Rough under load Options

[Dwagenfuehr]

Let me start at the beginning, 74 2.0 fuel injected. The car has ran great for 10 years one day a few weeks ago after being inspected it started running very rough then died. The one part you never expect to fail had gone. The fuel pressure regulator, as a result I had 80 pounds on the lines for a short amount of time. This has now been replaced back to 29 pounds on the line at idle.

The car idles fine maybe a little dip in rpms from time to time. But the second it is put into gear and start off down the street its very rough lack of power and back firing at me with a white-ish haze left behind anytime under heavy throttle.

I recently upgraded and removed the old points and put in a Pertronix unit. By there recommendations Dwell should be 50+ and its riding right around 75-80.

I was immediately drawn to timing after all this checked out, but I cannot put together how timing would of been thrown out the window just on a around the time drive. My issue with timing has always been, its close enough I have NEVER successfully got timing perfect on this car because I believe the last time we had the motor out the impeller was put on wrong some how. Finding TDC is simple enough by pulling #1 plug out and turning the impeller until it is found. checking to see if the rotor is with in the 12 degree window. and then marking the impeller with white out, even with this being done I cannot find it.

This car has been auto crossed and ran around Texas world speedway un-countable times with the timing "close enough" could this really be my issue?

My other concern is injectors with 80 pounds on them is it possible they were damaged? From my understanding is its probably very unlikely just because of how they are built.

[dr914@autoatlanta.com]

injectors are ok, and if you are SURE that the ignition system is good (I have lost faith in the Pertronix) then you may want to check the head temp sensor

Let me start at the beginning, 74 2.0 fuel injected. The car has ran great for 10 years one day a few weeks ago after being inspected it started running very rough then died. The one part you never expect to fail had gone. The fuel pressure regulator, as a result I had 80 pounds on the lines for a short amount of time. This has now been replaced back to 29 pounds on the line at idle.

The car idles fine maybe a little dip in rpms from time to time. But the second it is put into gear and start off down the street its very rough lack of power and back firing at me with a white-ish haze left behind anytime under heavy throttle.

I recently upgraded and removed the old points and put in a Pertronix unit. By there recommendations Dwell should be 50+ and its riding right around 75-80.

I was immediately drawn to timing after all this checked out, but I cannot put together how timing would of been thrown out the window just on a around the time drive. My issue with timing has always been, its close enough I have NEVER successfully got timing perfect on this car because I believe the last time we had the motor out the impeller was put on wrong some how. Finding TDC is simple enough by pulling #1 plug out and turning the impeller until it is found. checking to see if the rotor is with in the 12 degree window. and then marking the impeller with white out, even with this being done I cannot find it.

This car has been auto crossed and ran around Texas world speedway un-countable times with the timing "close enough" could this really be my issue?

My other concern is injectors with 80 pounds on them is it possible they were damaged? From my understanding is its probably very unlikely just because of how they are built.

[Dwagenfuehr]

Ive never actually had the car running correctly with the pertronix. So no i'm not 100% on them but they are brand new and have helped the time to start greatly.

[Chi-town]

Check the plugs, that much fuel pressure can push right past an injector pintle.

Also check all your hoses for a vacuum leak.

[Dwagenfuehr]

Check the plugs, that much fuel pressure can push right past an injector pintle.

Also check all your hoses for a vacuum leak.

I have replaced the spark plugs since this happened. Wouldn't a vacuum leak cause the car to idle higher than normal?

[mgphoto]

Try replacing the fuel pressure regulator, sounds like that could be the issue. Cheep fix, probably lots of used ones in good shape here.

[Mblizzard]

If you are not sure on the TDC mark have you ever used a piston stopper to find TDC?

https://www.amazon.com/dp/B06X94WSZY/ref=ss...a2-b1026cf64ad1

Good video of what it does here.


https://www.youtube.com/watch?v=2Yh2ZpKHkq4

[Shadowfax]

Mine had a similar issue. Turned out to be a bad MPS. Was going to get it rebuilt but found a NOS unit. No problems since. Might want to check if your MPS is holding a vacuum.

[Dwagenfuehr]

If you are not sure on the TDC mark have you ever used a piston stopper to find TDC?

https://www.amazon.com/dp/B06X94WSZY/ref=ss...a2-b1026cf64ad1

Good video of what it does here.


https://www.youtube.com/watch?v=2Yh2ZpKHkq4

This is a good idea, Ive done the ol screw driver trick for years, I might have to give it a try.

[Dwagenfuehr]

Try replacing the fuel pressure regulator, sounds like that could be the issue. Cheep fix, probably lots of used ones in good shape here.

This has been replaced as I said car is on running on about 29 pounds now.

[Dwagenfuehr]

Mine had a similar issue. Turned out to be a bad MPS. Was going to get it rebuilt but found a NOS unit. No problems since. Might want to check if your MPS is holding a vacuum.

I found a brand new still in the box one a few years ago. Ill have to try and swap it out or try pulling a vacuum with my hand pump.

[yeahmag]

Stop. Do not pass go. Time the car.