March 31, 20195 yr comment_572259 you are just going to run a quick test, 2 gall should be fine. Link to comment https://www.classiczcars.com/forums/topic/61841-1976-280z-engine-runs-rough-then-dies-will-not-idle/?&page=12#findComment-572259 Share on other sites More sharing options...
March 31, 20195 yr comment_572260 the idea is do you still get those over 40 psi readings with the engine running. Link to comment https://www.classiczcars.com/forums/topic/61841-1976-280z-engine-runs-rough-then-dies-will-not-idle/?&page=12#findComment-572260 Share on other sites More sharing options...
March 31, 20195 yr comment_572261 fyi, the low pressure 30 psi engine off pump on makes no sense what so ever, I am throwing that aside for now. Link to comment https://www.classiczcars.com/forums/topic/61841-1976-280z-engine-runs-rough-then-dies-will-not-idle/?&page=12#findComment-572261 Share on other sites More sharing options...
March 31, 20195 yr Author comment_572262 24 minutes ago, Dave WM said: Next test will be to remove the return line from the fuel rail and have it dump directly into a empty container. Can I do this at the hose the connects to the metal return line by the fuel filter? I ask because of the easy access it would be preferable. Link to comment https://www.classiczcars.com/forums/topic/61841-1976-280z-engine-runs-rough-then-dies-will-not-idle/?&page=12#findComment-572262 Share on other sites More sharing options...
March 31, 20195 yr Author comment_572263 10 minutes ago, Dave WM said: the idea is do you still get those over 40 psi readings with the engine running. So, to be clear, with the fuel return line disconnected and draining into a bucket, if the fuel pressure is still high (like 38-40 psi), then there is a clog somewhere in the fuel rail to the return line? AND, if the fuel pressure is normal (36 psi), then it would indicate a clog in the metal fuel return lines that run under the car. Is that right? Edited March 31, 20195 yr by mbz Link to comment https://www.classiczcars.com/forums/topic/61841-1976-280z-engine-runs-rough-then-dies-will-not-idle/?&page=12#findComment-572263 Share on other sites More sharing options...
March 31, 20195 yr comment_572264 8 minutes ago, mbz said: Can I do this at the hose the connects to the metal return line by the fuel filter? I ask because of the easy access it would be preferable. yes Link to comment https://www.classiczcars.com/forums/topic/61841-1976-280z-engine-runs-rough-then-dies-will-not-idle/?&page=12#findComment-572264 Share on other sites More sharing options...
March 31, 20195 yr comment_572265 3 minutes ago, mbz said: So, to be clear, with the fuel return line disconnected and draining into a bucket, if the fuel pressure is still high (like 38-40 psi), then there is a clog somewhere in the fuel rail to the return line? Is that right? more likely a defect in the FPR. I have a video showing testing the FPR with compressed air. See my youtube channel Dave WM Link to comment https://www.classiczcars.com/forums/topic/61841-1976-280z-engine-runs-rough-then-dies-will-not-idle/?&page=12#findComment-572265 Share on other sites More sharing options...
March 31, 20195 yr Author comment_572266 1 minute ago, Dave WM said: more likely a defect in the FPR. I have a video showing testing the FPR with compressed air. See my youtube channel Dave WM AND, if the fuel pressure is normal (36 psi), then it would indicate a clog in the metal fuel return lines that run under the car. Is that right? Link to comment https://www.classiczcars.com/forums/topic/61841-1976-280z-engine-runs-rough-then-dies-will-not-idle/?&page=12#findComment-572266 Share on other sites More sharing options...
March 31, 20195 yr Author comment_572268 2 minutes ago, mbz said: I have a video showing testing the FPR with compressed air. This video...? Link to comment https://www.classiczcars.com/forums/topic/61841-1976-280z-engine-runs-rough-then-dies-will-not-idle/?&page=12#findComment-572268 Share on other sites More sharing options...
March 31, 20195 yr Author comment_572269 Dave WM: To be clear, with the fuel return line disconnected and draining into a bucket, if the fuel pressure is still high (like 38-40 psi), then there is a clog somewhere in the fuel rail to the return line? (most likely a failed FPR?) AND, if the fuel pressure is normal (36 psi), then it would indicate a clog in the metal fuel return lines that run under the car. Is that right? Also regarding FPR test with compressed air, I do not have an air compressor. It would cost me less to just order the FPR and swap it out at this point. (providing it is the most likely culprit for the high fuel pressure) Edited March 31, 20195 yr by mbz Link to comment https://www.classiczcars.com/forums/topic/61841-1976-280z-engine-runs-rough-then-dies-will-not-idle/?&page=12#findComment-572269 Share on other sites More sharing options...
March 31, 20195 yr comment_572270 I hate to recommend replacement of parts unless you know for sure.. Your call on that one. But 1st things 1st try the return bucket test. I would also like to know the test gauge is working as it should. this would require some kind of comparison test with a known PSI source or a known working gauge. and yes that is the video, you can see how the FPR begins to bleed at 36 psi. Edited March 31, 20195 yr by Dave WM Link to comment https://www.classiczcars.com/forums/topic/61841-1976-280z-engine-runs-rough-then-dies-will-not-idle/?&page=12#findComment-572270 Share on other sites More sharing options...
March 31, 20195 yr comment_572272 33 minutes ago, mbz said: AND, if the fuel pressure is normal (36 psi), then it would indicate a clog in the metal fuel return lines that run under the car. Is that right? yes that OR a plugged return line in the fuel tank. If the tank was coated with a liner like "red kote" and the lines were not blown clear with compressed air, I would be concerned with a clog (that is what the red kote is designed to do after all clog holes...) Link to comment https://www.classiczcars.com/forums/topic/61841-1976-280z-engine-runs-rough-then-dies-will-not-idle/?&page=12#findComment-572272 Share on other sites More sharing options...
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