When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
whats up guys, so, first post, first Vette! Its way cool, pretty much bone stock 1984, 160k miles -- had to knock the 80's off (god awful wood grain kit) and order some bezels, shift **** etc etc -- headlights, ac, most of the gauges actually work and I did not pay much so I am calling it a win!
Reason for the post. Sometimes, and I mean at total random times...it can be hot, it can be cold, it can be in between, she will not fire. The battery is about new, and it turns over perfect. I god rid of the nasty old Autolite plugs, but still sometimes it will turn over and not start. I will kill the battery trying to get it to start. So then I take the cover off and spray the throttles down with ether and it fires right up. I let it idle, charge the battery. Sometimes I will turn it off and on the first turn over she is rocking, then sometimes it will not fire...sigh...
From I can tell it is not getting gas. I am thinking it is somehow dropping fuel pressure.
Is this a common issue?
Is there a fuel pressure reg or is it a returnless system? Is the pressure regulated from the fuel pump itself?
If I post the vin, can someone decide to see if it is in anyway unique or just a run of the mil C4
It sounds like the fuel pump relay is failing. The L83 has two ways of powering the electric fuel pump: 1) thru the fuel pump relay and 2) thru the oil pressure switch at the rear of the engine , behind the intake next to the distributor. If the relay fails then the pump will come on with sufficient oil pressure from cranking (or if it starts with a shot of either).
You should hear the pump run for about 10 seconds, to pressurize the system if you turn the key to "run" without cranking the engine. If you don't, the relay is suspect. Best way to sort this out is with a fuel pressure gauge for the L83 and see what is going on at start.
There is a fuel pressure regulator, its in the second TBI in the circuit and should control pressure to 13 psi for best results.
You really need a Factory Service Manual, the TBI motors are unique critters, lots of item specific issues. Welcome to the forum!
Good info, so, I am fairly good DIY'er....if I wanted to try something, would you say replace the oil pressure switch and relay? And if that doesnt do it, then get into it further?
Based what I said, would you think it is one over the other or hard to say
This is what we used to call a "1000 mile screwdriver" so take it for what its worth. I'd try the relay. Without more info, from a pressure gauge, you are throwing parts at it and its just a dart toss. The oil pressure switch is a backup and not the cause of this problem. You should be able to hear if the pump runs by listening at the fuel filler hatch when the ignition switch is turned to "run". If it doesn't the relay is suspect. This could be wiring or an intermittent ground issue also. As I said earlier you really want a FSM as the TBI engines are unique. Give it a try and let us know what happens.
While you are "in" there.... consider upgrading to a 85-89 fuel pump. The 84s are notorious for being under pressured causing all sorts of start and drivability issues.
While you are "in" there.... consider upgrading to a 85-89 fuel pump. The 84s are notorious for being under pressured causing all sorts of start and drivability issues.
I just didn't want to hit him with too much at one time.
Look under drivers side rear compartment lid for RPO codes. Then google to decode them. This will give you original options as built as well as paint color code.
Left front wheel on wrong side. Check right side. If the tires are non-directional, its an easy fix.
I just didn't want to hit him with too much at one time.
All these have been guesses. Are you guys saying "just replace everything" and maybe it'll work? Is this good advice? And then top it off with a ? C'mon guys, you can do better than that!
If the car runs okay after it starts, the fuel pump must be okay, so scratch that guess/suggestion. That also says your fuel pressure and fuel pressure regulator must be okay. Scratch those guesses.
How does the fuel injector spray pattern look? Remove the air filter cover and watch the injectors when you're trying to start it. Do get good spray sometimes, and no or poor spray when it doesn't want to start?
Try pointing your ignition timing light at the spray for a good look!
The fuel pump in my '84 is so quiet I have to test it with a low fuel level in the tank, then I put a hose into the tank (not into the fuel) with the other end of the hose in my ear. Listen for the fuel pump to run for a few seconds when you turn on the ignition. If it doesn't run, the fuel pump relay is suspect.
That's a start. Please report back to us! We're anxious to get you running good!
I have had random starting issues with my '84 and found a new fuel filter helped significantly. There may have been/still are some others, but this seemed to be key.
I am the original owner and it was first changed at 20,000 miles in 2008!
02-10-2018, 03:37 PM
1984 sometimes will not fire
I just didn't want to hit him with too much at one time. 
? C'mon guys, you can do better than that!
