ZCar Forum banner

1 - 20 of 62 Posts

·
Registered
Joined
·
41 Posts
Discussion Starter #1
Ugh I'm losing my mind here! So after redoing injectors, I had gotten it running. It would cut out at the end of first if I'm stepping on it or early into second if cruising, doesn't stall just no response. I went to take it apart again, my intake manifold bolts were loose. So I just redid cooling system, valve covers and lower and upper intake manifold, used shellac on everything and a torque wrench, just went for a drive same exact issue. I do notice air sounding like it's leaking/hissing near the throttle body on driver side of the intake, by the injectors. Spraying starting fluid near there had absolutely no effect on it. In park it will rev all day long no problems. Only in gear will it cut off I'm moving any faster than a jog. Can anyone help me I'm lost as to what it could be now.
 

·
Registered
Joined
·
836 Posts
Shellac? That's a painting material, not used on automobiles. If you used that to seal the manifolds (?) it could be the problem, but the description isn't very detailed. I don't recall that the intake and exhaust manifolds use anything to seal other than the gaskets.
 

·
Registered
Joined
·
41 Posts
Discussion Starter #4
^ that's correct, from permatex "Indian head gasket sealer", was recommended by my father, said he's seen warped head gaskets sealed with that stuff. So I used it on valve cover upper and lower manifolds. I've heard tell and take of the aur leak on the manifold but have read that they are still able to drive their car, so I'm not sure if that's 100%my issue or just a correlation
 

·
Registered
Joined
·
836 Posts
Butting in ... gasket shellac, old timey.
Wow, I started working on cars in 1968 and I may have heard that term decades ago. Maybe. I think it's slang for a gasket sealer, but it threw me off.

Question: is this car a manual or automatic transmission? I'm just throwing out ideas, but some automatics have vacuum connections with the engine that can cause odd problems. Not sure about the Datsuns.

I like the idea of using starting spray near the leak, if that's what you have. If it's on the intake side, I think the car would have responded by pulling the spray in.

I can understand taking a shot at sealing the manifolds, but If they are warped, in the long run you need to have them machined, not use goop on them. Gasket sealer is to assure a good seal on properly aligned surface, not repair mis-aligned ones. If they can't be machined, I suggest finding a replacement set of manifolds if there's really a problem.
 

·
Registered
Joined
·
41 Posts
Discussion Starter #6
I appreciate the fast responses. As far as warped, it was something my father had mentioned to support the use of the shellac, I'm not saying that my intake manifold are warped. As far as the vacuum goes my father did also suggest that I do know that there is a vacuum diaphragm on it I believe and it is automatic transmission. I'm planning on converting it to a manual at some point in time. And I was surprised at no reaction either to the etherether
 

·
Registered
Joined
·
836 Posts
I've seen some odd things happen in older cars with vacuum connections to an automatic transmission. In one case on a Ford, a bad check valve let the engine pull ATF out of the automatic and burn it - lowering the level of ATF in the automatic. Weird.

I don't know this system well enough to really know how it's set up, but if there are vacuum connections to the transmission, just make sure they're working properly and not causing a vacuum leak.

I may be way off on this, but if so perhaps someone more familiar with the automatics will correct me. I don't want to send you the wrong direction.
 

·
Registered
Joined
·
41 Posts
Discussion Starter #8
I'll take any place to start looking, because it's able to spin the tires in the driveway but it's like when it gets up to that certain speed that the speed pinion reeds it just cut it off. And there is so I will be checking out that vacuum whenever I have more Daylight as a starting point
 

·
Registered
Joined
·
836 Posts
You write that it "cuts off". Does that mean that the engine turns off, of that it only loses power?

If it turns off, then the problem should be electrical. If it loses power but continues to run, perhaps gas.

My knowledge extends mainly to the L6 Z-cars, so that's just a basic idea of where to look.
 

·
Registered
Joined
·
41 Posts
Discussion Starter #11
It stays on electricals still run and all that good stuff, just absolutley no response via throttle or shifting gears, it seems to only happen at a certain speed, I tested this theory by barely accelerating and i continued to have power until it gained a bit more speed. My instrument panel doesn't work so most of the numbers for speed or rpms are guess work. But I'd say around 15mph, the engine just goes unresponsive till it decreases and then I can throttle it again until i increase my speed. It only stalls if it takes to long for power to resume (judged again by speed)
 

·
Registered
Joined
·
41 Posts
Discussion Starter #12
And I just cleaned my fuel system (rust free the tank, change lines and clamps, new injector hoses and flushing of all injectors and power testing) so I don't think it would be that, I have a second relat wired in because my original would run the fuel pump constantly so I tapped into a wire that only supplies battery voltage when the key is In the on position
 

·
Registered
Joined
·
41 Posts
Discussion Starter #13
Well after getting my eyes on the tranny and associated wires and such running to it, nothing looks out of ordinary (albeit not to sure what ordinary really is) or was disconnected, and I put some more ATF in and hooked my oxy sensor back up (oops) and just took it for a spin, no changes. If I putt around it's fine, just anything faster than a jog and it goes unresponsive
 

·
Registered
Joined
·
836 Posts
I'm going to throw in an idea just for the heck of it.

I had a problem for a couple of years with my 280ZX Turbo missing above 3500 RPM. Another member here (Zmanofwashington) suggested a series of tests, including unplugging and disconnecting the ECU for 15 minutes or more to allow it to reset. I finally tried it, and was amazed that it worked. Now the ZX runs great.

It's free to try, and on my 83 ZX, it only requires removing the driver's side kick panel (2 screws) and the cover panel (1 screw) and I can reach all three plugs.

If you try it, disconnect the battery first, just in case. In my case it worked a miracle.
 

·
Registered
Joined
·
41 Posts
Discussion Starter #15
That's a good idea, I was running diagnostics yesterday so it's already pulled out, I'll try that after work today. And I charged the battery so it should help. But I'm currently starting to look for a donor car todo a 5 SPD swap when I can afford it
I'd like to figure out what's wrong but it was planned to do a swap anyway
 

·
Registered
Joined
·
41 Posts
Discussion Starter #16
No luck. And my speedometer either started working or I noticed it now but it's definitely at 10 mph. If I hit the brakes and keep it under that speed all is well
 

·
Registered
Joined
·
41 Posts
Discussion Starter #17
Weird symptom, can sit there and spin the tires till they just start to smoke before it cuts off, but wont go over 10 in D or gear selector ranges
 

·
Registered
Joined
·
836 Posts
I'm going to offer a possible solution, because it solved a problem for me in which my 1983 ZX Turbo wouldn't rev above 3500 RPM without missing badly. I had fought this problem for TWO YEARS and gone through everything I could think of.

Another gent recommended that I disconnect the ECU for 15 minutes or more, then re-connect it and try driving it. I was amazed that it completely fixed the problem. Evidently a total ECU reset was the solution. That worked for my '83, and it's free.

I know of no way this could harm your '87, so you might give it a try. I recommend disconnecting the battery first, then the ECU, and re-connecting the ECU before re-connecting the battery.
 

·
Registered
Joined
·
41 Posts
Discussion Starter #19
I had tried that a few days ago, along with doing the same process to the automatic transmission control unit with no change in results. It operates fine in all categories except when the speedometer registers 10mph+ and I just don't know where to proceed. I'll try your recommendation again since I got my pt cruiser turbo fan running again
 

·
Registered
Joined
·
51 Posts
This is a real shot in the dark here, because I’ve only been working on Z cars about a year now. However, in the past I’ve seen MAF sensors do wild things to Z Cars if they aren’t functioning properly. Im not an expert on the protocols the z31 ECU’s use, but I suppose the ECU could tell the MAF to operate differently, or the car to pull air differently somehow, whenever it reaches above 10 MPH. I would use www.xenonzcar.com and use it’s guide on how to test your MAF. Sorry for the not-so-expert answer, but usually when strange stalling issues and engine symptoms happen that don’t really make sense, the MAF is what I check first. I hope it may work! Good luck. -Retro
 
1 - 20 of 62 Posts
Top