Hey just curious if anyone knows or would be able to check what position the rotor should be in once the engine is on top-dead center? We did an engine swap on a 90 s10 blazer 4.3l and haven't been able to get engine to idle. It is getting fuel and spark yet won't run. Also have good compression in all cylinders but can't seem to get the timing right. Thanks for any help really need this truck to run!

 

That's easy! Rotor should point to #1 spark plug wire if engine is on TDC#1 for compression stroke. Rotor should point to #4 spark plug wire if engine is on TDC #4 for compression stroke. See how that works! Remember that TDC#1 compression stroke only comes up every second revolution of the crankshaft in a 4-stroke engine.

If you're not sure, take out #1 spark plug and stick your finger over the hole. When you feel the compression stroke blow air out of the cylinder past you finger, you are nearing TDC #1 of compression stroke. #1 cylinder is the driver's side front.

Does it start and run at all? Firing order is 165432 Distributor rotates clockwise. Drivers side has odd numbered cylinders. Passenger side has even numbered cylinders. Check the firing order to make sure the plug wires are on correctly.

 

That's strange, we've been trying to time this truck for a while now and we've had it pointed towards the 1st spark plug in the firing order and it sounds like it isn't timed right? The Hane's manual says to put in it so that before you drop it in the rotor is pointed between 1-6 and once we dropped it in, the rotor was aligned symmetrical with the distributor but that didn't work either. Technically the motor is from a 92 C1500 but as far as we can tell it is the exact same 4.3 motor and should be timed the same. It sounds like it wants to start at times and at one point it idled for a bit with a bunch of vacuum leaks but now that we fixed that it doesn't want to run. It might be a different issues then the timing but we are trying to cover our bases haha. We might be getting too much fuel which could be a computer issue since we have replaced all of the sensors. Ever heard of this problem before?

 

Maybe this helps?

 

You can point rotor wherever you want as long as you move the plug wires to the right place in the distributor cap. Looks like you need to study things a bit more. Not a criticism, just a fact. We all have to start somewhere. First thing throw that Haynes manual in the nearest trash can and go get a subscription to AlldataDIY.

• Roll engine over until your have it on TDC #1 on compression stroke. Google how to do it on your engine or whatever it takes - but be certain about which cycle and about the timing marks. Very common error to have the distributor in 180 degrees out.
• Put a mark on the distributor body at exactly the center of the terminal where #1 wire connects, and then remove the cap.
• Drop distributor in so that the rotor is pointing to that mark. (Turn the oil pump drive to position where it will pop down all the way).
• Put on the clamp and turn distributor counter-clockwise just a smidge past that same mark and lock it down.
• Trace each spark plug wire in the cap to make sure it goes to the correct cylinder.
• When you have it running smoothly, set the timing per manufacturer's procedure which will probably include jumpering a connector to put things into base timing.

Don't screw around with anything else until you are certain that you have this right.

Come back when you have done this.

 

Engine is definitely on TDC compression stroke, 13 teeth on distributor gear and 6 points on pick up coil tells me there is only one position that will mathmatically work on this one. The pic I was sent from a GM service manual places cap with space between one and six at front of engine but when I place the rotor at #1 I get fuel and spark but no start. Haynes says drop it in between 1 & 6 but that puts it at #6 when seated. Later models had distributor bolted in place but this one I have to time at zero degrees than hook up the PC advance wire under glove box when I'm all done. Bewildered at why this thing wont run ... no codes.

I ordered a factory service manual from ebay but it wont be here till next week.
Alldata is beyond my budget.

 

AS quote says make sure your at TDC. Too fine tune TDC or if you think you have went past that point while bumping engine over watch your timing marks and use a long slender screwdriver, coat hanger ECT. thu the plug hole, rock engine slightly back and forth until piston is at 100% TDC

Timing marks should be at or close too 0 Deg

As normal your Haynes manual is wrong { imagine that and you wonder why he said throw it in the trash } per arc rotation of teeth you will start the install of the dis. between 1&2 NOT 1&6,

When seated the rotor should point at #1 if not reach in with a long screwdriver and rotate the oil pump shaft until it does.

 

All you need for an engine to basically start and run is adequate compression (check with compression gauge), fuel (should be able to see it spray with a TBI motor, or simply dump some in), and spark at the right time. That's it.

This will be my last post in this thread until you convince me you have verified the timing and firing order per my previous instructions. You have not yet said anything that gives me confidence the distributor is in and wired correctly. How many distributor teeth and points on the pickup coil is irrelevant to the process. There are 13 positions the distributor can go in and work fine if the plug wires are long enough to reach all terminals and the distributor body can be turned to where you want it. There are also 13 positions the distributor can go in and still be completely out of time if you don't know exactly where TDC #1 compression is - or if the plug wires are out of order.

AlldataDIY subscription is $25 and gives you most of the factory info, but unfortunately it would not be much help in getting the distributor in right.

Once you have verified distributor installation and firing order, if it still won't start pull a spark plug and inspect. Take a compression reading on a cylinder. If spark plug is wet, remove them all to let them dry out. You can disable the injectors and coil and crank the engine with the spark plugs out to make sure cylinders are reasonably dry. If they won't dry out fairly quickly, suspect water in the fuel. You can prove this or not by putting the spark plugs back in and pouring some fresh gas down the throttle body with the injectors disconnected and trying to start the vehicle.