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steady88

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

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So you may have read on some other threads that I'm having a little problem with my automatic 280zx.

 

I thought I should post a dedicated thread to my problem, in the hope someone else has had this issue and might be able to give some advice. After reading plenty of other treads, I just can't seem to pinpoint what is happening and I'm unsure what to do next. I should also mention that the car has been sitting for 6 years (long story), but was in perfectly running order before it sat. I have removed the old fuel from the tank and flushed out any old fuel from the fuel rails and fuel lines, and replaced the fuel filter.

 

My 280zx starts fine, idles smoothly, revs up nicely and freely, but when in drive it has no power and will not rev past 1500rpm.

 

Things that have been replaced.

- New spark plugs

- New coil

- New fuel filter

- Replaced 2 broken pipes

- New fuel injectors

- New oil filter and oil

 

This I know and or tested:

- Every injector is receiving a pulse

- Every spark plug is receiving spark

- Vacuum advance is leaking vacuum and not working

- Checked other vacuum pipes for leaks, all looks okay. (Not sure if there is a vacuum to the auto that could be causing this issue)

- Timing light shows the timing is 10-11 degrees from TDC.

- Checked air flow meter and appears to be working.

- Tested the throttle position switch and it appears to be working.

- Unplugging the temp sensors makes the car run rough, so I think they are working.

 

I'd really appreciate anyone who might be able to help!

 

Cheers, Steady!

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Somethg to do with it being placed into D, which sends a signal, or a switched position sensor on the auto trans selector, to the ECU, telling the ECU, "hey, i'm in D we can go now" ,,, not working.

 

Will it rev past 1500 in 2 nd or 1st on the trans selector?

And, what about in Reverse?

 

Tried jacking it up, placed on jack stands, ie with no load on wheels?

 

Just taking a stab in the dark here!

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So you've diagnosed that your timing isn't advancing, thats your problem right there?

 

Check your timing at idle then give the engine a quick stab from the engine bay and see if the timing advances itself. If not, this is why you have no power in Drive.

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Looking at you list of stuff replaced, I'd look at fuel pressure.

 

You don't need much fuel to rev in neutral, but once the engine is loaded, you notice poor fuel pressure fairly quickly.

 

The manual says it should be 250.1 kPa, if it's not near that, check your fuel pump and regulator.

Your list includes new fuel filter, but there's also a tank filter mentioned in the manual.

 

I'm no expert, but that's what springs to my mind at least.  :)

 

 

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The filter at the electric fuel pump may be blocked, ours was.

 

Ah, okay. How do I go about checking this? Is it in the actual pump?

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Somethg to do with it being placed into D, which sends a signal, or a switched position sensor on the auto trans selector, to the ECU, telling the ECU, "hey, i'm in D we can go now" ,,, not working.

 

Will it rev past 1500 in 2 nd or 1st on the trans selector?

And, what about in Reverse?

 

Tried jacking it up, placed on jack stands, ie with no load on wheels?

 

Just taking a stab in the dark here!

 

Thanks. I know that in 1st is revs even lower and hardly moves at all. Reverse is the same as drive, struggles up to 1500.

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I take it the ignition advance is not computer controlled, sounds that way (why else would you have vac advance). Vac advance isnt for power, it is for economy. If it is leaking, try plugging the hose so there are no leaks and see if you fair any better.

 

The 2 times I have had my L28 running it was also a pig to drive, much like yours. I think it was the gearbox being shitty. I planned to flush the oil and stick a new filter in it, costs little bucks and an hours work.

 

I am not sure if the gearbox has some sort of vac modulator or similar that could be causing problems.

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Check the sensor connections around the temp sensors and throttle position sensors. I quite often get a bad connection when I've been playing in the engine bay. The result is exactly as you have described. It will idel fine but as soon as I try to use the throttle it falls in a hole. As soon as I fix the connection it is fine again and remains fine until the next time I play.

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Check the sensor connections around the temp sensors and throttle position sensors. I quite often get a bad connection when I've been playing in the engine bay. The result is exactly as you have described. It will idel fine but as soon as I try to use the throttle it falls in a hole. As soon as I fix the connection it is fine again and remains fine until the next time I play.

 

Hmmmm, interesting. I have checked them and cleaned them. An interesting thing, is that when I disconnect the TPS, there is no difference to how the car behaves. Not sure if it is meant to make a difference or not.

 

I have tested the unit with a multimeter and it all seems good. I will have another clean and check again.

 

Cheers1=!

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MPO to be able to rev freely and only bog down when it is in Drive, I think you have a problem with your drive line, Ie your auto is stuffed, or your diff, or wheel bearing or brakes

You need to eliminate, Can you freely push the car in neutral with the hand bake off, if not it will be wheel bearings or diff or brakes.

If you can push it in neutral it maybe something wrong with your auto,and the motor will struggle and stall if you try to rev it

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Just looking at your list of items replaced, I see a few missing that I'd investigate - might be useful if you can find another member locally who'll let you swap some parts off their car for diagnosis, or even has spare parts lying around.  Also included some rambling thoughts off the top of my head, which may or may not lead to something.

 

So, the list:

 

Leads?

Distributor cap?

Rotor button?

 

Have you checked that the advance mechanism in the distributor works correctly?  Not the vacuum 'advance' (which is actually often a vacuum retard), that's fairly irrelevant.  If you take the distributor cap off, you should be able to turn the rotor button around a little by hand, and then release it and it should spring back.  Should also move smoothly, not sticky at all.  Or the other (probably better) way to check, as mentioned above is to have the timing light on it, and check that the advance increases when you rev the motor up.  Incidentally, I have a vague memory it is reasonably common for the mechanical advance in these distributors to seize, but I could be way off.

 

If all of the above checks out, I'd see if someone can lend you an ignition module to try.

 

Fuel pressure is also a good one to check, as has already been mentioned.

 

And just for a random really simple check that probably will come to nothing, but may help - are you getting full throttle?  Get someone (or a brick or broomhandle) to hold the accelerator pedal down to the floor, and see if you can open the throttle butterfly any further by hand.  If you're really lucky, you're only getting 20 or 30% throttle opening. 

 

Actually recently instructed a guy at a clubsprint, and I drove his car for a session to show him the lines.  First thing I noticed was the pedal felt funny, and it was pretty sluggish after about 4,000rpm, and didn't want to go over 5k.  I knew the car should rev to almost 6k, so the first thing I did when we came back in was flip the bonnet up and have a look.  Sure enough, the retaining clip for the cable was in the wrong spot, he was only getting about 75-80% throttle.  Put it in the right place, and the thing flew in the next session, 5.5k easy as - he was rapt.  He'd had the car for about 2 years, and always thought it didn't seem to go like he reckoned it should!

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How old are your spark plug leads? I would try swapping some old ones over! you could have a couple streched leads it can appear you have good spark but I would guess your loss of power is from the spark jumping in the damaged lead! I've seen this happen before  :-\ something else to try lol

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Thanks for the advice everyone!

 

I'm going to try your suggestions this weekend and I will report back!

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Saturday Update!

 

Well, today, I checked the fuel pump and discovered it is a little different to the one shown in the manual and it has no filter. It must be after market... I did change the fuel filter again just to be sure and emptied the old fuel from the filter into a clear container. The fuel was a very light yellow colour, smelt fresh and had a few very small brown specs in it. I also had a spare ignition module and swapped that over. I took the cover off the TPS and all looked okay and tested out okay on the multimeter, I did make a slight adjustment to the angle though. 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!

 

 

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  If you are going to the trouble of replacing components ,suggest that you replace the vacuum advance canister i would also suggest that you check the plastic? unit that this operates inside the dissy which moves the internal units to function properly with timing. These are notorious for causing similar problems you are experiencing especially when revs are reqd. Also recommend that you get the g/box pressure tested by the appropriate people. Could be blown internals.

 

                                                                                Regards: Alan.  :D

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  If you are going to the trouble of replacing components ,suggest that you replace the vacuum advance canister i would also suggest that you check the plastic? unit that this operates inside the dissy which moves the internal units to function properly with timing. These are notorious for causing similar problems you are experiencing especially when revs are reqd. Also recommend that you get the g/box pressure tested by the appropriate people. Could be blown internals.

 

                                                                                Regards: Alan.  :D

 

Yes, I have been doing some research on replacing the advance unit and intend to. But, at the same time been looking at perhaps replacing the distributor. I did come across this on eBay, which is nearly the same cost as repairing or sourcing a new advance unit. Perhaps this might be a better option? http://www.ebay.com.au/itm/ws/eBayISAPI.dll?ViewItem&item=200806516048#ht_2808wt_920

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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.

 

 

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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.

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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.

 

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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.

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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.

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