kiboy6

My '83 has been my daily driver since I bought it last September, and by and large it runs great. It has only 105000 miles on it. However, there is definitely at least one thing that is keeping it from running in absolutely peak condition, and in addition I'm worried that if left unattended the minor problems I'm experiencing may become more serious and make my trusty ride unreliable.

I'm hoping that the symptoms below might just be caused by the same factor. I'm very inexperienced as a mechanic but I definitely want to try to learn about and if possible attack any probs myself.

Here are the probs:


1.) The car hesitates a little and is a bit sluggish for the first 5 minutes or so when started from cold. Nothing major, certainly doesn't backfire or anything, but it's definitely noticeable. This seems to go hand in in hand with a kind of breathy pffpffpffpff coming from somewhere under the hood during these first few minutes. This noise is pretty much gone after the first few minutes as the car starts to run fully smoothly.

2.) VERY occasionally, the car has randomly sputtered and stalled altogether after driving fine for over half an hour. When it has done so it has cranked back up successfully right away, only to idle very rough and stall again straight away. Given an hour or so to recover, the car will then run as normal as if this episode had never happened. I think this has happened twice in the last 3 months. I can't think of anything in particular the two days had in common. May both have been very hot days, but I can't even be sure of that.

3.) I'm also pretty sure that the car is guzzling more gas around the city than it should, and perhaps also more than it used to since I first owned it, although I haven't measured it!

I live in CA, so cold weather is not a factor in any of these probs.

I thought the first thing I would do is carry out jfairladyz AFM clean/restore. (http://www.geocities.com/jfairladyz/...?1144191577198)

Could the AFM be the cause of all of the above?

If not, my very limited knowledge was leaning me toward thinking that perhaps the fuel filter or fuel pump needed looking at? Any other ideas?

Many many thanks in advance for your help!

NismoPick

Welcome to ZDriver!

For being an "inexperienced mechanic" as you say, you seem to know a lot about the car.

#1: Sounds more like an air regulator prob (cold air valve to allow more / less air into the intake).

#2 - #3: Have you checked all the basics?

-CHTS
-AFM
-TPS
-O2 Sensor
-Timing
-Spark Plugs
-Cap & rotor
-Vacuum hoses
-All sensor & ecu connections (corrosion can impede performance)

kiboy6

Thanks Nismo,

I know a fair amount about my 280zx just by lurking around this and other forums, but in terms of getting my hands dirty i am indeed an extremely inexperienced (if willing) mechanic.

What I'd really love, would be to have someone advise me on the things to try out one by one to try and diagnose and fix the problems.

I won't necessarily have hours and hours every week to put into it, but i do want to tinker around myself and see what i can do. If i could try one thing and then report back someone kind and helpful like yourself and the others on this board that would be far less daunting then opening the hood and not knowing where to start!


So with that said, do you think the air regulator should be the first thing to check out? Do you think that seems more likely to be playing up than the AFM?

As for checking out the Air Regulator, or indeed the other basics you said I should look at, do you have any recommendations / advice beyond what I would find in the FSM? If there were any links you know of to pages like jgairladyz's AFM guide that would be awesome!

Speaking of that, do you think the AFM could still be playing a part in the symptoms I describe? That first 5 minutes thing is like clockwork, so I was hoping it may be a tell-tale sign of a well-known (easily fixable!) problem


thanks so much again

NismoPick

https://www.zdriver.com/forums/showt...ight=regulator

https://www.zdriver.com/forums/showt...ight=regulator

https://www.zdriver.com/forums/showt...ight=regulator

https://www.zdriver.com/forums/showt...ight=regulator

https://www.zdriver.com/forums/showt...ight=regulator

kiboy6

Thanks for the links Nismo

I guess I will start by looking at the air regulator / cold air valve. From what you are saying that does seem to be a likely culprit for what I'm experiencing.

Are the air regulators easy enough to tinker with, or do you reccommend replacing it?

duowing

Chances are you're going to need to just replace it if bad. Once the Air Regulator fails, there's really nothing you can do to fix it.

For your other issue with stalling out and having problems, my thoughts would lie with the AFM or the Ignition Module, both are easy things to remove and replace. The Ignition has a tendency to start having problems once warmed up, but not so much cold. The occasional problem there might be a sign of a failing ignition.

The fuel pump is also a possibility. A week or so ago I was looking at a 240Z, at times it would run fine, then all of a sudden it would run like crap. Mainly just stalling out and being a pain to drive. It was kind of off and on, turned out it was a bad fuel pump.

kiboy6

Thanks for the tips guys...

I did jfairladyz' AFM clean/restore today. (http://www.geocities.com/jfairladyz/...?1144191577198).

All seemed to go well, but when I was testing the car after replacing the AFM I smelt a bit of gas and to my horror noticed a significant fuel leak from around the front-most fuel injector!

Not good.

Is there any way something going wrong with the AFM "repair" could have caused this?

If not, is it possible that I've had this leak for a while and just not noticed it?
(I have been noticing very poor mpg lately, but i figured that if i had been driving around with gas leaking under the hood I would probably have started a fire by now!)

Pretty bummed by the whole thing...I will attempt to attend to the leak myself (any pointers?) but if i can't I presume it's very unsafe to drive the car to my z-mechanic who's about 20 miles away, no?

Thanks a lot in advance for any advice you can throw my way

NismoPick

Not unless you whacked it while working on the AFM.

Yep.

kiboy6

yep

I definitely didn't whack any of the fuel injectors...is there any way an initial burst of air after I removed and replaced the AFM could have pressured fuel to leak from the injectors as a one off?

I only say this because the leak was so noticeable I can't believe I could have missed it before

As it is, if fuel is continuing to leak I presume it would be unsafe to drive any distance. My Z mechanic is 20 miles or so away (maybe through L.A traffic). I really want to have my car driveable again by Sunday as I was planning a trip to the desert with my friends who are visiting from London

In general, do you think given my level of inexperience I should have a pro look at any fuel leak if it persists? Or is there an easy potential fix I could try?

Thanks so much for any suggestions

duowing

It could even be maybe the AFM was causing running issues, you've had the leak, and maybe you weren't getting a good signal to the fuel injector. You moved stuff around, injector starts working better so you notice the leak. I wouldn't worry too much about it, as every Z I've had comes with leaky injectors.

The injectors are pretty easy to do. It takes a little time at first, but it's not too hard. If you have a haynes guide that will be helpful to follow. You need to relieve the fuel pressure. While car is running lift up the padding and such in the hatch, there's a little connector. Unplug it, watch the car eventually die. Crank it a few times to relieve pressure, then disconnect the battery. Now just start following the fuel rail and any bolts attached to it. I think there are about 4 bolts holding the rail to the intake, then the nut on the power steering tensioner pulley, then another bolt over on the passenger side. Loosen fuel hoses, remove them. Then go loosen the injector screws, and get the connectors off. Pull the rail out.

For reinstallying just make sure you WD-40 the hose of the new injectors and test fit them to the rail. Then pull them off and put the new injectors and new O-rings in one at a time and work the rail into the injector hoses. It's so much harder trying to work the rail back in with the injectors connected.

kiboy6

Thanks Duowing...I do have Haynes so I will try to follow it on this...

Are you talking about replacing all the injectors and o-rings. If so, is there a specific type of injector I have to find? Or are they a generic part I'll find at most auto stores?

Also, do you think that the fact I noticed this significant leak right after "repairing" the AFM could be because I somehow screwed up the AFM? Or is that not even a possibility?

Thanks so much for your reassuring advice

NismoPick

www.autozone.com

I coulda sworn I just answered that question:

lifegrddude

Air won't make fuel injectors leak. Only fuel will. Your injectors' fuel lines are probably old and are starting to weep from the fuel pressure. It's not a huge biggie if the fuel leak is small, you should be able to drive it to your mechanic. However, it's not something to put off either. Changing the fuel injector for the first time will probably take you ~ an hour if you do things slowly like I do. Get that fixed first, and then see if you still have issues with driveability.

As for #2, it could be the coil getting weak, vapor lock, or the ignition module getting old. #3 can be from the fuel leak, and also is your Z an a/t or m/t? With an a/t I was getting ~17-18 mpg in mixed driving, and with the m/t I'm getting anywhere from 21-25 mpg in mixed driving.

kiboy6

Well, amazingly enough when I went back to the car the next day, the leaking area of the fuel line was bone dry even after quite a bit of driving. The car seems to be driving fine now; at least as well as it was driving before I fiddled with the AFM.

If it's not visibly leaking whatsoever, do you think I should still worry about it? I can't be sure if the leak was actually on the injector, or coming somewhere from the fuel rail, but now that it's not leaking at all I wouldn't know what to focus on...

I know that air itself wouldn't make the fuel injectors leak, but maybe after removing and replacing the AFM there was a moment of uncommonly high fuel pressure? Only explanation I can think of, but then I don't know much!

My Z is an a/t, and I think it;s not getting much better than 13 mpg in the city here...but given that there's a lot of traffic and hills here maybe that's not too bad after all

Thanks so much for all of your advice

lifegrddude

I would change that fuel injector before it becomes a headache. Just because it's not leaking now, won't mean that it won't leak again, like during a road trip or a long drive, leaving you stranded, or worse yet with a car-bq. The fuel pressure wouldn't spike unless your regulator is going bad, but that's unlikely. 13 mpg is a little on the low side, maybe your Z could use a minor tune up, and inspect the CHTS, TPS, and catalytic converter to make sure they still in good shape. Even going to the track and making 6-8 passes for the 1/4 mile, the worst mileage I got in my a/t Z was 15.

thxone

If it comes down to it I have an AFM from my turbo...it works perfectly and has already been adjusted. Send me a PM if you need it. Will sell it cheap+ shipping.

kiboy6

Thanks so much for all your advice duowing and lifegrddude

I'm going to go ahead and buy a replacement fuel injector...just had a couple of questions:

The injector sold at autozone doesn't specify if it comes with o-rings and seals.

Whereas the remanufactured one listed here does specify that it comes with all that:

http://www.rockauto.com/catalog/x,ca...4,partGroup,22


Any reason to avoid that remanufactured one?

Also I know it's not ideal, but I can get away with just changing the leaky one right? (I can't afford to buy 6 new ones!). While I have the fuel rail off is there a procedure I can do to check / clean the other injectors?

Anyone have any other advice / warnings before I embark on switching this out?

Thanks so much again.

@thxone: many thanks for the kind offer, but for now I have no indication that anything is wrong with my AFM. If I do find that i need one I will certainly bear you in mind

duowing

I have used the remanufactured injectors for both my Turbo and Non-turbo cars and have had no problems with them

kiboy6

thanks duowing I'll go ahead and buy that one i linked to then. Are there any other hoses/seals etc that I should buy that don't come with the injector?

duowing

Not that I know of. The new hose comes already crimped onto the injector, has a hose clamp with it to connect to the rail, and comes with the O-rings. So as far as that injector goes you're good to go.

kiboy6

awesome...what's your take on switching just one injector out vs switching them all at once? I know the latter is ideal, but if only the front one is leaking will i be alright just switching that one out?

Do you mean that after test fitting it to the rail with WD40 I should
1) attach the new injector to the engine,
2) then reinstall the rail,
3)and finally connect the new injector back to the rail?

If so, can I leave all the injectors I'm not changing attached to the engine the whole time, and remove the rail without them?

In fact, If I'm just changing one, is it still necessary to remove the entire rail?

thanks so much for all your help

duowing

You can change one injector. In my injector experiences the first time I did it, I switched out my injectors for 300ZX injectors I had. These started leaking, I took it all back apart. One of them was just a leak from the hose which was my fault, but then the others were leaking. So I just bought a whole set and did it all at once. You'll be fine with just changing out one injector, you just may end up having to do it again. From my experience, when one leaks, more on on the way.

As for reinstalling basically what I did, I just put some WD-40 in and on the injector hose where it connects to the rail, pushed the injector up onto the rail, so it would help expand the hose some. Then I took the injector back off the rail and installed it into the manifold with O-rings and injector holders, then I put the rail on and then with the injector bolted down to the intake manifold I just worked the injector hose up onto the rail.

kiboy6

Great, I thought that's what you meant. So is there any reason I can't leave the 5 injectors I'm not changing attached to the manifold the whole time? (ie. not remove them with the rail)

runningjalapeno

hi, if you are going to change the injector that is leaking it would be wise to change all the o-rings on the rest of the injectors . you can buy the o-rings at autozone , as for the ignitor there is one on e-bay or autozone sells them for 120.00 dollars with a lifetime warranty also change all your vaccum lines and the fuel filter , i was having the same problem the car would run fine then it would just die ,i would wait 20-30 minutes and it would start right up it was the ignitor. i changed it now it runs great. another thing when the car runs rough in the morning do you have any black smoke coming out of the tail pipe ? if you do the ignition system needs to be checked out plugs, wires, cap,rotor, ignitor, or coil.

kiboy6

thanks for the advice runningjalapeno - is changing the o-rings a very easy job? I just want to keep my novice mechanicing to a mininum for now at least! So if I can just leave the other 5 injectors connected to the manifold the whole time I'd be temtped not to push my luck!

If I am doing it just wanted to check that these are the right ones
http://www.autozone.com/R,APP1172976...ductDetail.htm

Thanks!