April 13, 20196 yr comment_573160 if you have no vacuum with with the engine running you are going to have to start listening for an air leak, if its not the EGR anyway (doubt you could hear that). some other leaks missing o rings on injectors, stuck open PCV with massive hole in PCV hose, split vacuum lines. Bottom line is if no vacuum you need to find the leak. Some folks use smoke, plug up the TB inlet, break out a stogie and puff into the brake master vacuum port, look for smoke, Link to comment https://www.classiczcars.com/forums/topic/61841-1976-280z-engine-runs-rough-then-dies-will-not-idle/?&page=18#findComment-573160 Share on other sites More sharing options...
April 13, 20196 yr comment_573161 42 minutes ago, mbz said: Yes on March 31st tests: 4). Fuel Pressure while Sucking on the vacuum hose from the FPR = 40 psi [PRESSURE DOWN] However... I was just sucking on the vacuum line of the FPR when the pressure dropped. I did not test vacuum coming from manifold. So, at this point the next step is to pick up a vacuum gauge and check the intake manifold vacuum going to the FPR? If so, I'll be at harbor Freight first thing in the morning. Just be sure to separate the two things, in your head. You're planning to look at why pressure isn't reducing from an already too high baseline number. Link to comment https://www.classiczcars.com/forums/topic/61841-1976-280z-engine-runs-rough-then-dies-will-not-idle/?&page=18#findComment-573161 Share on other sites More sharing options...
April 13, 20196 yr comment_573162 I mean really, you could just hold your finger over the power brake port, if you have a vacuum you will feel it. Question do your brakes feel like they have power assist? That's another place you can lose vacuum (brake booster). I had a brake booster give out on me, it would leak every time I applied the brakes. engine would die. Edited April 13, 20196 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=18#findComment-573162 Share on other sites More sharing options...
April 13, 20196 yr Author comment_573163 3 minutes ago, Zed Head said: Just be sure to separate the two things, in your head. You're planning to look at why pressure isn't reducing from an already too high baseline number. Yes I understand, and am starting by checking for vacuum reading from the intake manifold that goes to the vacuum line of the FRP. Link to comment https://www.classiczcars.com/forums/topic/61841-1976-280z-engine-runs-rough-then-dies-will-not-idle/?&page=18#findComment-573163 Share on other sites More sharing options...
April 13, 20196 yr Author comment_573164 2 minutes ago, Dave WM said: I mean really, you could just hold your finger over the power brake port, if you have a vacuum you will feel it. Question do your brakes feel like they have power assist? That's another place you can lose vacuum (brake booster). The brakes do not feel mushy (like pressing a marshmallow), nor too hard (like pressing a brick). They feel "normal". Brake fluid levels are good. I did disconnect the vacuum line to the brake cylinder a few weeks back while engine was running and the engine idle went up very, very high, and the idle adjust screw was able to adjust the idle. Link to comment https://www.classiczcars.com/forums/topic/61841-1976-280z-engine-runs-rough-then-dies-will-not-idle/?&page=18#findComment-573164 Share on other sites More sharing options...
April 13, 20196 yr Author comment_573165 Just reading up on the EGR valve, and I can't help but wonder if this all goes back to what was mentioned wayyyyyyy back at the start of the thread, maybe it's a bad water temperature switch? Link to comment https://www.classiczcars.com/forums/topic/61841-1976-280z-engine-runs-rough-then-dies-will-not-idle/?&page=18#findComment-573165 Share on other sites More sharing options...
April 13, 20196 yr comment_573166 and you can feel a suction at the port on the intake then? if that is the case something is just not adding up. Â Link to comment https://www.classiczcars.com/forums/topic/61841-1976-280z-engine-runs-rough-then-dies-will-not-idle/?&page=18#findComment-573166 Share on other sites More sharing options...
April 13, 20196 yr Author comment_573167 Just now, Dave WM said: and you can feel a suction at the port on the intake then? Not sure I follow...... Link to comment https://www.classiczcars.com/forums/topic/61841-1976-280z-engine-runs-rough-then-dies-will-not-idle/?&page=18#findComment-573167 Share on other sites More sharing options...
April 13, 20196 yr comment_573168 finger over brake port on intake does it suck. Link to comment https://www.classiczcars.com/forums/topic/61841-1976-280z-engine-runs-rough-then-dies-will-not-idle/?&page=18#findComment-573168 Share on other sites More sharing options...
April 13, 20196 yr comment_573169 I think it was covered a while back, but the FPR vacuum line is connected directly to the intake manifold. If you have brake booster vacuum you should have FPR vacuum. On the other hand there is a ported vacuum line that only gets vacuum when the throttle blade is not on idle, not closed.  Link to comment https://www.classiczcars.com/forums/topic/61841-1976-280z-engine-runs-rough-then-dies-will-not-idle/?&page=18#findComment-573169 Share on other sites More sharing options...
April 13, 20196 yr comment_573170 if you have a cali car, which I think you do, then the water temp switch turns of until the water is warm. You should not have a vacuum at the EGR when the engine is cold, you can just un plug the vacuum line from the EGR valve. BUT I doubt a malfunctioning water temp switch controlling the EGR would cause this much issue, unless the EGR is hooked to the wrong vacuum port, It should only get what they refer to as "ported" vacuum. The other problem is if the valve it self is stuck open. You need to remove it clean it, and test it for function by applying vacuum to it and seeing if it works as it should per the FSM. Link to comment https://www.classiczcars.com/forums/topic/61841-1976-280z-engine-runs-rough-then-dies-will-not-idle/?&page=18#findComment-573170 Share on other sites More sharing options...
April 13, 20196 yr comment_573171 Maybe you should take a pic of some of the vacuum hookups, specifically the FPR and the EGR. Edited April 13, 20196 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=18#findComment-573171 Share on other sites More sharing options...
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