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changing efi hoses on 78 280z


no.never

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oh i see the mix up, we were talking about vacuum but i was referring to rpm then. sorry about that. vacuum hasn't been measured yet, ill pick up a vacuum and a compression tester.

Oh! OK... Well, if your engine starts out with a slow idle, and then the idle increases as it warms up, you may still have a rich condition. You might also have a bad auxillary air regulator (AAR). Vacuum readings should tell us a lot more.

BTW, the fellow who we helped called himself "argneist," not "angriest." He wasn't at all an angry fellow! :-) I wonder what's happened to him...

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ha that's right! seemed like he got bit by the australian z bug, i hear those are bigger. hehehe

the idle has gone up as far as 2 and gotten stuck there. after a gas tap it decreases to the average 1.5.

oh i did remember one thing about the vacuum while reading the FSM: the oil dipstick. it's loose, may not be sealing properly. i think there's a rubber piece that goes to the top tube or dipstick. or do i have to replace the whole dipstick? that'll pop up in the vacuum test, scratch one leak.

i love the rain. but when it gets between me and the z...

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since i'm checking valve lash i'm also gonna check timing. http://atlanticz.ca/zclub/techtips/timing/mechtime.html

never checked timing before. steered clear of it. another first. no gun necessary? just turning the rear wheels CCW in 4th gets me to TDC?

ugh, forecast gives me rain until monday. maybe i can at least sneak the vacuum test.

Edited by no.never
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Got home and caught a small break in the rain.

Popped the hood and pulled the dipstick, rpm dropped. Put it back, rpm returned, plug sits better than I thought. Pulled the hose from pressure reg, rpm dropped but not as much as the dipstick. Attached tester, vacuum reading was 18 then crept up to 19. Increased rpm to about 3 and the reading briefly dropped to 15 initially, then shot up to 20 or 21.

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Im not sure when your doing the vacuum test. If the engine is not fully warmed up the cold start valve and engine temp sensor could be effecting richness.

Basic vacuum readings.

If vacuum is steady around 17- 20 in/hg thats is normal for a warm engine at idle. Vacuum under that can be caused by small leaks, valve clearance, low compression or efi sensors effecting fuel mixture. If the needle keeps bouncing around then you have something with one or more cylinders.

Have you done the checks Zed mentioned in post 49. It has been standing for some time you could drive it a couple of weeks and see how it goes.

Edited by EuroDat
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Thanks ED. Sorry, did the test after driving 20 min, engine temp normal. I got a healthy reading, but ill try again I did quick. This tester also does fuel pressure. compression tester en route. Y'know, I'm close to the end of my first tank and it seems to be running slightly better and better, may be just me. I don't remember my odo on fill up so no mpg ballpark.

So more info coming up, stay tuned...

Edited by no.never
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Do I understand that you connected the vacuum gauge with the vacuum hose disconnected from the FPR? If so, and if you got a reading of 18 or 19 by doing that, I would say that your engine is running lean. (Pulling the hose from the FPR causes fuel pressure to rise, which richens the mix.)

On the other hand, if you took your reading with the vacuum hose properly connected to the FPR (or perhaps with a T fitting that let you tap the vacuum at that point while keeping the vacuum supplied to the FPR), then your engine is probably pretty close to the right mixture.

FAIW, though, being at the right mixture doesn't necessarily mean your engine is right. You can have problems like vacuum leaks that result in a leaning of the mixture, combined with problems like a misadjusted throttle position switch that results in a richening of the mixture. If the errors in both directions are the same, then the engine will have the right mixture. However, it will still not respond correctly to changes from this operating condition. Just saying...

Yes, you do need a seal on your dipstick. An O-ring may work. I don't know.

If I were you, I would time the engine with a proper timing light. They're not particularly expensive. Depending on how your distributor is functioning, and depending on how the electronic ignition triggers with the magnetic pickup, timing by TDC could give you errors. With the timing light, there's no question that your timing is correct.

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sorry, haven't been able to work on the car. been hanging back home with my childhood dog, after 18 years he's reached the end of the line. plus with the rain i didn't drive it, just warmed it up. yesterday the rain stopped so i drove, all day no problems. got home parked it, after clearing up parking space i went to start the car and it just clicked. car was fine and i couldn't find anything wrong up front. then i noticed all lights weren't turning on. pulled and checked all the fuses and everything was fine. went to start the car and it started fine, headlights were dim as usual but everything turned on. went back to the fuses and i noticed a wire going to the steering column was hot. turns out there's a short when the lights get turned on.

i knew it needed attention when i was checking the electrical and the headlights were very low plus the left was brighter than the right. i thought it was the bulbs but also thought it was weird they were really low even with the high beam indicator on. they turned on last night and i don't drive at night much so i wouldn't have noticed. i'm guessing when i went to move the car i turned the lights on while starting and caused a short. she stayed home today.

i was gonna start a new thread but since you guys helped this guy out with similar problem: http://www.classiczcars.com/forums/thread42858.html

looks like i gotta hit the wiring diagrams and attack the steering wheel. my high beam indicator is always on and the dash lights are low so i definitely need to look in there. i also don't have any fusible links.

Edited by no.never
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I'm sorry to hear about your dog, NN. Cars can wait, but your four-legged friend can't. My son recently put down his childhood dog, but before doing so, he let her enjoy as much bacon as she wanted to eat. Losing an old friend is never easy.

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thanks. he's still around, his legs gave in so he can't get around anymore. we have mixed feelings in the family about putting him down. taking a life is a tough decision but in the end it's mom's house and her call and she opposes. i guess i'll keep stopping by until then. he's a good dog, german shepherd/lab mix. was overprotective, killed animals that dared come in the yard. but very loving and playful, great family dog. the only one that didn't get stolen or ran off from an open gate. i wanted to wait a couple of years after his passing to get another dog, maybe a rescue. but last year, the same time i got my 260z, someone gave me a puppy and i couldn't turn it down. i used to take him home for play time with the senior, although it annoyed the senior. now i'm not too sad since i see some of the senior dog in the pup. and in turn the pup is partially the reason why i have this 280, thus on this forum. the circle of life, mufasa.

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