Gang -

This is bizarre and I know my mechanic thinks I'm nuts (I'm not arguing that point any more).

My car doesn't like to come home.

When I take it out for a drive, runs great all the way out and on the way home, it runs rough - almost feels likes it's missing. Naturally when I stop by my mechanics shop, it's tight as a drum and running great.

Basics:

440/.030" over one year past 2nd rebuild (balanced, ported heads etc)
10.25:1 (tested)
mild cam
Holley 850, rebuilt same time as motor
Mopar electronic ignition / accel wires and Super coil
Hooker headers
Vacuum at 10 mm, with "cam" oscillations, but yes greater oscillations on the return trip
Heat is NOT an issue, averaging 160 - 165 (both going and coming)
727 with reverse, manual valve body
3.23 rear

Lastly when I try to test almost anything (carb, timing, wires - seems to be running fine - again.

I've got $10 bucks on it just would ranter be out ...

Archer

 

Only because this is what I just went through, does it have a electric fuel pump with a pressure regulator? I drove a 50 mile trip with no problems. Next day the truck "ran out of gas" twice almost within 100 yards from the same spot in the road.

Point being, it acted up on a regular and irregular basis and it turned out to be the pressure regulator. It stuck completely closed when I "ran out of gas" but most of time just ran really bad when I stomped down on the accelerator.

It always ran great idling in the driveway.

Joe.

 

Joe -

Thanks.

Mechanical (Holley) fuel pump and fuel gauge on the carb feed, showing normal pressure.

Acceleration is fine.

I wasn't kidding about it being only on the return trip!!!

Haunted?

Archer.

 

lol, I feel ya archer.my runner does simaler stuff to me. every spring for the last 6 years,i take my car to town put 10 miles on it, t runs great, the next trip to town, something happens. always in the driveway. no lie. pull it out ,let it warm up, runs great. go to back out bang. dies, wont stay running. play with it. find the problem,back it out, runs great, go to leave, dies in driveway. this happens for the first two months os summer. end of Aug. just starts runing no hitchs. drive it a month, then it goes up for the winter. next spring starts all over again.

 

rr -

Just for the record, we're not talking about dying. It's doing doing something that only seems to "measurable" by slight fluctionions in the steadiness of the tach and vacuum gauge. And again, only on the trip home.

When driving with my wife, she can't feel any difference between when I think the car is running "well" and not so well.

Archer

 

Just a shot in the dark Archer but I had almost the same thing going on, turned out to be the coil was getting over heated and suffering from coil saturation - you have compression and the fuel system is good so all that is left is spark, try another coil and dont mount it on the engine .... even the cleanest newest coil can be hiding a problem inside - you could try a inline spark tester from the coil to the cap which will glow very bright and have no pluse..... when it starts to run **** see if it is still the same pluse, if you can see it flashing then the coil is crapping out. might want to make make sure the ignition module is good, same thing will happen when it starts to go bad...... hope this helps you and if worse comes to worse you can always move and confuse the car lol

 

scamp -

That's kinda where I'm headed. It's an OLD Accel Super Coil and might have issues. (And yes, it's mounted on the fender wall, not the engine - and again, it doesn't seem to be heat related.)

Seeing we're talking about a relatively "simple" engine, unless there's a sticky valve, it really does come down to electrical or fuel.

Where do you get one of those in-line spark testers???

Thanks,

Archer

 

i was adressing your'bizzare' part of the post.about odd thingsthat repeat themselves.thats all.

 

It's a mopar.

 

You should be able to get one at any place that sells auto tools, got mine off the snap on truck and it works really good, has a spark plug tip on one end and a wire & boot on the other, I have run engines for hours with one on and it does not effect performance get hot and no shocks lol ..... ignition module and / or coil is gonna be my guess without driving it ..... Scamp