CIS problems?

Talonz82 · 04-01-2002, 03:41 PM

I bought a 1980SC that suffered a light engine fire, I removed the motor , replace the fuel lines and soft goods, (fire started on the 4,5,6 side) I cleaned and inspected everything, installed all new fuel lines new, spark plug wires, plugs, cap rotor, engine wire harness etc. I reinstalled the motor, serviced and tried to start it.

After purging the air, she will start and idle roughly, she backfires through the intake and exhaust, (mildly)(not all the time) If I play with the throttle, I can occassionaly(while she is spitting and sputtering) pull her up on the power band for a few seconds.

I have ordered a CIS manuel from pelican, any suggestions where to look first while I am waiting for it to arrive? I have checked and rechecked the ignition and timing circuits, I have seen several references to the warm up regulator, I do know there is fuel and pressure there, should I take off and clean?

rstoll · 04-01-2002, 03:51 PM

Are there any cracks in the airbox?

emcon5 · emcon5's Garage

Vacume leaks? There is a ton of CIS plumbing under the Fuel distributer, are you sure none of the hoses got damaged in the fire? The breather hose from the oil tank is back there as well. Does the idle change when you take the oil cap off?

Tom

Superman · 04-01-2002, 03:56 PM

Oh, this is fun! Ignition is pretty straightforward, so in other words, you should be able to get the ignition system working fine so that you can dismiss it as a cause of trouble. Check whether it advances about 25 degrees when the engine speeds. If it approximately does that, and if the engine will start, and if the spark is a snappy blue thing, then assume ignition is fine.

The only other thing you need (besides compression which you can also assume is fine) is a proper fuel/air mixture. Place each injector in a separate jar, still attached to the fuel line. You'll have to be careful to secure them so they don't tip or spill. Then turn the key to the 'on ' position, take the air cleaner off, reach in and push up on the air flow sensor plate. This should run the fuel pump and make the injectors spray. Nothing fancy here, you're just looking to verify that all injectors are spraying. If one or more deliver a WAY different spray pattern or volume, note this. If they all spray about the same (close anyway) then put them back in their homes.

Next, when you start it and it runs poorly, run back to the engine and move the sensor plate again. pushing or pulling gently on it may cause the engine to run better. If pushing it up helps, the engine is not getting enough gas, and vice versa.

Beynd that, the fuel injection books usually provide a troubleshooting procedure that is a step-by-step way to isolate where the problem is. It requires a pressure tester, available from JC Whitney at a very reasonable price.

wckrause · wckrause's Garage

With the fire on the right side, is it possible you may have damaged the fuel distributor? I think gas boiling inside the distributor could mess up the internal diaphrams. Did you also replace the airbox? I'd pull the injectors out, one at a time. With the ignition to ON, lift the sensor plate and see if you're getting fuel out of each injector.

There's no point in cleaning the WUR, or messing with it, unless you can measure control and system pressure with a CIS pressure tester.

rstoll · 04-01-2002, 04:06 PM

Hey Noah, send me one of those $25 pop off valves.

Talonz82 · 04-01-2002, 05:59 PM

Thank you all very much, I will start my tests tomorrow, I replaced all injectors, I only took one fuel line off and lifted the plate, I had fuel, but not very much, when I replaced my fuel lines I took the little plastic cone filters out of the fuel distributor, they came through fine, the lines were burn't (injector lines) to about 4 inches of the distribitor, it did not show any signs of being ingulfed in flames. I had the airbox and attaching parts off, cleaned and replaced anything that showed any signs of fire/wear/fatigue etc. once I can get it running somewhat better, I'll do the leak check with the carb cleaner trick.

john walker's workshop · 04-01-2002, 06:46 PM

so is the frequency valve buzzing? that's the thing that looks like an electric fuel injector behind the fuel distributor. it's controlled by the computer under the right seat, which is controlled by the relay sitting next to it, which gets it's power from the dome light switch. if the system doesn't work, the engine will run like crap. perhaps the wiring wasn't fixed for it, or it's unplugged. if it still buzzes, the spitting is typical of a warmup regulator that runs the engine too lean thru it's warmup period. they are adjustable. do a search for that.

Talonz82 · 04-02-2002, 03:46 AM

John does the freq valve buzz continually? the only buzzing I hear is when I reach in to the air box and lift the sensor plate, I was in a quandry last night as I worked, over vapor recovery line configuration, I have three lines, a small one(goes to the fuel tank) and large one coming out of the back, and a large one coming out the front(which actually points to the rear of the car, also I noticed my pop off valve is not sealed properly.

I did all the repair work with the engine removed from the car, today I'm hopeing to check for good fuel pressure at each injector followed by all the other helpful hints, thanks again.

john walker's workshop · 04-02-2002, 07:46 AM

if the frequency valve buzzes when the sensor plate is lifted, that's good. if the sensor plate electrical plug is attached, the fuel pumps and freq valve do not come on with the key. normal. don't confuse the whirring of the injectors with the frequency valve buzz/rattle. the air leak at the popoff can certainly cause wierd running.