83 280zx non turbo 5 speed runs rich. heavy black smoke/ soot coming from exhaust. rough idle before warm up. how do i fix this problem?

Asked by Dec 03, 2011 at 03:55 PM about the Nissan 280ZX

Question type: Maintenance & Repair

83 280zx 5 speed, non turbo coupe. car has a rough idle at start up which smooths out as car warms up. exhaust is very black and sooty. car is running rich. spark plugs also covered in black sooty carbon. car is stock except for cold air intake. what is causing this problem? what should i check or adjust? thanks.
rod

2 Answers

2,535

Need a little more information...mainly, when did this start? Did it start after you put on the Cold Air Intake? If yes, check any related sensors first for condition and proper connection... MAF and IAT..... very important to mixture control. If there's no connection with the Cold Air Intake, there's a few possibilities and it would take some diag work to narrow it down.... Stuck EGR valve is one possibility. Another possibility is if the fuel pressure regulator operates on vacuum with a diaphragm, sometimes the diaphragm will blow which will increase the fuel pressure and also allow fuel to be sucked through the vacuum line directly into the intake. I'm not familiar with the fuel delivery system on the old Nissans......I'm assuming it's an early generation fuel injection setup though...?

10

on these late models check all your vacuum lines they are notorius for hardening around the nipple hook ups and cracking there i had the same problem on my 83 turbo if left to long it can cause damage to the engine one trick is get some rubbing alcohol and start car pour some of it in a small cup 4oz. about disconnect a vacuum line to the intake manifold leaving it connected to the manifold allow the hose to slowly suck it in with out stalling the engine and plug it with your thumb this will clean you maybe running to cold of spark plugs

Your Answer

Add photo

Related Questions

Search Nissan 280ZX Questions

Nissan 280ZX Experts

#1 enginecreator
enginecreator
Reputation 50
#2 dandyoun
dandyoun
Reputation 40
#3 F_O_R
F_O_R
Reputation 30
View All

Related Models For Sale

Used Nissan 240SX
9 listings
Used Nissan 300ZX
133 listings
Used Nissan 200SX
18 listings
Used Nissan 370Z
63 Great Deals out of 2,707 listings starting at $10,994
Used Nissan 350Z
55 Great Deals out of 1,209 listings starting at $2,850
Used Ford Mustang
689 Great Deals out of 44,320 listings starting at $1,500
Used Nissan GT-R
5 Great Deals out of 488 listings starting at $50,888
Used Chevrolet Camaro
375 Great Deals out of 31,274 listings starting at $2,500
Used Datsun 280ZX
17 listings
Used Mazda RX-7
63 listings
Used Datsun 280Z
8 listings
Used BMW M3
42 Great Deals out of 1,334 listings starting at $5,995
Used Subaru Impreza WRX STi
36 Great Deals out of 634 listings starting at $7,500
Used Chevrolet Corvette
230 Great Deals out of 22,187 listings starting at $3,750

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.