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Discussion Starter · #1 ·
Okay:

So, I spent Saturday mid-day on my back at a local park, tearing the gas tank out of a MkIII. Pretty hot outside, mid-90's, but I was glad to help out a local FFR owner. I recently posted about one of our newest members in the KC area, "KCSHANER". Well, he had problems this weekend, and the car died at a local park.

Background/Setup:

He bought the car from the original owner last weekend. MkIII, built 18 months ago, 3300 miles on the car. 408, with lots of Edelbrock go-fast goodies, and carbureted. Not sure what carb. MSD ignition, not sure which ignition box.

Anyway, he was driving it Friday night, and it was behaving itself for awhile, then he noticed when he came to a stop at a stoplight and depressed the clutch, the RPMs actually came up a bit from idle, to, say, 1600RPM. Then after that, the car idled rough, and was dogging out something fierce at high-RPM load. Then Saturday, at the park, he called me and asked me to come look at it. He fired it up, it idled rough for about a minute, then died. After that, it wouldn't start at all. He noticed he couldn't hear the fuel pump cycle like normal, which threw me for a loop since I figured he had a mech pump hanging off the front cover. Not so much. So, I started tracing out wiring to make sure he had 12v to the in-tank electric pump, and he did have 12v and a good ground all the way to the tank. In testing the fuel pump by cycling the key several times, it would sporadically cycle, sometimes indefinitely, other times for a few seconds or not at all. Also, it sounded very weak when it would cycle.

So, I dropped the tank, pulled the fuel pump, and it looked like the donor EFI pump, but I figured it couldn't be, or his carb and carb fuel lines wouldn't be able to take the high pressure of an EFI pump. We called the guy that built the car, and he claimed he didn't remember what pump he used. KCSHANER went to the local auto parts store with pump in hand, and they cross-referenced some numbers on the pump to a 79 Toyota Corolla, or some such.

Now, I'm thinking if the builder used an oddball pump like this, he surely would've remembered what he used.

Does anyone know if a 79 Toyota pump would even fit in the donor fuel pump chassis, cause this one fit right in just like the donor pump?

And, based on his symptoms Friday evening, does a failing fuel pump seem reasonable?

He's got the fuel pump on order, and should be in Tueday, so I'll put it all back together at that point, but I'm not convinced this is going to solve the problem.

I sure wish the car was EFI, because I was absolutely LOST in the engine bay of a carb'ed car.

Anyone in the KC area want to turn some wrenches with me Tuesday night? KCSHANER is providing the beverages. I can get the car back together no problem, but I don't know beans about this carburetor stuff, and how to diagnose problems.

P.S. I did check the 1 or 2 vacuum lines from the dizzy to the carb, to make sure they were hooked up, as increased idle on my EFI car has been traced back to vacuum leaks in the past. That's as far as I got.

Thanks,

Greg
 

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Greg, Trace the fuel lines and make sure theres not a couple fuel pressure regulators on it. Does he still have a return line? I'm running a donor pump with my carb and I have a return style regulator and the a standard one behind that. Works great.
 

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Discussion Starter · #3 ·
Lex:

No return line to the tank. I traced the fuel line from the hard line at the front of the passenger footbox to the carburetor. No FPR, just the rubber flex line, rated at 18PSI, so it is a carb line. I guess it's possible the guy that built the car put an FPR on the hard line from the tank to the engine bay somewhere under the car, but I doubt it.
 

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Ive seen some low pressure in tank pumps that were sort of universal. I'd say thats what he used. Hard to believe the builder cant remember. Check ot that Toyota and make sure its carbed. Most imports by 1979 were EFI.
 

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Greg,

His best bet, will be to ditch the intank pump, and replace it with a section of tubing so it can reach the bottom of the tank still. Then have him buy a Carter external fuel pump through Summit. They also carry the Holley ones, but I've been told they are noisier, and sometimes problematic for a street car. A lot of guys on here run them, though, so they must be ok. Anyway, the only installation trick is to make sure that it is mounted as close to the level of the bottom of the frame as possible. This is because they are designed to push fuel, not pull it from the tank, so they can lose suction if parked on an incline when mounted too high (ask me how I know! :rolleyes: ). Since he already has the 12v. supply wire, back there, he can just lengthen it if necessary to reach the new pump, add a ground, and a couple of hose clamps, and he's all set! At least with the external it is very easy to diagnose if there ever was an issue, but the Carters are extremely reliable for a street car. Also a fuel filter should be put inline before the pump to protect it from any crap in the tank. I would also recommend another one in the engine bay right before the carb, because any particles in the fuel can get trapped in the needle/seat in the carb.

good luck!
Brian
 

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Originally posted by Lex:
Ive seen some low pressure in tank pumps that were sort of universal. I'd say thats what he used. Hard to believe the builder cant remember. Check ot that Toyota and make sure its carbed. Most imports by 1979 were EFI.
Hey all, its Derek...the one with the broken Cobra :(

First off, Greg, thanks again....you have been a huge help.

The pump is from a 75-79 Toyota Celica, we thought it sounded like it could be the correct pump because it is electric and a low volume pump, although I do believe its for an FI car. The picture in the cross-reference book looked identical. I definitely want to get this sorted out right so if anyone has any other thoughts and/or suggestions please let me know. I also want to change the fuel filter while I have the tank dropped.

Well, as Greg said I have lots of cold beverages in the fridge if anyone wants to come by, and I will include a link to some pics that were taken of my car on Sat. at the park.

Thanks again, Derek

http://www.weekendwarriorz.com/shaner.html
 

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I'll be flying in to Kansas City in about 3 weeks but it will be quick. I was raised in western Ks and taking a little trip to see my family.
 

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If the in tank pump is going to be retained (not recommended) then get one that is for a carb application and not an FI application. Get one that for sure does not need a return. I would do what Brian recommended and put an external pump on. Depending on how the lines are run it should be very easy. Take some pix of the set up and it should be one trip to the parts store to get what you need. Cheers Richard.

PS is the garage cooled as it will be about 100 on Tuesday evening with a dew point of about 75 so it will feel like 110 which is NOT a dry heat.
 

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Originally posted by Richard Oben:
If the in tank pump is going to be retained (not recommended) then get one that is for a carb application and not an FI application. Get one that for sure does not need a return. I would do what Brian recommended and put an external pump on. Depending on how the lines are run it should be very easy. Take some pix of the set up and it should be one trip to the parts store to get what you need. Cheers Richard.

PS is the garage cooled as it will be about 100 on Tuesday evening with a dew point of about 75 so it will feel like 110 which is NOT a dry heat.
Thanks, that would be great....maybe I could get this thing fixed tonight!!!!!!!!

I will head home over lunch and shoot some pics, anything in particular I should get a picture of?

Thanks, I am getting excited that it may be able to get done even sooner, and it will be an upgrade!
 

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Discussion Starter · #11 ·
Take some pics of the fuel lines and how they are plumbed, in the rear of the car, just above the tank. There are two rubber lines back there; a large on that was connected to the pump, and the smaller one was connected to the white vent nipple on the tank. Lay under the car, and snap a few pics of that whole area of the underbelly, then post them here. Or, send them to me in an email and I'll post them.
 

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Greg them carbs ain't so bad? Personally I like the mechanical pumps on carbed motors if your concidering a change. For now with what you have. Once the pump is back in the tank. Get a pressure reading. Very possible it's a low pressure pump since yotos did use them on some years. They also had carbed motors with electric pumps towards the end of the carb years before efi.
As for checking for this being the cause of running rough and no run. Easyest way to check on a carb motor is with engine off look down the carb bore. Moveing the accelerator should result in gas squirting down the throttle bores.
Engine running, a quick jab f the throttle should see the same. No gas here. Pump could be the problem. Holley or holley clone you can also remove the site glass plug and check for gas there. These would be quick checks to see if gas is reaching the carb. Pressure still needs to be chack looking for a min of 5lb and max of 7lb.
A higher then normal idle could indicate a too lean contition caused by the pumpas would the engine breaking up under load.

Do you have a fuel filter in line somewhere? If so check it. If not add one in line right before the carb. Do not rely on the in tank filter.
Hope the new pump solves the problem.
 

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Originally posted by gbranham:
Take some pics of the fuel lines and how they are plumbed, in the rear of the car, just above the tank. There are two rubber lines back there; a large on that was connected to the pump, and the smaller one was connected to the white vent nipple on the tank. Lay under the car, and snap a few pics of that whole area of the underbelly, then post them here. Or, send them to me in an email and I'll post them.
Will do, I will get them to you right after lunch....hey, just a few more posts and you're at 3,000 :cool: I have some catching up to do
 

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Originally posted by Hind Sight:
Greg them carbs ain't so bad? Personally I like the mechanical pumps on carbed motors if your concidering a change. For now with what you have. Once the pump is back in the tank. Get a pressure reading. Very possible it's a low pressure pump since yotos did use them on some years. They also had carbed motors with electric pumps towards the end of the carb years before efi.
As for checking for this being the cause of running rough and no run. Easyest way to check on a carb motor is with engine off look down the carb bore. Moveing the accelerator should result in gas squirting down the throttle bores.
Engine running, a quick jab f the throttle should see the same. No gas here. Pump could be the problem. Holley or holley clone you can also remove the site glass plug and check for gas there. These would be quick checks to see if gas is reaching the carb. Pressure still needs to be chack looking for a min of 5lb and max of 7lb.
A higher then normal idle could indicate a too lean contition caused by the pumpas would the engine breaking up under load.

Do you have a fuel filter in line somewhere? If so check it. If not add one in line right before the carb. Do not rely on the in tank filter.
Hope the new pump solves the problem.
Thanks for the reply....I hope I wasn't running the car when it was to lean :eek:
 

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Discussion Starter · #15 ·
Hind Sight:

I did blip the throttle with the car off, and no gas squirted into the throats on the carb.
 

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Discussion Starter · #16 ·
Okay, so I think I'll just use the "cap" that goes on the tank, and attach a hose to the underside of it, so it will pull fuel out of the tank. Then, we'll attach an electric fuel pump to the frame somewhere above the tank, and run the power and ground that used to connect to the top of the tank over to the new pump. I'll also put a new filter between tank and pump.

Sound about right? Only other thing I need to know is what pump to buy.

Thanks,

Greg
 

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Cheers Greg!!
 

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Hind Sight, I too would normally recommend a mechanical pump, but the reason I recommended the electric is that it is a way more straight forward and easy install for his finished car. A street electric pump is very reliable and easy to set up - especially since he already has the wiring in place. With a mechanical he'd need to get the correct timing cover, pull all the front accessories, and cover, then install the drive cam for the pump. Too much trouble to be worthwhile inmo.

Brian
 
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