changed cap & rotor, plug wires - now it won't start

[ehummelman]

I was having a bouncing tach issue, so after some research I thought I would test a few things. I pulled all the plug wires and tested the resistance. All are within spec. Being an idiot I didn't take note which ones went where, so to reconnect them I looked up the pontiac firing order and reconnected them. While I was at it, I pulled the HEI cap to check the connections inside and noticed the the rotor button was very sooty and the copper contacts on the inside of the cap were corroded or burned. Although the engine was running fine before, I figured I'd put a new cap and rotor kit on there.

OK, so now I can't start the engine. It cranks over fine, but just pops out the exhaust. I need to have this running ASAP - someone please tell me what I hooked up wrong!!
Thanks so much.

The setup is a Pontiac 350 with an HEI. The module is removed, with the wires connected to the green and purple to an MSD box. Again, everything was fine before I started messing with it. It's either I have something screwed up in the distributor or the plug wires are somehow out of order. At first I thought maybe i put the rotor back on 180 degrees out, but it's notched on one side so you can't do that. I never moved the distributor (timing) so it can't be that either.

[dontlifttoshift]

Check firing order and rotation....Pontiacs spin counter clockwise don't they? Bring number one cylinder to TDC on compression stroke.

More than likely, where number 1 was and where it is are two different things. Pull cap and look at where the rotor is. My money says that it's not pointing at your current number 1 wire.

[andrewb70]

Check firing order and rotation....Pontiacs spin counter clockwise don't they? Bring number one cylinder to TDC on compression stroke.

More than likely, where number 1 was and where it is are two different things. Pull cap and look at where the rotor is. My money says that it's not pointing at your current number 1 wire.

Yes, a Pontiac distributor spins opposite of the direction of sbc or bbc.

Andrew

[ehummelman]

OK, just checked #1 TDC with the old "finger in the hole" ;) trick. I'm thinking that you're right, I might have the wires on the cap off by one going all the way around. The wierd thing is, at #1 TDC the rotor is pointing at what is labeled #7 terminal in this picture:
58254.
Regardless, I hooked up the wires according to the rotor at #1 TDC, and got it start and run for about 5 seconds. Then it automatically cuts out. I can start it again, but it cuts out again.
I'm closer, but it still isn't correct.

[andrewb70]

Confirm the wiring again. Get a timing light and see if you can see what the timing is from the short time that it runs...

Andrew

[ehummelman]

I can't, it dies before I could get out of the car. I haven't moved the distributor at all, I never loosened the hold down bolt for any reason. It just seems weird that the rotor is pointing way off to the side at #1 TDC according to the picture. God I wish I had a picture of how the wires were beforehand.

[MrQuick]

Distributor may have been dropped in the wrong place before.

Pull number one and repete the finger test with the dist cap off. See where the pressure comes up and the rotor location. Its always a good idea to mark number one on the cap before you pull it apart.

[ehummelman]

Can anyone else help? I am totally at a loss. It starts now, goes for 5-10 seconds, then dies abruptly. While it's running it sounds normal, so I'm thinking I may have the plug wires correct now. Why would it be dying out?

[ehummelman]

Distributor may have been dropped in the wrong place before.

Pull number one and repete the finger test with the dist cap off. See where the pressure comes up and the rotor location. Its always a good idea to mark number one on the cap before you pull it apart.

Thanks, but the distributor was absolutely correct before I pulled the cap, rotor, and wires. I did do the finger test, and the rotor matches the mark on the housing (from PO) and it's where I've stated (where #7 is in the above picture).

[ehummelman]

Could I have messed up the coil or MSD box somehow by having them wired up wrong the first try? I don't know how, I'm just trying to think of anything that could have happened.

[ehummelman]

OK, my wife is home now. I'm going to go unplug the vac dist, plug it and try to get a read on the timing. This damn distributor clamp doesn't clamp for sh*t and it's maybe moved again. Be back in 5.

[ehummelman]

Timing at idle is fine, right at 15. As before, runs fine for 10 seconds or so, then nada.

[Chevelle598bb]

Test it for spark. It sounds like a fuel pressure issue more than ignition but the box could be crapping out after running a few seconds.

[ehummelman]

Anything is possible I guess, but going focusing on only the things I changed, I wouldn't think fuel issues. I will test the box tomorrow and get another coil from NAPA. Can't hurt, it can be returned if it isn't the problem. Thanks everyone for the advice, keep it coming. I'm giving up now for thie night, it's starting to rain.

[MrQuick]

you didn't knock a hose off did you....i agree, sounds like fuel or a vacuum leak.

[ehummelman]

nope, all hoses intact. no vacuum leaks prior to the cap/rotor swap. I got it to run for about 5 minutes this morning, checked the timing again, and the fuel pressure was at 5psi at idle. Then, once again, it just all of a sudden shut off. Not a sputter or whatever as if it were fuel, it was definitely just an electrical shutdown of some sort. I'm going to get a new coil today. If it isn't that, the MSD box is my next guess.

[ehummelman]

New coil, same problem. Now I have an extra spare! I'm thinking MSD box now, in fact if it was starting to go bad, that might explain my bouncing tach problem I reported a while back that I haven't been able to solve either. The MSD box triggers the tach directly so all of these issues could be related. That's what I'm hoping anyway. I have a brand new 6AL in my truck only used for engine break in, so I know it's good. That's going in next.

BTW, I tried to get the ignition lock cylinder out to put in a new one (already had planned this because it's very loose). I punched out the casting slot as all web instructions say, but couldn't feel or see the tang or whatever in there I'm supposed to push down on to release the cylinder. Anyone got any wisdom on that one? Maybe I'll start a new thread.

[JEFFTATE]

Pull both valvecovers off. Spin motor over until the timing marks on the balancer line up at 0 degrees BTDC. Check the #1 valves and the #6 valves. If the #6 valves are open and the #1 valves are closed, the engine is ready to fire #1. If the #1 valves are open, just rotate engine 1 full revolution and NOW its ready to fire #1.

Install distributor. You may need a long flat head screwdriver to line up the oil pump driveshaft. Make sure distributor seats properly against engine block. Turn distributor body until rotor lines up with a sparkplug socket on cap. That is now #1 plug wire. Connect plug wires in firing order 1-8-4-3-6-5-7-2. Remember that Pontiac distributors turn counter-clockwise. This is for any Pontiac engine made before 1979.

Install cap, and all wires on distributor. Hook up a timing light to #1 plug wire. Try to start engine. You may have to twist dist body back and forth to get it to fire up. When you get it running, set timing for 12 degrees at 700-800 RPM. Lock distributor clamp down, and make sure timing hasnt shifted.

Check your total advance too. Pontiacs like 32-35 degrees BTDC at 3000 RPM.

[ehummelman]

Thanks Jeff. I'm sure all of that stuff is correct because I never took the distributor out and the finger in the hole let me know exactly where the compression stroke TDC was. I think my problem is either that my box is bad, my ignition switch is bad, or the connection at the bottom of the column is faulty. I will be addressing all of these this weekend. Gotta go to Van Halen tonight!

[ehummelman]

Well, I got it running. :) Funny thing is I can't say for 100% what did it. I was 99% it was the MSD box going bad, but now after thinking abo ut it I'm not sure. I just took it for a 20 minute drive and the tach doesn't jump around anymore either, so I think my suspicion was right about that also being related. The only other things I did this morning were check all the fuses, jiggle the ignition switch wiring on the bottom of the column, and I had the trickle charger hooked up overnight (although according to MSD I had enough voltage there before).

I still suspect that the ignition tumbler and/or ignition switch could be at least partially at fault. The tumbler activates the switch mechanically through the rod, and then the switch will send a signal to the original coil + wire, or in my case to the MSD box small red wire. From what I understand, that wire just powers the MSD box, not giving it a signal to fire. The box gets it signal to fire from the distributor pickup (green and purple) then sends it signal to fire out to the coil through the orange wire (connects to coil + on the HEI cap.). So if this is all correct, then it could be possible that the switch was only intermittently sending power to the MSD box through the small red wire. The starter would still turn over, but the box wouldn't be sending any spark as it wasn't powered on. If that is true, then I suppose I could have replaced a perfectly good box, and just got lucky by jiggling the switch down below the column.
Anyone care to comment on this? If my logic is correct, then I wonder if the same problem will pop up again and I should really replace the ignition switch. I'd love to hear what you guys think.

[JEFFTATE]

Glad to hear that you got it running ..
It sounds like you "MAY" have some electrical gremlins ..

[ehummelman]

Yeah, but I'm after them with a vengeance! The car seems to be running awesome now after replacing the MSD. I'm going to give the ignition tumbler another try just so I know it's tight and new. As far as the actual switch on the lower column, I need to read up on how it is adjusted - that may have been part of the problem. I don't know. Like I said, the new MSD box has made a huge difference.