help with lost power

[FastWoman]

Nissan put a beautiful engine in our Z's, but the distributor wasn't the best designed component of the engine. I read that almost everyone with a Z has a frozen breaker plate. I checked mine, and sure enough, it was frozen up. My approach to the problem was to get an AutoZone Duralast lifetime warranted rebuilt distributor. OK, I accept that these rebuilds can be junk, but it's easy enough to check for a bent shaft (apparently commonly damaged in the rebuild process), and the R&R process is pretty easy on this part. The price for the unit was right around $100. The distributor works great for now, and when I see that the advance mechanisms are no longer working or that the shaft has some wobble to it, I'll be off to AutoZone for a warranty replacement. I figure this is a pretty good deal, because I plan to own my Z for quite a long time, and I anticipate at least a few changes of distributors.

[mlc240z]

which car are we talking about here? you have 2 in your profile.

if it's the 240Z, you're already getting worthwhile things to check.

if it's the '82 280zx......someone can correct me (please) i believe they came with a catalytic converter. you said earlier the exhaust sounded like a low rattle.

is it possible the internals of the cat let go and are plugging the exhaust flow? sounds like the typical symptoms of a plugged exhaust, idles fine, dies at higher revs.

[Pomorza]

which car are we talking about here? you have 2 in your profile.

if it's the 240Z, you're already getting worthwhile things to check.

if it's the '82 280zx......someone can correct me (please) i believe they came with a catalytic converter. you said earlier the exhaust sounded like a low rattle.

is it possible the internals of the cat let go and are plugging the exhaust flow? sounds like the typical symptoms of a plugged exhaust, idles fine, dies at higher revs.

I didn't think of that. Yes check the catalytic converter. I had one on my Jeep get clogged and that refused to run at all. It would start and idle for all of about two minutes and then caput.

Jan

[clindayag1]

Make sure that the timing is on and that everything, EVERYTHING, in that used dizzy is in good shape. Don't just assume that because it looks better that it IS better. Looks can fool even the best mechanically inclined person.

Jan

yeah the timing was waaaaay off. i got the timing down now. the vacuum advance plate is good. but it still struggles when i drive it. could it be carb or fuel related?

[Pomorza]

(*I'm assuming we're talking about the 240z if not please let me know) Now when you said you pushed your car exactly what did you do? I mean were you going 55 in first gear? Did you red-line the motor? Now were the plugs oily or were they wet? If they are wet and smell of gasoline then your car is running fairly rich. When was the last time the carb was adjusted? Fuel pressure checked? When you did the plugs did you also change the cap and wires? Check both your oil and the coolant and see what they look like. Make sure all the vac lines are connected to where they're supposed to go.

Could you be a bit more specific on how your car struggles? What exactly does it do when you give it gas? Does it just plain die, not want to go over a certain RPM, miss fires, back fires?

Jan

Edited December 3, 2009 by Pomorza

[clindayag1]

(*I'm assuming we're talking about the 240z if not please let me know) Now when you said you pushed your car exactly what did you do? I mean were you going 55 in first gear? Did you red-line the motor? Now were the plugs oily or were they wet? If they are wet and smell of gasoline then your car is running fairly rich. When was the last time the carb was adjusted? Fuel pressure checked? When you did the plugs did you also change the cap and wires? Check both your oil and the coolant and see what they look like. Make sure all the vac lines are connected to where they're supposed to go.

Could you be a bit more specific on how your car struggles? What exactly does it do when you give it gas? Does it just plain die, not want to go over a certain RPM, miss fires, back fires?

Jan

yeah its a 240z. i redlined the motor when i was racing. the plugs were black, i guess its burnt up oil. #3 plug was oily and #1 was the only normal one. havent checked the carbs or fuel pressure yet. coolant looks good. oil looks dirty and i just changed the oil last month (possible suspect?). vac lines are good.

hmmm its kinda hard to explain in words...i guess you can say it miss fires. like at idle, when i rev, it sounds like a sport bike. but when i drive it, it sounds like a cheap dirt bike with no power.

Edited December 3, 2009 by clindayag1

[Pomorza]

For future reference, if the engine is original (never rebuilt) I won't recommend that you don't red line it. The engine is old and the tolerances that it can handle have probably gone down a bit in that time. Not to sound over cautious here but it may lead to some pretty unwanted damage.

That being said, take your car for a drive with someone driving behind you. Try to drive as normally as possible and have person behind you observe your exhaust. Color, smell and the amount (density) is what your looking for. Secondly I would look at the fuel and carbs. Make sure that your getting enough fuel to the carbs and enough fuel into the engine.

When you say the oil looks dirty does it look anything like a milkshake in color?

Jan

[mlc240z]

are you running with points for ignition?

if so, another wild shot in the dark.

check the condenser in the dizzy.

long ago as a kid, was 'helping' my dad work on an old buick and accidentally floored the pedal. engine screamed and then shut down, when finally restarted after many attempts ran like crap.

replacing condenser solved issue.

never understood why, but there you go.