Engine Mechanical problem
2002 Chevy Express V8 Two Wheel Drive Automatic
5.7L Vortec Engine and it's a van. It has had a history of hard time starting the vehicle. It would turn but hard time starting. Now won't start. I've changed spark plugs and rotor and distributor cap and it started (but not easy). Then I changed ignition wires. Then it won't start. It is getting fuel out of fuel port (splashes out if I open and press it for a splitt second) and it is getting spark at the spark plug wires. I can rotate the distributor slightly if I force it with hand so I am thinking it could be timing issue. I would back fire occasionally as it wants to start somtimes. So maybe it is misfiring. What are other components that I should check?
Check your fuel pressure with a gauge and comeback with the readings we start here.
November, 2, 2009 AT 7:17 PM
Fuel Pressure is reading slightly above 60 psi which is within factor spec (60 - 60 psi).
Current Status: It back fires as frequently as it tries to start. Occasionally, the engine would turn then very briefly pause (hesitate) slightly and then keep cranking. The inside light would dimm slightly when it does this.
Other note: Fuses were checked and they seemed to be all fine. No code comes out when I read the ECU with the OBD reader.
Caveat Note: When I changed spark plug wires, I did accidently broke coolant temperature sender wire (for gauge, not ECU). I spilled coolant all over the places. I did reinstall brand new sensor to make sure it is not the cause of the problem. That was couple of days ago and coolant being slightly spilled over to the side are all dried up by now. I did unplug couple of wires and let it dry to make sure. I did refill coolant on overflow to the top but not main one since I have to break the coolant cap to refill the coolant.
Here are some of my possiblies that I can think of but it would be great if I knew which direction to go first.
1. FUEL ISSUE.
Clogged fuel injectors or some other fuel issue. I am thinking this because I did find pretty good amount of black deposits in the throttle body. I did clean them off with carb cleaner by spraying them few days ago. The van did start after I did this operation.
2. TIMING ISSUE
The distributor rotor moves slightly if I hold it firm and turn it. So I am concerned with timing.
3. SPARK ISSUE
I am not sure if I am getting weak spark or good spark. It looks good spark to me as I tested it with spark plug tester. It is hard to tell without more accurate equipment. So perhaps coil might be failing?
November, 3, 2009 AT 11:23 AM
Fuel pressure: Perfect
Ignition system: what's the color of the spark-if orange looking its weak -test the coil's primary and secondary winding resistances-make sure you have battery voltage going into the coil positive terminal
Do this put the engine no.1 piston on its compression stroke remove the dizzy cap is the rotor pointing to the no.1 tower? If not the valve timing is off.
When you attempt to start-do you hear actually hear the fuel pump come on for 2 secs?
November, 3, 2009 AT 6:09 PM
Fuel pump is good for sure for now at least. Also, nothing is leaking down at the throttle body.
Color is yellowish orage looking using spark plug tester. I did change iginition coil. It has only one coil ports so I didn't know how to test the coil. So I just changed it. I confirmed that it's getting all 8 spark plug using test lights. I used a can of starter fluid. It back fired out of throttle body if I sprayed too much. However, couple of occasion it sounded as if I quieted and started and died off if I sprayed right amount and let the throttle body door open. I have lack of experiecing in adjust timing but I will read up on it and attempt to do so if everything else fail. However, I am thinking it's more matter of fuel injector issue since it almost almost started with starting fluid. I have no easy way of telling if injectors are clogged without tearing things apart. Also, since it's electronically controlled, how do I know what controlls fuel injectors are failling instead of fuel injectors being clogged up. My next move is attempt to take it apart and see the injectors themselves. What do you think?
November, 4, 2009 AT 9:39 AM
Check and test the camshaft and crankshaft sensors to include the injector/s solenoid resistances-
November, 5, 2009 AT 1:57 PM
I am going to do that but I think I over looked ignition control module. I changed ignition coil already but not the ignition control module. Since I need a scan tool to test this, I am looking to replace it and see if it makes a difference.
November, 5, 2009 AT 4:58 PM
Check and test the crankshaft positioning sensor before you replace the ICM.
November, 6, 2009 AT 5:39 PM
Three wires to CPK and by connecting 1st and 3rd wire, I got resistence reading. CPK resistence reads at 5.2 at 200K OHM scale so it's 520 Omhs?
I hooked up fuel pressure gauge again and after couple of ignition on position and off suprisingly, the van started. It was a first time from long time. I didn't want to idle it too long with fuel pump guage hook up so I turned off the engine. I did start relatively easy when it did start. I didn't have to crank it too long. The pressure guage didn't seem to drop below 50 psi. After I turned off the car and when the car didn't start, the PSI level was up again about 65psi. Also I could hear fuel pump in the back.
I also checked voltage feeding into ICM and it was slightly below 12v. Now the van of course won't start. It will keep on turning over and making usual sound but won't ignite.
Another theory I heard was the starter motor perhaps drawing too much power? I don't think that's the case since the starter motor turns over strong.
November, 6, 2009 AT 5:51 PM
Also, I inspected the spark plug. The spark plug was slightly wet and I can smell slightly unburned gasoline. I cleaned it off little bit, but it was pretty black. Maybe becuase I used starting fluid so much couple of days ago, and I was unsuccessful when I tried to start the van.
November, 29, 2009 AT 1:29 PM
I had this problem before with my van and it was the fuel pump the PSI is supposed to be 65 any less it will give problems