ZCar Forum banner
1 - 5 of 5 Posts

·
Registered
Joined
·
6 Posts
Discussion Starter · #1 ·
I have a 76 coupe, 4 speed, in New England so it only goes a few hundred miles a year. I've owned it for about 20 years. Last year I noticed a wet spot on an injector hose to #5 cylinder so I took it off the road and began what I hoped would be one injector replacement. Because the injectors were probably originals, the machine screws were frozen solid which led to actually all new injectors, all new little hoses and clamps, all the air hoses and the PCV hose, all new vacuum hoses to the carbon canaster and all new cable connections, except the AFM, Thermotime and temperature sensor plus a very nice replacement intake manifold I got on EBay. I cleaned out the rust from the coolant unit under the bypass air unit and at the thermostat housing. I reused the throttle body after removing the deceleration damper that was frozen in place, reused the cold start, bypass air and pressure regulator. I didn't touch the AFM. I cleaned and painted all the fuel lines and replaced the fuel filter.
When I start it, it sounds great and there's a little white smoke but there has always been. After a couple minutes there's more white smoke and once it's warm there's a lot of smoke, particularly if you push the throttle. The engine sounds great the whole time. I don't have the ability to differentiate the smell to know if it's oil, fuel or coolant. Putting a pressure gauge on the fuel line, I get 40 as it's cranking, 30 as it's running, jumping up to 34 or so pushing the throttle and then coming back to a steady 30. The pressure stays reasonably constant after shutdown. I've put a vacuum gauge inline near the pressure regulator and get a pretty steady 24. If you push the throttle, it drops quickly, then quickly shoots back up to 50 and drops right back to 24. I did a compression test and had 5 cylinders with 150 and 1 with 160. I confirmed TDC and the timing reads as correct.
The car was fine last year short of the permeated hose on the injector and for the 20 years I've owned it, it goes through the same storage cycle each year. It seems odd that there would be something mechanical, particularly with the compression readings, though I'm sure it could happen. Any help would be appreciated. The next step for me would be to go through the EFI Bible to step by step it but it's not going to do me much good if it's oil related. A mechanic who works on some other vehicles for me thought it sounded like oil might be getting pulled into the intake manifold. Short of the PCV hose, I don't know where that would happen. Thanks in advance for reading this and for any assistance..
 

·
Registered
Joined
·
6 Posts
Discussion Starter · #3 ·
Thank you for the response. In that case, it definitely isn't steam. It's like a mosquito fogger. I'd be embarrassed and concerned to take it on the road. If it's oil, do you have a suggestion for the first step to checking for the source? Thanks again
 

·
Registered
Joined
·
67 Posts
May be valve stem seals. If they've never been changed, they're probably hard and oversized. Also, are you running the car often? My valve seals are relatively new (within the past year or two), but I'll get a lot of smoke if the engine hasn't been run for a month.

Or, worst case, could be piston/piston ring issues. I ended up with a fog machine of a Z several years ago after the lands on one of my pistons broke.
 

·
Registered
Joined
·
254 Posts
Well its either oil burning or engine coolant burning. Do you loose coolant level if you drive the car? Bad head gasket, cracked head, frozen piston ring, bad valve seals. If you are burning oil you should see a difference in the color of the spark plugs after you drive the car. Take the car on a long drive and check your plugs. Before the drive make note of how much coolant you have in your coolant tank (not radiator). After the car cools, check the tank level to see if you are loosing coolant. Head gaskets are a common issue.
BTW if you don't change your engine antifreeze every couple of years, it will go bad and eat away at your head, water pump housing, thermostat housing and anything else that is aluminum.
 
1 - 5 of 5 Posts
Top