Make it stop!! Literally.. (videos included)

[ngbizzy09]

[youtube]http://www.youtube.com/watch?v=o9eZeJtX ... ata_player[/youtube]
Rpm dip
[youtube]http://www.youtube.com/watch?v=-yiU1NqQ ... ata_player[/youtube]
Rpm bounce 1
[youtube]http://www.youtube.com/watch?v=N8tTr-SI ... ata_player[/youtube]
Rpm bounce 2

Okay, now that you've seen the videos let me explain the main problem that I'm having. My car is a 1990 automatic na 100% stock other than catbacks btw. When I approach stop signs or lights the transmission acts like it is still in gear and tries to push through the brakes. Imagine trying to approach a stop in fourth gear, foot on brake but not on the clutch. Then just as you are about to stop it snaps out of it and acts like you shifted into second or first and hit the clutch. But it doesnt always snap out of it.. I replaced the brake booster hoping I was loosing vaccuum when applying the brakes, and it helped make the pedal less firm so I stand a chance against the pushing. Now I've got the idle bouncing issue sometimes when I'm accelerating, sometimes at part throttle cruse, and sometimes upon deceleration. All have their negative effects as you can imagine.. When accelerating it comes as a power no power power fashion, cruising it causes the car to buck/trailer hitch, and when decelerating it is very frustrating/scarry trying to bring the car to a halt.
Any ideas? One other thing, the rpm bouncing also varies with the transmission fits, sometimes not very bothersome, and sometimes like in the video very violent and uncontrollable. This leads me to believe that perhaps they are related somehow? Please help!!! New tps as of last summer, recent maf, base idle set per tutorials, iac valve cleaned, coolant temp is in the required ohm readings at relevant temps, checked for codes found a non-helpful 55, idles perfectly at ~1000 in park and ~850 in drive. I've done my homework and searched a bunch. This one has gotten the best of me though. Thanks everyone.

[A Paratroopers 300zx]

My best guess is your automatic transmission is jacked up. It sounds like it doesn't want to pop out of the gear that you're cruising in when it needs to. It may need to be rebuilt, but I'm not 100% sure because I lack a considerable amount of info on the auto transmission.

[sexyfatkid21]

1990 auto-trans 300 zx
135k same problem only mine is in the 400-1000 rpm range, has the same under braking circumstances and bounce"s up and down. I assume because you have a brake booster is why yours has a high range of bounce to it. Only perfomance mod i have is an AMS underdrive pully.I too will keep my eye on this thread for any possibly advice

[ngbizzy09]

Ok a little update here.. The bouncing issue just magically disappeared but now the issue I am having is no power in the low end. Like sometimes when I go to turn into traffic or go through an intersection, the car will only go like 5-10 mph no matter how much gas I give it then it will snap out of it and go like hell. So I have been trobleshooting as usual. No engine codes, and cannot get any codes out of trans computer, nothing, not even an ok code. Checked out the maf, couple of things here.. First I found that the maf connector has five metal inputs but there is only four prongs on the maf itself. Is this normal? It is a reman but peeling off the sticker revealed Nissan part number 74-10051-C which according to google is a 300zx maf. Can someone confirm this? And another thing I thought id try.. I took off the maf, started the car, put my hand over the intake tube and the tube collapses, car ALMOST dies, but barely stays running. I think I had a pretty good seal judging by the perfect red ring on my palm. Does this indicate a vaccuum leak somewhere? I thought I could hear a faint hissing from the iacv area while I had my hand over the intake but couldn't reach my ear over there obviously lol. And last but not least, sometimes on the first start of the day, when engine is completely cool, the car will be running on 4 or 5 cylinders, but by the time I back out of the driveway I have all 6 again. Adding lucas fuel injector cleaner and upper cylinder lubricant makes the problem go away, but if I don't add some with every tank, the 4-5 cylinder start will come back. Maybe I am slowly loosing some injectors? My tailpipes are very sooty black also. Any thoughts?

[Ace2cool]

DO NOT use Lucas fuel injector cleaner or any other type of "fuel system" cleaner. It contains chemicals that are not designed for our "pintle-less" injectors, and will eat the discs of the injectors away. If you have been using that for extended time, the damage may already be done...

As far as the MAF, is it an orange Nissan label under the reman label, and does it have the designation "N62" anywhere on it? That would be the one and ONLY correct MAF for our cars.

As far as the other issues, pull ECU codes and report back with findings.

[ngbizzy09]

DO NOT use Lucas fuel injector cleaner or any other type of "fuel system" cleaner. It contains chemicals that are not designed for our "pintle-less" injectors, and will eat the discs of the injectors away. If you have been using that for extended time, the damage may already be done...

Yes I have read of the old style injectors needing lubricity to function properly and because of the 10% ethanol blend they are putting in fuel nowadays the lubricity is lost. I have read of people using marvel mystery oil to add the lubrication, and that was the idea behind it. As stated in the previous post the Lucas product helps the situation. If I had to guess what probably ruined them is when I first bought the car and was a noob, I figured id do the "responsible thing" and add seafoam to the gas and oil before I did an oil change..

As far as the MAF, is it an orange Nissan label under the reman label, and does it have the designation "N62" anywhere on it? That would be the one and ONLY correct MAF for our cars.

Will check on this today, don't recall any orange Nissan label, it was black next to the flow arrow. Is there a specific spot where the n62 should be?

As far as the other issues, pull ECU codes and report back with findings.

Again no codes/code 55 for ecu as stated in previous post

Thanks for the valuable info ace. Is there anything I could do to perhaps improve my situation with my injectors?

[ngbizzy09]

So it looks like our mafs do only have 4 prongs.. it is weird how my connector has 5 metal slots however.
Ace, this must be the orange sticker you speak of ^^ (not my maf btw!!) I have a white reman sticker where the orange one is, but I think it's safe to say that I have a n62 maf.. Might check spark plugs today, and re-ohm my injectors. Will report on findings.

[NolimitZ32]

Maf has 4 prongs.
1990-1992 NA / 93 TT had old style (pintle-full) injectors, although I still wouldn't run anything but seafoam (toluene) through the gas.

[ngbizzy09]

Alright, got to check out my spark plugs and injectors last night. When I pulled all of the plugs initially, five of them were dark brown and smelled of gas while 1 was very light brown and had no smell of gas. The one that was light brown was located on the #4 cylinder. So keeping that in mind, I started to remove my injector connectors to find that all of them, except my new one, had the famous green build-up I have read so much about. The build-up of the injectors ranged from mild to terrible with relation to front of engine being mild and becoming more severe towards the rear of the engine. In fact, the #6 cylinder had so much green build up, I literally picked out a solid green block of that stuff!!

After cleaning the injector prongs and connectors throughly, I started ohm testing using 12.1 ohms from my new injector as a baseline. All but the #4 injector ranged from 11.9 to 12.1 ohms, with the #4 injector reading 26.5 ohms!!!! Does this indicate that the coil is going bad? Perhaps causing a piss poor spray pattern? The reason I ask is because the car idles so smooth that I would have never guessed I had an injector going bad. Could a weak or bad injector cause throttle tip-in hesitation and, my newest symptom, the HUGE lack of power before 3000rpm? Like the car will literally not go over 15mph until it hits 3000rpm, which takes approximately 5 seconds to get there, not kidding!

So after putting everything back together the car runs 20 times better. There still is some hesitation and the no power issue has improved, but still lingering. Anyway, yay for the stories spark plugs can tell you!

Good day everyone!

[nissanfreak12]

Sounds like the #4 injector is going bad, i would definitely replace that one if you have the funds. Before long it will die and this will cause the hesitation you are talking about. Your coil should be fine, but test it out just to make sure.

Have you tried a balance test to see if the car makes a diff when the #4 injector is unplugged?

[ngbizzy09]

I was talking about the injector coil, that makes it fire, not the coil-pack/COP. No, I haven't tried that yet, but good idea! Maybe that can show me how well that injector actually is working. Does anyone have a good used injector for cheap?! rofl..

[Ace2cool]

Glenn (txq45) should have some on hand. He usually has a thread in the classifieds section.