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Discussion Starter #1 (Edited)
78 280 sat in my garage for 10 years. I'm trying to finish my projects or they will be sold (and I don't want to sell them).

Anyway, moved the car out, drained the gas, changed oil, coolant, filters, dusted off the FSM, ohmed the AFM and the ECU, checked sensors including TVS, CSV, thermotine & CTS. got out the Deolit cleaned every terminal that I could think of and the car is running RICH. All of the sensors test exactly where they should. It fouls the plugs within minutes. I took the K&N air filter off in case that was clogged.

Ran a compression check and #6 is at 105 and comes up with oil. The other 5 are very close to 165 #. Something is screwed up with the distributor spindle or perhaps the outer ring of the harmonic balancer has moved because the timing has to be way advanced for the car to run. Finally, I adjusted the AFM to lean it out. The spring is tight and the engine still runs rich.

My next step is to carefully check distributor orientation and timing but that doesn't explain why it is pig rich.

What am I missing?

Edit: injectors were clogged from sitting 10 years and replaced with remanned. All 6 are clicking away as they are supposed to be.
 

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Discussion Starter #3
Doubtful because I disconnected the thermotime and pinched off the fuel to the CSV using chanel locks with the jaws covered to not cut the line.
 

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You probably have a vacuum leak. Smoke your engine with the cigarette/hand-pump method and your leak will show itself immediately.

Also, check your coolant temperature sensor bullet connectors (the one for the ecu not the temp gauge). If there isn't continuity between the temp sensor and the ecu, the car will run in 'max rich mode' automatically.

If neither of those fix your problem try this: https://www.atlanticz.ca/zclub/techtips/electricalconnections/index.html
 

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Discussion Starter #5
I'll look up the smoke since I've been out as long as the car sat.

The CTS was direct on the money when resistance was measured at the sensor and at the ECU plug.

I'm wondering whether the distributor has always been off a tooth thus throwing timing marks off. The PO could have rigged something and it was good enough that I didn't pay attention. I forget how the spindle comes out.

Been messing with diesels and no spark plugs.
 

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If the coolant temp sensor checks out at the ecu plug, then its definitely a vacuum leak. I don't think timing being slightly off would foul plugs so quickly. If the timing was off you'd know it - it would be running rough.
 

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did you check the timing with a timing light?
I had a very odd super rich (according to the plugs) running engine on a test stand. It was not the fuel mix at all but rather I had the distributer pickup coil wires reverse. Not saying that is the case just sometimes things are not what they seem.
 

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Discussion Starter #8
I started timing with a light. It ran very rough and idle was low, almost quitting.

I then timed with a vacuum gauge advancing to the highest vacuum then retarding slightly. Timing mark is advanced (to passenger side) pretty far past the timing marks.

Moving the plug wires 1 terminal on the cap in either direction makes it worse - but I'm going to revisit and take better notes.

I did spray carb cleaner around manifold, throttle body etc looking for vac leaks.
 

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Do the smoke test. You have to be pretty lucky with the carb cleaner 'spray and pray' method. For example, my vacuum leak was the distributor's vacuum advance dashpot - I would have never thought to spray the distributor.
 

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Discussion Starter #10
It will be this weekend before I build a smoke machine. Prior vac leaks have caused lean conditions sometimes only on 1 end of the engine depending on where the leak was.

How does it cause rich conditions?
 

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assuming everything else has been checked (sensor input, AFM operation, fuel pressure,CSV,vac leaks, EGR operation, timing) don't assume the ECU has to be ok. Before going too far if you have a known working ECU I would try that.
 

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you dont need to build a smoke machine. Go to harbor freight and buy this - Multi-Use Transfer Pump and a pack of cheap cigarettes.

disconnect the brake booster and plug the "out" side of the hand pump into the brake booster inlet port of the intake manifold and put a lit cigarette on the "in" side of the pump and start pumping. Any and all vacuum leaks will have smoke leaking out of them.

Be sure to put a rag or something into your air filter so the smoke doesn't just leak out of there of course.
 

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Discussion Starter #13
Cool. I already have the transfer pump. It's good for lots of stuff. Hate to spend money on cigs but don't know anyone who smokes. I think the store in the hood sells them 1 at a time.
 

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Cool. I already have the transfer pump. It's good for lots of stuff. Hate to spend money on cigs but don't know anyone who smokes. I think the store in the hood sells them 1 at a time.
You'll need at least 4 to fill the engine with smoke. A pack of cigarettes is like $5...
 

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Discussion Starter #15
I was mostly kidding. I was in the health insurance business. When we were enrolling people who made $100,000 or more, none smoked. Enrolling the plant and 50% or more smoke. I quit when the price went to 55 cents. It's been a while.

I'll give the rest away after I'm done.
 

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I noticed that one thing you did not mention was if you checked the fuel pressure. Get that FSM back out and do a check if you did not. A stuck or bad Fuel Pressure Regulator could cause a high f/p and a rich condition.
And remember to THROW AWAY THOSE CIGS when you're done testing!;)
 

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Discussion Starter #17
FP gauge is installed. I think 32 at idle but know that it matches the FSM.

I'll smoke it and post back. There may be 2 issues - rich and timing. Wife thinks I should reconcile to driving new cars instead of having old cars in various states of repair.

That probably won't happen. An 86 911 came available near me and I'm thinking about it.
 

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FP gauge is installed. I think 32 at idle but know that it matches the FSM.

I'll smoke it and post back. There may be 2 issues - rich and timing. Wife thinks I should reconcile to driving new cars instead of having old cars in various states of repair.

That probably won't happen. An 86 911 came available near me and I'm thinking about it.
If you buy that one, it will make ANYTHING you do to the Z look very cheap. Good tactic. Just park the Porsche and threaten to buy parts for it, and you wife won't say a word about the Z.
 

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Discussion Starter #19
I just smoked my engine and not a vacuum leak anywhere. I ran 6 cigs through the transfer pump connected to the brake booster port. I had a clear hose as the 1st hose connected to the engine so I'd have a visual on how much smoke was going into the engine. Some smoke came out of the CAI that goes to the K&N. I plugged that leak with a baggie and rubber band which worked until the baggie was pressurized and came off.

I changed the fuel filter in the engine compartment and the fuel was discolored (slightly brown) even though the tank has been drained and new fuel put in. I didn't start the engine and will change the clear add on filter that I installed back by the diff close to the tank.

Hopefully the problem will turn out to be bad fuel and also hopefully, I won't have to drop the tank. I think I did that years ago when I was driving the car before it sat for 10 years.

Any other thoughts? Anyone want to smoke some cigs?
 

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Junkman,
This may or may not be of any assistance but welcome to see discussion where I ended up having a fuel pressure regulator go bad and apparently had slowly been going bad for some time and was running to point it always seemed flooded until 1 day it wouldn't start and fuel was running out the air filter. Very easy to check thanks to all those who responded with assistance.
Discussion was under 1978 280z gas dripping out AFM
Good luck.
Cruizin
 
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