vacuum problem?
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vacuum problem?
I have a 77 Ford 4x4 with 400 engine. Has light knocking noise under light gas pedal load. Thought it was collector gasket on right side exhaust. Changed gasket same noise. Checked timing and when plugged up vacuum line with golf tee to check timing the ticking went away. Put it back on vacuum advance and it began ticking again. What gives? Don't really understand the vacuum scenario. Thank you for any advice. Dean
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vacuum problem?
77's had an EGR setup as part of the emission controls - if it isn't working correctly you will have too much vacuum advance. Is all the original emissions stuff still in place on the motor?
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vacuum problem?
I have edelbrock intake manifold with aftermarket distributor. Everything else is pretty much stock. Would too much vacuum advance cause that ticking sound under light gas pedal load? What would be the cure? Readjust the timing? Thanks for the reply.
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vacuum problem?
Yes, that vacuum advance being to agressive would cause it; I'd check a few other things before blaming it:
Edlebrock makes both EGR and non-EGR manifolds... so that doesn't necessarily mean the EGR has been removed...
if you just readjust the timing you are going to loose power - since you have an aftermarket distributer you may want to check with the manufacturer on how to re-curve the vacuum advance section to be a little more conservative at part-throttle (if you no longer have the EGR setup...)
Edlebrock makes both EGR and non-EGR manifolds... so that doesn't necessarily mean the EGR has been removed...
if you just readjust the timing you are going to loose power - since you have an aftermarket distributer you may want to check with the manufacturer on how to re-curve the vacuum advance section to be a little more conservative at part-throttle (if you no longer have the EGR setup...)
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vacuum problem?
This current topic is about the same problem:
https://www.ford-trucks.com/forums/s...hreadid=138472
https://www.ford-trucks.com/forums/s...hreadid=138472
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