second then went back up to 11.9v

dkgeen/yellow turned key on and my meter kinda bleep didnt seem like it went up to 12 especially not for any noticable length of time. then it went down to 6.6v and stayed there.

also when all was done i went to check the codes again and it threw 542 again. but then it threw another different one that i had not seen before. i dont get it?? 116 engine coolant temp higher or lower than expected. ihave no clue. help?!!

 

[shamaal]

Your first three readings are correct. Your fourth says that the relay is bad or there is a short in the fuel pump circuit. unplug the inertia switch and repeat the Dk Grn/Yellow test. It should clearly go to +12. If not the relay is bad.

With the relay still unplugged, measure the resistance to ground from the pink/blk wire. It should read 2.5 ohms. If less somewhere in the circuit there is a short to ground or the auto place gave you the wrong pump.

I have no explanation for the 116. The ECT sensor is on the front of the engine. Examine to make sure you didn't break a wire on the connector. This is moving into the realm of flaky ground connections. Picture below.

 

[jammin636]

Your first three readings are correct. Your fourth says that the relay is bad or there is a short in the fuel pump circuit. unplug the inertia switch and repeat the Dk Grn/Yellow test. It should clearly go to +12. If not the relay is bad.

With the relay still unplugged, measure the resistance to ground from the pink/blk wire. It should read 2.5 ohms. If less somewhere in the circuit there is a short to ground or the auto place gave you the wrong pump.

I have no explanation for the 116. The ECT sensor is on the front of the engine. Examine to make sure you didn't break a wire on the connector. This is moving into the realm of flaky ground connections. Picture below.

I feel like im going nowhere. my knowledge sucks and its pissingme off. i just got done doing more testing and this is whati found.

i unplugged t he inertia switch and repeated the green yellow wire test. this time it did clearly go 12v for about a second. but then it went back down to 6v and stayed there.

then with the inertia switch still undone i measured resistance. it was pretty much an open circuit, measured in the millions. i dont know whats goin on witht the 116. i looked at all the connections and they all seeemed fine. went to check the codes again and it was gone so i dontknow whats going on.

thanks for this pic i would have know where to look. so what now????

 

[shamaal]

All right, there is a problem between the inertia switch and the pump. Either a bad connector or a bad pump. Yes I know it's a new pump, so I would bet you have a bad connection at the pump. There are no ambiguous readings here. Drop the tank, ohm out the pump (<2.5 ohms) and ohm out the wire between the inertia switch and the pump connector.

For those following on the diagram, there is a momentary +12v at the Dk Grn/Yellow wire at the Fuel Pump relay with the inertia switch disconnected. This establishes that everything prior to this is good.

Measuring the Pnk/Blk wire on the inertia switch connector to ground shows an open. This should read the pump coil resistance (<2.5 ohms). The next step is to drop the tank and resolve why the pump is reading bad, this is a new pump. The working hypothesis is that the pump connection is honked.

 

[jammin636]

alrighty ill get on that. one question. how do i ohm out the wire between pump and switch? and do i ohm out the pump by the prongs on the connector? i can get to that without dropping the tank, but im guessing theirs some other things i need to do. thanks