91 Maxima-Perfect for a few days-then Dying in the Streets-then Back to Perfect?

[twhite]

Hey guys, I'm new to this forum and can see there's a lot of experience amongst the group, wonder if anyone ever came across this one!?!

This Maxi has been fairly well pampered. It's just turned 100k, still has the original Nissan Tan/Pearl looking good, is always garaged (I work from a home office), lives in sunny/saltless PhoenixAz, and get's routine oil changes and maintenance. This car belonged to the "proverbial little old lady in Sun City" for the first 24k, then I got it in about 1996. (Maxi actually belonged to my dear departed Dad and Mom [not-departed and feisty as the d!ck], so there's some sentimental reasoning for me to want to hang on to her a bit longer.)

Nuf about the history, here's the problem. This car runs perfect 80% of the time, I mean strong and with "ice-cold AC" blowing STRONG. It's got the little VE in it too! The other 20% of the time, it coughs, sputters, occasionally refused to even start. You can smell gas being wasted out the tail pipe and can hear a faint miss in the exhaust, but not gawd-aweful obvious, if you know what I mean. When the 20% happens, It doesn't matter wether it's hot or cold, dry or damp (car condition or local weather:-). It doesn't matter if it's the first or last start of the day? At stop lights, I gotta shut off the AC and throw her in Neutral or she'll rough idle and die on me. Then the next day she's perfect again?!?

Four years ago a local "quick change artist", agh, so-called-mechanic wanted to sell me new fuel injectors for about $1200. It didn't much checking to find that quote was a bit "out there".

My "gut hunch" was telling me that maybe something with the fuel pump or pressures were low. I found that by keeping the tank over 1/2 full of quality fuel, it ran perfect for another almost four years, without new injections.

It's got fairly new plugs and wires (can't see any sparking in the pitch dark). I just gave her a new cap and rotor. I just checked the fuel pump pressure and found it at about 45 psi, I think spec is like 30+/-? I checked the resistance at the injectors all with in that 12-20 ohm range, except #1, which is at 0 Ohms. Clearly that one's junk.

I checked the computer and at the level 3 test it showed code 55.Not really sure if there are tests at the other levels, but I tried that and got:level 1 = Solid Red and Green diodes on, no blinking.level 2 = Red off, Solid Green only diode on, no blinking.level 3 = Red blinks 5, Green blinks 5, repeats.level 4 = Blank, both diodes off, unlit, no activity at all.level 5 = Blank, both diodes off, unlit, no activity at all.(key in "ON" position, engine at warm condition.)

btw, I have checked all the fuses for continuity, up front and in cabin, not by "eyeball" but with voltmeter. Everything on it is OEM (except the oil filter) as far as I know. I had an awesome mechanic a few years ago who worked with me on some of these things and he was a big believer in "real parts".

One last thing, prolly doesn't matter, the heater core started leaking on the passengers foot a couple years ago. Figured it rusted thru? I just bypassed it at the firewall. Haven't missed the heat at all here in the Arizona desert.

Any ideas or suggestions would be "HUGELY APPRECIATED" :-)Tw


Modified by twhite at 4:14 PM 8/20/2006

[audtatious]

Moved to NOM for additional help

[twhite]

Was it something I said? Am I "mal-odorous"?! :-)Come on guys, we're yacking up a storm everywhere else on this forum, but I can't get the first whisper. I know there's a ton of experience here and gotta believe someone may have an idea for me?! Too much detail, not enough? Help! :-)Tw

[twhite]

Hey audtatious You had me "Moved to NOM for additional help". I appreciated the idea, but I haven't had the first bit of feedback of any sort. Any chance of being returned to the regular forum? Thx Tw.

[onosqv]

I just checked the fuel pump pressure and found it at about 45 psi, I think spec is like 30+/-? I checked the resistance at the injectors all with in that 12-20 ohm range, except #1, which is at 0 Ohms. Clearly that one's junk.

Have you replaced the bad injector(s)? Maybe you found your own problem w/ the bad injector... why it only goes bad 20% of the time beats me.

When it goes bad, does it stay bad until you shut off the car? Does the check engine light come on when it's bad?

One thing you could do is to remove the injector plug for the one that is bad, while the car is running perfectly. If it seems to behave like it does that 20% of the time, then it's probably just that injector which is working 80% of the time, and failing the other 20%.

Have you tried cleaning out the throttle bodies/maf sensor/fuel injectors. checking the o2 sensor/coolant temp sensor.

[twhite]

Thank you for your interest "brokeAs240sx", I appreciate it.I have not replaced the injector, am a little "ginchy" about that being a muther of a job, I don't know?

Yes when it goes bad it stays bad at least until I shut it off. Meaning I may restart it once and it's back to right, or it might be 6 restarts and the next day before it's right again.

That's an intriguing thought you had about the #1 injector failing just some of the time, I gotta check the resistance on that while it's acting up and then when it's good, thx..

I have not done the cleaning you mentioned, (other than cleaners thru the gas tank). I would like to do that if I could find a good "how to- pictorial". I say that cuz I like doing it, I've done a fair amount under the hood, rebuilt carbs and even a 4 spd transmission, but I can hardly ID the parts under this Maxima hood, (Chiltons/Haynes assisted or not:). Maybe getting to old to recognize the technology?! :-)

Thanks again, I'll be trying your good suggestions.Tw

[onosqv]

You can try seafoaming... sea foam can be found @ most local auto parts stores & online:

DIY Seafoam Treatment

I did mine when my car was acting a bit up on idle (and I've already fixed the maf/coolant sensor/etc). Definately helped.

Directions are for a 240sx, but you should be able to figure it out for a maxima.

Definately have the injectors looked @, if not by yourself, then by someone more knowledgeable - 240 injectors commonly fail by now, I'm guessing maximas might have the same problem .