kastmaster

I had the same problem as described in the first post. My solution was to lubricate the throttle linkage. Now it falls down to idle nice and smooth and quick.

i am agreeing with spacecase. I had a subtle idle problem that was cleared by spraying carb cleaner and brushing off small excess carbon that was accumlating on the butterfly valve of the throttle body. It was preventing the car from dropping to the proper idle. Just my two pennies.

hey thanks for posting this thread. It was definitely helpful for me as well. Sorry to hear that you had to take off the entire head only to find it was just the radiator. But a lesson well learned is right! Very helpful thread.

If I'm not mistaken, yes you will have coolant coming out. I usually hear it's good to do just do a coolant flush while you're changing those sensors. Top it off with the fresh stuff. If I were you, just as a precaution you should relase the pressure (if any) in the coolant system, perhaps remove the radiator cap, etc... I'm actually about to do the same sensor replacements as you, within the next month. Just curious, why are you changing the sensors? To cure a problem of some sort? BTW, where are you buying your head temp switch and thermotime? (I'm looking around to buy them as well, that's why)

Larry, thank you for that link! I check up on the link titled "AAR" and it seemed to confirm the problem I was having. If any luck with the new part installed, I'll be sure to update back for others having same problem. Thanks again Larry, that was a helpful read!

Thanks again for your valuable input!! I finally had a free weekend (busy with school) to pull the Air Regulator off my 280zx after it sat through the whole night, and I looked through the air hole to find that it was almost completely closed (about 1/8" of a gap was opened) I then stuck the Air Regulator in the freezer, let it sit in there for 20-30 mins, and took it back out, and the gap hardly even changed! It was neither completely open NOR completely closed both before and after the freezer test! I have come to the assumption that the inner spring inside is possibly worn out? Let me know if anyone agrees. Time to replace the Air Regulator? NOTE: I did spray the inside with Carb Cleaner to free up any gunk that may have been restricting movement of the spring inside Air Regulator BEFORE i did the freezer test, but it did not help any. Dead Air regulator would justify my wacky stumbling at idle during initial warmup wouldn't it? Have a great weekend all.

yenghua, so you're from Fresno too? I'm from Fresno (Clovis actually) Nice to see a neighboor on these boards As for the post, I agreee with these guys. I was thinking about doing the same thing as you were, when my AFM went bad on me. Have you tried looking online for a used one? I see a quite a few used ones online from N/A 280zx's.

I'm no mechanic, and I am just throwing this out there in an atempt to be helpful, because I had the same problem to diagnose. It ended up indeed being an ignition problem. For my situation, if I drove it medium to hard (in terms of acceleration) then I'd be LUCKY if I could get it to rev past 4,000rpm while on highway. It did feel like a limiter was on mine, but was just misfiring. My solution to my similar problem as you, was to give new spark plugs (I used genuine Nissan) and made sure to gap them to the specs in manual (I think for my l28e it was 1.0mm) Anywho, that's my 2 cents, hope this helps guide u in the right direction! EDIT: I also did replace distributor cap and rotor, for they were showing more scoring than usual. Due to age, etc.

Thank you for the input, my gut has been telling me that there is some kind of flow restriction possible, thus not getting enough fuel pressure. I did some other test to help narrow stuff down. I pinched a fuel hose, right before it connects to the metal fuel rail itself, but after the fuel filter, and the idling did smooth out considerably (not perfect, but I was surprised anyway) since the pinching of the hose with a wide needle nose plier caused the engine to go from the usual initial startup lumpy idle at 500-550rpm, to a more steady and (audibly) stronger 700-800rpm. Doesn't the pinching of the fuel hose line create more pressure in the line? (I just tried this by pure curiosity)

Hey guys, I've been trying for the last 2 weeks to trouble shoot this problem, to no avail, and I wanted to see if any of you wise men (and women) could put in your thoughts before I go and starting buying little specialty diagnostic tools. PROBLEM: -Car ran fine, zero problems a month ago. But was running WAY too rich for smog test. Air Flow Meter was the problem, shop had it replaced and passed smog test with flying colors Ever since that AFM swap, car starts/idles like crap for the first few mins ONLY if it sits for more than 30 mins. Upon initial start up, it usually cranks the first time but does not fire. Second time cranking fires up but ACTS like it wants to die due to not enough fuel (or too much air?) THINGS REPLACED SO FAR TO ATTEMPT TO SOLVE PROBLEM: -New Fuel Pressure Regulator -Swapped brittle vaccuum hose going from FPR to the intake manifold. -New Oxygen sensor -New Fuel Filter -New plugs (genuine nissan NGK) -New Distributor cap, and rotor POSSIBILITES I AM THINKING OF FOR PROBLEM -Possibly a vac leak? Maybe around common spots for Zs like Orings, intake manifold gasket, etc? I read a little trick to detect vac leaks, is to blow a gentle stream of propane around suspected areas of leak, and see if the car "evens out the idle"? Hmmm. -I also thought, possibly a faulty Cold Start valve? Maybe plugged with small debris or something. -I'm also going to try pulling the air regulator (does that sound like a worthy culprit?) and do some visual checking as per the Haynes manual visual inspections. Maybe it's stuck closed? (Since I have to MANUALLY open the throttle plate with my pedal to alow more fuel delivery to the injectors. Let me know if I'm taking non-sense haha Any thoughts? I have to push the accelerator pedal down about half an inch to keep it revved around 1200 rpm, just so it doesn't die on me, and THEN I can feel a change in engine rev after 30 secs of doing this. It's like something is warming up? I'll do my best to post a video of the problem, because I'm sure visuals are more helpful than just words. Thanks a bunch you guys, your help is much appreciated. EDIT: A few more things I've thought of. The new plugs are OEM NGK BPR6ES I have them gapped at 1.0mm (0.039") (As per the Haynes manual specs) Should I perhaps try bringing them down to 0.035"? I was doing a lot of reading in the archives about what plug gaps most of you guys are doing. I mean, there is no missing through the RPM band when accelerating, just missing and chugging upon intial cranking and firing. Just thought I'd throw that in there

As someone who does own an l28e stock, yes it is the same. And yes, to put my two cents in with everyone else, that is indeed the air regulator. Just wanted to further confirm that

naviathan, I did a little research, and found that they offer Aluma Seal that you were mentioning, in both powder and liquid form. Which did you go with? I may have to use it soon. Thanks in advance.

Ahhh, i never thought of that! I will definitely keep that in mind if I still have temp rising issues and/or coolant leaks again. For awhile I thought I had the same problem as you, regarding the bad head gasket. I did not know of that "quick fix" for running it through your system. Looks like I have a little reading up to do. I'm interedted to know if your quick fix really did help, so when time tells, keep us updated. Glad it seems to have stabilized. I've been chasing my annoying overheating problem since February

Beautiful! Love how the powdercoating turned out. I'm jealous haha, looking really clean!

Hi there, I had the same, exact (word for word!) problem not even a few months ago! My problem all started (unfortunately) with a hairline crack on one of the coolant hoses. I'm no mechanic, but since we're in the same boat, have you run your fingers across ALL of the coolant hoses when cold? That's how I found out which hose was slowly dribbling out coolant little by little. I also had to do the usualy coolant fillup every week, so i feel your pain. I've had to replace all the coolant hoses all around, just to make sure. They didn't LOOK old, but the crack on mine was on the underbelly (out of view) side of the hose. Hope this helps. Keep us updated, I'm in the same situation so maybe we can help eachother out Now, my car overheats only with AC on when at stops for more than a few minutes. Time to replace the fan clutch. It's just one problem after another...