hlee96

Extremely raw noobie here trying to clean out the '78 manual's fuel system

1. When I jumped the fuel pump relay with 14G wires and spade ends, the fuel pumps began to run without the key in the igition. Is this normal? Sounds scatchy, since I always leave battery ground off before messing with the CE panel, but when I hook up the ground cable to the car, the fuel pumps would start running. Is my ignition switch bad?

2. I am running chemtool b12 through the tank with some gas, and when I press on the sensor plate to give it more "gas", the injector lines and mostly at the injectors, would emit a loud whistling-whining noise. Is this a sign of bad, clogged injectors and giving a bad turbulance flow noise?

Thanks for any and all advice and of course, criticisms too. Learning here.
-Hoi

docmirror

1. Perfectly normal. You are applying 12V directly to the pump. The relay is there to apply the power to the pump when conditions are met(key on, engine cranking, or running).


2. Perfectly normal. The CIS type injector actually vibrates which causes atomization at the nozzle. Be worried if one of them does not whistle or give a whine.

When you do this, you dump raw fuel out of the injectors. Be very careful if they are still in the manifold as you can partially fill a cyl with fuel, and if you try to start it, may bend a rod, break a piston, or damage a head gasket. If the injectors are out, you are dumping raw fuel somewhere and it becomes a nasty fire hazard.

There is no real good way to clear the cylinders of raw fuel once you are cleaning them in the manifold. You can remove all the spark plugs, and disable the ignition then blow it out and let the cyls dry for a while, but do not leave things all together and run the starter.

hlee96

Thanks so much Doc.

So, once I stopped the fuel pumps, I should not start the car for an extended period of time, because the fuel remaining in the engine (without having it ignited) would cause too high of a combustion pressure and cause havoc?

You would recommend taking out the injectors and blowing out any accessible fuel from the inserts, and letting it dry as much as possible before starting.

Great advice, and thank you for saving my a$$ from burning down the new house or the "new" old car.

GlenL

1) I'd want to see how you're jumpering it but at least you know when it's on and off.

2) What was said above. Easy to petrolock the cylinders which is even worse than hydrolocking them. The gas that gets shoved into the exhaust will burn and explode when you actually start the car.

3) Go ahead and run the car. The injectors may dribble and fill the cylinders even if you're not cranking the engine. Don't over-dose the fuel system cleaner. Change the fuel filter and get the hidden screen at the inlet of the fuel distributor. That's the thing below the air filter. THe screen is hiding inside a banjo fitting and is very often clogged.

Good luck. Many people have gotten old CIS cars running again without rebuilding the FI system. The key is patience and running it so it cleans out all the gunk and varnish.

atb

I don't believe running the pumps will fill the cylinders if the sensor plate is closed, it will just build pressure in the lines.

docmirror

He's pushing down the sensor plate to distribute the B-12 through the system.

No one knows how much fuel he's put in there, whether it's a few CCs or half a gallon. Either way, the combustion chamber of a high comp engine is NOT suitable place for liquids of any kind.

GlenL

I have petrolocked an engine tuning the WUR while running the fuel pump with the engine off. Apparently the injectors opened with the closed sensor plate position.

There was fuel in all cylinders, in the exhaust system and in the oil. A huge blunder on my part that I hope others can avoid.

docmirror

Ok, here's the deal. That fuel is going to go somewhere. If you leave it in the engine for a while it will drool past the rings, and contaminate your oil, thinning it down to something that won't provide adequate lube of the engine. If you try cranking it, that fuel is going to either block the piston from reaching the top of the stroke due to hydualic pressure and damage something, or if it doesn't do that, it'll blow a ton of gas out the exhaust where it will burn its way down the whole exhaust and may cause some damage. If you take the spark plugs out, you'll blow much of it right out into the engine bay, where there's a lot of ignition sources.

So, you really don't have any good options at this point. I would remove the fuel pump jumper, remove the wire from the distributor to ground the ignition, remove all spark plugs, have 47 fire extinguishers handy, and then crank the engine until all the fuel is blown out. Then let the engine sit for a while to evap the remaining fuel, put the plugs back in, wires back on, relay back in and you can start the engine(I hope).

Alternately, let it sit for a few days, then change the oil/fuel mix and try turning the engine over at least once by hand before crank starting it.

tlister67

To run the cleaner through I disconnected the lines to all eight injectors and put bottles under them. Then you can operate the plate carefully. Don't go to far as you might jam the plunger, I know the hard way. The injectors are obviously not cleaned but other parts are.