buick 225 oddfire - not firing on 2,4,6

I have been trying to research and troubleshoot this issue with my 225 only firing on the odd cyls. It runs very well, has plenty of power, but it is only running on the 3 cyls and seems to backfires under load, ie starting out or putting the throttle down while heading up a hill.

I started by pulling the wires off the dist. cap one by one and heard the engine chug a little when I pulled 1,3,5, but there was NO difference in idle when 2,4,6 were pulled. There was spark on all wires when I reconnected them.

I read through a few threads on this, and this one is exactly what I am experiencing. The guess was that the dist. was one pole off. So, I pulled the dist cap and looked for which pole (on the cap) matched the rotor contact. I shifted the spark plug cables each way, once clockwise and once cc. It wouldn't even start. However, I am not entirely sure I understood this properly so maybe I need to do something different?

I smell gas on all the spark plugs when they are pulled and the fuel appears to be clean and flowing well through the filter.

The poles on the distributor cap are not worn evenly. The 2,4,6 have more corrosion, while 1,3,5, look nice and clean. I cleaned all the terminals but no help. Also, the 1,3,5 plugs looked textbook brown, while the 2,4,6 look black (rich). These seem to be related to me. The cyl isn't firing, thus coating the plug and the voltage passes back through the cap (Maybe...maybe not?)

Sorry for the long winded post...just easier to get it all out there in one shot.

I am quite new to this, so if possible, err on the side of to much detail! thanks in advance.

 

You're probably one pole off AND 180* out,

OR you've got an even fire dist and/or possibly a tooth off.

Is it points or HEI? Can you post pics of your dist? Can you pull the rotor and inspect the lobes to see if the are even or odd? Pics of the cap?
There is an excellent OF V6 article linked in the Tech section. Here is a pic from that link, note the uneven spacing of the lobes:
http://home.off-road.com/~merls_garage/oddfire/pdist.jpg

Clean up the even side plugs to reduce the variables.

 

thanks.

It is not HEI.

Ok, I am editting this b/c I found the tech article you mentioned. An even points dist cap should work. I also noticed mine seems to have some wiggle to it, about as much free play as the contact tabs are wide.

I will look into your suggestions today and try to get some pics.

 

boy a guy tries to make a freakin joke around here and the post gets deleted....thats messed up...time to find a non communist webpage....

 

There's also a difference between Delco and Prestolite, Delco probably being preferred by most. The Delco version has a metal tabbed "window" for adjusting dwell.

In order to make sure a points distributor is infact an odd fire dist, you pull the rotor and inspect the lobes on the shaft. An even fire are evenly spaced, an odd fire has a flat-flat-hump-flat-flat-hump pattern to it. Sorry, don't know how better to describe it. The hump is narrow in comparison to the flat spots. If need be, parts are easy to come by, post up a Classifieds ad or PM me if you need anything; I've got a couple spares laying around.

I think it's just because this is the tech section, and trying to keep posts tech related. Plenty o' folks have ripped on the Hurricane and "odd" comments about the Dauntless in the OT without deletion. I would say with a great deal of certainty that the page doesn't affiliate itself with communism, or any political party for that matter, and has even fought off Billy's "Viva la Resistance" on more than one occasion.

 

ok...pulled the cap and rotor off and snapped a few pics.
distributer cap

rotor

distributor


I think that last picture shows that the distributor is an oddfire. If the distributor shaft is hexagonal, then every third one has a bump, while the other 4 are flat.

So...if it is out 180 and off a pole, I need to pull the distributor and start fresh.
If so, how does the distributor come out?

thanks

 

That's a Delco.

Yup.

Rotate the engine to #1 TDC. This will be the zero mark on the balancer, piston at all the way up. You can pull the #1 spark plug and stick a straw in to verify.

Theres a hold-down at the base of the dist. One bolt removes it. Pull the cap aside. The dist should come right up.

 

thanks very much for the info jayhawkclint.

I set #1 cyl to TDC and observed that the rotor contact was pointed at #3. This would be 180* out and one pole off I guess?

Now, does the engine actually care? Let's say I connect the #1 spark plug to the number 3# dist cap point and shift all others accordingly, so spark plug #6 would be connected to dist cap point #2, and so on.

The spacing in degrees (for lack of a better term) would be fine. The dist cap spacing would also be ok.

The firing seq. is 0* (#2), 90* (#1), 240* (#6), 330* (#5), 480*(#4), 570* (#3) and 720* (#2).
That is a spacing of 90, 150, 90, 150, 90, 150. connecting #1 plug to #3 cap and so on like explained above would lead to a firing spacing of 90,150,90,150. Since it is odd->odd, the spacing of the firing (90,150...) and dis cap (45,75,45,75...) stays the same. So my question is, is the only reason this doesn't fire is b/c the rotor contact is asymmetric or can the timing be adjusted so that it fires without removing the distributor?

This is more for my own understanding than anything...I am going to pull the distributor and reset it, but I was just curious.

thanks

 

I attempted to remove the distributor last night but had a little trouble. The bolt holding it in place was very difficult to get too and after loosening it a little, I was not able to get the distributor out or rotate the shaft 180*. I didn't want to pull the tab and bolt out b/c there would have been NO way get it back in.

Anyway, I decided to retighten the distributor in its initial place. It shifted a little and now the engine fires on 1,2,3 and 5. Only missing on 2 and 4. Hmm. Does it sound like it is just a timing issue now? I rotated some spark plugs and wires and verified that they all work when connected to #2 cyl. So, I know I am getting fuel to the passenger bank, the plugs and wires are good. The only thing left is timing right? Or a bad distributor cap?

How do I remove the distributor? Does that bolt and tab come completely out?

thanks again!

 

best thing to do in my opinion is to pull the dist out, bring engine up to TDC, then reinstall the dist.
the bolt needs to be removed along with the holddown.
you might have to really wiggle and pull the base at the same time to get it to come out.
It's a tight machined fit.

 

the firing order on the cap is 1-6-5-4-3-2.
#1 would be in about the 8-9 o'clock position
looking down on the dist over the drivers side fender

 

Why?

It could be that you weren't 180* out, that you just weren't at TDC when you observed the rotor pointing at #3, and instead you're just a tooth off.

I agree with Jim, you need to get that engine back to TDC and set the dist in there with #1 indexed properly and the correct firing order on the correct posts.

 

it was such a pita to get a socket/wrench on that bolt and holddown that I was a little worried I wou;dn't be able to get it back in. Tight squeeze in there and the bolt is a tight fit.

Does the eintire distributor rotate (with the vacuum port mount, etc) or just the distributor shaft?

I will give it a go again tonight.

 

your friedly napa store /harbor frieight has a special wrench for gm distributer bolts you wont regret having one you dont use it often but it keeps the bad language down

 

i thought the cap was even fire, but b/c the rotor has an asymmetric contact tang, 50% of the time it fires on the leading edge and 50% it fires on the trailing edge. So an even fire cap works with an oddfire engine b/c of the rotors asymmetry.

It is in this link...1/2 way down
http://home.off-road.com/~merls_garage/oddfire.html

thanks for the help. i will have at it tonight.

 

Maybe you're thinking of the HEI cap? Kercher's looks Delco to me, too.