Connor280ZX

I understand. Thank you for your help. I will replace the faulty components in the carb before I attempt to tune it further,

Ok, I've gone through the FSM/tuning pages and I have all the screws and knobs adjusted to factory settings. Can't narrow it down too much because my flow meter hasn't arrived yet. BUT! I discovered something interesting. Every time I give the engine around 2/3 throttle or more, the rear carb piston gets stuck up. I pulled down the piston with my finger and the engine started to idle much smoother. I believe I need to replace the needle and needle seat in the carb to fix this. Correct me if I'm wrong.

On the way. In the mean time, I'd like to know how to at least get the car driveable/running on all 6. I left them all the way unscrewed, and for like 5 miles the car ran much better. Still idled very rich, but would run great above 3k rpm. Next day the car would barely start... Screwed the knobs in all the way this time, and car still runs like shit, but now backfires flames out of the exhaust when I try to gas it off of idle occasionally.

Car supposedly ran "perfect" last time it drove 3 months ago according to the P.O... Got the car yesterday with it running super rich. It would only idle on 4-5 cylinders and puff out black smoke, and when throttle was applied, huge pops out of the carbs and the engine would cut down to maybe 2-3 cyl. Today, I unscrewed the mixture adjustment knobs all the way, cleaned the needles and pistons in the carbs (Weren't gummed up much at all) set the timing to 10BTDC, checked fuel pressure (4 psi), ran a compression check (175-185psi on all 6) and verified that the chokes aren't sticking. The car runs much better, but still runs stupid rich, sputters and wants to die out below half throttle. Carb backfire is no longer present however. When I put my foot in it, the engine clears out and pulls good on all 6. Other than that, still having issues. Could this may be related to the carb floats being stuck or something? I'm kind of new to the carburetion game...

I mentioned that when holding the engine speed at 2000 RPM, that the ECU light does not blink, or come on at all for that matter. I've been corresponding with a local shop that specializes is classic Datsun/Nissan cars, and the owner advised that I put a multimeter to the o2 sensor connector and read voltage at 2000 rpm. He told me that the voltage should fluctuate between 0.01-1.4v constantly at that rpm and should not remain steady. The lower the voltage, the more the ECU is trying to enrichen the mixture, and the higher the voltage, the more lean. I'm getting a rock steady 0.021v throughout ALL rpm ranges including idle and 2000 Rpm, which means the ECU is trying to enrichen the mixture. HOWEVER, no matter what I do to change the mixture (pinching off return line, introducing vacuum leaks, unplugging CHTS etc) I cannot get a different voltage result. Tried 3 different o2 sensors and swapped ECU'S but the results stay the same! I'm at a total loss... May the Z gods have mercy on my soul.

Any thoughts? Still having issues

Ok, with the infrared laser thermometer I got 202-206F in front of the cat, and 297-301F after the cat. This was after an 8 mile spirited drive.

Is there anything else besides the CAT temp that I should check before I go back in to smog it?

I'm also getting 21 in/hg of vacuum from the manifold.

Got the valves adjusted, and the car idled smoother for sure. There's hardly any fluctuation in the tech needle now. When I got the car, the o2 sensor wire was severed, and I attempted to reconnect it with a splice connector along with a new sensor. There seemed to be two layers of copper inside the wire, and they may be contacting each other with the way I spliced them together. Not sure if that matters though.

Checked my valve clearances. .007-.009mm cold. Should be. 017mm cold according to the Haynes repair manual. Couldn't adjust them due to the lock it's being way too tight and starting to round off when I turned them. Will have to take it in to get them adjusted.

Are you talking about the teeth being worn? I pulled the oil pump to see if the shaft was lined up correctly (which it was) and the teeth looked fine to me.

Swapped ECU's with one from an '83 Turbo. Green light comes on with key on, but still nothing at 2000 rpm. I also can't get the timing under 22, the dist is turned all the way ccw and that's as far down as it'll go.

I have done resistance tests per FSM at the sensors themselves, and at the harnesses. Both yielded results in acceptable resistance range. There's a receipt in the glove compartment of a work order to replace the AFM and TPS with new units. This was from 2008. I can assume that the AFM is a rebuilt one. In that case, I will re adjust timing before next test. I also found that the inspection light from the ECU is not coming on. Not at they key ON position, or at 2000 RPM.

Car is also bone stock.

It's got a visually good cat on it. No broken/melted cells, and can see right through it. I have not tested before and after exhaust temps yet since I haven't bought an infrared thermometer. I cannot retard the timing past 22 BTDC because the "Functional" test will fail if the timing is set further than 2 degrees beyond factory spec. My N/A failed smog once because timing was set at 11 BTDC over 8 BTDC factory. The spark plugs were all equally dark brownish. If it matters, the results at 2500 rpm were: HC = 285 ppm NO = 131 ppm CO = 0.36% CO2 = 13.4% O2 = 1.7%

I've been trying to get my ZXT smoggsble for weeks now, but for whatever reason it just runs so damn dirty. Results at idle: HC 1042 Max 192. Results at 2500 rpm: HC 238 max 168. This is the third test. First test I got 1459 HC which is insane. Replacing the following seemed to help, but the car is still a GP. NO: 1PPM CO: 0.54% CO2: 13.5% O2 3.4% I've replaced all Vacuum hoses, set timing to 22 BTDC, changed the oil, replaced spark plugs with proper NGK type, ran fuel system cleaner, checked resistance at AFM and CHTS and are within proper resistance, cap and rotor are new and plug wires look new too. New TPS, New o2 sensor, and cleaned electrical connections. Car runs pretty well besides a rough idle and hesitation when cold. Any suggestions? Car was also sitting for 6 years prior.

Car has been scrapped

The car is all original including being all stock in every way w/5speed. We recently got the car running after sitting for a year. We went to drive it the weekend after, and it wouldn't crank. Just a bunch of clicking of the relays. We were told that the starter/starter solenoid was bad, so we replaced that and unfortunately no change. Tried two different IGN switches, two different batteries and terminals. Everything else is working, all the accessory lights and fuel pump work it just wont crank. All of the fuselinks seems to be good, but we replaced them anyway and still no change. Don't want to try and roll start it because the driveway is on the top of a hill, so if it doesn't start we're F***ed six ways from sunday... Is there something else besides the switch and the solenoid on the starter in the circuit that might have gone bad?

Alright, got the new pump, put a few gallons of gas in and sucess!! 31 PSI at idle, 38 PSI free-revving, and 42 PSI under load. She really kicks now! I also found out that my timing was only at 12 BTDC, Bumped it up to 18 BTDC and she runs even better.

Alright, I've just gone through the whole fuel system, and to find that the insert filter in the pump inlet is mostly clean besides a few deposits on the end, and that the pickup screen from the tank is clear from any blockage. Even cleaned off the sender connections a bit, and now my fuel gauge works. I'm going to pull the trigger and get a Walboro type 255 series pump.

Took the good off so I could see the fuel pressure gauge, and once I floor it under load it drops about 10-15 psi.

Well, let me clarify further. Max pressure when free revving: 32PSI, Max pressure when idling 29PSI, max pressure under load: less than 32PSI since it won't accelerate unless I unplug the FPR, which I shouldn't have. If I pinch off the return line so I get 50+ PSI the engine runs like a raped ape unless I lay on the throttle too long which then the pressure decreases too much and I have to let it build up again.

Ok, I understand but I thought I already mentioned that I had already checked all of the major electronic components (ECU, AFM, VCM, CHTS) and everything checked out fine. I'm going off the 1982 FSM, when I said "or something" I meant that I hadn't remembered 100% exactly what it was. Once I get home, I'll find the page and take a picture of it if you'd like. I have no way of checking the fuel pressure when I'm actually driving the car. I'd need $200 more in equipment to route a gauge to the dash. The pressure could infact be dropping when I'm driving under load since it drops under no load. But, replacing good parts?? Come on, it seems pretty obvious at this point, so I just wanted to get final clarification here.

When I pinch off the return line (FPR plugged in) The pressure rises slowly. Watched it come up to 55, then I removed the pinch fearing I would blow a hose, then it quickly dropped back down to 29. However, with the pressure up the engine would rev so much quicker and smoother than i've ever seen it do... I've also noticed that injector #1 loses connection (Stops firing) occasinally. Once i wiggle the connector a bit, or restart the engine it will come back on though. Problably need to clean the contacts, there was white paste all over it.