[GP67]

Have a question about fuel filter or fuel pump?
Normally at the schrader valve you get a healthy dose of fuel. I press the needle in and get a dribble. I've heard the fuel pump come on momentarily but still a small amount of fuel at the valve. Is it possible the fuel filter could cause this? The pump is in the tank. I'm having someone else do the job and told him to replace the filter first and test it. He says its the pump and want to drop the tank from the get go. I'm leaning towards the filter first. Is that reasonable? Can the filter suddenly plug for a no start situation and the pump may be fine?

[WARPed]

changing the filter is a natural first step.

[Lemans64]

Yes changing the filter is usually the first step. But depending on the model you are dealing with, some fuel systems require 50 psi minimum to operate, (96 chev truck) won't run with less than 50 psi, so pump can run but not enough pressure to run system, poppet type injectors, they have a check ball at end of injector line and need the pressure to overcome the seat. Not sure what vehicle you are dealing with?? Filters don't usually cause no start issues.

[Schurkey]

Replace filter first--but--I expect either a pump failure, an internal rupture of the in-tank plumbing, a plugged strainer, or an electrical failure.

In-tank rubber hose must meet special standards for "submerged" use, and high-pressure. Some folks cheat by installing standard fuel hose. The hose can rupture creating a massive internal fuel leak, low pressure, low volume. A defective pulse dampener can do the same thing. Even the hose clamps on the hose can make a difference:

sh!tty worm-gear clamps and the hose damage they cause, compared to proper fuel-injection hose clamps


The strainer "sock" on an in-tank pump can plug. In any event, if the pump/sock/internal hose is replaced, the tank must be checked for grit and other contamination.

The fuel pump should be supplied with adequate electrical power. OEM in-tank pumps often have corroded in-tank fuel pump wire harnesses. Replacement harnesses can be had for about $20. The external harness and fuel pump relay are also suspect. Check voltage as close to the pump as you can, and check fuel pump amperage draw, too.

A professional should be testing the fuel pump amperage draw with an oscilloscope and a low-amps probe. The oscilloscope can show amperage draw for each individual bar of the armature, and with very little work, can show pump RPM. Knowing fuel pressure, voltage, amperage, and RPM is a big help in diagnosing fuel pump failure.

[HWYSTR455]

What Schurkey said.

Depending on the age/miles of the pump, if there's a delivery issue, shotgun approach is to drop the tank and swap the pump, sock, line, & harness (filter too). Most do so to avoid additional hours for diagnosis. Most of the time all it does is confirm what's suspected anyway.

A lot of replacement pumps come as an assembly, and have new hose, clamps, harness, etc already installed.

Let's hope the shop knows to flush/rinse the tank since it's a pump swap.

Might want to go ahead and swap the sender too, for the couple bucks, it good insurance, since the labor to drop the tank is already spent.

.

[TedRamAirII]

What year/kind of car are we talking about? If it was a filter, the fuel would still come out the same pressure, but no volume. The pump is toast.

[Tom Vaught]

The E-15 fuel (gas pump gasoline) at the pumps today will kill a 80s style EFI system pretty quickly. By the 90s the OEMs were protecting for the "Flex Fuel" requirement.

I had a 2001 Ranger and a 2003 Windstar both have pump issues within 3 months of each other. Both had no issues with the E10 fuel but the E-15 Fuel has killed them and a lot of other vehicles in the last 3-4 years.

I would drop the tank as suggested and inspect everything if you have access to a couple of friends and a proper jack to lower/raise the tank.

Tom V.

[TedRamAirII]

Originally Posted by Tom Vaught

The E-15 fuel (gas pump gasoline) at the pumps today will kill a 80s style EFI system pretty quickly. By the 90s the OEMs were protecting for the "Flex Fuel" requirement.

I had a 2001 Ranger and a 2003 Windstar both have pump issues within 3 months of each other. Both had no issues with the E10 fuel but the E-15 Fuel has killed them and a lot of other vehicles in the last 3-4 years.

I would drop the tank as suggested and inspect everything if you have access to a couple of friends and a proper jack to lower/raise the tank.

Tom V.

I have not noticed any E-15 here locally, but I dont get out much. Its all E-10 with a few Non-Ethanol stations. Soooooo glad we are supporting corn farmers. I have read that ethanol cost more to manufacture than they get, which is OK, because they get Govt Subsidies. ; )

[Tom Vaught]

Very True. I ran E-10 for many years in the same vehicles that failed when the E-15 stuff was authorized.

Tom V.

[GP67]

It's an 04 grand am se. The mechanic is charging $175 and I'm buying the parts. I would do it but he has a lift so the $175 is worth it to me.
It's just strange how it all came about. The Passlock system locked up the pump according to the literature. Thats why I'm hesitant to say the pymps dead all of a sudden. I described the situation on the Other Pontiac Tech thread.
Oh and I have checked every fuse and relay in all three fuse locations. Drivers side, passenger side and under the hood.

[TedRamAirII]

Originally Posted by GP67

It's an 04 grand am se. The mechanic is charging $175 and I'm buying the parts. I would do it but he has a lift so the $175 is worth it to me.
It's just strange how it all came about. The Passlock system locked up the pump according to the literature. Thats why I'm hesitant to say the pymps dead all of a sudden. I described the situation on the Other Pontiac Tech thread.
Oh and I have checked every fuse and relay in all three fuse locations. Drivers side, passenger side and under the hood.

What do you mean the Passlock system locked up the pump? What is the anti theft light doing? flashing? any codes? I think it only stops it from cranking?maybe not? tell me more.You should be able to at least bypass the fuel pump relay and get fuel pressure and/or hear the fuel pump working.

[GP67]

WCI read up on the Passlock and it states it cuts the fuel to the injectors. This makes sense because it gives the impression the fuel pump is dead. I did the Passlock bypass with a resistor off the ignition to fool the security system. It didn't work.
Normally when it trips the security light flashes, wait ten minutes with the key in the on position and the security light goes out. Turn key to off and restart. Car runs.
This time the wife went to start the car and the Sevice Engine Soon light came on and the securit light. The security light was solid not flashing which indicates a total lock out. (Not Service Engine Light or CEL). "Service Engine Soon.
So, I cut the black and yellow wires as instructed and a 2200 resistor all tied to a terminal block which in turn goes to the BCM. Simple bypass. Didn't work so I put everything back to normal and crank the car. Security light was blinking. Goid I thought. Waited 10 minutes, tried to start the car and wouldn't start. The security light however went out. The only lights on with the car NOT running are the battery light the oil light and the "service engine soon" light.
I think the Passlock security system is still malfunctioning and denying fuel.
I have heard and read alot of horror stories about VAT, and Passlock systems.
Especially when it comes to mechanics replacing everything from ignitions to crank sensors when they haven't a clue about the GM crap Security systems.
The codes. I don't have an ODB2 scanner. The mechanic is going to do this job Saturday. I will be there to see each step.
How can I bypass the fuel pump relay? I will do that tomorrow night if it is explained to me.

[TedRamAirII]

Before getting in deep, you need a trouble code. With Passlock, it should be a B (body) code. I would get a code, and that will tell you what direction to start looking. When you turn the key on, the theft light should light, then off. A Scanner to show PID values is a must.

[GP67]

http://troubleshootmyvehicle.com/gm/...-fuel-pump-2#3

[GP67]

Originally Posted by TedRamAirII

Before getting in deep, you need a trouble code. With Passlock, it should be a B (body) code. I would get a code, and that will tell you what direction to start looking. When you turn the key on, the theft light should light, then off. A Scanner to show PID values is a must.

Got it. I'm actually going to be relieved if it is the fuel pump. The Passlock has been nothing but a PITA. . I bought the car used and I like it. Just the PASSLOCK I can do without. The new ignition with the hall effect is $285 stealership installed AND it's not a cure. I also fiund a AM2 keyless remote under the passenger dash connected to the BCM. I've read this is how some have gotten ariund the passlock and ignition alignment by not having to use a key. I'm still reading up on that. It may be the way to go.

["QUICK-SILVER"]

The key resistor is just one component in the passlock system. By-passing the key wont correct the problem if something else is wrong.
To by-pass the entire system you need to locate the relay that supplies power to the fuel system. It's part of the anti theft stuff not the normal relays that make the engine run.
I do not have a component locator for the grand am, so can't help with where it's at. Google search on that.
Once you find the relay: The ECM is suppose to ground the relay to turn it on. Ignition switch power and ECM ground are what trip the relay. If the relay is good, key on and a jumper to ground on the ECM wire should power up the fuel system.

It's been a long time and I would have to do some digging to come up with details on this.

Maybe someone else with more experience will chime in on this.

Good luck...Don't buy a pump just yet.
Clay

[GP67]

Thanks Clay. I hear the relay is in the steering column. Haven't confirmed that just yet though.
Maybe somebody will. I know just eniygh about electrical to be dangerous. But I'm learning.
Kudos to the internet. Got me through troubleshooting my ICM and got that done.

["QUICK-SILVER"]

Originally Posted by GP67

Thanks Clay. I hear the relay is in the steering column. Haven't confirmed that just yet though.
Maybe somebody will. I know just eniygh about electrical to be dangerous. But I'm learning.
Kudos to the internet. Got me through troubleshooting my ICM and got that done.

Last one I worked on was a newer f-body car. The relay on it was behind drivers side kick panel. Behind insulation and all. If not for seeing the wires going in would never have found it. Yes, on the back side of the metal that likes to cut the heck out of you. Hidden very well and makes um extremely difficult to take without permission.

Good luck again and keep us updated.
Clay

[TedRamAirII]

There is no relay to bypass the passlock system. Its not going to run until everything is working correct. If I had a trouble code, I could tell you where to begin diagnosis.

[TedRamAirII]

If you are looking for the fuel pump relay, its in the fuse/relay box under the hood. Easy to get to, and bypass.