popping through exhaust SOLVED

[1970440RT]

    Ron, I'll chech the length on the rod the first chance I get.  Hopefully Monday night.  The new owner is coming to pick up the car this sat. so I'm running out of time.  This motor has to come out of this car soon.

Timing:
Approx. 17 deg at a 950 rpm idle and 35 deg. all in at 3200 rpm.  Vacuum advance is unhooked.

The motor does break up in neutral but not nearly as bad as when it is under load.

I initially thought the problem may have been detonation but it sure doesn't sound like it.

[firefighter3931]

 
Timing:
Approx. 17 deg at a 950 rpm idle and 35 deg. all in at 3200 rpm.  Vacuum advance is unhooked.

The motor does break up in neutral but not nearly as bad as when it is under load.

The timing looks good.  What type of MP box is on the car ? Orange ECU ? This problem could still be ignition related, inmo.

Is the fuel line, pickup, tank sock all original ?


Ron

[1970440RT]

 

The timing looks good. What type of MP box is on the car ? Orange ECU ? This problem could still be ignition related, inmo.

Is the fuel line, pickup, tank sock all original ?


Ron

     I originally had a Napa stock replacement ECU on it and changed to a Mopar orange box when I started having this problem.  The ECU swap did not help. 

     The pick up, sock, and fuel tank are all new.  The hard fuel line under the passenger seat is original or replaced by a previos owner.  It actually seems to be in good shape.  I can temporarily run a 3/8 rubber line to by-pass it.

On a side note, how can a mechanical fuel ( the Carter ) pump push so much pressure as a malfunction?  Have you ever seen that before? 

[firefighter3931]

[On a side note, how can a mechanical fuel ( the Carter ) pump push so much pressure as a malfunction?  Have you ever seen that before? 

Carter makes 2 high volume pumps....one high pressure (race/10-12 psi) and the other standard pressure (street/6-8 psi). The race pump needs a regulator or it will overpower the needle & seat while flooding the engine. I have used the 120gph street pump on several motors w/o issue. You want 6-7 psi max for a carburated application....anything more will cause problems.

Ron

[1970440RT]

    Well guys here goes:

     I initially reasoned that if I put the high volume carter on and took it for a quick test drive, the extra fuel would surely solve the starvation problem.  I installed the Carter and checked the pump rod at the same time.  The rod checked out at slightly less than 3.25" but matched an extra one I had on the shelf.  I buttoned everything up and fired it up for a drive.

     No go.  Still missing.

   At this point I was done.   The motor was going to have to come out without the problem solved.    I started to put the tools away when I noticed, by chance, on the Challenger, the vacuum pot on the distributor was at a different position than the vacuum pot on the Charger.  I adjusted the Charger's to match the Chally and fired it.

   NO MISS!!

     I vaguely remember when tuning the Charger this year that I had to adjust the timing a little further than on the other cars to get the marks to read as I stated above.  I didn't think this was unusual especially with the problems I had over the winter.  The timing marks do not reflect the actual timing.  I don't know what could have happened? Damper slipped?  Distributor drive gear?  Oh well, the motor is coming out anyway and I know what the problem was.  Much headache over something simple.  I'll tear into it this winter to find out what happened.

    Everyone... THANKS FOR YOUR HELP!!

side note for Ron: I must have gotten by mistake the Carter race pump.  My plugs are all black because of too much fuel.  The car was actually flooding out and shutting off at idle. 

[1970440RT]

Add:

    The minor timing adjustments I made early on in the process did not affect the miss so I really must have been off.  10 or 15 degrees maybe.  This is weird because the car wasn't overheating or acting strange other than the miss.  Another chapter in the book.

[firefighter3931]

     
     The timing marks do not reflect the actual timing.  I don't know what could have happened? Damper slipped?  Distributor drive gear?  Oh well, the motor is coming out anyway and I know what the problem was.  Much headache over something simple.  I'll tear into it this winter to find out what happened.

    Everyone... THANKS FOR YOUR HELP!!

side note for Ron: I must have gotten by mistake the Carter race pump.  My plugs are all black because of too much fuel.  The car was actually flooding out and shutting off at idle. 

Good work finding the problem. Sounds like the dampner outer ring has slipped for sure. This is a common problem with old balancers. I'll post a link below on how to verify this....it'll give ya something t do while the engine is on the stand. 

http://1970chargerregistry.com/70messageboard/viewtopic.php?t=1885


The strip mechanical pump is fine as long as you run a regualtor in front of the carb.


Ron

[1970440RT]

     Roger that Ron.  Thanks again for all your help.

[firefighter3931]

You're welcome, glad to help.

Ron