inn0v8

hey guys, im looking for any EXPERIENCED Z32 people with this issue...

i have a 1990 twin turbo z, with a really apparent fuel odor...
basically i was looking at the engine diagnosing if i had a bad C.O.P or a non-running injector, all the lines leading to the C.O.P.'s checked out ok

but.... on cylinders 1,2,and 3 when i disconnected the C.O.P. harness the engine rpm did not drop, which i found to be kinda weird, on cylinder 4 it did drop, which is the reaction i was expecting...

i also noticed that between cylinders 4 and 6 there was some visible smoke/fumes coming out that smelled like unburnt gas, im thinking either its a fuel injector seal, or the damned head gasket or both, god ohhhh god i hope its not the head gasket,,, anyhoo please help and if you guys have any ideas besides basic stuff like did i check my fuses!?!?!

id appreciate it...

snwbrderphat540

sounds alot like an injector seal. that would be the cheapest idea to try and fix first... very time consuming but cheapest... could just be pinched. if you want to know if its a head gasket.. not guranteed but very good test.. check the compression.

91zxtt

The BHG doesn't exlpain why it fails the power balance test on #1 - #3. If you want to check for a BHG, get a BHG test kit at your autpo parts store....it can detect combustion gasses in the collant. Far easier than checking compression. A BHG isn't your problem anyway, so you probably shouldn't bother.

Check the fault codes.

Fuel leaks are very common this time of year. I suggect you follow the fuel line from the fuel filter all the way back to fuel return.

Check your injectors with an OHM meter. It should measure somewhere around 11 - 15. Injector seals don't fail very frequently....people usually run into problem when they try to install new injectors using old seals.

inn0v8

thanks for the responses guys, i would have responded sooner, but was out "pimping" the z, these cars grab A LOT of attention dont they???

anyway 91zxtt you said i can find a blown head gasket kit at a local auto parts store (autozone/o' reilly/napa)??? I'll try that, ive never even heard of a BHG that tests for deposits in the coolant,,,(makes sense though doesnt it...)

I have two more questions for you guys,,,

1.the car runs REAL rough at idle, im thinking its the IACV, so I'm assuming the symptoms of a bad or clogged IACV are:
when car is stopped and the IACV attempts to open the car starts to run rough???
sometimes the car stumbles upon a cold start???

2.My dumb @$$ started my friendship with "my baby" by using iridium plugs that call for "no gapping required", i purchased a z1 ecu upgrade and they call for the ngk pfr6b-11's which i then gapped correctly to .035" but upon taking out my old plugs i noticed that cylinder 4 was a real dry-looking rust color, if you know plugs and their color/health youll find that octane boosters can make this color on a plug,
my a. part to this question is besides this color difference why did the plug look so dry? it looks like part of the fuel system enters here on cyl.4
now the b. part, cyl.6 had mechanical damage to the plug's electrode (hooked part), the old plugs were gapped at .040" and torqued to 25ftlbs +/_ .4% (due to the limits torque wrenches),,,, so my question is what are the chances of the piston being the culprit that physically collided with the plug??? I'd like to beleive that something got inhailed in cyl.6 and caused the electrode to break, or that ngk made a defective plug...

3. last question guys, thanks for the patience,,, early model Z's had synchros made out of balsa wood/toilet paper, so my question is how long on average do you think people ride on these trannies/synchros without swapping them out???

thanks again guys, regards AaAB.

91zxtt

Toss the iridiums and replace them with the NGK's. The missing electrode is a concern. You're best hope is that it was pushed out one of the exhaust valves, or disintingrated in the combustion chamber (less likely). The piston didn't hit the spark plug, so don't worry about that.. I've seen those iridium plugs do exactly what you described. The new plugs will likley sure most of the problems you have been experiencing.

Don't waste your time on the BHG test....it's not that.

Try cleaning your throttle bodies also.

inn0v8

91ZXTT,,,soooo you think the bad idle would probably be the IACV???

inn0v8

forgot to mention that i've allready ran 3 bottles of seafoam through my baby... through the gas tank and vacum lines and throttle bodies...

CanyonCarver

With the damaged plug, I would say to do a compression test right away. Not for a blown head gasket, but more for possible damaged valves. It'll also give you a good idea on the internal condition of your motor.

snwbrderphat540

go compression test. its easy and if i got an ongoing problem it will be my first check. cuase i put it off on my z32 saying no no its an injector its this its that... and nope.. it was 95psi cylinder compression... so chekc the compression. and check your TPS to that can do crap to your idle. might neede tuned/cleaned.

inn0v8

you know what.... you guys are right,,, a compression test is easy , i can do that myself, just a pain in the *** what with taking all that balance tube crap off...

thanks again guys...

snwbrderphat540

yeah only for the rear two.. and dude.. once you do it 3 times liek i used to do it all the time.. its easy as hell i could take it off fully replace teh 2 rear plugs put it back on if 10 minutes... its like second nature now lol

inn0v8

yeahh im lazy, I.T. industry does that to you... laziness i mean...

anyway, imma compression test it sometime soon, really not wanting to drive it like it is...

the lack of power and rough idle, you guys think that the ignition timing could have changed??? and if not changed you think since Z1motorsports recommends 15 btdc that would give me the lack of performance issue???

im still thinking that stupid IACV is the culprit,

also besides a weird noise comming from the motor what does pre-detonation sound like, i know its supposed to be a knocking noise, but its too hard to tell what a used car with problems may have sounded like when it was new...
i only bring that whole discussion up because ALLDATA says that the PCV valves can produce a knocking noise...

anyhoo just some questions for you guys to stir on,,, its weird though when i bought the car one C.O.P. wasnt even connetced and now i fixed all the C.O.P. harnesses and when i put the avc-r in there it runns worse, guess i need to check all my vacum related stuff as well as that compression check huh...

awww what the heck how bout another question ^_^

ignition timing you guys know any bass aackwards ways of changing the timing??? if so can i get a write up of how you created an adapter to use with one of those el-cheepo timing lights???

anyhoo thanks again guys, still love my Z but man oh man you gotta have money to dump into these things, unlike my 90 celica with a whoping 8 moving parts, and 100 whopping horsepower...

regards AaAB...

91zxtt

Check the compression. That destroyed iridium plug could've caused some serious damage.

You change the timing by rotating the Crank angle sensor. Do not do this without a timing light.

Detonation sounds kinda like marbles in your intake plenum, or pennies in a tin can. This is the least of your worries right now.