Changing 84 Fuel Pump to an 85 Model - Any Difference? Mike's 84 Corvette
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- čas přidán 15. 04. 2021
- I've read that switching to the upgraded 85 fuel pump can help with fuel flow, drivability, and performance. I gave it a try.
- Auta a dopravní prostředky
Nice install Mike, haven't had fuel pump issues yet on my 84 but if I do I will know how to fix it. Thanks, Jack.
Thanks for watching. It's an easy job!
Hi Mike, thanks for the video, looks like a easy job. Going to replace mine tomorrow. I Look forward to more videos from your channel.
These videos are SO helpful, thank you!
Thanks!
I always run TPI pumps in my CFI cars. Even on a stock LU5, it will lay down above 4000-4200rpm with a stock LU5/L83 pump. I run the TPI pump and adjust my FPR up to 13-14psi on a stock or mild car. The difference in volume from the TPI makes a huge difference in top end, as well as off-idle response.
Thanks for the info! I feel like it's a great upgrade.
very nice job mike! I want one of these cars so bad but I have to be patient as you know
Thanks!
The reason you replace the 84 pump with the 85 and newer is so you can increase the fuel pressure. I set mine to 14psi. It's not faster just better throttle response
I can definitely feel the better throttle response!
You can increase the fuel pressure while running the stock LU5/L83 pump as well. I’ve had my fuel pressure adjusted up to 14psi with a stock pump many times. The TPI pump swap is more to gain an increase in volume.
I’m not sure this sounds like a great idea. I’m currently working on a 1984. Did an injector, fuel pump and filter along with replacing all ignition and about to balance TBI’s with manometer. Higher pressure pumps were invented before 1984 yet GM chose to go with a low one. I assume the regulators will keep fuel pressure to the injectors the same and line pressure low too? From what I’ve seen the 1984 rubber lines are a set up for low line pressure only. Especially the fuel filter connections. The TBI system seems very simple with few sensors and the computers almost total reliance that all parts are stock and functioning optimally to achieve proper fueling. I’m also suspicious that a higher volume pump may stress the regulators over time.
All good points. I've been running the 85 pump for a year now with no issues. This mod also seems to have fixed a hot start issue I had where the car would start then stall when hot. I guess time will tell if there are any adverse affects. Thanks for watching!
Correct me if I am wrong but doesn't the fuel pressure regulator need to be adjusted to take advantage of the 85 pump setup?
I believe you need to increase this by about a pound or 2?
You are probably correct. I did not do that. But I do feel the engine is benefitting from the increased fuel flow. I used to have a problem where it would die after a warm start. With the new pump - haven't had the problem at all. Fingers crossed.
@@Mikes84Corvette I'm in Tacoma Washington You?
I got a 84 back in July. How has the fuel pump working? I need to replace mine for the same reason you replaced yours.
No problems at all.
Another good video and relevant to what I will be working on soon. Have you rebuilt your throttle bodies?
Thanks for watching. I haven't rebuilt the throttle bodies - yet. My car seems to be running good - but I'm getting the itch to see if it will run better with new TBIs.
It won’t do anything! It also won’t increase your pressure either like the other guy suggested! Each one of your injectors pressures are controlled by fuel pressure regulator diaphragms that regulate the injectors pressure. That 85 pump is just rated at a different flow rate than the 84 hence more flow but no go! Lol it’s def a placebo effect you were feeling.
Thanks for the video. Question1) did you RTV the mounting plate to the gas tank. Question 2) I bought a NAPA fuel pump and had to solder the negative wire to the fuel rail and make a jumper cable with the provided fittings. I put it all back together and cranked for a long while, would not fire up. (oh yea, also replaced the fuel filter). Just curious how long it took, quite sure the fuel lines were drained both directions when I replaced the filter..maybe have an air trap going on. Question 3) Did you check the fuel pressure at the fitting near the intake manifold. Would be glad to hear any recommendations. Thanks
Hi! I did not use any sealant at all - anywhere. When I installed mine it cranked and started as before - no delay. I did not check the fuel pressure. I hope this helps. Good luck’
It's important to use OEM pumps. Pay the money, there is no soldering. It's plug and play basically. Napa pumps are not OEM typically. I have a fuel pressure gauge in line between my TBI's It runs about 12 psi at idle. I do plan on adding a vacuum fuel pressure regulator, as I'm not wanting to put so much stress on the regulator in the TBI. You can adjust the TBI regulator, but it's something for serious motor heads only.
@@davidsafely732 David, thanks for the feedback. After a long winter I'm back to giving this another try...going to switch the wires...the pump may be turning in the wrong direction...the NAPA installation sheet did not provide any directions to get this right the first time.
@@Mikes84Corvette Mike, thanks for the feedback. I shared my next steps below. Will be sure to share anything I learn along the way...
Where did you get the 85 fuel pump
Rockauto.com
Why would spliced wires in the gas matter when theres already bare connections in there
Dunno. But I don’t like to mix electricity and gas.
@@Mikes84Corvette theres already electricity in the gas.