hchase17

My 83 turbo has a slight misfire all the way through that you can't barely hear at higher rpms. I have adjusted the timing and that has helped but not goten rid of it. Anyone have any suggestions?

nismo619

Please check to see if all your fuel injector clips are connected and " no green stuff " or corrosion. use eletrical ooze to make a clean connection. pull off all spark plug wires and make sure there fully pushed on . check to make sure your spark plugs are fully tightend to nissan specs. check cap and rotor replace if the connections are corroded.. If all that doesnt fix it " time to buy ad new better coil. i bought a blaster 2 with the reducer 2 ohms " ? or buy the blaster 3 that already has it installed. Thats my thoughts on misfires.

hchase17

already has new plugs, wires, cap, and rotor. Thats the first thing I did when ui bought the car and it helped a great deal. ive checked the injector connectors and made sure all the injectors are working. I might give the coil a try.

NismoPick

What did you set the timing to?

hchase17

I adjusted it until i got it as smooth as I could get the idle. I don't really have much experience adjusting the timing with a distributor.

jverz

he means he adjusted the ignition timing?

NismoPick

It is wise to use a timing light to set your timing... otherwise you have no way to tell if it's set right.

hchase17

It ended up bein exacctly where it was when I started messin with it so i figred its probably been that way since it was original

hchase17

My 83 turbo is misfiring pretty bad when I first start it and occasionally have to pump the gas to get it to start. It backfires when I let out of the gas. and the misfire almost completely goes away when I have the gas down more than about 50%. So it is at its worst at low rpms. Could it be the fuel pump?

NismoPick

Merged with your previous Misfire thread... no need for two threads on the same problem.

Have you checked / adjusted the TPS & AFM?

duowing

First get a timing light. Buy one or borrow one from an auto parts store. Even if you buy one they're not that expensive and useful to have around when you need it. Then set your timing to 20* Before TDC.

Does your car get better as it warms up? If so I'm going to say the Cylinder Head Temp Sensor(CHTS).

The TPS will cause some issues, but there's been times when I've driven with it unplugged and it does make a difference when accelerating or revving right off idle, but usually doesn't affect driving much.

hchase17

yeah I unplugged the tps and it didn't make much difference, and I've never used a timingg light before. Is it fairly simple. and yeah it gets better as it warms up but it still has the miss pretty good in low rpms. and I haven' adjused anyhing I'm kinda new with the older imports.

NismoPick

#1: Grab timing gun
#2: Connect power cables to battery
#3: Connect pick up clip to sparkplug wire #1 (make sure it's connected w/ arrow pointing to the sparkplug)
#4: Loosen the 2 10mm bolts at the base of the distributor, just enough to twist it.
#5: Disconnect TPS plug
#6: Start motor
#7: Point timing gun at crank pulley & pull trigger so it flashes
#8: Rotate distributor until the V mark on the pulley lights up at 20*
#9: Turn off motor, tighten distrib, plug in TPS.

hchase17

Probably a stupid question but I know nothing about timing lights. How do I know when its at 20*?

NismoPick

Turn to page 45 of your 280zx Haynes manual. If you don't have a Haynes manual yet, get in your car right now, drive to your local parts store and buy one. Or download the FSM at www.xenons130.com

hchase17

So the cylinder head temp sensor worked great and it helped out a lot. Now I jus need to get to the timing part. I think that should do the trick and put it running just right.

duowing

Another thing that caused a lot of low end hesitation for me was a bad or dead O2 sensor. Pull off the kick panel covering your ECU. Get the car warmed up, then with the car idling get a mirror or get down and look at the bottom of the ECU. There's a little green LED. This should be flashing. I believe it's 5 flashes per 10 seconds or something like that. Anyway if it's not flashing or it's just staying lit then your O2 sensor is bad. Also when you go to start the car, with the ignition on check to see if that light is lit up. So you'll know whether the light works or not.

NismoPick

Hey Duowing (kinda off topic... but not), I was reading in my fuel injection book last night & came across a section talking about the "burn off cycle" for MAFs. In the "trouble shooting a hesitation" section it says to check if the burn off cycle is working. From all my research on the Z31T ecu conversion, the burn off cycle won't work if the speed sensor isn't hooked up (which mine is not). Did you ever have any issues w/ this? I'm wondering if I'm not getting all the performance I can, because it's not cycling.

hchase17

well the temp sensor helped a lot but i still have a cold start issue. Hard to start if it has sat for a few hours but after maybe 4 or 5 miles its fine but runs rough until it gets warm.

hchase17

anyone know what it could be?

NismoPick

Did you set the timing yet?

hchase17

i dont have access to a light but there is no where that I can turn it that it runs any better. plus i dont believe that it would run better after it got warm if the timing was the only issue

NismoPick

Okay... just trying to make sure all the bases are covered and that the car is tuned right before diagnosing.

I say take it to a shop.

hchase17

too much money when they will go thru the same process unless you find a good mechanic and thats just too hard to come by these days...im thinkin i have a fuel pump issue cuz ive noticed also that when under 1/4 tank it gets worse

NismoPick

Have you checked the fuel pressure? Have you pulled all the spark plugs & checked / compared tips? Have you checked the AFM as I mentioned before?