Jack Pearcy
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Everything posted by Jack Pearcy
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I messed around with mine, it would change slightly in rpm when I adjusted it but then go right back to 2500, I took a video but it won’t let me upload it
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My AFM is brand new so I don’t think it’d be stuck but it might be worth a shot
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That’ll do, thanks!
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Thanks it was a good read, I’ll be sure to reference it if I end up doing any AFM tuning, but I’ll wait until I run the tests like the instructions said
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Sweet! Mines a 78 so I’ll use the former, all my injectors are new and while the CSV isn’t working, it also isn’t leaking, it’s completely gummed up with black soot, I’ll still be doing all the tests to be certain but I’m hoping I won’t have to buy injectors twice. Also for the tests what in line fuel pressure gauge do you use, my local auto parts stores don’t carry them for some reason and a lot of what I’ve been seeing online doesn’t look like it would work.
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If I unhook the 12v clip it just idles at 300 and dies like it’s been doing, if I detach the fuel line it will spray fuel and I will lose pressure to the rail. I think the big takeaway here is that it’s the vacuum create by removing the CSV that allows the engine to idle where it wants with the amount of fuel it’s getting. Since it’s idling at 2500 it’s getting as much fuel as it would need to run at 2500 but at idle so the air fuel mixture is off and it dies. If I close this vacuum and try and open the throttle enough to allow this much air in the AFM picks up that’s more air is entering and dumps even more fuel in, throwing off the mixture again. I wonder if there’s a way to adjust the AFM to put less fuel in aside from opening the bypass screw since that doesn’t allow enough air in to solve the problem. Maybe removing the cover and adjusting the prong? Probably a bad idea but I’m interested to hear what you all think
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At this point I’m pretty certain it’s not a pressure issue, it’s just that the injectors are giving it a crazy amount of fuel and it’s not something that can be tuned away anywhere else but through editing the amount of fuel the injectors are putting into the engine if at all possible. Eurodat thank you so much for the fuel pressure test instructions, I will continue to review them and hopefully find a way to do what I have described!
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I’ve been messing around with the car and it’s stopped doing that, couldn’t tell you why, but I’ve discovered a few things: one is that my newish plugs are filthy black and two that my CSV is broken but in addition to that the engine runs amazing with the CSV removed and the hole it went into left open, although it idles at 2,500 when I do that. It also starts to die if I open the throttle at all. I’m going to run a compression test next but hopefully this info can help lead to a solution.
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Oh that's awesome! Thanks so much for that I'll be sure to try it out and let you all know how it goes! Now on the original topic of this thread I've been running some more tests now that the trans is back in and today I pulled the return line off the fuel rail and ran the car with the fuel pump on and plenty of fuel was coming out of the return line but the car was still smoking and running really rich like it had before. I turned the pump off and sure enough fuel stopped coming out of the rail but the idle cleared right up and it started running great which I still wish I could explain. Since I've replaced the AFM, fuel injectors, fuel pressure regulator, and tried tuning the air-fuel mixture with the screw on the back of the AFM, and ruled out the possibility of a return line clog, how else can I adjust the air-fuel mixture to make it run right? Could this be a problem with my ECM? I didn't think that controlled the ratio but I could be wrong. Thanks to everyone who has replied to my posts you're all awesome I love this community!
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Okay that makes sense, I was only messing around with the slave cylinder because I assumed it would have the same effect, just would be easier to access
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I didn’t compare the pressure plates but I did use the Nissan brand clutch and pressure plate replacements that are supposed to be oem quality
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It didn’t work without grinding, it would go into every gear fine except for 1st and reverse but that was with the old clutch, now with the new one it’s doing the same thing but worse. I decided to test if the clutch was the culprit so I put it in reverse with the engine off and then started it with the clutch fully in and sure enough it just started driving.
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Also here’s a video of my car running with the fpr hose cut and the pump off 03792E8C-1B58-43D2-B07E-DED329CDBFD1.MP4
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I do have a new master cylinder, but I installed it a while ago, it may need to be bled again, as far as the pushrod goes do you mean use the original push rod? I still have it so it shouldn’t be an issue but right now it has the reproduction push rod in it
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No, I haven’t had the chance to mess with it anymore I’ve been pulling doubles everyday in addition to replacing the clutch and flywheel, hopefully I can figure it out today. Now I’ve got another issue as the clutch grinds going into gear even though it’s brand new
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Well at least I’d know lol
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Actually come to think of it this wasn't a stand alone event, when I first got my car moving under it's own power I had vitually no understanding of how the wiring worked and so I bypassed the fuel pump relay with a fuse to prime the engine, took out the fuse stopping the fuel pump and drove the car exactly 3.6 miles before the engine died of fuel starvation. The only issue I had the whole way was if I took it above 4k rpm the engine would start to die out. Eventually I came to a stop sign and made a turn and for whatever reason the car stalled and continued to do so no matter how high I reved the engine up or how slowly I let off the clutch.
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Another thing to note is that I went under the car and checked the fuel pump while the car was running with the switch in the off position, and the pump didn't appear to be running. It was making no sound and when I grabbed it to feel if it was running I felt no vibration or hum other than that of the engine. This was also only a one time deal, every other time I would turn the fuel pump relay off with the engine running the car would die from fuel starvation. Still no idea how this happened but I don't think it was from a swelling fuel line. All of the fuel lines were rotted when I bought the car so I replaced all of them along with the fuel filter in the engine bay.
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The AFM is brand new I bought it because the old one was crap, one thing that I have seen is that there is a fuel pump control relay alongside a fuel pump relay. Could that possibly be controlling the pump at idle and me flipping the switch on the fuel pump relay is messing up the power to the fuel pump? Just a thought.
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Here's the thing, I'm not saying I can explain how or why this happened, I am saying that it did and the point of me posting that my car ran w/o the fuel pump on wasn't to impress you guys it was to voice my confusion as to how that's possible and maybe shed some light on the problem as it is most certainly a symptom.
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My car's a 280z, so it has EFI instead of carbs
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That’s what I thought but the switch was off and when I went under the car the pump wasn’t running but the car was, I can’t explain it, normally the car just dies out pretty quickly with the pump off but it ran for about 8-10 minutes before I turned it off. Honestly I can’t explain how it happened unless there’s another way to turn the pump on other than the fuel pump relay.
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I tried all of the above and no liquid, just the smell of gas, I also just turned the car on with the fuel pump turned off and it’s been idling smooth as silk for about 5 minutes straight and still going strong with the fuel pump turned off, it’s not even smoking
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I pulled the vacuum hose off while it was running and the idle cleared right up, I didn’t find any liquid fuel in the vacuum hose but it does smell strongly of gas
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Okay thanks!
