I went to get my compression test done on my Z at my local auto-shop, they said they didnt find anything wrong it, but they said i needed to get my fuel filter and spark plugs replaced, so i went ahead and got that done. once that was finished, they called back, and said i needed new injectors and a new wiring harness. parts/labor came out to 1600 >.< now thats getting pricey, but is that what it normally comes out ? so, i looked on COZ for the parts, came to 1100. but + the labor, is that really pricey ? id hate to get this done and find out ive got something else to fix, so what do i need to look out for ? thanks.

 

Where are you in Tennessee? How many hours of Labor did they quote you?

 

Jonesborough TN, its near Johnson City

nah, i didnt get a quote on labor hrs

 

id take it somewhere else first and see what they say about it. do you have a z shop anywhere around you

and when are you gonna get me some clips of your exhaust??? i wanna hear it
mine is rusted through now, so hopefully i can get a new one soon

 

not sure if there are any z-shops near me, if my memory serves me right Z1 has a place in Atlanta, few hrs drive from me.

yea, im definitely not willing to hand over 1600 for a job that might not fix it. if anything, ill buy the parts and do the work myself with the help of you guys of course ^.^ odd enough tho, when i took the Z home, once i left the auto place, it road rough, very hesistant and shaky. so im not ever going back there again.

b300z - i do have a vid clip of it, but ive got to get a usb connector for my camera, so once i get one, ill post it up.

 

what were the compression numbers?

I don't see any of those issues causing the smoke that you described in your other post. Leaky injectors might cause black smoke but it would prolly be worse at idle and starting off, not so much when shifting.

Does it smell like fuel or oil?

I would try another shop. $1600 might be in the ballpark. Ruzzell, here paid half that for two new injectors installed. You might try cleaning all of your connections, especially injectors and coils.

 

they said the compression was 150-175, is that correct ? thats the #s i got. im going to try the ECU diagnostic and see what i come up with and go from there, then ill start working on removing the plenum >.<

 

did my ECU diagnostic and got codes 34 and 53

 

34 is your Dentonation (knock) sensor
53 is your Oxygen sensor

Below is a list of the codes

http://pages.cthome.net/bbachinsky/nissan_ecm_codes.htm

 

thanks man, so do i have to pull the engine to replace these 2 ? if not, could ya help me locate them, thanks.

 

You'd trust someone that drives one "uglay Z" to tell you how locate them?
And no you don't have to pull the engine to replace them. I suggest you check the connectors before you replace them. What model an year of Z do you have?
This is most likely most of your problem your having. If your Dentonation sensor is giving a false signal to your ECU it well put you in safe mode which retards your ignation and richens your A/F mixture to protect your engine.

 

well, i guess i should apologize for that. its just not my taste. but its whats under the hood that counts! right ?

but anyway, its a 91.

 

How good a mechanic are you? Or do you have a REAL good friend thats a good mechanic? The knock sensor is under the bottom plenum. The o2 sensors (2 of them) are on the header's close to the flange.

 

yeah, im no mechanic but i am doing my homework. ive got a friend tho that knows what hes doing to help me out. but if ya gotta go all the way to the lower plenum to get to the o2s that sounds evil, just from reading on how to get the upper plenum off is enough. well, if i have to do that, ill go ahead and clean the injectors

edit- yay, won my '91 Z service manual

http://cgi.ebay.com/ebaymotors/ws/eB...tem=7965967765

 

On the compression numbers, you're not too bad........

Standard is 186 psi. Minumum is 142 psi. And the max differential is 14 psi per the fsm. That 25 psi differential that you have will cause it to run a little rougher than normal.

that low cylinder(s) could be a leaky h/g or rings or valves. I wouldn't say that you should do this, but if I happened to have the valve covers off at any point I would re-torque all of the head bolts. I have been successful in the past with doing this to get the compression #'s back up. Hence, I say maybe a leaky h/g and not a blown h/g and re-torquing the head seals off the leak.

On the error codes, fix everything before going after the code 34. Lots of other probs will also cause a 34. When every things else is fixed the 34 might also go away.

 

To go from advising you replace the fuel filter and plugs to saying that you need injectors and a harness....4 words....never go there again.

O2 sensors aren't to difficult to change. Knock sensor is a b*tch. Replace the O2 sensors and try cleaning your injector connetors and the knock sensor connector. See what happens.

 

Now you have been giving some very good advice. One of the most important is the 4 words 91zxtt said,"never go there again".
Start with the easiest first, clean the connectors. And go from there. Keep us advise and keep asking questions.

 

yea, thanks 91, i plan on never going back there. for now, im going to wait till i get my Z manual and see if that'll help me get in there and clean everything

 

Seraphic--There is a really good Z-mechanic in Greenville, SC which is only about 1:45 from Johnson City. The guy's name is Bill Wilson at Japanese Auto Specialists. www.japauto.biz

I'm in the local Z Club with him. If you get in over your head and it looks like you're going to be spending a small fortune with trial and error work, you might want to have him look at it. He knows Z's very well and he's very reasonable.