1982 280zx : I got a really good one here,, what do i test now??

[Jomz Shakes]

okay, n/a 5 speed 280zx near 180k+?

 

so, i just had one of my techs at the dealership i work at do a timing chain for me because i thought it may fix my problem and it hasn't.

 

when i got my car 9-10 months ago i went to smog it and the guy said he couldn't get the timing right.... when he set the timing he got it t run well. after the timing chain and distributor my tech assumed he got it a tooth off so he went and removed everything to check and stated the timing chain is on the right tooth and set the timing perfectly with a timing light.

 

here's whats happening:

 

when my car starts up it runs really strong and then once its warm/even slightly warm it loses all power when reving but more so when giving the engine a load. its misfiring. its like the timing goes down or up "i havent learned how to tell by engine symptoms". it used to backfire when the timing was off now it just has a misfiring issue and power can sometimes be there. if im on it sometimes it will rev all the way up but sometimes drops out of time and misfires all the way down. i took it onto the street and it feels like it barely makes it around the block.

 

heres what my tech and I have done:

 

my tech looked up the thermotime switch which when working it causes a timing drop after the car has warmed up?

-ive learned that the ecu advances the timing when cold starting so it eases starting and then once warm it drops the idle. im guessing this has to do with the thermotime vacuum switch.is this right?

 

after replacing -no change in behavior

 

we replaced the spark plugs and wires - no change in behavior

 

i grabbed a old coil i ripped off a parts car - no change in behavior

 

he performed a valve adjustment, found 3 tight exhaust valves - after more power, but no change in behavior

 

he had me order the coolant temp sensor ,i believe it was installed on the passenger side of the engine in the cylinder head temp sensor?

i believe these are the same part number or two sensors are the same part but used as 2 different temp sensors?

-after installed no change in behavior

 

he tesed the compression, good on all cylinders , about 50psi i believe?

 

he did a leakdown test - "-i dont know the unit"but 13-14-15 was in tolerance and my clyinders were at 4 "psi?" so results were great on all cylinders

 

he checked the firing order, all good

 

he chacked the vacuum lines, they are in the right places

 

 

 

 

heres things i know that may be factors :

 

theres a header leak at the stud closest to the firewall...

this has happened before the timing chain install and before the problem started, i saw no change in behavior after doing this

 

 

i removed the cruise control and eliminated a vacuum line and the crankcase vent tube that go into the intake

this was before the timing chain install and before the problem started, i saw no change in behavior after doing this

 

my engine does not have a knock sensor??? he looked in my manual and him and i looked and its not there?

is this cause its N/A?

"there are 2 pairs of wires that come from under the battery, i know i unplugged atleast on pair to my cruise control unit, was there 2 pairs that eaded to the cruise control or was one pair of wires hidden there to plug onto the knock sensor that i dont have?"

[Skib]

I have a Nissan factory L28e diagnostic tester

 

kinda like todays consult computers for OBD1/OBD2.

tests everything on the engine harness.

 

but Im about 3 hours north of you.

[Jomz Shakes]

whats up i live in redwood city please help me out somehow

[Skib]

only problem is youd have the bring the car to me.

[datzenmike]

Some stuff to think about.

 

 

http://forums.hybridz.org/index.php/topic/86041-tps-throttle-position-sensor-adjustment-preguide-76-280z/

 

 

[ggzilla]

sometimes drops out of time and misfires all the way down

Pull the distributor cap, and with two finger, see you can move the rotor back and forth. It should not move when lightly turned. It it easily moves back and forth, the advance springs are broken. This can cause the symptoms you report.

[Jomz Shakes]

only problem is youd have the bring the car to me.

im down maybe i could just mess with the timing so its drivable for now?

is your diagnostic tester like one of those oldschool electrograph type dealies???

[Jomz Shakes]

Pull the distributor cap, and with two finger, see you can move the rotor back and forth. It should not move when lightly turned. It it easily moves back and forth, the advance springs are broken. This can cause the symptoms you report.

the distributor is brand new

[Jomz Shakes]

Some stuff to think about.

 

 

http://forums.hybrid...eguide-76-280z/

 

http://www.youtube.com/watch?v=-11J8XawQtc

 

http://www.youtube.com/watch?v=Qgp-LKysxbE&feature=related

 

this is something else i read could cause an issue, i think its timing related but i guess it could be this?? should i pop off the cover and see if its broken inside??

[Skib]

this is something else i read could cause an issue, i think its timing related but i guess it could be this?? should i pop off the cover and see if its broken inside??

 

the AFM can be a few teeth off and it will screw with stuff. its adjustable.

 

but dont just go screwing with it willynilly cuz its spring loaded and it you let it go the gear just goes spinning.

and youl never get it back to where it was lol

[ggzilla]

the distributor is brand new

You can test a brand-new distributor. If it's mechanically bad the store will take it back.

[Skib]

im down maybe i could just mess with the timing so its drivable for now?

is your diagnostic tester like one of those oldschool electrograph type dealies???

 

[Jomz Shakes]

okay i took off the AFM and slid the contact lower on that resistor strip, seemed to accelerate better but no change in behavior of problem. when i start my car the second it gets hot its like a switch and boom it wont rev past 1,000rpm. im not sure what to test now.

 

theres a turbo model AFM for 40 bucks do you guys think that will work,

i remember dropping the afm on the ground maybe the spring made it lose a tooth on that wheel looking gear in the video???

[I'm BLUE]

Well I did pm you a lot of good info a while back but here we go again lol.

 

Even though I would love to have Skib's 280zx diagnostics tester for efficiency (probably 10x faster to). It is not 100% necessary. A multi-meter/common sense/basic record keeping/patience will do the same thing.

 

Don't go throwing parts at it. It wastes your time/money/energy and worst of all kills the attraction of the car to you! !!

 

Please take pics of harness connectors and post them up.

 

So... go to xenon.com and download the fsm for 1982 280zx n/a. You can test nearly every sensor/connector with a multi-meter before throwing cash/time at your car if you're willing.

 

Before starting: download and read the 280zx fsm bible. Measure AFM/Injectors/chts/cts/etc all sensors and their corresponding connectots with a multimeter per exactly fsm specs. Record them all. You can test harness and ecu even with a multimeter !!!!

 

(1) pull your o2 sensor and start up car ... if car runs better under idle/load ( either) you have a clogged cat or muffler

* if clogged exhaust unbolt/cut off cat and inspect with a very briht flashlight ... if you can barely see through replace.

 

(2) check your injectors for voltage ----> carefully take a multimeter and measure each pin side of the injector connecter for aprox 3.5v with ignition key in the "on" position. Make sure to clean each one prior to testing. Also ... test all injectors to see if any are dead. I will let you look that up yourself ;).

* Note: Clean/or replace the ecu harness grounds by soldering in new ones. There should be aprox 3-4 on drivers side bolted to intake manifold.

 

(3) pull your fuel feed line at the rail. Turn ignition key on and either pull oil pressure switch connecotr or pfuel relay #2 in engine compartment to activate fuel pump while ignition key switch in "on" position. Make sure a 1 gallon gas can is collecting fuel. At least should read 1-liter of fuel per 30 seconds.

*If above does not work replace inline filter and reperform.

**If above does not work take off fuel pump and perform externally from an independent fuel source ( 2 gas cans 1 feed 1 return) .

***If above still does nothing ... check all fuel lines for obstruction.

**** If no obstruction found ... replace fuel tank fine screen mesh filter.

Note: I have seen obstructions in a zx I owned.

 

(4) check/re-set your TPS per fsm. Check its connector and clean/replace if any corrosion ( rockauto.com has the connector)

 

(5) check your AFM with a multi-meter per fsm specs. I did this and it works 100% ! I found a bad air temperaturr sensor this way on a different zx.

 

(6) check for intake leaks around intake mani/intake boots/AIC valve/oil cap/oil dipstick.

** note pull oil cap/dipstick/breather hose ... your car SHOULD idle rough or act like an obvious intake leak .. if it does not you have issues.

 

(7) you dropped the AFM on the ground? ... uh oh ... hope its ok ... throughly check it again.... do not put a Turbo AFM on the N/A.

 

(8) while engine running gently wiggle harness conectors/wires. I did this on my 81zx and found a bad/shorting out thermotime switch connecter wire ( about 4 inches back). Replaced it on the spot!

 

(9) measure your 02 sensor but be very careful ... some 02 sensors can be easily ruined via testing if not handled gently.

 

(10) re-manufactured distributor or not ( tend to be faulty) make sure your vacuum advance is working smoothly and consistently. Check your IGN pickup module. Take it off and clean the corrosion off the back and reapply the special heat sinking grease to prolong its life as long as possible.

 

On my Blue 81 5spd zx n/a I had a clogged injector and 2 injector harness connectors that were causing me grief. 1 connector read high resistance/odd voltage and the other injector connector was reading non-existent voltage period. The catalytic converter was clogged as well. The car waz very gutless and I bought it as a parts car until I found out I could fix it easily. One of the 2 injector connectors was shorting out the engine haarness as well ... eeeekkk! !!!.

 

First things first = cleaned/replaced ecu harness grounds and engine grounds. I installed New fuel filter. I then took out and clean all (6) of my injectors/re-installed. For repair/maintance purposes I decided to install all (6) new injector conectors. In addition (4) sensors take the same bosch EV-1 connector so I installed them as well ( thermotime switch/chts/cold start/one other? ). I welded in a new cat converter onto some flanges and bolted it in. Car runs great now.

 

Nissan's 1981 280zx FSM will even tell you that the #1 problem/potential problem is the connections... that they may even lead to ruined components.

 

Did you drop the AFM before or after having problems?

[I'm BLUE]

I've diagnosed/fixed (4) 280zx's this very method ^^^ within 1-week of owning or working on them.

 

Simply stating if I can do it .. anyone can do it.

[Jomz Shakes]

i dropped it and then the problems started happening, how do i test my afm??

 

okay i have a multimeter, and 2 service manuals,

i just look up engine electrical specs for the certain sensors and then do i unplug the sensor and hit the positive on the multimeter to the harness for the sensor to see if its in spec/tolerance?

or do i poke it thru to see the current volt/amp comming out?

 

i put it on "20v" on the multimeter right??

[CanyonCountryRon]

This is my exact problem on my 1982 280ZX n/a.  Did you ever find out what caused this?

 

Thanks!

[racerx]

Did u note that comp. Is 50 psi?

[CanyonCountryRon]

Speed Racer, I know right!  I was hoping it was a typo and he meant 150. Mine is around 140. Guess there is not quick fix and I will have to go through all the steps. I'm going to try fuel pump first since it has close to 250k on it and I'm on borrowed time with it anyway. Thanks for the feedback!