I've had a very similar issue before on the 85 I used to have. In my case I think the issue was a combination of a bad MAF and a bad ground to the crank positioning sensor. So what I would try, if the connector you ordered doesn't fix the issue, is to replace the MAF wiring harness since it seems your issue is in the MAF circuit. The wiring in these cars really seems to be their Achilles heel. Good luck and thanks for the videos!
@TheZGarage5 жыл бұрын
Thanks! I'm going to be getting the new connector installed because I found that is the bad point in the circuit
@franklynpertuz7669 Жыл бұрын
Yes I have the same problem I just got my 85 running yeah Lotto has a lot of wire issues Battleground check the cylinder head sensor
@franklynpertuz7669 Жыл бұрын
Anyways good luck with it
@atomikrobot3000995 жыл бұрын
If you’re going into a STEM field, consider taking a large I/O a/d count microcontroller and wire it into all the sensors (to log all the data). I did this during my EE undergrad while diagnosing my z31 88 Turbo. I had a closed loop issue which ended up being an O2 sensor issue (the O2 sensor behaved perfectly under test, but under WOT it would misbehave - logging all the data made it stand out as the culprit). Maybe try running a temporary harness back to the ECU to rule out the MAF wiring?
@jy12356895 жыл бұрын
Crazy this car made me excited too about my EE classes since it was mostly analog electronics.
@gekkoman4853 Жыл бұрын
What
@stuckonline3985 Жыл бұрын
i may be late to the party but i had this problem about 8 years ago which was a result of water leaking through windscreen into ecu destroying the fuel pump circuit, the fuel pump cuts off about 10 seconds after starting the car unless you put your foot on the gas raising the revs, i have a second ecu that works but it operates on a different o2 sensor so i just added a fuel pump relay that turns on when the ignition is on, car no longer cuts out. if it was an air flow sensor issue it wont happen with sensor unplugged but you also wont be able to go over 3thou revs with no air flow sensor
@worldpeace58493 жыл бұрын
You can send it to rockauto and they will rebuild it.. I had the same issue... after rebuilding the MAF same issues.. it turned out both grounds from the MAF connector need to be grounded to the body. I spliced wired leading from c & d and grounded them to the body - runs fine now. I literally tested all leads to ECU..
@Dookieandsons3 жыл бұрын
I don't mean to be a pain in your ass I just wanted to let you know I really respect your videos I've had these cars for 20 years I know I told you that a million times I've got a picture of me in front of my first one in July of 99 it was my slick top 84 Datsun LOL but I just wanted to tell you that I put your videos playing back-to-back and listen just to learn anything I don't already know and get ideas and advice I listen to you even when I can't watch your videos I just listen through my Bluetooth while I'm walking around at work I've recently started a little KZbin video and I'm going to start making them better but mine's just more less to show off my car and I really don't work like you do on video but I do show off a lot of things and show my new parts but you've motivated me to do the KZbin channel you know I'm not trying to compete against you or anything like that but I just love seeing videos of the Seas when I come across them I had to add mine to it too anyways save as many of them cars as you can busy car anyway I want the z32 I have a 74 240Z it's going to be a strictly v8 car though I wish I still had my 87 but it got stolen when I was in a wheelchair but anyways I'll still have my 86 that I've tried to get you to look at there's multiple videos on my KZbin of it I'm done about everything I want to do to mine other than paid it turbo it and coilover and I'll be finished pretty much
@atomikrobot3000995 жыл бұрын
Compare what values you get at the MAF and at the ECU plug to rule out the wiring.
@TheZGarage5 жыл бұрын
That's a great idea! I'll definitely try it out! Thanks
@WARRIOR4CHRIST70 Жыл бұрын
I love your channel, can you help me with a question I just purchased a 1984 300ZX turbo. And I noticed they have the same cold air intake filter like you do. But he left the old equipment in the trunk. Why is everyone removing the old filter and putting in this cone looking one like you have?
@TheZGarage Жыл бұрын
For me it was mostly because it creates induction noise. The factory box is very good a keeping the noise down and with a cone filter you can hear it a lot better when you jab the throttle. That being said there's really no real advantages in any other regard
@gekkoman4853 Жыл бұрын
Do these cars have IAC valve? If you have to feather the accelerator air may not be bypassing the butterfly valve… could try cleaning
@adamshook60393 жыл бұрын
I'm having the same exact issue with my Z, I went ahead and changed out injectors, FPR, spark plugs and wires and will still have to feather it to hold the idle
@TheZGarage3 жыл бұрын
You may just need to adjust the idle control valve on the side of the intake plenum. I would also check your Tps to make sure it's calibrated properly
@adamshook60393 жыл бұрын
@@TheZGarage awesome Thankyou i will do that! I unplugged that maf and ran perfectly up until 2000 rpm, also running very rich
@adamshook60393 жыл бұрын
I'm also new to these Z engines so learning as I go hahaha
@bryandm74 жыл бұрын
Where could I find a replacement MAF for my Z31? Could I use a Z32 MAF?. My z31 only starts/runs under 2000rpm with the MAF unplugged, won’t run at all with it installed. Any advice would help thanks !
@TheZGarage4 жыл бұрын
You can get them from parts cars, used of course. A lot of people have them sitting around. Or you can send yours in to get rebuilt on rockauto. (they also have a new one but it's 550 dollars)
@guayoz282 жыл бұрын
I am curious to know what the fox to this problem was. Im having the exact same issue. I sometimes start the car and runs fine, after few mins it stalls, sometimes it will run very rough since starting it. i hit the gas and it revs up for a second and comes right down amd stalls or almost stalls. Please help!!
@mrslapside9 ай бұрын
Have you fixed it? I got same issue
@jeffwolfe40582 жыл бұрын
My 85 NA starts but only idles and with and gas pedal it dies immediately. Been trying to figure it out. Would you look to the MAF
@TheZGarage2 жыл бұрын
It's always good practice to clean the maf just to make sure it's reading as accurate as possible, but if it runs well with the throttle pressed slightly, you may just need to adjust your idle and possibly the throttle position sensor.
@stuckonline3985 Жыл бұрын
read my post above, this is a fuel pressure issue. and unfortunately is most likely your ecu, open it and see if anything looks burnt out, if so just rewire a fuel pump relay to the ignition to keep the pump going when the key is on as the ecu will be shutting the fuel supply off again
@jefff10162 жыл бұрын
Did you find what the MAF issue was? Also I have an 86NA which actually runs ok - feels like a bit of stumbling sometimes on idle. I unplugged the MAF and it was definitely worse, wouldn't run at all, just start and die.
@TheZGarage2 жыл бұрын
If it runs bad with the maf unplugged then you have something else going on. I would check timing (mechanical and electronic), CHTS, and fuel pressure.
@jefff10162 жыл бұрын
@@TheZGarage it's a strange one though, like I said it runs pretty good with the MAF plugged in. Believe timing and fuel pressure are fine. CHTS is a big question mark though. Maybe the MAF is slightly off and I've adjusted the idle too low to compensate?
@rawhide12313 жыл бұрын
Hello again guy, was just watching your MAF videos again thinking maybe that has something to do with my current issue in my 85. I have tried all the forums with absolutely no luck so the hunt to find a solution for my mid range power loss continues and it's driving me mad. It's a long story but have you ever had a power loss around 2500 rpm that drops back to 1500 rpm and pulsates back to 2500? I looked through your videos and didn't see anything similar so I thought I would ask you directly. Thanks for your time. LB
@TheZGarage3 жыл бұрын
Do you have an automatic transmission by chance?
@chrisrizo52645 жыл бұрын
Where can you locate the check engine light connecter on the ZX?
@TheZGarage5 жыл бұрын
I'm not sure which connector you're referring to. There is a 'sensor' light in the dash but that doesn't really do much and then there's a diagnostics mode in the ecu
@greasemmonkey5 жыл бұрын
Have you fixed it yet? I’m having the same problem when I unplug the maf it runs only to about 2000 rpm
@TheZGarage5 жыл бұрын
When you unplug the maf that is what it's supposed to do. My problem was actually my fuel pressure. The maf was reading correct but the fuel pressure was too low so it was running lean
@greasemmonkey5 жыл бұрын
Ok I will check it when I get home
@mikecorleone67973 жыл бұрын
My z has the same issue.. I’m trying to figure it out.. the idle smooths out when I disconnect the vacuum on the fuel regulator but has new regulator and new pump.. 🤔
@TheZGarage3 жыл бұрын
Unhooking the fuel regulator will make it run richer and mask any problems. Have you checked the ecu for codes?
@mikecorleone67973 жыл бұрын
@@TheZGarage no codes so far. It just flashes all good
@mikecorleone67973 жыл бұрын
I limped it over to the muffler shop with the maf disconnected because that’s the only way i can get it to idle smoothly.. second time my cat was stolen this month...
@TheZGarage3 жыл бұрын
When was the last time you replaced the CHTS? If it's bad it can idle and run bad without throwing codes
@mikecorleone67973 жыл бұрын
@@TheZGarage it has a brand new chts sensor.. i just replaced it a few days ago thinking that was the issue. Replaced the water pump and timing belt n tensioner while i was in there
@englishbannana12324 жыл бұрын
So my 85 Z31 is having a similar issue but i checked the maf and it looked fine. What my car does is it runs and cranks up just fine but when it gets to a certain RPM it bogs down and doesn't wanna go any higher in rpms. Any idea of what it could be?
@TheZGarage4 жыл бұрын
Does it rev freely in neutral? Have you checked the ecu for codes?
@englishbannana12324 жыл бұрын
@@TheZGarage no its an auto so when its in park or neutral it bogs down. I dont know how to check any ecu codes
@TheZGarage4 жыл бұрын
What rpm does it start to bog at? If it's fine under 2.5k but over it starts to bog, it's definitely the maf
@englishbannana12324 жыл бұрын
@@TheZGarage my rpm gauge doesn't work but it sounds like its around 3 when it bogs down. But again im just assuming. It might be 2 im not entirely sure
@TheZGarage4 жыл бұрын
It sounds like it's the maf. Unplug the maf and see if it changes at all. If it doesn't that's the problem
@legendkiler6194 жыл бұрын
Did you ever fix this bro? I have a similar issue with a rough idle.
@TheZGarage4 жыл бұрын
In my case it actually turned out to be low fuel pressure from a bad pump.
@legendkiler6194 жыл бұрын
The Z Garage Ah well shit. I have a high idle around ~1400 rpm and I’ve tried everything but can’t seem to find the issue. I’ve replaced the intake coupler which had a little hole, all vacuum lines, did smoke test and deleted EGR bc it was leaking I believe, checked TPS, but nothing has changed. Any idea what else I should look at?
@TheZGarage4 жыл бұрын
@@legendkiler619 1400 is pretty high. Adjust the idle down a bit (there's a small screw next to the throttle that it rests on, or the actual cable itself has adjustment nuts) and get it closer to 800-900, possibly higher since you removed the idle air control. Then readjust the tps. If that's still not making it better, make sure to check the ecu for codes.
@legendkiler6194 жыл бұрын
The Z Garage I actually got the block off kit, and deleted the IACV but I couldn’t get the idle screw on the throttle body to budge so I put it back. I soaked that little screw in pb blaster and I’m going to try again tm. When I unplugged the IACV however it did go down to ~900 but it did kinda like “sputter”
@TheZGarage4 жыл бұрын
Did you adjust the tps afterwards?
@jy12356895 жыл бұрын
That looks exactly like my slicktop
@jy12356895 жыл бұрын
White with red interior
@luisantonio52882 жыл бұрын
Mine wont even start without maf
@brandonlyons11192 жыл бұрын
I am having this exact issue on my Z31. Watching this video definitely helps with troubleshooting and diagnostics. Just super close to being able to drive my car again. Once i get the MAF figure out, I'll be able to take it back out on the road. Other than that, what was the ultimate fix you had to do to get your car running again?
@TheZGarage2 жыл бұрын
I replaced my maf connector as I could wiggle mine and hear it change how it ran, and I also found I had low fuel pressure. Those two seemed to fix everything
@brandonlyons11192 жыл бұрын
@@TheZGarage okay cool. I bought a connector on eBay. For checking fuel pressure what are the normal numbers for the pressure and how did you check it?
@TheZGarage2 жыл бұрын
I don't remember the exact numbers. I would look in the fsm on XenonZcar.com to see what it lists, but it's around 40psi. And you just tap into the line after the fuel filter. There's a rubber line that goes to the fuel rail. Just undo one side, use a spare piece and put the gauge right in line. That will be the exact pressure your fuel rail sees
@brandonlyons11192 жыл бұрын
@@TheZGarage sounds good. Thank you so much for the quick responses! I have subscribed to your channel!
@coltonbarney79013 жыл бұрын
How do I tell what maf I need
@TheZGarage3 жыл бұрын
There are only 2. California, and everything else. Just match the color of the label on the maf. It's either blue or yellow
@coltonbarney79013 жыл бұрын
@@TheZGarage oh ok thank you so much
@celsse665 жыл бұрын
Nissan Service Manual 300ZX PDF Format, for free.
@emanuelorozco1439 Жыл бұрын
I’ve unplugged my MAF and my car still won’t start
@TheZGarage Жыл бұрын
Then the maf is not your issue. You should look into fuel pressure, and the crank angle sensor. Check the ecu for Cas codes and put a timing light on it if you have access to one
@emanuelorozco1439 Жыл бұрын
@@TheZGarage so I have done the fuel pump and filter. It has a new distributor which has the cas. My ecu has only given me a MAF code. I think my injectors might be clogged but I’m not sure. Thanks for the reply👍
@TheZGarage Жыл бұрын
I think you're on the right track. Have you verified that the spark plugs are actually sparking?
@emanuelorozco1439 Жыл бұрын
@@TheZGarage I have not yet, but they are pretty black. I’m going to replace them.