Engine Blues, for Technically Inclined

[fulo]

Hope any one here can give me a pointer. I have a 1999 Isuzu rodeo 4 Cylinder, 5 speeds. Engine X22SE. The car started fine and run, but suddenly it will hesitate. It did it randomly.

At first, I though It could be something a vacuum leaks. Since I have a severe valve cover oil leakage, I decide to take advantage and replace valve cover gasket, check intake manifold gasket, etc. I disconnected the battery, remover the Ignition Coil and Fuel pump fuse.

Took my time cleaning the parts, replacing the gasket and putting everything back together. I also took the change to clean the injector with some mild degreaser. I did it gently and quickly I did not soaked the injectors.

Then when I decided to start the car, the rough Idle I mention before suddenly became e heavy engine vibration. My first impression was that I must have put something wrong. So I discontented the battery and check the whole set up. Everything fine.

I checked the spark plugs, spark plug wires, and check for spark. Spark on each spark plug. No problem there. The ignition system seems to be working properly. I then decided to start the engine and disconnect the Crank Position sensor (engine stop as suppose too). Connected that sensor back and disconnected the Camshaft Sensor and no difference. That got me thinking, since the cam sensor has to do in the order of fire for the injectors.

I decided to start the engine and then disconnect the sparkplug cable from each (running) cylinder to detect a change. I noticed that nothing happened when I disconnected the last to cylinders.

I have spark on every wire, so I must be the fuel injection system, right? Connected everything back, started the engine (it vibrates heavy). I decide to disconnect the electrical connector, one at a time, for each fuel injector (kind like I did with the sparkplug wires). I noticed that nothing changed when I disable the last two injectors (same cylinder that where unaffected when disconnecting the spark plug wires).

So, in conclusion, I must have to ‘dead” cylinders. The ignition system seems to be working, and apparently the injectors might be faulty. But, then why northing happened when I disconnected the camshaft sensor. Since this sensor is the one responsible for determining when each injector fire the fuel to the intake manifold. Also, I did a compression check on each piston. Guess what. The two piston with the best compression where the two death ones!

This is where my puzzle is. I not very experienced with fuel injected engines. I do not have an OBDII scanner yet (I ordered one, and should arrive in a week). My real question is what should happen when you disconnect the camshaft sensor on a running engine?

Thanks for reading this LONG post. I will really appreciate all your opinions.

Regards

[rodeo02]

Originally Posted by fulo

..... My real question is what should happen when you disconnect the camshaft sensor on a running engine?

Most engines will stall out completely & wont run without a CPS . Maybe this 2.2L daewoo/holden/GM/isuzu engine runs in some type of 'closed loop' mode without the CPS?
G/luck
Joel

[fulo]

It must, but i runs bad and I even have back fired. The ignition is distributerless (me no like). The other thing I am noticing is HOW HARD IS TO FIND PARTS for this engine. I cannot seem to find CPS in regular places. Haven try the Dealer, but I am affraid that might be the only source. FUnny, since is a GM engine. I will assume there should be plenty of parts!

[Donkeypuncher]

Go to Autozone or O'reilly for an ODB scan(it's free). Also, if you have trouble finding parts, I beleive the 2.2L is the same as the 98-current Chevy S-10. I drive an '02 S-10 at work and it looks the same as the 2.2's I've seen in the Isuzu's.

[rodeo02]

Originally Posted by Donkeypuncher

... I beleive the 2.2L is the same as the 98-current Chevy S-10. I drive an '02 S-10 at work and it looks the same as the 2.2's I've seen in the Isuzu's.

Nope, it's a completely different engine. The daewoo nubira shares the exact same 2.2L. as the 1998-2003 rodeo 2.2L

G/luck
Joel

[fulo]

Hi to all, I have finally manage to get some things done, I landed a temp job, so my time was compromised.

I did check the resisitance for each injector. The haynes book indidacted that the resistance for 2.2 liter engines should be between 11.5 to 12.6. 3 of the cylinders were in range (12.4 ohms). Only one was above range (12.9). I dont know if 0.3 ohms makes a big difference on the ijector performance.

I then decided to check the voltage going to each injector while the engine was running. In the two original cylinders that were having combustion, the voltage was about 5, on the two cylinder absent of combustion, the voltage going to one injector was 2 and on the other was 1.8. Keep ion mind that I can disconect the to eletrical wires going to this two injectors and there si no change on engine idle.


Also, I notices that the check engine ligfth flashes continuously. I just recieve the OBDII form Auto Tap. Is the one tha you connect to your PC. I will install it and see what code I get.

My prognosis so far is iether a faulty ECM (PLEASE NO!!!!) or one of the Sensors (CPS or the CRPS).

Thanks for your previous Feed back.. And PLEASE keep sharing those thoughs.