I replaced mine with an "upgraded" one, it did make it run a bit nicer, but the cold start issue remained. I noticed if I feathered the pedal when starting, just tapping a few times very lightly it started right up but if I pushed down the pedal to floor it did not. But it would not start the first crank at all and I needed to switch off and on again, then on second crank it would start right up usually. I traced to corrosion in the plug to the throttle position sensor. Cleaned that up and vroom, starts now without even touching the gas pedal. Tapping the pedal probably jostled the corroded plug connection into the throttle position sensor and let an extra volt or two into the ECU to tell it to use the startup routine. What I learned: connections first, components second.
I know this is an old video but one thing I'd like to mention for anyone out there in the future - if you're going to clean contacts, make sure to put dielectric grease on them afterwards to protect them! They'll stay cleaner for longer.
Cool !! I just jumped to check out my z31 CAS after watching your video. I cleaned the rotor bering, was dirty and wasn't moving freely. Contact clean also was a useful step. The engine now runs more smoother than before. You get me the problem I was diagnosing long time. Will step farther by requesting the upgraded one. And I appreciate your feedback if the fuel economy has been improved or not.
Hey. Sorry for the late reply. Sometimes my account doesnt notify me about responces. Anyways Im glad it helped you out! I dont drive my z enough at the moment to be able to comment on the fuel economy but hopefully in the future I will be able to take it out more!
great video and info --i have a 1988 300zx 2+2 Z31--had engine rebuilt and it runs fine but sluggest on start up --new wires-plugs -cap-rotor-coil but still turns over too many times before it starts--wheh it starts it runs fine nerver stalls-and maintains rpm fine on highway and no hesitation based on your video the CAS may be my proble --your feeligs Tks lou
That's a great place to start! I finally found mine was due to low fuel pressure so you could check that if the CAS doesn't fix it. I just made a video on how to check
Hey, curious if you know it will be my problem. But my car had a fuel pump issue, took care of it, also went ahead and did the relay. Went to start it and it wouldn't start at all.. swtiched a few fuses, theyre all fine, and after that it had started. But it slowly idled off cause i needed more gas. Went ahead and put more in there, and it wouldn't start anymore... one magical day, someone saw me working on it, "use to have one of them blah blah blah." Told me to unscrew the distributor cap and see if it spun.. it does. So we later on figured out that the car has no spark to it at all. Left the key in the ignition and the car made a very loud noise, followed by white smoke coming from the intake. Went to go starter up and it started again. This time though, it didnt idle off as fast, i drove it for about 10 minutes after going over some railroad tracks, and the car shut off when i tried to push the gas. Changed the fuel filter, and also someone reccomended the ignition coil, NOTHING! So could shit actually be the CAS, and how can i find out?
Sorry it took so long for a reply, sometimes I don't get notifications. Anyways it sounds like there may be a wiring issue of some sort. It's unusual for it to not run and then decide to run another time. It is very common for grounds to become corroded and that could be causing an issue. Have you checked the computer diagnostics? That would be a great first step to see if it's identifying anything as a problem and not allowing it to start.
Late reply, but some additional info for anyone reading through the comments. The CAS can indeed work for.... really however long it feels like it, and then not the next. In my experience, this symptom has more to do with heat than anything. My first bad CAS acted this way. I could drive the sucker for 20 miles before it would start random misfiring. Then once shut off, it would not start back up until the motor cooled down just a bit, not even completely. Changed the CAS, the issue went away.
@@TheZGarage this may sound stupid, but what coil? I'm getting a '86 GLL this weekend, and the current owner had the digital dash refurbished and everything should work, but the tach doesn't read.
Ouestion: did you have to remove the dowels on the underside of the upgraded CAS? One online store stated that they had to be removed as not to damage the CAS because the upgraded unit is for later models. Thanks for your help.
I would replace the CHTS first as that deals with temperature fueling maps and can make it hard to cold start. If that doesn't work then I would replace the CAS as well
Hi i just got a 1985 300zx n/a a few weeks ago and its been giving me issues with starting. I drove it home after work one day and everything was fine, parked it, came out an hour later and it would only click and not turn over. I put a brand new battery in it the day before and everything else was working but the seat belt light was flashing even with it clicked and it didnt used to do that. The next day I push started it and it drove normal but when I parked it I tried to restart it but now it doesn't click at all. I have no idea What the issue is, i heard on newer ones it might be a short but nothing on my model particularly. Any help from anyone is greatly appreciated
Well, the most obvious answer is your starter is just bad. It's not too bad to remove and you could go take it to get tested at a place like pep boys. Other than that, it could be some weird electrical gremlins. Make sure the battery connections are really secure and there is no corrosion on the cables. You could check the fusible links right next to the starter which may show something. I hope that helps you out! Let me know what happens
@@TheZGarage appreciate the info, I'll take a closer look at it later. Also the sensor light has been on, do you think that would have anything to do with it? Thanks
That's interesting. Might be something related but I'm not quite sure what it's supposed to indicate. Try looking in the factory service manual on XenonZcar.com under the reference tab
Hey great video, I'm having a problem revving over 2000 My Zed which is a 1988 Turbo 300ZX It starts up no problem I ran a direct wire to the fuel pump so I can troll it through a switch, but it revs up to 2000 only have changed the math the CHTS but still gives me only 2,000 RPM, please help as you seem to know a lot of what these cars
Hey man my Z does the same thing and I'm suspecting faulty CAS, Tach starts to freak out around 2k RPMs, on cold mornings it will get to about 2400 but on hot days it limits to around 1600 before random multiple misfires, I know it's cutting fuel because plugs are lean burnt, have also replaced CHTS/Harness and Maf, did you ever end up sorting out this issue??
Best place would be a parts car. If you're on the Facebook groups, there are a lot of people who have parts cars and can send one, or if there's one in a local junk yard. If that fails, 300zxpartsforyou.com probably has the entire assembly
Hey I'm getting a 1984 300zx delivered to my house that I'm completely rolling the dice on and it doesnt start so I'll be coming to your videos to get it going again. Is there a way I can directly message u for any quick questions?
Hey man! Thanks for your help with the CHTS. I was wondering, my car also starts fine but idles for about 10 seconds before it idled rough and then dies out. Do you think the CAS is to blame or the CHTS? I only have the money for one right now and I’m trying to fix the one that matters hahah
The Z Garage haven’t done any mods at all. Completely stock. And when I push on the gas lightly, it’ll hesitate and gurgle but if I press it any harder, the car just stalls.
To the best of my knowledge, the fuel temp sensor doesn't affect anything but the tps sensor may be why it boggs down when you push the gas. Is it an auto?
Hey man! How is the Z running now after the install? My Z doesn't start well when it's cold. The RPMs drop to about 600 until the engine warms up, then the RPMs goes back to normal. Did you have similar issues prior? I'm looking into buying a new CAS but kinda don't wanna drop $70 on it. :P
Yeah! My Z is running a lot better with the new cas install. It used to have a mis when running and thats been fixed but I still have issues starting. I know the MAF sensors can go out and that is going to be my next check as Ive already cleaned mine so its gonna need to be replaced which is a bit more than $70. Id say for your car, most Z's drop a bit in rpm when cold so thats probably normal. Have you deleted the Idle Air control valve at all? That might need adjusting if its still on there.
Theres a screw on the side you turn to adjust it but theres a procedure to it. If you have a haynes manual it says in there and i believe the FSM says it as well. You can get the FSM on Xenonzcar.com
I need help! This is an old video but I’m really hoping that someone will see this and be able to help I have an 86 na and 1. It has trouble starting cold or won’t start cold at all 2. It randomly cuts power with what feels like either a misfire or fuel starvation, and usually comes back 3. It’s extremely intermittent and has no pattern, sometimes it’s perfect and other times it’s not driveable 4. I’m getting a code 21 (ignition signal missing in primary coil) but I have all new cap, rotor, wires, and plug I’m stumped please help!!
Have you replaced the PTU with a PRW-2 mod? And you didn't mention the CAS was replaced. Have you at least looked at the current CAS to make sure it isn't corroded or dirty? Usually for cold start issues I recommend replacing the CHTS sensor as its a known failure point and it controls the fueling for starting.
If it's not getting any signal yes, but most commonly it it just really hard to start and it runs rough. Have you checked all your spark plugs and made sure you have fuel pressure? Those are a good place to start
If it's not turning over its the starter or the wiring to the starter. You can jump the starter with a cable to the battery to see if it will start spinning. If it does then it's the wiring to it, if not then it's the starter itself
I replaced mine with an "upgraded" one, it did make it run a bit nicer, but the cold start issue remained. I noticed if I feathered the pedal when starting, just tapping a few times very lightly it started right up but if I pushed down the pedal to floor it did not. But it would not start the first crank at all and I needed to switch off and on again, then on second crank it would start right up usually. I traced to corrosion in the plug to the throttle position sensor. Cleaned that up and vroom, starts now without even touching the gas pedal. Tapping the pedal probably jostled the corroded plug connection into the throttle position sensor and let an extra volt or two into the ECU to tell it to use the startup routine. What I learned: connections first, components second.
I got a non running one and it’s driving me crazy! Replaced coil, have power to coil but no spark at coil whatsoever! All fusible links are good!
Has to be Cas or cpu
I know this is an old video but one thing I'd like to mention for anyone out there in the future - if you're going to clean contacts, make sure to put dielectric grease on them afterwards to protect them! They'll stay cleaner for longer.
Cool !! I just jumped to check out my z31 CAS after watching your video. I cleaned the rotor bering, was dirty and wasn't moving freely. Contact clean also was a useful step. The engine now runs more smoother than before. You get me the problem I was diagnosing long time. Will step farther by requesting the upgraded one. And I appreciate your feedback if the fuel economy has been improved or not.
Hey. Sorry for the late reply. Sometimes my account doesnt notify me about responces. Anyways Im glad it helped you out! I dont drive my z enough at the moment to be able to comment on the fuel economy but hopefully in the future I will be able to take it out more!
great video and info --i have a 1988 300zx 2+2 Z31--had engine rebuilt and it runs fine but sluggest on start up --new wires-plugs -cap-rotor-coil but still turns over too many times before it starts--wheh it starts it runs fine nerver stalls-and maintains rpm
fine on highway and no hesitation
based on your video the CAS may be my proble --your feeligs
Tks lou
That's a great place to start! I finally found mine was due to low fuel pressure so you could check that if the CAS doesn't fix it. I just made a video on how to check
This part is same as used on 240SX model. STANDARD MOTOR PRODUCTS LX653
I have a z32 and its giving the crank angle sensor code but i cant find any videos on it does this happen to the z32’s?
Hey, curious if you know it will be my problem. But my car had a fuel pump issue, took care of it, also went ahead and did the relay. Went to start it and it wouldn't start at all.. swtiched a few fuses, theyre all fine, and after that it had started. But it slowly idled off cause i needed more gas. Went ahead and put more in there, and it wouldn't start anymore... one magical day, someone saw me working on it, "use to have one of them blah blah blah." Told me to unscrew the distributor cap and see if it spun.. it does. So we later on figured out that the car has no spark to it at all. Left the key in the ignition and the car made a very loud noise, followed by white smoke coming from the intake. Went to go starter up and it started again. This time though, it didnt idle off as fast, i drove it for about 10 minutes after going over some railroad tracks, and the car shut off when i tried to push the gas. Changed the fuel filter, and also someone reccomended the ignition coil, NOTHING! So could shit actually be the CAS, and how can i find out?
Sorry it took so long for a reply, sometimes I don't get notifications. Anyways it sounds like there may be a wiring issue of some sort. It's unusual for it to not run and then decide to run another time. It is very common for grounds to become corroded and that could be causing an issue. Have you checked the computer diagnostics? That would be a great first step to see if it's identifying anything as a problem and not allowing it to start.
Late reply, but some additional info for anyone reading through the comments.
The CAS can indeed work for.... really however long it feels like it, and then not the next. In my experience, this symptom has more to do with heat than anything. My first bad CAS acted this way. I could drive the sucker for 20 miles before it would start random misfiring. Then once shut off, it would not start back up until the motor cooled down just a bit, not even completely. Changed the CAS, the issue went away.
If the CAS is faulty, do you know if that'd make the tach not function?
No, the tach is driven from the coil if I remember correctly
@@TheZGarage this may sound stupid, but what coil? I'm getting a '86 GLL this weekend, and the current owner had the digital dash refurbished and everything should work, but the tach doesn't read.
Great, thanks!
Ouestion: did you have to remove the dowels on the underside of the upgraded CAS? One online store stated that they had to be removed as not to damage the CAS because the upgraded unit is for later models. Thanks for your help.
Yes you have to remove the dowels or it won't seat properly and can ruin your Cas disk and Cas itself
Hey mate I have a 86 300zx turbo it’s hard to start but after three goes it starts up and runs fine
I would replace the CHTS first as that deals with temperature fueling maps and can make it hard to cold start. If that doesn't work then I would replace the CAS as well
i have nissan laurel c33 rb20 engine spark problem
Do I have to re time the engine after I replace this sensor? Getting real mixed answers on forums, thanks!!
I don't see where you would have to, no, as all the parts assemble in the same orientation, since they're keyed.
Hi i just got a 1985 300zx n/a a few weeks ago and its been giving me issues with starting. I drove it home after work one day and everything was fine, parked it, came out an hour later and it would only click and not turn over. I put a brand new battery in it the day before and everything else was working but the seat belt light was flashing even with it clicked and it didnt used to do that. The next day I push started it and it drove normal but when I parked it I tried to restart it but now it doesn't click at all. I have no idea What the issue is, i heard on newer ones it might be a short but nothing on my model particularly. Any help from anyone is greatly appreciated
Well, the most obvious answer is your starter is just bad. It's not too bad to remove and you could go take it to get tested at a place like pep boys. Other than that, it could be some weird electrical gremlins. Make sure the battery connections are really secure and there is no corrosion on the cables. You could check the fusible links right next to the starter which may show something. I hope that helps you out! Let me know what happens
@@TheZGarage appreciate the info, I'll take a closer look at it later. Also the sensor light has been on, do you think that would have anything to do with it? Thanks
That's interesting. Might be something related but I'm not quite sure what it's supposed to indicate. Try looking in the factory service manual on XenonZcar.com under the reference tab
@@TheZGarage it ended up being a clip/plug backing out on the starter lol.
I'm glad you figured it out!
Hey great video, I'm having a problem revving over 2000 My Zed which is a 1988 Turbo 300ZX It starts up no problem I ran a direct wire to the fuel pump so I can troll it through a switch, but it revs up to 2000 only have changed the math the CHTS but still gives me only 2,000 RPM, please help as you seem to know a lot of what these cars
Hey man my Z does the same thing and I'm suspecting faulty CAS, Tach starts to freak out around 2k RPMs, on cold mornings it will get to about 2400 but on hot days it limits to around 1600 before random multiple misfires, I know it's cutting fuel because plugs are lean burnt, have also replaced CHTS/Harness and Maf, did you ever end up sorting out this issue??
@@blackpsalmmusic9180 I've replaced the MAF but I had different readings from before and after the harness, so I'm replacing the harness soon
Do you know where to get the discs and washers for the CAS that fit a Z31? Mine are damaged and no luck finding a match. 87’ NA
Best place would be a parts car. If you're on the Facebook groups, there are a lot of people who have parts cars and can send one, or if there's one in a local junk yard. If that fails, 300zxpartsforyou.com probably has the entire assembly
Is it possible to test the part before replacement? I have a 86 300Zx Turbo, that refuses to start
I don't know of any way to test it other than seeing if the ecu is giving a code for the CAS. Have you checked for spark and fuel as well?
New CAS worked great. replaced and the engine came to life, very quickly
Hey I'm getting a 1984 300zx delivered to my house that I'm completely rolling the dice on and it doesnt start so I'll be coming to your videos to get it going again. Is there a way I can directly message u for any quick questions?
You can shoot me an email at Thezgarage.net under the contact section, or on instagram @the_z_garage
@@TheZGarage I need some assistance with the MAF wiring diagram, can you assist by chance
Hey man! Thanks for your help with the CHTS. I was wondering, my car also starts fine but idles for about 10 seconds before it idled rough and then dies out. Do you think the CAS is to blame or the CHTS? I only have the money for one right now and I’m trying to fix the one that matters hahah
What other mods/ repairs have you done to it and does pushing on the gas do anything?
The Z Garage haven’t done any mods at all. Completely stock. And when I push on the gas lightly, it’ll hesitate and gurgle but if I press it any harder, the car just stalls.
Have you checked for any codes on the ecu?
The Z Garage yea I got Code 23 and 42
Tps and fuel temp sensor
To the best of my knowledge, the fuel temp sensor doesn't affect anything but the tps sensor may be why it boggs down when you push the gas. Is it an auto?
Hey man! How is the Z running now after the install? My Z doesn't start well when it's cold. The RPMs drop to about 600 until the engine warms up, then the RPMs goes back to normal. Did you have similar issues prior? I'm looking into buying a new CAS but kinda don't wanna drop $70 on it. :P
Yeah! My Z is running a lot better with the new cas install. It used to have a mis when running and thats been fixed but I still have issues starting. I know the MAF sensors can go out and that is going to be my next check as Ive already cleaned mine so its gonna need to be replaced which is a bit more than $70. Id say for your car, most Z's drop a bit in rpm when cold so thats probably normal. Have you deleted the Idle Air control valve at all? That might need adjusting if its still on there.
I still have the idle air control valve. Do you happen to know how to adjust it?
Theres a screw on the side you turn to adjust it but theres a procedure to it. If you have a haynes manual it says in there and i believe the FSM says it as well. You can get the FSM on Xenonzcar.com
I need help! This is an old video but I’m really hoping that someone will see this and be able to help
I have an 86 na and 1. It has trouble starting cold or won’t start cold at all
2. It randomly cuts power with what feels like either a misfire or fuel starvation, and usually comes back
3. It’s extremely intermittent and has no pattern, sometimes it’s perfect and other times it’s not driveable
4. I’m getting a code 21 (ignition signal missing in primary coil) but I have all new cap, rotor, wires, and plug
I’m stumped please help!!
Have you replaced the PTU with a PRW-2 mod? And you didn't mention the CAS was replaced. Have you at least looked at the current CAS to make sure it isn't corroded or dirty? Usually for cold start issues I recommend replacing the CHTS sensor as its a known failure point and it controls the fueling for starting.
does it have to be tdc
Nope. The CAS disk can only go on in one direction so everything will go back exactly as it should
Would it cause a no start?
If it's not getting any signal yes, but most commonly it it just really hard to start and it runs rough. Have you checked all your spark plugs and made sure you have fuel pressure? Those are a good place to start
@@TheZGarage it ended up being a big vacuum leak. Never replied!
My z is not turning at all I have spark but it wont turn over at all
If it's not turning over its the starter or the wiring to the starter. You can jump the starter with a cable to the battery to see if it will start spinning. If it does then it's the wiring to it, if not then it's the starter itself
I was