I am attempting to install the distributor on my truck. It is a 91 Suburban, V2500, 350, vin K. I looked thru the chilton book and it described a white painted line on the base of the distributor, it also said to align the rotor with the number stamped "8" or "6" on the distributor. I am using a new distrubutor that has no line or number, the old distributor has no line or number either.
I have installed it using the old "point at number one cylnder when at TDC" method, it doesnt work. I tried going up to 3 teeth forward and backward with little results. I am thinking that I am just not installing this thing correctly.
There is spark, flame and it backfires often during these attempts.
Does the distributor's flat side have to be aligned in any particular way? I have been aligning it with the flat side on the right (drivers side).
remove spark plug from #1 cylinder. hold your thumb over the spark plug hole while your friend bumps the starter a little bit at a time. (like you just turn the key to engage the starter and as soon as it turns the engine over you turn the key off) you do this until you feel pressure in the #1 cylinder which tells you the piston is coming up towards TDC on compression stroke. (you are turning the engine over a little bit at the time, so you can stop when the timing mark gets close to zero at the harmonic balancer)
A good tip is to take some white out or other white marker and mark the timing line on the harmonic balancer where you can see it better.
So once you feel pressure you then can take your thumb off the head and slowly bump the starter over until you can get the timing mark close to zero (at the harmonic balancer). If you mess this up...start the whole process over again.
Place distributor with the rotor pointed toward #1 cylinder which also has to correspond to the number one plug wire on your cap. This does not have to be exact but it does have to be fairly close. ON the firewall near the accumulator you need to disconnect the ECM timing wire which allows you to set base timing. Start truck with wire disconnected and adjust base timing to 0 degrees. (timing light needed). Shut engine off and tighten distributor hold down clamp and re-connect ECM timing wire. The allows the ECM to control the timing, like its supposed to, you cannot adjust the timing on these truck with that wire connected, because the timing you want to set is the "base" timing. You cannot modify the advance (that's what the ECM controls)
You'll need to clear the ECM codes by disconnecting the battery for about 5 min and you should be good to go.
IF the truck backfires you are doing something wrong, or if it pops through the throttle body you have done something wrong.
You have to set timing when #1 piston is at TDC, therefore the distributor has to be in the correct "phase".... if you get this off the engine will backfire and generally run like crap, it will be pretty obvious. Also you need to set the base timing like it says on the sticker under the hood which on my 92 says 0 degrees (350 engine) I you don't get this right the engine will run like crap too, because the ECM assumes the base timing is set at 0 degrees and therefore it advances the timing based on that....so plus or minus here can make the ECM advance the tinning either too much or too little.
If you removed the plug wires from the distributor you need to make sure your firing order is correct on the distributor and starting from plug wire number one make sure the plug wires are in the correct order.
The distributor will "sit down" flush ....so if there is a gap at the base of the distributor and the engine you are wrong. You can't shortcut the business about TDC on compression stroke and setting at the proper base timing (with wire unplugged).
I'm no expert but I've been a few rounds with my 92 K1500 350 when I've changed the intake gasket and also one time when I replaced the distributor. Get the timing mark as close to zero at TDC on the harmonic balancer...install distributor with rotor pointing to number one piston and number one spark plug wire on the cap and you should be ready to start and set base timing.
I'm played this game a number of times and you'll hear different stories on the same theme but this is what works. The only really good shop manuals are the GM ones...the others tend to leave important details out or just skip over various things.
Popping through the throttle body or backfires are a good clue that the timing is off.....start from zero and do it again...unless you are experienced at this the assumption is that you've screwed up something so its best to start the process from zero and try again.
Hope this gives you some help....I know this can get really aggravating...I've been there a number of times myself.
Of course you'll need to replace the spark plug you removed and reconnect the spark plug wire before you start the engine. Its also good to leave the wiring disconnected from the distributor so the engine does not start before you are ready to do so, since on these trucks you generally have to climb in under the hood and so it becomes a safety issue.
Thanks, you are correct about the book I have being only fit to catch the dripping oil. I will attempt what you said and remove the timing wire (first I have heard) that makes sense. I really appreciate the quick response.
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