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Need a specialist
http://forums.ctzcc.com/viewtopic.php?f=4&t=10215		 Page 1 of 1
Author:  JS280ZX [ Wed Sep 21, 2022 3:41 pm ]
Post subject:  Need a specialist
Well we have rebuilt our 1980zx from the ground up and she looks great. BUT we cannot get her running just right. We have done all the self diagnostics we are capable of but need an expert at this point. I am looking for a few shops in the area that I could take her to get the engine fine tuned. Our last job was to recoat the fuel tank. We have good vacuum 17 and fuel pressure is at 37 and holds well. All new injectors. Timing is 8 advanced. She fires right up but is sending out white smoke and after she stops she will not start again for an hour or so. I am thinking valves or leaking head gasket or rings.
Thanks

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Author:  Frank T [ Wed Sep 21, 2022 4:37 pm ]
Post subject:  Re: Need a specialist
Disclaimer: I'm not an expert on Fuel Injected cars (but I slept at a Holiday Inn last week).

Yes, white smoke is usually water (coolant) leaking into the combustion chambers thru a gasket. (Or more seriously, thru a crack in the head or block). Bad rings or leaking valves would give you blue smoke (burning oil) and over-rich fuel mixture would give you black smoke.

Check your compression, looking for low pressure in one (or two adjoining) cylinders. Look at your oil for signs of coolant pollution. Check your radiator for signs of oil ingestion. If either fluid looks like a frothy milkshake, you have a leak somewhere.

Still pondering the hour-long wait to restart. :? Does your temperature gauge read normally? Maybe the gasket only leaks at operating temperature and the car will start as soon as the head/block cool off enough to mate properly again.

Other opinions from the Clubbies, please?

Frank T
Author:  Paul [ Sun Sep 25, 2022 9:11 am ]
Post subject:  Re: Need a specialist
I really doubt you will find a mechanic who knows how to actually fine tune it, but simple basic engine operation is the same. For one, white smoke is not good. A leak down test of the engine should be top priority before doing anything else. They sell the gauge at NAPA. All you do is pump air in each cylinder at TDC and see how much leakage you have by the gauge. If there is excessive leakage then you look and listen.......Bubbles in radiator will tell you there is a head gasket leak, Air out of dipstick is bad rings or hole in piston, air out intake is bad intake valve and bad air out exhaust pipe is bad exhaust valve. Machine shop SHOULD have pressure checked and milled the head. If not, that's leaves alot to wonder. If you want to know you have fuel, just take top hose off filter, put it in bottle and turn the key to watch fuel, it should be like a garden hose, not a trickle. Fine tuning is just that, it has to run fairly decent before fine tuning.
Author:  johnnyZ [ Sun Sep 25, 2022 9:39 am ]
Post subject:  Re: Need a specialist
Let me first say that your engine bay is one of the most impressive I've seen. You have gone above and beyond restoring all the hoses, lines, and metal parts on this build. :thumbs_up: Where did you get all of the cad plated metal lines done? They look fantastic.

Paul's advise to you looks right on. I wish I could help, but my knowledge rests more on the old 240Z hardware, but mechanically the fix for the white smoke issues in either Z series would be similar. I trust that you had this smoke issue even after the engine has run for awhile? It's not uncommon to see white smoke coming from the exhaust on a cold car that has been sitting awhile when the pipes are cold and the condensation evaporates from the warming exhaust system. The not starting when hot issue could be a vapor lock issue. I've seen some Z cars that had insulation installed on the fuel supply rails (metal lines) to help prevent that issue. Some Z's even have a small fan blowing on the rails to help prevent the vapor lock when the car is shut off.

In any event, I wish you luck in getting your precious Z car sorted out.
Author:  Frank T [ Sun Sep 25, 2022 3:50 pm ]
Post subject:  Re: Need a specialist
I considered vapor lock too, but he has fuel injection.
Author:  JS280ZX [ Wed Sep 28, 2022 3:51 pm ]
Post subject:  Re: Need a specialist
Thanks for the input all! It turned out to be the new fuel pump was not holding pressure so I put the original back in and presto held right at 32PSI. The white smoke was from a bad cold start valve. It was not stopping and flooding the engine with fuel. I noticed the plugs were all fouled with black soot. So I disconnected the cold start and presto again, she has never run better.
Author:  JS280ZX [ Wed Sep 28, 2022 3:53 pm ]
Post subject:  Re: Need a specialist
John,
Thanks for the engine compliment. Reliable Plating in Bridgeport did them for me. Very reasonable.
Author:  Frank T [ Wed Sep 28, 2022 10:21 pm ]
Post subject:  Re: Need a specialist
I love stories with happy endings! :D

Zee you at the meeting JS!

Frank T
Author:  Paul [ Tue Oct 04, 2022 7:31 am ]
Post subject:  Re: Need a specialist
Well I guess that would do it, you had grey smoke then, not white smoke. The fine tuning is within the AFM and I can do it by ear, but having a CO machine is helpful.
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