Suburban fuel pump replacement
My noisy fuel pump finally quit and blows the ECM fuse when turning on the ignition switch which tells me the fuel pump relay is shorted out. So I need to change the pump and relay but my 1999 unit is almost 10 years old and has 30G of gas in the tank. There is no way to drain it (250 lbs) which will slosh around while dropping it so I want to replace it in the truck.
Why didn't GM put a removeable panel under the carpet to access the pump from above? And you think this one is hard, the later Camaros and Firebirds have to drop the rear axle to drop the tank!!
My plan is to cut the floor and replace from above,
then replace with a galvanized metal sheet, sealed and popriveted in place.
Anyone else out there done this??
Any comments or suggestions??
Why didn't GM put a removeable panel under the carpet to access the pump from above? And you think this one is hard, the later Camaros and Firebirds have to drop the rear axle to drop the tank!!
My plan is to cut the floor and replace from above,
then replace with a galvanized metal sheet, sealed and popriveted in place.
Anyone else out there done this??
Any comments or suggestions??
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Seems like you are making an awful lot of work for yourself to cut out the floor.
The older noisy pump died shortly after installing a Whipple supercharger on the GMC to help tow my 7k trailer easier....492 torque. The pump couldn't handle the added boost needed.
When you checked for fuel coming out of fuel line was your engine running or not? I guess not as the pump quit?
When you turn the key ON the pump comes on only for a couple of seconds if you do not start the engine. Fuel pump will not run constantly with key in ON position if the engine is not running.
When you check for fuel being present in the fuel rail it should even when the pump is not running because the pump charges the line during the brief moment it runs. If you do not have any fuel pressure in the fuel line after you just turn the key ON it simply means that either your pump is not working at all or fuel regulator does not hold pressure.
After replacing fuel pump numerous times I would not think the pump is the problem (even Mr. Murphy would get tired of this) so it leaves you the fuel pressure regulator to check. If the regulator is bad it does not matter how many pumps you replace. It will not work until you fix the regulator issue.
There is a chance that you really "destroyed" several fuel pumps during the process you have gone thru. This could be possible if there is no fuel back pressure in the fuel line due to pressure regulator problems. This could let your fuel pump to operate on much higher rpm that it is designed for. This may be a far fetch but could be possible.
Step 1 for you is to replace the fuel pressure regulator and then the pump again if needed. Of course you need to check/change the fuel filter too but they seldom fail in a way that no fuel get thru them at all.
Arrie
Your engine is designed to run if 4 basic thing take place.
1. Your engine gets air.
2. Your engine gets fuel (at correct spray pressure)
3. The spark plugs have good spark.
4. Spark plug firing is timed correctly.
1. Your engine carburetor probably has an idle air valve. Idle air valve is used to control your engine's speed when you take your foot off of the accelerator pedal. With foot off of the pedal the air intake butterfly valve of the carburetor closes and air that engine needs for running idle enters engine thru this idle air valve that the computer controls for correct idle speed. This is also the route for air when you are starting the car, i.e. when your foot is off of the accelerator.
Problems with idle air valve should show up also with engine cutting off when you are driving and come to a stop with foot off of the acc pedal but it also could be that the valve is failing so that when engine runs it can pull enough air thru the valve but when you are starting it is not getting enough air.
To check for this is simply to open the throttle valve by pressing slightly on the accelerator pedal when starting. If it starts then the problem most likely is with the idle air valve.
2. You mention that your spark plugs get wet with gasoline so definitely engine gets fuel. The question is if it comes in at correct spray pattern, i.e. if fuel pressure is too low or injectors are too worn out (seldom happens) fuel spray might not atomize to fine enough mist for it to mix correctly with air to fire up.
There is a fuel pressure check point in the fuel rail. You need a special fuel pressure gauge to check it. Just to rule out fuel pressure regulator as a problem I would change it. Part probably cost about $20.
3. You mention that spark plugs have spark but is it timed correctly? I don't know a '99 engine spark timing. I think it still use distributor? If so, it has a vacuum or electronically controlled timing adjustor which retards spark timing when starting the engine. Make sure this moving part inside distributor freely returns to spark retarded position, i.e. if spark is too much advanced for starting the engine it would have problems starting up.
Also, even when you see a spark make sure spark is strong enough, i.e. it is a good blue colored spark. Sometimes spark is present but not "hot" enough for firing up the engine.
If your spark is too weak check that the ignition coil is not bad, i.e. it does not have a leak in ground etc. Ignition coil should not cost much at all to replace ($60 or so) so this is something that could be done just to rule it out.
Another low cost easy "rule it out" is to change distributor rotor and cap.
Arrie
Arrie is correct, change the cap and rotor and check when the last time the fuel filter was changed. The fuel pressure can be checked at the port on the line using one side of a AC gauge set (R12or R22) and should be around 52psi.
Good luck....
McGyver
I don't think a '99 is a "fly-by-wire" yet, or is it?
Arrie
I purchased the replacement at a local parts store. last weekend while traveling home from visiting family are truck broke down on the highway.
are mechanic says its the fuel pump. i told him it was already replaced not too long ago and that it had a life time warranty. he said that they do not use the Carter brand because they don't last in GM trucks. I aslo talked with a different parts store and they told me the same thing, they do not recommend Carter fuel pumps for GM trucks!!
has anyone experienced the same thing??
does anyone know of this??
Thanks
bready.
The Carter pumps are loud, the A/C Delco are quite. I wish I could get a pump that would last as long as the orginal pumps did.
I have a 2000 Chev Suburban 1500 2wd.
Just a thought.
By the way, I was advised to keep the fuel tank at least a quarter full so that the fuel pump does not have to work so hard and apparently this way will last longer.
____________________________________________________________________'
A friend of mine who has a fleet of GM work vehicles was told by a GM rep to keep the gas tanks at least 1/4, better yet at 1/2. Seems it helps to keep the pump from heating up which is a major cause of pump failure.
I'd go with the Bosch pump if it were mine to do again. Also check the regulator or kinks in the line causing extra work on the pump that may cause premature failures. The running pressure is normally around 52psi at the check port.
Good Luck....
was this in a Suburban? if so can you give me an idea where the hole is cut? thanks
which causes lots of havoc with electrical systems. Then check all your plug connections for a firm positive feel. When there is no operation, check the hot side of the fuel pump relay for voltage going to the pump. If there is none there you may have a bad ECU which sends a signal to send voltage to the pump.
Good luck.....
notech
Many thanks
Took it back to the shop that replaced the pump and they checked the error code, which was a 420 code - Catalytic Efficiency incorrect.
I am now told that I need to replace the driver side catalytic converter.
Seems to me that we are fixing the problem, but not addressing the cause. If the engine is runnig too rich, it would cause the catalytic converter / 02 sensors to be reading a bad catalytic converter. They can't tell me what caused the mileage to go from 16 to less than 10.
Has anyone run into this problem? Talked to the dealer and they thought there could be a couple of injectors stuck open. I am also reading online that one sign of a fuel pressure regulator being bad is dramatic drop in fuel mileage.
The old fuel pump was only putting out about 25 lbs in pressure, and I'm wondering if that could have caused the fuel pressure regulator to go bad.
Any ideas before I let the repair shop go on a fishing expedition?
Thanks
Thanks for the update. I had to replace the pump in August and had to buy it at Autozone $300+ as it was the flex fuel pump. My Suburban is not flex, however, that is the pump it uses.
I will check on Amazon and see how much less it would have been. I know I will need a new one in 100K miles!!
Thanks again
Zr1george
I have owned 2 suburbans and in both of them I cut an access hole through the floor right over the pump replacement location and replaced the fuel pumps ...Simple job with an access hole !! Why do you suppose GM didn't come up with the ideah ???