aminus21

iTrader: (14)

I have a rough idle problem, and have checked pretty much everything. I changed cap/rotor, wires, plugs, and ohm tested injectors. I found a crack in one of the vaccuum hoses that goes from the air intake collector to this black football-sized container under the battery (whats that for??). So next week when I have some time off, I plan on changing all the vaccuum hoses, and also cleaning the TB and IACV valve since I heard those can also cause idle problems.

I want to change all the vaccuum hoses. I think its about time, since most of them are hard, and my car is about 16 years old. What sizes are the hoses, and how much do I need? Can somone give me a rough estimate, like 3ft. of 3x8 hose, or something like that.

I have already ordered the pcv to rear crankcase hose, since that one is different sizes on each end. Thanks in advance for everybody's help..

Wiking

- Cold, hot or both? TPS=cold, O2=hot. Both=none of those.

- Measure MAF.

- New cap may be doa... dead on arrival.

- Check voltage at ECU. Groundings. Connectors cleanup...

eric93SE

iTrader: (1)

If you can afford it, replace all the injectors. Even thought they have the correct resistance, they have a filter screen that gets plugged up, and their are o-rings that leak fuel into the cylinder. As a cheap way out you can remove them and clean their screens and buy a all new seals.

aminus21

iTrader: (14)

The idle will go to like 5500rpm, and then go back up to 7000 at a stop light while in Drive. No codes at ECU, cleaned ground connectors already, and ohm tested MAF. It does this both, when the car is cold or hot. I am planning on changing the O2 sensor anyways. All the injectors were changed at 50k with OEM Nissan ones.

I remember Wiking saying that all vaccuum hoses should be changed at 100k. My car now has 98k. Is there a way that I can find out how much I need to buy? Should I get them from local parts store that sell hoses by foot, or get from Nissan?? and should I also change all those coolant hoses that go to the Air intake collector??

Wiking

- ECU is a lol lottery machine: first need to buy a ticket...

- There are lots too many connectors...try to find them all.

- Was that 7000/5500rpm a typo or actual? Thats not question of idle... U must mean 550...

- Ohm tested MAF? ...but did u check the gradual voltage rise?

- The need for hose replacement can be viewed: take out the engine attached (=typically hot end) hoses. View with good light, press and look for brittles. I just cut off half inch... Bend hoses and look for cracks: if found, replacement keeps towing company bankrupt.

- Do the IACV cleanup: infinidecimally small leak may cause problems. Use liquid sealant if necessary. Even installing the feed tube back may be cause a leak; it may not seat at first 100%.

- If money problems [=too much] go to stealer$hip. Or send a boatload to me and then autozone...


e-dit
Check also Nissan TSB NTB94-085.pdf; idle fluctuation due to filter.
TSB's see for http://maxima.theowensfamily.com/tsb

eric93SE

iTrader: (1)

yeah, I hope that was a typo.

aminus21

iTrader: (14)

yes it was a typo, my bad. i meant 700rpm down to 550.
so has anyone changed their vaccuum hoses?

eric93SE

iTrader: (1)

Idling between 700 and 550 is very normal. You might want to bump your idle speed in park up to 800.

I've replaced all my vacuum lines a few years back, so I don't know lengths or sizes, but make sure they fit fairly tightly. They are all metric, but I don't they they are all whole numbers.

Nickpisp

I would guesstimate that I used about 6 ft of 3/8"