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280zx revs up in park, but has no power in drive.


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#21 Patch

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Posted 16 December 2012 - 08:45 AM

Saturday Update!

The timing does appear to advance when I rev it up, though, Im assuming the white line moving from 10 to 20 + is advancing or should be it going backwards towards TDC? Car rolls in neutral, brakes definitely are not sticking...

A few things I have noticed, which may be related. When I put the car into D or R (or put load on the motor I guess), there is a whinging, hissing, squealing type sound that comes from the throttle, distributor area. Not sure if this is normal... Also when the car warms up, it seems to start missing and runs really rough (also backfires if I plant my foot, esp under load). Let it cool for 5 mins and all is good again for a bit. An interesting thing I noticed today, it backfired as it was warming up and I was accelerating very slowly in D, but just after the backfire or pop under the bonnet, it felt like it had full power and was about to take off for 2 secs. But then dropped back down to 1500rpm. hmmmmmmm!


Shouldn't your timing be before top dead center, my book says 8 deg BTDC, from reading what you have says you are running after TDC, timing mark should be at 11 o'clock not 1 o'clock.this would make it retarded, and backfire. also faulty coil will do all this
Has this car been running with the auto or have you just installed it, lots of people put them in wrong and jamb the oil pump with the tork converter.
Does this car move when you try to drive or does the motor try and stall, just trying to work out if it is your auto.

I have some good PDF's here on fuel injection 280z and 280zx, that show alot about trouble shooting not sure what you have, if you want send me your email.



#22 steady88

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Posted 16 December 2012 - 11:08 AM

Shouldn't your timing be before top dead center, my book says 8 deg BTDC, from reading what you have says you are running after TDC, timing mark should be at 11 o'clock not 1 o'clock.this would make it retarded, and backfire. also faulty coil will do all this
Has this car been running with the auto or have you just installed it, lots of people put them in wrong and jamb the oil pump with the tork converter.
Does this car move when you try to drive or does the motor try and stall, just trying to work out if it is your auto.

I have some good PDF's here on fuel injection 280z and 280zx, that show alot about trouble shooting not sure what you have, if you want send me your email.


I probably didn't explain that too well. The timing marker is at -10 degrees before 0. When revving up, it continues to move further backwards towards -20, then to -30. The manual I have, says 10 degrees BTDC.

The auto was factory and the car does move when in drive. Just gets to 1500rpm and wont go any higher. Sometimes, if I'm lucky, it takes off for a second, but then something happens and it only revs to 1500. Car also moves in reverse and in 1st and 2nd. Though, in 1st it moves very slowly and doesnt appear to rev as high.

The car doesnt stall at all, but when it does warm up (temp meter at half way) it will stall, miss, backfire and hardly move at all. Wait 5 mins, so worries.

#23 Patch

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Posted 16 December 2012 - 12:06 PM

Pdf's I have are the same as you have, timing and advance are working with what you have described, Not sure if you mentioned it or I missed it but did see in your PM , which is a very important thing and may help others, is The car has been  sitting and not going for 6 years.
The fuel will be old and contain water  dump it and try new fuel, The fact your auto allows your car to move, it will not be the pump jammed, but could still be an internal issue and the fact it has been sitting could be a seized clutches or valve body, I would not exclude the auto yet, but also sounds like you are having problems with the motor as well, I think you have a couple of issues and not just one.
Start with changing the petrol and filters.Electrical system may have breakdowns as well from sitting.

Is there any signs of Rats in the engine bay.


#24 steady88

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Posted 16 December 2012 - 12:55 PM

Pdf's I have are the same as you have, timing and advance are working with what you have described, Not sure if you mentioned it or I missed it but did see in your PM , which is a very important thing and may help others, is The car has been  sitting and not going for 6 years.
The fuel will be old and contain water  dump it and try new fuel, The fact your auto allows your car to move, it will not be the pump jammed, but could still be an internal issue and the fact it has been sitting could be a seized clutches or valve body, I would not exclude the auto yet, but also sounds like you are having problems with the motor as well, I think you have a couple of issues and not just one.
Start with changing the petrol and filters.Electrical system may have breakdowns as well from sitting.

Is there any signs of Rats in the engine bay.


No signs of rats in the engine bay. I have removed all of the old fuel (very little), and replaced the fuel filter. I bled any old fuel out of the fuel rails and fuel lines.

#25 steady88

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Posted 23 December 2012 - 05:08 PM

I think I have made a major discovery. Cylinders 1, 2 and 3 are not firing. I'm getting spark and the injectors are receiving pulse.

I can unplug the first 3 injectors and they make no difference to the way the car runs. I can swap the injector cables around and still no difference. Unplug one of the last 3 injectors and the car nearly stalls.

#26 PB260Z

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Posted 23 December 2012 - 05:23 PM

Gidday

You have probably already tried this but,

Assuming all the injectors are getting fuel, I would be doing two things
1. Compression test
2. Swapping one of the injectors from No. 1,2 or 3 with one from 4,5 or 6

Just my 2 cents

Cheers

PB


#27 Zedman240®

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Posted 24 December 2012 - 08:08 AM

Have you checked the resistors for the injectors? I think they are mounted near the manifolds on the side of the engine bay....

#28 dat2kman

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Posted 24 December 2012 - 09:46 AM

Having now recieved the PDF's of the workshop manual, and the use of a multi meter, you have begun checking and testing all components in sequence?
If not , why?
The injectors are on "group fire" in the Bosch L Jetronic system, and your unplugging them to "discover" the above is not correct procedure, as they fire when you think they are not supposed to.
This helps to relieve their max duty, and the Dropping Resistors in inner guard are to "clip" volt/amp spikes.

The TPS sounds like it may be faulty, it is a four stage variable potentiometer, the correct operation of the AFM and its flapper valve can cause issues if not right.

As before, get a multi meter, the manual, and start from the beginning of the test procedures.
Not difficult, but to have a proffessional workshop go through this, if they can be bothered will take a couple of hours labour, you will save yourself that.!

#29 dazzed

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Posted 16 January 2013 - 12:51 PM

disconnect both vaccuum hoses to the disributor and plug them and try it then if this makes a big change the distributor needs overhauling, the most common fault i find with 280zx is air flow meter sticky flap or electrical component malfunction internally very common.

#30 steady88

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Posted 09 February 2013 - 08:19 PM

Thanks for the advice everyone! I cleaned out the fuel sender unit from the tank, as the fuel line to the pump was full of red gunk. I also replaced the fuel pump as it was also full of gunk. Now the car runs very well and has lots of up and go!

My problem now is, the runs great for about 5 - 10 minutes, then slowly starts to run worse and loose power. Now here's the interesting thing which I can't work out. I wanted to rule out if this was a fuel pressure issue, or something else, so I disconnected the fuel pump to relieve the pressure. When I do this, and plug the pump back in, the car runs great for another 5 - 10 minutes. I thought, ah, this has to be fuel pressure. I swapped my fuel pressure regulator for another one and put a fuel pressure gauge between the filter and the rail, and the pressure is right on spec. I don't understand??? Why does reducing the fuel pressure (unplug the fuel pump for a minute) make it run good for another 5 - 10 minutes - because, as soon as I plug the pump back in, the pressure builds up straight away anyway.

I should also note, that the car is warmed up and appears to make no difference if the car is warm or cold.

Cheers!

#31 steady88

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Posted 10 February 2013 - 09:55 PM

Having now recieved the PDF's of the workshop manual, and the use of a multi meter, you have begun checking and testing all components in sequence?
If not , why?

As before, get a multi meter, the manual, and start from the beginning of the test procedures.
Not difficult, but to have a proffessional workshop go through this, if they can be bothered will take a couple of hours labour, you will save yourself that.!


I have checked the sensors with a multimeter and they are all good. I have tried to test the harness connector at the ECU, as per the FSM only to discover that the pins do not match the FSM, in fact, many are missing.

One thing I will note, if I disconnect the TPS, there is no difference to the way the car runs. Not sure how big of a difference it is suppose to make...

I'm new to this world and want to learn and have the enjoyment of fixing the car myself.

#32 Zeddophile

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Posted 11 February 2013 - 08:17 PM

Thanks for the advice everyone! I cleaned out the fuel sender unit from the tank, as the fuel line to the pump was full of red gunk. I also replaced the fuel pump as it was also full of gunk. Now the car runs very well and has lots of up and go!

My problem now is, the runs great for about 5 - 10 minutes, then slowly starts to run worse and loose power. Now here's the interesting thing which I can't work out. I wanted to rule out if this was a fuel pressure issue, or something else, so I disconnected the fuel pump to relieve the pressure. When I do this, and plug the pump back in, the car runs great for another 5 - 10 minutes.


Disconnected how?  Electrically disconnected, or removing a hose?

I'm going to guess you are disconnecting a hose, and I'm also going to guess you didn't clean the fuel tank itself out when you cleaned the pickup.  If that's the case, pull the pickup out again, and you'll more than likely find a new buildup of crud on it.  Over that 5 or 10 mins of running, the pump sucks all the loose crud off the bottom of the tank, and even when the car is switched off, holds it there by suction, as the fuel lines are sealed up to the reg.  Over time, the crud will slowly drop off the pickup by itself, but when you disconnect the hose at the pump, it allows air into the hose to the pickup, and most of the crud is washed off by the fuel in the pickup tube suddenly returning to the tank.

This was a common fault with the early Land Rover Freelanders, the plastic lining on the inside of the tank would come off in thin sheets, and clog the pickup screen over a period of driving, until the car stopped.  Half an hour later, you'd be able to drive again for a little while.  The only solution was to completely drain the tank, remove the intank fuel pump, and stick your arm in with a rag and wipe all the loose crap out.  I suspect a Zed tank doesn't have a big enough hole in it for this approach, so you may have to remove the tank, and either wash it out properly yourself, or take it to someone to be cleaned.  Some radiator places will wash out fuel tanks for you.  The bigger issue though, is when you say 'red gunk', I'm immediately thinking rust.  The tank may not be worth saving, depending how bad it is....

#33 steady88

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Posted 11 February 2013 - 08:27 PM

Disconnected how?  Electrically disconnected, or removing a hose?


I electronically disconnected the fuel pump. Besides wiping it out with metho, I didn't clean the tank as it was clean and there was no crud in the tank at all. The only crud was actually in the sender pipe going to the pump. Even the strainer in the tank was clean.

I have since checked the strainer and pipes and all were still clean. Even the fuel filter was clean. But what you are staying is interesting. There could be a build up somewhere which goes down when reducing that pressure. But, the fuel pressure gauge shows about 31psi and doesn't change at all when the car has a lack of power. You would think there would be a change in pressure.

When I originally saw the red gunk, I thought exactly the same. Rust. But, I now think it was the old fuel in the pipe. It seems to have only been in the metal pipe, not in the rubber hoses. Perhaps some sort of reaction to metal. Inside the tank is amazingly clean. There was some discolouration on the bottom, but thats about it. I did my best and wiped it out with metho while I had it open. But, I'm confident it is clean.

#34 kuyz

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Posted 24 February 2013 - 05:34 PM

Hows the ATF level??

#35 neRok

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Posted 25 June 2013 - 05:41 PM

What happened with this?

#36 steady88

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Posted 25 June 2013 - 09:03 PM

What happened with this?


I've come along way, but I still have a problem and I'm pretty sure it's fuel pressure related. I have a fuel pressure gauge hooked up between the fuel filter and the rail and discovered after a short amount of driving, or even just idling, the fuel pressure sometimes drops from around 30-34psi to as low as 15psi. I found that removing the fuel cap would solve the problem and so I though it was an issue with vacuum or the tank breathing. But, this no longer makes any difference.

I have changed the fuel lines from the tank to the pump and also and have changed the fuel filter a couple of times and have even cut the filters open to discover they weren't clogged, just a couple of black specs. The pressure doesn't always consistently drop down low, just have noticed it a few times. I have also changed the pressure regulator, but perhaps the replacement could be stuffed. I know that if I revv the engine, the fuel pressure drops about 6 - 8 PSI.

At the moment, the car is drivable, but it does run very rough and struggles to get over 60kmph. Up until about 2 weeks ago, It was running much better, not perfect, but I was able to comfortably cruiser on the highway at 110.

On a side note, might be unrelated - the other night when I stopped the car, I checked the pressure and it was 15PSI, then next morning, without starting the car, the pressure was sitting at 30PSI.

#37 neRok

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Posted 26 June 2013 - 11:40 AM

I would just put in a new electric pump. There are some good after-market efi pumps available at fair prices. I would also replace the wiring to the pump. Lastly, check the exhaust around the fuel tank is in good condition. I have seen dodgy exhaust systems blowing hot air all over the fuel tank, which causes it to heat up and vapour lock etc.




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