1985 Fuel Question!!!
Pro
Joined: Dec 2008
Posts: 658
Likes: 0
From: Lubbock for now, headed for Oklahoma
To check for leaking injectors, just start the car with gauge connected and pressure regulator disconnected and plugged. Shut the car down, and let it set. If you lose more than 10lbs in 10 minutes you no doubt have a leak. Less than that you can still obviously have a leak but it is less severe. Be sure you do this with the car totally cold!!! Hot fuel rails will give false results.
Pro
Joined: Dec 2008
Posts: 658
Likes: 0
From: Lubbock for now, headed for Oklahoma
This sounds like a bad intake gasket, and a bad injector.
1. if the gasket is bad, the thing won't run because of the massive vacuum leak.
2. when it quits, and the injector is leaking, the manifold gasket is allowing the fuel into the oil.
OR
he has a cracked intake manifold, cracked head, or just a plain ol' mystery.
1. if the gasket is bad, the thing won't run because of the massive vacuum leak.
2. when it quits, and the injector is leaking, the manifold gasket is allowing the fuel into the oil.
OR
he has a cracked intake manifold, cracked head, or just a plain ol' mystery.
Well I disagree to a point. A stuck or popped injector is going to pour fuel into the engine. This will of course wash the cylinder walls and put fuel into the oil. It's also going to foul that cylinder and cause a whole world of raw oxygen to cross the O2 sensor. This in turn will cause the ECM to richen the system and make the entire engine run like crap.
Start with a mechanics stethoscope and listen to each injector with the engine running. You should able to easily identify the bad injector for the lack of TICK TICK TICK. You could try pulling the plugs but with as rich as your system will be running you may have several fouled plugs by now.
You are however far better off to replace the injectors as a set. Updates and design changes will leave you with one injector flowing different than the others and cause all kinds of issues.
Start with the injectors and some new plugs. Then see if all of your issues clear up. I am betting that they do. You need to take a mechanical diagnostic approach to this though. Changing a bunch of things can leave you at a loss for what helped and what hurt.
Melting Slicks
Joined: Mar 2008
Posts: 2,141
Likes: 76
From: Santa Maria, CA
To check for leaking injectors, just start the car with gauge connected and pressure regulator disconnected and plugged. Shut the car down, and let it set. If you lose more than 10lbs in 10 minutes you no doubt have a leak. Less than that you can still obviously have a leak but it is less severe. Be sure you do this with the car totally cold!!! Hot fuel rails will give false results.
I did notice when I replaced the fuel pump that the connection between the pulsator and the fuel pump fits looser than I would expect. I think it's probably due to age and I think that can be a source of leak-down as well. Since the car starts and runs fine I have not pursued the issue as a science project.
What got my attention is that his fuel pressure drops with throttle. It should be just the opposite.
