yeah thats right. The spary pattern on these injectors is not very ideal as I found out. If you look close to the nozzles of the injectors you should be able to see where the pattern slightly fans out before it continues into a straight stream. The injectors fire in quick bursts, so that fan near the tip of the injector is close to what happens when the injector is fired. The stream never has time to form.

What you experienced with injector #1 is what happens when a partially clogged injector gets cleared up

 

Awesome, so now I'm gonna get some new injector hose and put it all back into my car. I'll upload the pics we took of our awesome setup when my friend sends them to me.

 

Well...I reinstalled my injectors and the car runs pretty much no differently. The car doesn't even seem to start up faster like j said his did. I go to rev it and it just wants to cut out. I'm pretty stumped now. I was thinking maybe the TPS? Anyway when I was switching the TPS one of the adjusting bolts broke. I have no idea how to get at this one to get it out. Man I just can't seem to figure out what the hell is wrong with this car. I'm almost feeling like I should just replace all the injectors also. I went through and started disconnecting the harness for each injector while it was running. As soon as I pulled a clip from each injector the car ran worse. So it looks like all the injectors are contributing.

Edit: When I unplug the #5 injector it does make a difference, but I noticed that there's gasoline in the connector? I'd imagine this means the injector is leaking? Because I don't know how gasoline leaking from the bottom of the hose could get into the injector. Maybe some of them are just plain bad, either that or they were about to go bad and cleaning them up revealed a problem? Also when I got the injectors and everything I turned the key to the on position, then off, then on, off, then on again just to try and make sure I had gotten fuel pressure back in the lines and it took a really long time for the car to crank over. Finally it caught and then died, then I held it and then finally it started. It still doesn't make sense how it ran so well 2 different times then crapped out on me. Would a really leaky injector be enough to interrupt the flow of fuel?

Any suggestions would be greatly appreciated.

 

one leaking injector would make a difference, but not a major difference. I've driven my Z on 4 cylinders and while you could feel the mis at idle and it acclerated rather slowly, to the casual observer it wouldn't appear as if anything were even wrong with it. If the car is having that much trouble then I doubt its that one injector. Have you Ohmed the TPS to make sure it's working correctly? A bad TPS is the reason it took me twice as long to get my turbo Z home as it should have. It made the car nearly undriveable at times and getting it to go over 40-50mph was impossible if most of the time. If I gunned it it would just fall on it's face until I let off the throttle. I tested the TPS and it was sticking. So I replaced it with the one off my NA motor and problem fixed

 

Well I have ohmed the TPS and the tests seemed to show it was fine. I swapped over the one from the N/A and I believe when I OHMed it on my 2+2 it was fine. The car just has to rev really slowly and it seems to be ok, but it will still fall over at about 2500 rpm. Not to mention that the adjusting bolt broke. So I have to try and get that drilled out. I've ordered remanned injectors from rockauto. So I'll put all of those in and see if that makes a difference, I'm going to re-OHM the TPS to see if it's still working. It should be, I just have no idea what it might be. I was thinking maybe an intake leak, but that wouldn't explain how it ran so good, then terrible, but got better when I made it home. Then ran good when I switched the AFM, then after cooling down all the way ran crappy again. I've also done the test where I sprayed brake parts cleaner around to see if I had a vaccum leak and I got no response indicating there aren't real obvious leaks.

Can hooking the injectors directly to the battery mess them up? I remember after I put the injectors back on the rail we tried to do the cleaning test again and we weren't getting anything to spray from the injectors. I don't know if maybe the filter was clogged or we killed the pump or something. Also the 2000 RPM miss that I would normally get seems to be better. Can the ignition coil itself cause problems like this? I've been meaning to swap in my new ignition coil.

 

I am having the same problem as described. The car runs fine when it is cold but when it warms up, it starts to crap out at 2500 rpm.

I have checked the TPS and it seems to be working correctly (as per Haynes manual).

I have checked my fuel pressure and found that it is 28 psi @ idle and if I disconnect the vacuum line to the pressure regulator (i.e. 0 vacuum), the pressure goes up to 37-38 lbs. I have also recently replaced the fuel filter.

When it is relatively cold, the car pulls to over 6000 rpm but when it warms up, it starts acting up at exactly 2,500 rpm.

In my case, I know that I have a problem with my AFM because the resistance between terminals 32 and 34 goes up steadily as I manually move the air flap but it briefly goes to zero resistance as I get to a certain point and then the resistance starts to climb up as I open the air flap more. I can't believe that this is what is causing my engine to not go over 2500 rpm but I will be replacing the AFM as soon as possible (I have tried to adjust it as per the instructions but I can't seem to find a better track).

The problem that I am having is temperature related and I can't seem to figure it out!

BTW, my car is an 82 ZX non-turbo.

Mike

 

Is there a physical difference between the N/A and the Turbo injectors? If you had an injector that was meant for an N/A with 5 turbo injectors, how much of a difference would it make if the other 5 are running. I'm beginning to wonder if the injector the guy had installed was for a turbo or not. Because after swapping the injectors I moved their positions, my 2000 RPM miss is pretty much gone, and now it's at 2500. Anyway I've got new injectors on the way so I'll try those out and let you guys know.

So far:
Swapped CHTS really no difference
Swapped TPS no difference(maybe my connector is messed up, sometimes it seems like it makes a difference, sometimes it seems like it doesn't)
Am getting spark to all 6 plugs
The injectors seem to be firing because when I pull the connector the engine will act worse
Newer Dizzy, Cap, Rotor, Plugs, and Wires
New Air Regulator
Remanned AFM
Last I checked Compression was perfect(I don't believe compression is an issue considering it was running really well the other day after it had started this crap.)
Cleaned some connections
New Pressure Regulator that seems to be working correctly.
Ignition timing set between 20-24* before TDC
Relatively new Fuel Filter
New O2 Sensor
Fuel pressure shows 28psi at idle and 37 at full throttle

Finally for some reason my idle seems to be kinda high over 1000 RPM, is there a way to adjust that does that hint at something? I don't believe there's an intake leak either because it wouldn't make sense that the car would randomly run at times then randomly run bad.

 

The non-turbo and turbo injectors are different. The turbo injectors are higher flowing. However, it's not likely that the non-turbo injectors would cause severe issues at only 2500RPM's. They should be able to keep up well past that point. It would be in the upper RPM's that they would start to lean things out. The ECU would compensate for their lower flow rate up until the injectors just can't flow anymore.

 

Well I guess at this point I'll just recheck the TPS and see if those remanned injectors change anything.

 

Ok started messing with my TPS and I noticed on both of them I was getting no continuity at Idle, so I started adjusting the TPS until I got continuity from it. Then I kept messing with it until the point where it was that basically as soon as I touched the throttle it would shut off. That seemed to help the car out alot better. I got a bunch of consecutive revs with alot more pedal than normal. It would still kinda sputter but catch and keep going with harder throttle. Idle was alot better in Drive/Reverse and Park/Neutral. The Neutral Idle is still a little higher. I think my number 6 injector at this point is almost contributing nothing. It's leaking from everywhere. So maybe I'm finally onto something. I look forward to getting newer injectors in there and see how that helps.

 

now it sounds like you've got a bum injector. Hesitation/sputter when you first hit the gas? Most likely a bad injector or two (or their connectors). I only jump straight to that assumption because of everything you've already replaced on this thing. I'd say you're an injector or two from a healthy Z

If your idle is too high now you can adjust it at the throttlebody. (I wasn't sure if thats what you were getting at or not, but I thought I'd throw that in there anyways).

 

I'm looking through the Haynes and they show there's a screw on the throttle body for adjusting the idle, but I'm looking at that throttle body on both my cars and I can't seem to find the screw that adjusts idle. I was thinking maybe you could only change idle on the N/A like in the Z31, but I don't see the screw on the N/A. All of them look more like mounting screws. If anyone has a good pic of where the idle adjustment screw is that would be helpful.

 

Look at the passenger side of the throttlebody and you'll see where the throttle linkage rests against the throttle body. There is a small screw that threads up from underneath, through the throttle body and contacts the throttle linkage. This screw determines how far open the throttle plate sits when you have your foot off the gas. Adjusting the screw up will open the throttle more and raise the idle. Bringing the screw down will close the throttle more and lower the idle. There is no external idle adjustment screw like on the NA's. I'll see if I can find a pic.

 

Heres a quick pic. It doesnt show the actual screw but it does give you a visual idea of where it is.

 

Thanks, that really helps out. I couldn't figure it out from the picture in the Haynes.

 

I have one more question. I know that j, you said there wasn't much difference when you set the timing wheter you set it with the TPS connected or disconnected? When we set the timing with the TPS disconnected at 20* with the TPS connected the timing would be at like 10-12* more, so like 30-32* before TDC, and when we would set it with the TPS connected timing with it off would be about 10-12 less. Should there be that much variation, or could it have a lot to do with the TPS just being improperly adjusted?

 

I wasnt very clear on that point. There was a difference when you put it like that. And that is why I ended up setting it with the TPS left on. If you set it with the TPS disconnected, and reconnect it your total initial does go up (but I dont know by how much. It raised the idle which was the give away, but I never measured the difference). But overall driveability wasn't affected by whether I set the timing with the TPS connected or disconnected. It seemed as though the total advance was unaffected either way though. Which is unlike the non-turbos which rely on vacuum and mechanical advances which need an accurate initial advance to dictate their total advance.

 

By the way, what size allen wrench do I need to remove the mounting bolts for the throttle body? I want to pull it out so I can try and drill out that broken TPS mounting screw and I need to get an allen head socket. So if you can let me know, that'd be great. In other news, my injectors don't arrive until Monday. So this kinda kills my hopes of having it running by the weekend. Assuming this all fixes it...

 

Anyway, I've got my new injectors in and adjusted the TPS as per FSM/Haynes. The .3 mm feeler gauge to make TPS turn off. Anyway, I started the car and at first it seemed really bad the engine was studdering and shaking and everything. Found out one of my injector connectors wasn't plugged all the way in. Plugged it back in and it was running real smooth. The idle seems to be really smooth and I don't notice any misses or popping at idle. I can give it gas, but if I give it too much gas it seems to studder, and then finally catch and then keep going rather than it did before where it would just get gas then die if I gave it more than a slight press. It kept wanting to cut out closer to 2800 RPM now. The 2000rpm miss is gone. I know the distributor cap had some water on it from all the rain we've had, plus I was working on the car yesterday hood up when it started to rain pretty hard. I don't know if maybe I have water or moisture in my distributor or TPS? I was trying to clean out the TPS connector and it looked dry. I guess I'll wait a day or so and see if it has a chance to dry out and see if that makes any difference.

EDIT: Ok. I found the CHTS from my Blue Z. It had fallen into a trash can. Anyway after a horrific struggle to get the CHTS out of the turbo. I found that the head of it had warped or something. I got it out by prying on it with a screwdriver and turning with a wrench. This was after the threaded part came out. Anyway comparing them up the head was a slightly different shape than the CHTS from my N/A and the one that came out of my turbo was also longer. I put them into a cup of water to see if they would read the same. I was getting 1.17 from the one out of my N/A and 1.07 from the one out of the turbo. I assume that means the one that was in the Turbo was bad, since I never had problems with the 2+2. Anyway was the water temp sensor that these cars used to have in any way similar to the CHTS? I'm thinking they might have been and the previous owner bought the wrong sensor and it just turned out that they were similar enough that it worked to an extent.

 

Just recently I was having problems with my engine not wanting to go past 2500 rpm and I found that it was my IC that is mounted on the side of my distributor. Once I replaced that, I was able to go past the 2500 rpm and the engine runs really well now. Just thought I would pass that along to you.

 

Apparently the IC unit u r talking about is a pretty common problem, more so in the turbos than the n/a. The owner of a shop I used to work at said they were replacing them on a regular bassis in the early/mid eightys. In fact I know a guy whose 82 280T started doing something similar, missing, etc,etc finally it would run until it got warmed up then die and wouldn't start for a couple of hours. He was convinced it was the ecu/injectors, I suggested the IC, but he ended up tradeing it for a 240sx ...and I was broke, so no turbo for me. Any ways it sounds like the last post might be on to something.

 

IC? Ignition Coil? Cus I do have a new Ignition Coil that I just haven't installed yet.

 

They are talking about the module on the side of the distributor (FOR THE NA MODELS, LIKE mdigiovabc's CAR), and the module on the side of the coil bracket on the turbo car.

 

Well in the chance I need to replace this thing. What is it called, so i can at least look it up? This would be the first I've heard of this thing causing problems. Would it be able to act that randomly though? Also would the one from the N/A be interchangeable with the one from the Turbo?

 

No the NA and turbo IC's are not interchangeable.