Hello, new guy here. I just recently won this car at an auction.









Lovely car, looks great, its all there. 700-R4 shifts fine, engine hums wonderfully. Runs like a sowing machine. The issue is though is it being an auction, obviously something has to go wrong right? In this case, upon turn key you can hear a loud prime of the fuel pump. Fine, that's whatever. It starts perfectly and rolls and drives. For a good two minutes. Afterwards, it has symptoms of a starved fuel pump. I realize a noise is roaring behind my two seats underneath the bonnet that stores the tonneau cover. I stop the car, then it stalls. Okay, fuel starvation. I put it on stands and look underneath to find a fuel filter. The filter is not where they usually are, tucked underneath the driver-side door-side. Instead, the fuel lines follow up the frame, attached to a big cylinder, out the back of that cylinder the fuel line then circles back around to above that cylinder, attaching to the fuel filter. All of this is hidden behind a shield by the way that sits above the exhaust.




After asking what the hell is going on, i was able to remove the shield and get a closer look. Upon turning the key, the bottom cylinder whirrs. That's the fuel pump. That's why my fuel pump is so damn loud, its external! It has no branding and the fuel filter looks like a 5 dollar tin barrel 3/8ths male end on both ends filter you get from AutoZone.




So my question is why did they make it external fuel pump? I don't think it is factory and I don't know if AutoForm did this intentionally. I imagine my symptoms literally stir from the fuel because it acts like its starving. Upon hard acceleration after warming up for a good two minutes it will jump and lurch and act like its dying from no fuel. Upon gas pedal release, its all normal and coasts fine. Sputters upon acceleration. Am I correct with my assumption? If so, What fuel pumps and filters do you guys recommend? I guess ill be sticking to external since its all done. Nicely done actually.
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Update! the fix was replacing a clogged fuel filter. The rough running issue has been solved.

 

Thats most likely an aftermarket setup a PO installed. If the car was originally carbed it would of had an engine mounted fuel pump. My 67 used to have a holley red external pump and it sounded like a giant bee in the car. I swapped it to an in tank pump and now its silent.

 

I thought it was po work. I don't hate it, and I will be doing things here and there to help bring the car out better. I wouldn't use a holley, I know they are loud as hell and it only makes at most 190hp. I'm going to get a gauge and measure my pressures. I suspect the pump dosent even put out 45psi. Also, does that sound normal to you? Fuel filter before fuel pump? Because I know these had tank pumps then it went to the fuel filter before the front of the car.

I know too that the car WAS carburetor driven then swapped to TPI sometime later. It starts and sounds good. Just under load once warmed up it lags. Parked for now to prevent damage from being lean or burning out the pump. At the moment im replacing the filter. Napa and AutoZone didn't even have 3/8ths filters. The world we live in.

 

that pump looks like a Bosch from something like a 1980s Volkswagen or Audi...

 

Precisely. Something that came off of a beetle or more importantly, something carburated. If it's not even rated for fuel injection I guess any upgrade to the fuel pump would be bennificial. The question then would be what brand would be recommended? I've never played with external pumps or specific brands. I just usually went OEM on vehicles on in tank pumps. But here, nothing about this is OEM. Just wana approach this from the best angle.

As I said, filter first. Then if it needs it, pump. But what pump? So many to choose from.

 

That looks like a pump designed for in-tank installation. They don't last long outside the tank (no liquid bath to keep it cool).

You will have a hard time getting any external high pressure pump to last long outside of a tank. If it is just an occasional driver and never more than 20 or 30 miles from home maybe I would keep something like what you have now, but for long term reliability you need an in-tank or sump mounted mount.

 

I'll look into this moreso. I've read back and forth on reliability. Both for external pumps and internal tank pumps. GM seems to have been having issues with these tank pumps as many times as I've been seeing them appear on the forums, people claiming to change them out annually with less milage than what calls for an oil change. That could also be because of the general mess of wires people had on these cars as teenagers and the lack of driving. I don't mind external being its right there and I can keep one or two in the trunk. I won't need to drop the rear axel and wheel hub and fight with the awkward tank.

Ill research in tank pumps more, but I understand the general trade off. If you have brand suggestions I'd be happy to consider it.

Edit: since the vehicle was converted to TPI from carburation, wouldn't that mean the oem in tank pump wouldn't work on this car as is with the TPI installed?

 

Pump is probably meant for port injection-German cars started EFI around 1975 That pump may be well suited to the aplication-original TPI pumps are smaller that that one on the car-just need to see if fuel pressure is up to specs at the fuel rail under all conditions.I have seen that style of pump used in the tank and outside.There might be P/Ns or other identification under the foam sleeve of the mystery pump.I once salvaged a frame-mounted port injection suitable pump from a wrecked 1986 Ford F-150 with port injection 302: do not know the specs.

 

Well im starting to realize what the smoking gun is that made the po have this done to the car. The car was 4 barrel beforehand. The owner had it converted to TPI. I'm under the assumption that the oem tank pump was not up to spec anymore and instead of upgrading the tank pump and doing alot more work, they opted out with a bypass for the external pump.

As for the pump we're looking at on this Autoform, wouldn't that mean that the pump potentially is already dying because it just wasn't adequate for the job since German cars were a bit smaller in the 70s? We're talking beetles here, not Mercedes. I might at this point drop the tank anyways to see what the hell is going on. If I do that, it could just be a greenlight to do the job correctly. But I am unsure what I would have to get to make sure it works for TPI and my gauges.

 

Find if the engine bay fuel system has a Schrader valve connection. After you replace the filter (jot down PN on the pump) hang a pressure gauge on the system for base fuel pressure. If it isn't 2.5 bar, the TPI injectors will need a pump for the (too low) pressure, or tune / pressure regulation update for too high.

if baseline pressure is okay, and you can set the gauge so it is visible for a drive, that's an easy way to monitor pressure drop under load. Your current pump may have info by PN that tells you rated pressure. GM in the 80s was rating injectors at 2.5bar pressure and ford by higher.

To the best of my knowledge, 83 4bbl V8 models didn't automatically get an in-tank pump. Some 80s carbed models did get an in-tank pump. At this point, the car isn't atock and it doesn't matter.

If you can pull a stock later tank, sending unit, and all lines from a salvage car, that's a great way to go. I have used third gen fuel lines for the high pressure side to retrofit EFI into other vehicles. I can't remember if the lines on the TBI models were identical for fuel hose fitting locations underhood, but they are high-pressure ready, so parts from a TBI salvage and a port model pump would work. Later models or new aftermarket may have better tank baffling. Based on the age and unknown history, dropping the tank to inspect all pickup and hose parts is strongly advised.

Cool car!

 

The non HO (lg4) didn't get an in tank pump in 82-83. You can run an inline pump/filter for the TPI in it. You need a high quality pump and unrestricted return lines. Even a quality inline pump will run too hot it the return flow is restricted. My 82 had an inline pump for years. The pump and filter was under the rear seat where the lines run. The pump only lasted 3-4k miles because it ran hot. The lg4 cars have a 3/8 feed line and a smaller (5/16?) return.

The pump placement in this car is not ideal, if it leaks it's gonna leak all over the exhaust.its proximity to the exhaust will heat the fuel pump more. An in tank pump is ideal but an inline can be made to work if you match the flow to the fuel requirement well and allow it to run cooler.

 

This is wonderful insight. Ill be sure to check the fuel system, see if the valve is there. The filter comes in tomorrow so I will be working on that. If what you say is true, what's the chances that this pump that's on it is actually what came with the car? It surely cant be, people are claiming they've seen these pumps on European vehicles. GM was trying to beat Europe not join them so I imagine the pump and fuel filter are put in during while the TPI work was done. Ill look around the back of the plate and see if the valve is still there. Watch this be an o2 sensor issue.

As for Firechicken, yes its 3/8ths and 5/16ths return. I was thinking while at work today if there is a better spot to place the external pump if i decide to keep it this way. Its definitely not going to be a commute. I drive between two towns for groceries and errands and its so post to be the Sunday car now. I've been eyeballing fuel tanks from 85 thought that have the rails with the and the 3 wire. 500 bucks I saw one. Wonder if there's better spots in a junkyard. Well the saying can be true, you get what you pay for so might be a decent idea to just pony up.

 

Hehe, looked up fuel pump for a 1977 beetle with optional fuel injection and it looked identical to what you have on the car Do you know what TPI was installed? is there a MAF in the air intake duct?

 

If this was my car there is only one way to do this and that would be source the proper parts to set it up the way a TPI car would be. Internal pump. TPI needs specific pressures to function properly. The looks of that HP pump externally mounted with hose clamps just make me cringe. The car looks to be in great shape and outside the graphics I like the look of this car.

Do you know if they swapped a complete TPI motor or did they just put the top end on it? The reason I am asking is with TPI comes an array of sensors that need to be controlled by the proper ECM.

We usually see peeps wanting to ditch the TPI for a carb, this may be the 1st time I am seeing the process reversed.

 

So they took the top of an EFI end and stuck it into the car along with potentially some other work. Also I was horribly wrong, it is not TPI. It's just EFI. Two sprayers down into the dish, like a throttle body. I was misinformed by someone saying it must be TPI. No. It's just EFI. I'm sorry everybody.




Update! The fuel filter came in and I changed the fuel filter. The car is fixed! Runs perfect. Cycles through all four gears lovely and boy it kinda scoots! I plan on dropping the tank and investigating how this is set up sometime. I'm also going to run some injector cleaner through the fuel system too, make sure it dosent clog back up and inspect the tank sometime soon. As for now, it rides beautifully. Thanks for the insight guys. I'll be sure to consider the following that was said here.

Till then, the hair flys high.

 

There dosent seem to be a MAF in the duct. I see something for the smog system but that is all. I will have to Desmog this when I put H pipes on the car one day, let the 305 breathe. I'm looking into alternatives for the pump, even though my issue is solved now from changing the fuel filter. Being proactive is key to keeping stuff nice.

 

Glad you got it running right. The above various comments have all been good recommendations. Also, I can't tell from that pic if you have a carb or throttle body EFI. Those both require a lot less fuel pressure than TPI.

 

it has the two injectors below that air filter. I'll show it tomorrow when im home from work. As for the suggestions, they are great ones. I'm going to look at the options and try to structure a road map for the car. Like fuel tank swap, desmog and exhaust. It rides like a Cadillac at the moment. Very smooth for the chassis. I own a 2011 Mustang California Special and a 1987 Chevy sprint turbo and this car is by far the most comfortable. Pleased with it and how it rides.