Question I have a 92 chevy 350/5.7. Did long block engine swap and timd it according to book specs and specs on fan shroud were the same TDC or O*BTC. Isn't those two the same? During swap I found O2 sensor wire with no place for that sensor.Iknow I need to change that exhaust manifold for the right one. My problem is when I set the timing to specs the engine would not stay running and crsnked several times before starting so I turned the distriutor a little and all seemed fine. Now i have little power on take off and engine seems to surge. I thought I may have the timing off so I pulled the distributor again and looked at pic. in manual for reference as to where mine is and it looked good to me. So I put everything back got it started tried to time it at 0 again and had same result as before. Tested MAP sensor acording to book and it was less than books recomendations.Would this cause my engine to surge up and then idle down repeatedly and a loss of low end power. Engine is stock and was purchased at local engine exchange shop. PLEASE HELP
AnswerHi Tim,
First of all I want to say I found this quesiton discarded in the 'question pool'. If you have any more questions about this I will be happy to try to help. I am C J S.
YOur question doesnt say what this motor is going into. Is this an even up swap? Or are you changing things a bit. Is the '92 going in the same application?
At any rate, with the cap off, yOu should have the rotor pointing at or in the direction of the #1 spark plug when the crank pulley is on zero. HERE IS THE CATCH: YOU COULD HAVE THE DISTRIBUTOR 180 DEGREES OFF. Just because the crank pulley says zero, it doesn't mean the cam is in the right position. YOu could have dropped it in with the motor on top dead center exhaust stroke. If so, the car could start but would run crappy.
YOu want to pull the plug out of the #1 cylinder. Turn the crank with a wrench. Top dead center the way you want is when the piston comes up and the valves are closed on #1 cylinder. When this happens, you will notice a rush of air out of the #1 plug hole as you turn the wrench. If this happens, set the harmonic balance pulley to zero. Is the rotor pointing at or near the #1 cylinder? OR is it pointing toward the firewall? If the firewall, you are off 180 degrees.
If you are pointing toward the front of the motor or toward the #3 cylinder, you are off a tooth.
You also need to remember to unplug the connector that sets the motor into basic timing mode. This is usually a one plug wire off the distributor. IT is usually pink. YOu can find it under the hood near the distrubutor, or along the passanger firewall inside the car at the top of the carpet under the dash. Unplugging this wire eliminates the spark advance. You will get a service engine light on the dash while this wire is unplugged. Dont worry about that. Do not unplug or replug this while the motor is running.
The O2 sensor needs to be hooked up too. If you need to add more wire to reach the sensor, remember to solder the connections. Crimps, connections, splices add voltage drop. YOu are dealing with zero to 1 volt. Any .1 or .2 lost to a connector can skew the O2 reading. Soldered connections are the best way to avoid voltage drops.
Also look for a vacuum leak around the intake, look for EGR system issue, look for bad plug wire.
Good luck. cschevy@yahoo if you need more advice. I am on vacation here for a while. Just looking in question pool since I have a little time to kill tonight.
C J S
