Rough Idle & white smoke!!!

[RGVZX]

Hello everybody im having an issue with 91 300ZX TT!!! It is running idling very rough and is throwing white smoke outta the passenger exhaust pipe only!!!
I purchased this car turned off previous owner didnt know what was wrong! Engine wouldnt crank when I brought it home I found out injector was replaced and the idiot that replaced it didnt put the lower O ring so the fuel was being dumped into cylinder 1 and would fill up to the point that the car couldnt crank! Well I fixed that issue but now my Z is idling rough and seems to have no power, also engine makes a sound, I performed a power balance test and cylinder 1 is not firing!!! Is this whats causing the rough idle and smoke and power loss issue???

Also the injectors that the previous owner put on the Z TT are red, I looked em up and for the TT they are supposed to be like bluish! Is this correct???

Thanks!

[es.biggs]

Compression test asap...fuel injectors are the least of your worries right now - you might have a head gasket job in your hands

[BigTDogg (MA)]

Compression test asap...fuel injectors are the least of your worries right now - you might have a head gasket job in your hands

2nd, if it's white smoke, that's bad. If it's just steam, no biggie. A compression test will tell you.

740cc/min Nismo injectors have red tops.

[RGVZX]

Ok ill perform compression test and post results!!! The white smoke does not stop however last night i left idling for a good while and smoking minimized!!! The previous owner did have the car parked for almost a year!!!

[BigTDogg (MA)]

Also, you have an NA, and IIRC your OEM injectors are a reddish brown color. No way you'd have 740s on an NA. Unless the previous owner loved to waste money.

[RGVZX]

No my car is a twin turbo!!! The injectors that he had replaced are red tops and I found the boxes to the injectors their Bosch brand!!!

[BigTDogg (MA)]

No my car is a twin turbo!!! The injectors that he had replaced are red tops and I found the boxes to the injectors their Bosch brand!!!

Your thingie to the left of your post, under your name says NA. Better update that in the control panel.

Bosch injectors... do you have a top feed fuel rail? I don't know of any Bosch side-feed injectors which work on our cars.

[RGVZX]

Sorry about that I corrected it already! Ok update! I havent been able to perform compression test but I turned on my car right now and it no longer smokes white. It just idles very rough and has no power! I swapped spark plugs from cylinder 1 to 3 and also coils and problem is still on cyl 1!!!!

[BigTDogg (MA)]

Sorry about that I corrected it already! Ok update! I havent been able to perform compression test but I turned on my car right now and it no longer smokes white. It just idles very rough and has no power! I swapped spark plugs from cylinder 1 to 3 and also coils and problem is still on cyl 1!!!!

Fuel injector in cylinder one. Did you swap coil packs too?

[es.biggs]

Yep it's looking like a fuel injector...try ohming it (just read the resistance across the two pins with a multimeter). might as well check the others too.

[BigTDogg (MA)]

Yep it's looking like a fuel injector...try ohming it (just read the resistance across the two pins with a multimeter). might as well check the others too.

Could also be a bad install

I found out injector was replaced and the idiot that replaced it didnt put the lower O ring so the fuel was being dumped into cylinder 1 and would fill up to the point that the car couldnt crank! Well I fixed that issue...

Could be a bad coil pack if the packs weren't swapped.

[RGVZX]

I swapped both spark plugs and coils but issue stays on cyl 1, only thing is injector but its a new one, my doubts are that its a red top bosch injector and for the twin turbo they should be blue or purple! Also I noticed on the passenger muffler that it sputters kinda like when you have a bad valve!!!

[BigTDogg (MA)]

I swapped both spark plugs and coils but issue stays on cyl 1, only thing is injector but its a new one, my doubts are that its a red top bosch injector and for the twin turbo they should be blue or purple! Also I noticed on the passenger muffler that it sputters kinda like when you have a bad valve!!!

Are they at least all the same? What do the connectors look like? Get some pics up here.

[RGVZX]

No its only the cyl 1 and 4 that has red top injector! All the rest are original! Its the early style connector (squared connector)

[AchilleZ32]

Most likely, you're running 270cc (NA) injectors. You probably need to go get the 370cc TT injectors and replace them. However, the first freaking thing you should to is compression test your car.

[RGVZX]

OK guys here are the compression test results and they are bad!!! I dunno if i did compression test wrong but i followed the procedure on the z32 manual posted here in the forum!!!

cyl 1=10
cyl 3=80
cyl 5=90

cyl 2,4,6= 80 all three

I dunno why the compression is sooo low on my car on all cylinders when my car doesnt throw smoke or anything!!! What do u guys think??

[BigTDogg (MA)]

Jesus H Christ, I've never seen numbers that bad.

You warmed the engine up, correct? Then you checked the numbers. The gauge was fully threaded in to the plug hole right?

My thoughts? If the above is true, cylinder 1 is toast. The driver side headgasket is shot, and/or your timing belt is off several teeth.

BTW, something tells me the test wasn't done correctly. No offense, it's actually a good thing. I doubt the car would even run with numbers that low all around. My old Z had 90psi in cylinder 1, but the rest were at 140ish. Ran fine and still made 330RWHP at 11psi on stockers.

Also, your battery should be fully charged for this test, as that will give you lower numbers.

[RGVZX]

Thanks for replying TDogg!! I kinda think i did something wrong as well!!! I warmed up engine pulled all the spark plugs and tested ea cylinder. Batt is good I have a Red Top Optima batt!!!

[es.biggs]

holy crap dude. I doubt those results are accurate too...that's insanely bad.

Did you crank the engine over and over until the compression gauge stopped climbing? Did you remove the fuel pump fuse?

[RGVZX]

Yeah i followed the procedure posted here on nico, on the "everything you need to know about the z32"! I removed fuel pump fuse, released fuel pressure, removed all plugs, disconnected CAS plug, installed brand new compession test gauge, cranked until needle stopped moving! Those are the results i got but it cant be that all cylinders are bad, i mean the car doesnt smoke, it just idles rough and lack of power! Its still driveable!

[marty1mc]

Those numbers are incredibly low. I would try a different gauge first. The motor shouldn't run with compression that low. You did use WOT when you tested? (wide open throttle). That will affect the copression reading, but not as much as you have.

Also, do a wet test and put a little oil in the cylinders and see if compression jumps. That will tell you rings.

Next, do a leakdown. Put each cylinder at TDC and hold the crankshaft still. Put compressed air into the cylinder through the spark plug hole and listen. Exhaust noise is rings, intake is valves. You should bet an idea where the problem is.

[RGVZX]

Yes I did WOT when tested compression. I used the loan tools from autozone, oem brand compression test gauge but it was brand new sealed. I will do a wet test and post results, but still car turns on and runs without smoking at all, juss runs real sluggish like no power at all, i guess cuz my cylinder 1 is dead, theres no compression on that one.

[es.biggs]

Man get ready to tear it down and count teeth on the timing belt...