fuel pump problem

[Typhoon #2131]

Ok so I put the fuel pump in Sunday. It started right up so I took it around the block and it ran the best it has since the new motor. We packed up the garage sale and decided to take it for a spin to get gas and to my brother-in-laws house to check on things as he is on vacation once again it ran great. Got up this morning to go to work and I had a hell of a time getting it started just like before but it did finally start. Took off ran great went another 3 miles or so went to get on the freeway and all of a sudden it starts falling on its face and chugging can't get it over 60mph. I baby it 26 miles to work trying to stay out of boost get off the freeway and every light I try taking off from it would go fall,go fall, go fall. So I feather it get to work and then the same exact thing coming home. you step down on it any at all and it falls and almost dies try to pull a hill the boost starts to go up but RPM'S and power don't. I don't get it and I'm very frustrated. Can it still be the pump even though it went 10-15 miles and ran perfect? Oh yeah and I put a bottle of 108 octane boost in it for the trip home and it didn't help much. Sorry for the long post just trying to give as much info as I can... PLEASE HELP.

 

[blacktyaffair]

Re: fuel pump problem

First thing I would do is verify fuel pressure. Hook up a gauge and go for a drive. Did you reuse the fuel pulsator when you replaced the fuel pump? Let us know what you find.

 

[turbodig]

Re: fuel pump problem

Did you replace the sock in the tank and the external filter when you changed the pump out?

If you bought an ebay Walbro pump, beware. They're notorious for Chinese knockoffs = early failure.

 

[Typhoon #2131]

Re: fuel pump problem

i did change the sock. i did not change the little rubber hose and 2 hose clamps that came with the new pump. I didn't go with the walbro I went with a Carter 74074 pump. said its for the typhoon and also corvettes. I have a buddy coming over tonight after he gets off work with a fuel pressure gauge and a computer scan. However not sure the scan will do us much good because it has never set a engine light. But I will keep you up dated

 

[Typhoon #2131]

Re: fuel pump problem

First thing I would do is verify fuel pressure. Hook up a gauge and go for a drive. Did you reuse the fuel pulsator when you replaced the fuel pump? Let us know what you find.

If the pulsator is that little hose with 2 clamps yes I didn't change that out.

 

[V6 Kompressor]

Re: fuel pump problem

I've had a few of those same carter pumps fail within a year of each other. they are a stock equiv. rated at 50 psi @ 38 gph. Check your fuel pump relay and fuel pump ground too. I change the relay everytime I change a pump because of age. If your gauge has a long enough hose, tape it to the windshield and drive it. I also sometimes drive with a timing light taped to the hood to see if the ignition cut's off too. That technique is reserved for hard to find, don't know if it's fuel or ignition problems... That might be cool to try at night, then again, getting pulled over wouldn't lol...

 

[biggeolb]

Re: fuel pump problem

I think its a 2131 curse! my 92 #2131 does everything you say your has done. I have changed everything that has been suggested and to no success. still does the same thing. I dont have the time to mess with it but i will keep it as long as it takes.

 

[Typhoon #2131]

Re: fuel pump problem

I've had a few of those same carter pumps fail within a year of each other. they are a stock equiv. rated at 50 psi @ 38 gph. Check your fuel pump relay and fuel pump ground too. I change the relay everytime I change a pump because of age. If your gauge has a long enough hose, tape it to the windshield and drive it. I also sometimes drive with a timing light taped to the hood to see if the ignition cut's off too. That technique is reserved for hard to find, don't know if it's fuel or ignition problems... That might be cool to try at night, then again, getting pulled over wouldn't lol...

LOL yeah getting pulled over would be par for the course. However I just might try it a ticket is cheaper then a motor and I just got this one going after 10 years of sitting in my garage because it leaned out and blew up. What should the fuel pressure be? Also where is the relay?it probably has never been changed. All I know is it ran alot better before I changed the pump.

 

[Typhoon #2131]

Re: fuel pump problem

I think its a 2131 curse! my 92 #2131 does everything you say your has done. I have changed everything that has been suggested and to no success. still does the same thing. I dont have the time to mess with it but i will keep it as long as it takes.

Well please let me know if you figure it out and I will do the same.

 

[Typhoon #2131]

Re: fuel pump problem

There is an electrical connector at the top of the sender. The harness inside the tank plugs onto the connector at the top. These connectors are notorious for melting, and becoming resistive. Airtex has a replacement harness for the S/T-10. About 10 bucks.

when you changed the pump, you may have disturbed the connection enough to make it run OK for an hour or so. But then it became resistive, and problem is back. This may or may not be it, but I've found enough discolored connections here that I now change this harness with every pump change.

If you had a little hose and two clamps, a previous owner or tech has previously changed the pump, and eliminated the "pulsation damper". I haven't heard of one of these being found for years. Remember, these are almost 20 years old. The pump has been changed at least once by now.

I would change the hose to the one supplied with the pump. A special type of hose is needed for total immersion in ethanol-laced gasoline. If both the inside, and outside aren't a 'plastic' feel, it will melt in ethanol gas, and you will have all the symptoms of a bad pump, and you will be taking it out yet again....

so are you saying to eliminate the pulsator with the hose and 2 clamps that came with the new pump? And no I didn't use the new wires that came with it either. I guess I like pulling the tank to much to do it right the first time...

 

[Quickstop [UK]]

Re: fuel pump problem

stock fp is 42 psi, relay is the furthest one right on the firewall. grey and orange wires going to it.

 

[Typhoon #2131]

Re: fuel pump problem

stock fp is 42 psi, relay is the furthest one right on the firewall. grey and orange wires going to it.

Great thanks for the info. Still waiting for the guy to get here with the gauge. I will give update asap.

 

[SY2932]

Re: fuel pump problem

This is what a pulsator looks like:

"Pulsator that is removed during fuel pump swaps, the short length of rubber hose is used to replace it. Hose gets clamped from the output of the pump to the fuel line on the sending unit."

The fuel line that connects the fuel pump to the sending unit needs to be spec SAE J30R10 since it can be IMMERSED in gasoline as DaveP mentioned. If not, it won't last. SAE J30R9 which is for inline use is only meant to have gasoline on the *inside* NOT the outside. This is what another member's looked like when he pulled it out:

I agree with DaveP, you have an electrical issue. My guess would be a ground problem. When I redid the sending unit wiring on my old daily driver S10, the ground coming off the sending unit *looked* good until I gave it a little test tug and it busted clean off...

 

[The_Bronze]

Re: fuel pump problem

However not sure the scan will do us much good because it has never set a engine light.

A bunch. The scan tool is going to show you fuel trim, engine load, ignition retard, vacuum (via map) and more. Enough to have you going in the right direction. I mean if the fuel trim (Block Learn) is around 128 driving down the road and the O2 sensor is swinging along happily, then you can MOST likely assume it isn't fuel. If the O2 sensor is hovering around 100mV and the Block Learn (and intergrator) is around 150-160 than the vehicle is adding a ton of extra of fuel and that's where you are going to be looking first. Of course, with Datamaster, you can beam that info into our hands for a look-see...

Not saying I wouldn't be checking fuel pressure first, but if it was a TBI I sure would be checking data first.

A link to Block Learn: http://www.gnttype.org/techarea/faq/BLMINT.html

 

[Typhoon #2131]

Re: fuel pump problem

Thank you guys for all the Info. you have helped me a lot now I guess its time to go out and get to work on it once again. I will give progress report soon.,

Denny

 

[Typhoon #2131]

Re: fuel pump problem

Well my buddy just left with his fuel pressure gauge. When we turn the key on it has 4 lbs fuel pressure when we cranked on it it got to 14 lbs and as soon as we let off the key it hits zero right away. We cranked on it hard 3 or 4 times and it didn't try to start even once. So out it comes for a second time.

 

[Typhoon #2131]

Re: fuel pump problem

well Time to go out to the garage and pull the gas tank and change out the pump once again. Maybe this time it will work right and I can get it on the dyno this week.

 

[Typhoon #2131]

Re: fuel pump problem

Here's a few ideas. Learned with experience. Some have been mentioned above:

• Be sure the sock isn't jammed into the bottom of the tank. Measure using a tape. Bend pipes if needed.
• Be sure the tank is completely free of debris. You can use a siphon hose to "vacuum" any debris from the bottom. Use a paint-strainer to re-cycle the fuel back into the tank.
• Use the special hose for immersion in gasoline.
• Double-check the pass-through electrical connectors at the top of the sender.
• Use only a known Genuine Walbro pump. There are Chinese counterfeits all over the internet. Beware.
• If in doubt, hang the pump/sender assy into a bucket of fuel, attached to plumbing. Check pressure with a gauge.

Thanks Dave I will check all that. I sure as hell don't want to have to pull it a 3rd time.
I will let you know how it goes

 

[Typhoon #2131]

Re: fuel pump problem

Here's a few ideas. Learned with experience. Some have been mentioned above:

• Be sure the sock isn't jammed into the bottom of the tank. Measure using a tape. Bend pipes if needed.
• Be sure the tank is completely free of debris. You can use a siphon hose to "vacuum" any debris from the bottom. Use a paint-strainer to re-cycle the fuel back into the tank.
• Use the special hose for immersion in gasoline.
• Double-check the pass-through electrical connectors at the top of the sender.
• Use only a known Genuine Walbro pump. There are Chinese counterfeits all over the internet. Beware.
• If in doubt, hang the pump/sender assy into a bucket of fuel, attached to plumbing. Check pressure with a gauge.

Fuel pump fixed. runs good and strong when you do it the right way. The pulsator had come off the pump so we took it off threw it in the garbage and put the hose and the two hose clamps on and it runs. Now it is off to get dyno tuned tomorrow. Thanks for everyone's help on this problem.



Thanks Dave I will check all that. I sure as hell don't want to have to pull it a 3rd time.
I will let you know how it goes