two problems that I need help with.

[greendusk]

Okay maybe I lied it may be three problems now that I think about it.

okay my first problem seems to be little vacuum. I hope the vacuum tester to the AIV solenoid line. I got a reading of about 10 to 15. I was told that it should have been in the high 20s to 30. I have checked everywhere everything seems to be buttoned up. should I try the test from a different line?

The next problem will seems to be my power steering. It seems that the previous owner may have not been using automatic transmission fluid for it. And it seems to pulse on and off. At high speeds it seems to be fine but you know parking lot situation in this it is almost totally gone. I'm debating on replacing the power steering totally.

This one I don't even know how to explain but after changing three of the injectors and having the car run on all six cylinders now it seems like the gas is either on or off. While pushing the gas the car accelerates fine. Once you add speed though throttling the gas becomes difficult it seems to be all out or nothing. I'll try to have a video of this once it stops raining down here.

[CrazedZ32Owner]

yeah this weather blows lol

for the vacuum leak i'd have the car smoke tested... Take off the filter and plug up the intake T and then disconnect your brake booster line and pump some smoke in there and see where it leaks out.... there is a machine for this idk what its called im sure if you google it or call some shops they'll have one

for P.S. problem just flush it and fill it with ATF and see if it helps any...the previous owner put P.S. fluid in my car and my Hicas light would come on and it wouldn't work.... i flushed it and filled it with ATF and it remedied the problem... or at least the light

as for the last one?? i have no idea a video would be awesome lol

[Ace2cool]

Your vacuum issue and the throttle issue may be resolved in one swoop. Try hooking the vacuum tester to one of the barbs on the balance tube. That's where I hooked up my boost gauge for verification of stock boost levels.

[greendusk]

this is where i hook the vac tester.

[es.biggs]

Nothing beats a smoke test for finding a vacuum leak. It doesn't take long so shouldn't be too expensive to have a shop diagnose it. If you can be out there with them and bring that diagram you just posted, that might make it a lot easier.

[Ace2cool]

Yes, that's where I hooked the boost gauge up. I could give a crap about AIV's, lol.

[greendusk]

okay the video for the gas problem doesn't do justice so I decided to try to explain more.

while bringing the car up to speed the car seems to accelerate fine. it's maintaining a constant speed that is difficult. Say for instance I accelerated to 45 mph once I got there and tried to maintain that speed without accelerating more the car would quit giving gas but if I wish to accelerate to 50 mph the car would accelerate just fine.

so right now I find myself giving it gas than posting the keep speed. No way really to maintain a constant speed. This becomes even more apparent at very low speeds say for instance 15 miles per hour the car starts to jerk.

as for the vacuum leak I think the intake manifold may not be sealed 100%

[jeffbball2002]

Does that happen all the time? When the car is cold, warm, hot?

I ask because I recently had that exact same problem. I don't know the exact remedy because I did multiple things at once and I don't know which one fixed my exact problem. For me it was happening the worst when warm. It would still happen a little during cold and hot but driving during warm got so bad that I was started to go crazy. I bought and replaced a new fuel damper, fuel pressure regulator, and fuel hoses. Now I suspect that the main fix was the fuel damper but since I replaced it all at the same time who knows for sure.

I don't know if you know about this... http://www.ttxtz.com/tech.html ... help site but I have it bookmarked and it's my best friend when it comes to this car.

That may not be your problem but I hope it helps a little...

[greendusk]

happens all the time

[jeffbball2002]

Ok, well the fuel damper's job is to keep the fuel going at a constant rate (around 40 psi) which is why I believe that had fixed my problem. I read in the past that you can test the fuel damper by running your car for 30 minutes, then turn it off and unplug the fuel damper and if you smell fuel then it's supposed to be bad. I have never done this myself and I can't verify that it is correct but I did read it on this forum and I'm sure it's correct. I almost forgot I also changed the fuel filter when I did the fuel damper, fpr, and fuel lines. I wanted to do it all in one swoop and that's when my problem was fixed. It also makes things a lot easier when taking it all apart bc you can just cut the fuel lines which is much easier then trying to take it all apart carefully. If you do end up replacing the fuel lines when installing the new ones I recommend putting mild soap on the ends of the new hoses and a little on the inside to ease installation of them. It made a world of a difference.

The biggest problem with this car is every condition in a car is different and i what may have been my problem can be something very different for someone else. Another thread I have referred to at times http://www.premierz.com/300zx-hesitation/. When I had the hesitation I found that it was easiest to start with the simple free things to see if I could fix it without spending any money and then went to replacing parts. I started with cleaning the throttle bodies, the iacv vavle, making sure those hoses (idle air hoses, there's five of them) are not causing a vacuum leak and then moved onto the fuel system. You can also check the tps by checking the ohm's on it with a volt meter. Also make sure you check your air filter, that is something that I overlooked when I was trying to find my problem and my cone filter was completely black... Definitely not ok. Changing that out made a noticeable difference.

Where are you located? I would say you could stop by and I could try to help you with it but I don't even know if you are in the same state as I am. I am definitely not the most knowledgeable Z person but I have attempted and accomplished and learned a lot with this car. Hope this helps...

[greendusk]

Ok, well the fuel damper's job is to keep the fuel going at a constant rate (around 40 psi) which is why I believe that had fixed my problem. I read in the past that you can test the fuel damper by running your car for 30 minutes, then turn it off and unplug the fuel damper and if you smell fuel then it's supposed to be bad. I have never done this myself and I can't verify that it is correct but I did read it on this forum and I'm sure it's correct. I almost forgot I also changed the fuel filter when I did the fuel damper, fpr, and fuel lines. I wanted to do it all in one swoop and that's when my problem was fixed. It also makes things a lot easier when taking it all apart bc you can just cut the fuel lines which is much easier then trying to take it all apart carefully. If you do end up replacing the fuel lines when installing the new ones I recommend putting mild soap on the ends of the new hoses and a little on the inside to ease installation of them. It made a world of a difference.

The biggest problem with this car is every condition in a car is different and i what may have been my problem can be something very different for someone else. Another thread I have referred to at times http://www.premierz.com/300zx-hesitation/. When I had the hesitation I found that it was easiest to start with the simple free things to see if I could fix it without spending any money and then went to replacing parts. I started with cleaning the throttle bodies, the iacv vavle, making sure those hoses (idle air hoses, there's five of them) are not causing a vacuum leak and then moved onto the fuel system. You can also check the tps by checking the ohm's on it with a volt meter. Also make sure you check your air filter, that is something that I overlooked when I was trying to find my problem and my cone filter was completely black... Definitely not ok. Changing that out made a noticeable difference.

Where are you located? I would say you could stop by and I could try to help you with it but I don't even know if you are in the same state as I am. I am definitely not the most knowledgeable Z person but I have attempted and accomplished and learned a lot with this car. Hope this helps...

After watching that video it is kind of funny the first thing we did was pick up the car when it was running on only three cylinders was replaced the spark plugs with some cheap ones from advance. Another thing is the fuel filter was replaced I did this because the one that was in the car didn't even fill the bracket. But the replacement one that advance gave me for the Z. is too big for the bracket. I know that the fuel filter is supposed to fit snugly but this one is way too big with the bracket on the fuel filter making full contact there is still a gap of about an 5 cm or more. those maybe two things that I look into first I wish I never throw away the old fuel filter.
after looking for all the possible vacuum leaks the only conclusion I can come to is that the plenum is not sitting perfectly and there must be a gap between it and the gasket. So I know there's vacuum leaks and I've checked it and the vacuum always shows 10 to 15 of whatever degrees or increment it uses.

I stay in Wilmington and any help from anybody is always welcome especially if payment is just hanging out and having a good time.

[jeffbball2002]

You're not to far away then, only a couple hours. I was actually in Wilmington a couple of weeks ago. Yea the first thing I would do is replace that filter with a oem nissan fuel filter. You can find one on coz or z1. I buy from z1 mostly since they are in GA and their parts get here pretty quickly. One thing that I always do with this car is buy parts that are oem or an upgrade (or better quality). I personally don't like going to advnace, autozone, napa, oreilly's or any random auto parts store and throwing there stuff in my car. Well in my Z. I have a malibu and eclipse that I will do that with but when it comes to the Z quality can make a big difference.

With your vacuum leaks it can be hard to pinpoint. I have never taken the upper plenum off of my Z and I can't honestly say that I would be able to tell if it was seated properly. If you really think it's not then that is definitely a possibility. I do however know that just because a hose looks ok that it doesn't necessarily mean that they are. Those five hoses that I mentioned earlier looked fine in my car and were all secured properly but when they were replaced it was a night and day difference in my car. I never even thought that I had a vacuum leak, I just changed them bc the silicone hoses were only 40$ and I knew mine were still the original with 130k on them. Once I changed them though my car would start and die unless I kept gas on it. After like 15 minutes I thought that maybe I should adjust my idle and that maybe it was just breathing better then ever. It turned out that that was the case. I had to turn my idle screw about 2 full rotations to get it back to where it was supposed to be. My guess is that the hoses had pinhole leaks from being so old that you couldn't really see but even the smallest things can have big effects on this car.

I'm sure I will be in Wilmington again since My wife and I have been talking about going to the beach once the weather warms up but if you need help with something just let me know and you can come out here or maybe when we plan to go out there we can meet up for a little bit or something. I try and do all work on my car myself (never denying help of course) so I can learn as much as possible. So far I have dropped the exhaust, changed to a one piece driveshaft, dropped transmission and changed out clutch, flywheel, and added downpipes. Also installed a full stereo system, pulleys, belts, do all my own fluid changes, hoses and whatever else. I'm looking forward to the day I actually have the time, space, and tools to pull the upper plenum and engine but those will come... one day...