Replace the fuel pump on your 84!!

[hdguy42]

I just wanted to share that even though my fuel pump seemily worked fine on my 84, I decided to replace it with a pump for an 85 through 89 c4 (as so many threads and tech papers recommend) and wow, was I surprised! It cured many ails that I had thought were caused by other things. I replaced mine with a Delphi 85 through 89 pump, and it's the best money I have spent on my corvette thus far. It cured a small stumble or hesitation away from lights, very hard starting when hot, my car now idles smoothly at about 600 rpm's, rather than 700-750, a rough idle when cold, and more!

For me.......fuel pump upgrade=best money spent!

Proud owner of a smooth running 84 coupe with 159,000+ miles on original everything that's driven daily, weather permitting!

 

[douglas foster]

father & son

WOW,
Sounds like some fo my problems, I have a hot start issue sometimes, and have to feather gas peddle to keep it idleing. also on cold start rough idle till about 117 degrees, then smooths out. Run fine, have 62000 now, but maybe indications of thing to come. where is the info on the pump change? Thank You

 

[hdguy42]

Hi Doug...

...Great looking car!

Hmmmm...sounds very similar to my issues! Can I suggest another thing if it's not been done, replace the coolant temp sensor. It's right above the water pump, front of engine, front on intake manifold. On your 84, it's a one wire sensor and many times the wires are burnt. The replacement is a two wire sensor. You need to buy the two wire plug also, which you'll easily se how it attaches. It needs to be soldered to the existing wire lead and use a lil' heat shrink tubing and don't to put the heat insulator plastic tubing back over it....wow, hope this makes sense. That will likely help your cold start rough running problem.

It's easy to do....a socket fits right over the coolant sensor to remove.

Best Wishes!

 

[hdguy42]

????

Doug....where abouts in MN?

 

[gmhowe]

Douglas,
Not

 

[gmhowe]

Douglas,
Not sure if the 84 is like my 85 but mine is located under the Gas Filler cap, take out the 10 mm bolts under the rubber boot and disconnect the Electrical and hose connections and just pull out the whole assembly carefully. Be sure the Strainer is put back the way it was or you will have problems later ( Like I found out the hard way )
Gordon

 

[grumpyvette]

IF YOUR LOOKING TO JUST REPLACE A DEFECTIVE PUMP ILL OUTLINE THE BASIC STEPS
its not necessary to drain the tank but its a good idea to do so,
step one have the parts on hand PLUS 3 ft of 3/8" fuel line and 1 ft of 5/16" fuel line , I know, you may not need the fuel line but in many cases its faster and easier to remove the old line and replace with new ones
hose clamps, youll want several 1/2" size for the lines

fuel pump
http://www.ecklers.com/product.asp?pf_id=30666&dept_id=1277

fuel pump screen
http://www.ecklers.com/product.asp?pf_id=30668&dept_id=1277

fuel filter
http://www.ecklers.com/product.asp?pf_id=A3479&dept_id=1303
(optional but a GREAT IDEA)
ok, step one,
make darn sure the keys are out of the car and the battery is disconnected for extra safety
step two, open the fuel fill door center rear deck where you normally fill the car and remove the gas cap
step three
remove the four very small torx screws in the corners and lift off the door assembly
step four
theres a rubber bib fuel spill tray)(around the fill spout, remove the gas cap and work the bib fuel spill tray ) (out , and disconnect the water drain line and label it with masking tape/pen
step five
label the three lines with masking tape/pen (upper line/lower line /left side line)
remove each at the central point in the opening, then disconnect the electrical connector on the lower edge of the opening
step six
remove the 8 10mm bolts and look carefully at where the components go, after they are removed the pump lifts up and out, the pump normally comes with instructions also, but its fairly simple, the pump, lines and fuel level sensor lifts out as a sub assembly, look thru the link below for pictures and more info




NOW IF YOU WANT TOO UPGRADE HERES A MORE USEFUL LINK WITH PART NUMBERS
http://www.caspeed.com/boschpump/boschpump.html
similar thread
http://www.digitalcorvettes.com/forums/showthread.php?t=92123

 

[douglas foster]

father & son

Woodbury< the Edina of the eastside

 

[hdguy42]

Love Woodbury.....

......I lived there for 22 years!! Hope to move back!

I'm over there all the time.....have a number of homes listed in the area!

 

[topless82vette]

Did you upgrade to high pressure efi hose in some places where there is low pressure fuel line? Just seems like a TPI pump could cause issues there and also TBI regulator gaskets and stuff were never designed for the higher pressure do they ever seep fuel?

 

[nmvetteman]

'84 fuel pump replacement

I just wanted to share that even though my fuel pump seemily worked fine on my 84, I decided to replace it with a pump for an 85 through 89 c4 (as so many threads and tech papers recommend) and wow, was I surprised! It cured many ails that I had thought were caused by other things. I replaced mine with a Delphi 85 through 89 pump, and it's the best money I have spent on my corvette thus far. It cured a small stumble or hesitation away from lights, very hard starting when hot, my car now idles smoothly at about 600 rpm's, rather than 700-750, a rough idle when cold, and more!

For me.......fuel pump upgrade=best money spent!

Proud owner of a smooth running 84 coupe with 159,000+ miles on original everything that's driven daily, weather permitting!

Hi hdguy....Can you tell me why replacing the '84 fuel pump with one for an '85 to '89 is the best choice? Why not just one for an '84? I'm getting ready to change mine out and saw your quotes here, so thought I'd ask before I bought the new pump. Autozone had the Delphi for an '84, but I hesitated buying it till I asked you.....And do you think Delphi is that much better than their stock brand which they claim is oem? Thanks....!!

 

[geekinavette]

The upgrade to the TPI pump is because it FLOWS more...which means that under heavy load it will not starve like the stock 84 pump can.

Changing to a higher flow pump WILL NOT have an effect on the fuel pressure (assuming the system is working properly). Pressure is controlled by the Fuel Pressure Regulator, not the pump. The higher flowing pump is simply more capable of maintaining the correct pressure under heavy load.

That CTS (Coolant Temp Sensor) is also another great suggestion...that thing is critical to proper engine operation.

 

[K & B Special Products]

84 Fuel pump

The upgrade to the TPI pump is because it FLOWS more...which means that under heavy load it will not starve like the stock 84 pump can.

Changing to a higher flow pump WILL NOT have an effect on the fuel pressure (assuming the system is working properly). Pressure is controlled by the Fuel Pressure Regulator, not the pump. The higher flowing pump is simply more capable of maintaining the correct pressure under heavy load.

That CTS (Coolant Temp Sensor) is also another great suggestion...that thing is critical to proper engine operation.

This is incorrect. OEM fuel pumps for the 82-84 Corvette were set to 12-16 pounds of pressure. 85 up went to fuel injection and 30-40 pounds of pressure. An 85 up pump will damage the fuel system on an 82-84 Corvette, sooner or later. All OE pumps flow the same.

 

[ex-x-fire]

The regulator makes the pressure.
Using a 85 pump in a 84 will not have higher pressure unless you have a restriction in the return line. Dead headpressure is when there is a complete blockage.
Alot more fuel will be returned to the tank (in the return line) using an 85 pump.
The regulator sets the pressue, the pump makes the volume.

 

[geekinavette]

This is incorrect. OEM fuel pumps for the 82-84 Corvette were set to 12-16 pounds of pressure. 85 up went to fuel injection and 30-40 pounds of pressure. An 85 up pump will damage the fuel system on an 82-84 Corvette, sooner or later. All OE pumps flow the same.

:eyerole It most certainly is NOT incorrect.

Pumps do not create pressure, they generate fluid flow. Pressure is a result of flow (pump) and restriction (fuel pressure regulator) in this application.

To prove it: connect a fuel pump output directly to a "T" fitting, connect a gauge and an open hose to the other two ports of the "T" fitting. Set the open hose into a container to catch the fluid and turn the pump on (doesn't have to be fuel...be safe!). As long as your "T" fitting and hoses are not restrictive you will measure zero pressure. (in the real world there is no such thing as zero restriction, so you might measure a slight amount of pressure depending on the size and length of the output hose, but probably not)

These (positive displacement) fuel pumps are flow-rated (for example gallons per hour, liters per hour...etc) at some pressure. This pressure rating of a fuel pump is the maximum pressure at which the pump is capable of delivering the specified fluid flow rate, it can run at any pressure from zero up to the specified maximum. Above this maximum pressure the pump is not guaranteed to deliver the specified flow rate. That flow goes through a restriction (fuel pressure regulator), between the pump and that restriction is where your pressure will be measured, and of course where the fuel injectors are connected. Between the fuel pressure regulator and the tank (return line) pressure is zero. Basic physics.

For example see this Fuel Pump Technical Data document published by Bosch: http://www.bosch.com.au/content/language1/downloads/fuelpumps.pdf. Notice the pumps have a specified flow rate at some max pressure. Also note these sentences in the opening paragraph:

"the pump cannot produce pressure unless it is acting upon a
restriction. The only restriction in the system should be the fuel pressure
regulator. The regulator controls the system pressure; the pressure ability
or flow volume capacity of the fuel pump will not alter the system pressure."

(Note: the 250-350 Kpa they mention equates to approximately 36-58 psi)
The FUEL PRESSURE REGULATOR is set to 12-16 on the '82 and '84, and 30-40 on '85-up...NOT THE PUMP. I don't know the exact flow rate/max pressure specs on the '82/'84 v. '85-up pumps, but guaranteed the 85-up will have a higher flow rate spec.

The masses that have been running TPI pumps on L83 engines for 10+ years (that I know of personally, probably longer) problem free would disagree with your last sentence.

 

[K & B Special Products]

Fuel pumps

We sell & manufacture fuel senders & pumps for both Ford & GM from 1960 thru 2000 models. There is a difference between pumps. The regulator does not set pump specs.

 

[geekinavette]

We sell & manufacture fuel senders & pumps for both Ford & GM from 1960 thru 2000 models. There is a difference between pumps. The regulator does not set pump specs.

Not to me you aren't! I don't do business with companies that don't know how their own products work.

Over and out.

 

[K & B Special Products]

Not to me you aren't! I don't do business with companies that don't know how their own products work.

Over and out.

I'm pretty sure we know what we're doing as we supply all of GM's senders from 63 to 96 as well as AC Delco's senders & Delphi. But by all means chose whomever you want to buy from. Last I heard, you have a choice.