Fuel Injection Problem '79

[abl1111]

Aaahh,, keeping an old car running well...

My '79 Type 1 vert fuelie has been acting up. I don't drive her regularly - that could be part of the problem..

There are a few things that have me flustered:

1) She will start readily. Then, once warmed up, the idle comes down and starts to idle erratically. I cannot find any air leaks. If I rev her, she'll respond well, but then more often than not will start to idle erratically.

When I pull the airflow box ( airflow meter ) main plug, while running, her idle will smooth out immediately. Once plugged back in, it will run erratically again. After I take her for a nice spin, I notice that she'll backfire VERY lightly, almost unnoticeably, while down shifting...

Any ideas ?


2) I think she is burning oil after a rebuild just 3000-400 miles ago. I have thought so for 1000-1500 miles. I drive her maybe 300-500 miles a year ( LIFE; kids etc )

Is there a way to confirm if she is burning oil ? And what the culprit might be ?

Oil is not leaking from engine and or oil filter. Rebuild included engine and 'new' Mexican heads ( I wished for rebuilt German heads, but the $400-$500 price tag was steep ). I know this was short sighted ! I adjust the valves to perfection, but they do seem to fall out of adjustment too often. I also time her too. All to spec and I know how to do it very well... Had my dizzy rebuilt from a guy out West - EXCELLENT JOB. All FI wiring original but maintained with preventive maintenance in mind. The whole car is maintained with that mindset...

Sorry for all the info, but maybe some of it can help diagnose...

[SCOTTRODS]

Aaahh,, keeping an old car running well...

My '79 Type 1 vert fuelie has been acting up. I don't drive her regularly - that could be part of the problem..

There are a few things that have me flustered:

1) She will start readily. Then, once warmed up, the idle comes down and starts to idle erratically. I cannot find any air leaks. If I rev her, she'll respond well, but then more often than not will start to idle erratically.

When I pull the airflow box ( airflow meter ) main plug, while running, her idle will smooth out immediately. Once plugged back in, it will run erratically again. After I take her for a nice spin, I notice that she'll backfire VERY lightly, almost unnoticeably, while down shifting...

Any ideas ?


2) I think she is burning oil after a rebuild just 3000-400 miles ago. I have thought so for 1000-1500 miles. I drive her maybe 300-500 miles a year ( LIFE; kids etc )

Is there a way to confirm if she is burning oil ? And what the culprit might be ?

Oil is not leaking from engine and or oil filter. Rebuild included engine and 'new' Mexican heads ( I wished for rebuilt German heads, but the $400-$500 price tag was steep ). I know this was short sighted ! I adjust the valves to perfection, but they do seem to fall out of adjustment too often. I also time her too. All to spec and I know how to do it very well... Had my dizzy rebuilt from a guy out West - EXCELLENT JOB. All FI wiring original but maintained with preventive maintenance in mind. The whole car is maintained with that mindset...

Sorry for all the info, but maybe some of it can help diagnose...

Maybe changing an air filter..... sounds like it's starving for air to me. Back firing could actually be after-firing and would result from the running a bit rich..... Wouldn't be burning the fuel completely, due to lack of air mixture.... leaving a bit of un-burned fuel in the exhaust...... It's probably not going to set a "check engine" light either...