Newb needs help with engine sputtering

I tested the vacuum advance by sucking on the end of the vacuum hose. The distributor moved and held so I can mark that one off.

 

So now I am on my way to buy new plug wires. I drove the jeep after checking the vacuum and the back firing is thw worst it has been. Almost everytime I decelerate there are shotgun blasts coming from the passenger side header.

 

sounds like the dwell to me, easy enough to check if you can find a dwell meter. might retard the timing 1 or 2° to stop the backfiring. as i recall the 225 wasnt the smoothest ideling engine, and was that way by nature, something to do with the deg of the cylinders, a slightly steeper depature from the crankshaft makes it run a little rough at idle is the way it was explained to me, this was true for the 231 as well. there was a writeup on the dodge 3.9 as having the same symptoms, and it was a oddfire as well

 

If you are talking about this condition at idle, then you have a problem here. The low idle jets should make a huge difference when engine is a idle. Have you put a vacuum gauge on it and check all readings? Can tell a lot from that.

 

It starts up and idols great. The problem is when I get it out on the road and start to pull off the jeep starts missing spitting and sputtering. When you reach higher RPM.s it smooths out but when you shift to another gear and the RPM.s fall the motor starts running rough again. Then when you let off of the throttle and the Jeep starts to decelerate the exhaust back fires. I went ahead and bought new plugs, plug wires, and fuel filter. I will get it on tomorrow and will see how it does. As far as the dwell goes does anyone know where I can get that tested at? Will Advanced or Autozone be able to do it?

 

Ok so new plugs equaled failure once again. I have a new fuel filter that matches the one that they show in the Chilton manual, but I see nothing on this motor that looks like it. There is the fuel pump and then in between that and the carb is a clear bowl with a filter inside it with 1 inlet and 1 outlet. There is nothing in between that and the fuel cell. The filter they gave me has a 2 inlets and 1 oulet and is metal like most fuel filters.

 

Ok so I have been doing a little reading. Where do I find this ani-back fire valve and how do I check it?

 

If your filter is like mine, the fuel filter actually has one inlet and two discharges. The larger inlet on the bottom is for the inlet fuel line from the tank. The second smaller inlet on the bottom is a return line back to the tank. It is supposed to help prevent vapor lock. The last port is the single outlet on the tank that goes to the carb.

I think my return line under the jeepster is a hard nylon hose. Good luck on the filter.

 

The line from the fuel cell goes into the fuel pump and has another outlet that is capped off. The line from the fuel pump goes to a clear bowl with a filter in it. It then continues on to the carb. I see nothing on the line that looks like the fuel filter I have.

 

Here are some pics of what I am working on. I also took some pics to show the fuel line and the area that Chilton shows where the anit-back fire should be located at. I can;t find either one.

 

Here is what Chilton shows and what autozone sold me for a fuel filter.

 

I had a problem like yours when building my 75. In line 6, but same type of problem. Found it to be the dist. bearing was worn. Mine was a presto lite so I replaced it with an hei . You might want to pull your dist. and check it. Sounds like a timing problem. As for the fuel filter, Advance or Napa sell a filter with just a in and out if that is what you want. Or run a hose back to the tank. Good luck and by the way, you have a great looking Jeep.

 

Thanks Rusty. Now if I can getting running as good as it looks I will be happy. I am going to get new plug wires and swap the fuel filter out. Can anyone help me out with the anti-back fire valve. It shows it in the manual but I can't find anything that looks like it on the motor.

 

I see you have headers on there.Some one removed the emission eq.So you won't have a backfire valve.Do a search with the words air injection tubes 225 and look at the post Injection nozzle by Worth it has pics. of emission parts.

 

That is if this had emission eq. on it to begin with

 

dwell is just a better way to set the points, if you have the delco dist it will have a window in the cap, this allows you to set the points with a dwell meter with the engine running, honestly from what you describe it sounds like the dwell or point gap is off ever so slightly. try opening them up .001" if that dont work go the other way .001" from where they are set now. have you replaced the condensor? it can cause a headache as well
http://www.summitracing.com/search/Brand/Actron/Product-Line/Actron-Dwell-Meters/?autoview=sku

 

i went and dug thru a old book i have, there is no listing for a buick 225 or a jeep 225, the olds and pontiac dwell settings are 31°-34° jeep are the same readings. the chevrolet section calls for 28°-32° dwell. keep in mind 1° dwell is not much at all but does make a difference. i dont know why but gm engines seem to be a bit more tedious on the point settings, than say a f-head or anything else with points that i have worked on for that matter.

 

Thanks guys for the responses. I put new plug wires on it and tightened the header flanges up. I took it for a test run and it is still sputtering but it did not back fire once. So hopefully that is one thing fixed. I do not have a dwell meter where can you get the dwell tested at or do I need to buy a meter?

 

FSM for Dauntless is 29 degrees plus or minus 3 degrees-set with vac advace disconnected.

 

Well I used the dwell meter and set the dwell to 30 degrees. I then reset the timing to 5 degrees above TDC. I took it for a test drive and it was a real improvement. I realized though while I was driving that I forgot to take the golf tee out of the vacuum line and hook it back up to the distributor. I hooked the vacuum back up and it started spitting and sputtering again. Does that mean I need to change out the vacuum advance?