Engine issues

Engine issues

Common problems and their solutions.

Common poor starting problems

CIS Troubleshooting Chart Link
The CIS(Continuous Injection System) is very suseptable to vaccum leaks. Maintaining proper vaccum is important because vaccum is used to tell the injection system how much fuel is needed by the engine. If the Intake system (Intake manifold, Vaccum lines, Throttle body, intake tube) is allowing air to enter, the injection system can't meter the correct amount of fuel. <p> Depending on yor setup and what work you've done, I think that you may have an air leak on the intake system(between the head and throttle body) If you have a 8v CIS system 84 or earlyer. then this I believe applies
Here is my reasoning: when you start the car - put -put . It needs more air and more fuel than the warn running system(thus cold start injector and the aux air regulator).
As it warms up it all air must pass via the Throttle body from the fuel dizy and into the engine. Any amount of air that enters the system after the fuel dizy will mess with your air/fuel mixture. If the air enters the system between the head and the throttle body(place of the highest vaccum at low engine rpm{during starting}) messes with the air fuel mixure the MOST.

Replacing Vacuum hose

The majority of the vacuum hoses found under the hood are 2mm ID (inside diameter) 4mm OD (Outside diameter). If replacing all vacuum lines you'll most likely need more than 10'. When purchasing vacuum hose its important not to use hose ID that is too small or too large and designed to be used for auto vacuum use. Auto vacuum hose has to keep its structure(ID) under high temp conditions and under vacuum. When replacing the vacuum hose replace the cloth covered rubber couplers.

Here is a free(0$) way I use to test this on your car.(remember Keep It Simple)

1) all shops must have duct-tape

Narrow down the possibility and location of the vaccum leak is the game.

Remove the two vaccum lines from the front of the intake manifold and use duct tape to block off the ports. Install the tape so that no air will go in to the manifold throught the now open ports, while making sure the tape is installed so that it CAN NOT be sucked in to the engine.

Then use tape to block any air from getting in to the system from the idle screw(BUT DO LEAVE the screw installed). The idle screw leaks air at times.

Now give it a try. Is is better, most likly not solved though. Keep going.

Once the engine has started and ran for a minute you don't need the aux air regular just behind he cold start injector. Block that off by pinching the rubber host. (because both ends of that hose need to be blocked off from vacum leakage.

Give it another try. better or not.. Keep going..

Now the intake mainifold gasket its self. You'll need a 6mm hex socket and a torque wrench. Each of the intake to manifold bolts should be at 18 lbs. Do not over tighten the head is alumium and will strip the threads causing great pain and work to replace the head. Start in the middle and work your way to the outside runners checking to make sure each are to spec tight. (there are 6 bolts) You'll want a small mirror to help get the hex socket on the bolt heads.

Now at this point your intake system should be able to support a consistant air fuel mixure.

I'm speaking from experience here. I found the gasket was only partialy there. I can't believe it even ran. though I ended up taking the intake manifold off, and installing a new gasket.

Next may be to make sure the injectors have good O rings, this can also be a source of air leak between the head and throttle body.

Good luck -

Cleaning injectors

Recommended method of cleaning CIS injectors is to NOT clean them... replace them.

For cars that came equipped with the non air shrouded injectors, Bosch part number 0437502047 brass injectors are an inexpensive replacement part...and can be had for $25 each online by shopping around. For 84 and up cars that came with the airshrouded injectors, one option is to use the above injectors and move the shrouds over to the new injectors.

CIS injectors have a very fine built in filter that makes the injectors difficult/impossible to clean without the proper tools to backflush them. New injectors will have good injector to injector flow as well (<2% variance in my testing). Important for a smooth running motor.

Control Presure Regulator (CRP) Repair and cleaning

Adjusting control pressure, building a DIY pressure guage, diagnose system pressure, cleaning the pressure regulator CPR/WUR, Leaning out to soon. Check this article out at the Bad Habit Rabbit.

Oil Pressure

The oil buzzer keeps buzzing , but my car is running fine and idles perfect - FYI it can idle just fine and run great and have the oil pressure be below spec. Replacing the oil pressure sensor on the drivers side of the head has been known to fix the problem. (easy $1.50 fix)