hello everyone my name is adam and im a senior in high school and i got my z as gift from my father. i have been trying to fix my z to drive it. but i have replaced almost everything you can think of and the car still stays in idle and runs really rough here a small list

mass air flow

spark plus

timeing belt

timing belt sprokets

gas bump

gas filter

gas regulator

almost everything and it still runs like crap its as if its not breathing or not getting enuff gas. plz if anyone has a idea feel free to tell me at this point im ready to set the damn car on fire lol so plz help me out thank you.

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Have you checked the ignition timing, fuel pump, or throttle position sensor? Is it throwing any codes?

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Justin
1986 Z31 NA 2+0

would take a closer look at the CHTS/subharness (cylinder head temp sensor) and TPS (throttle position sensor). As Justin advised: run the codes and see what you come up with. It will, at the very least, point you in the right direction.

i have changed all of that and run codes as well and nothing comes up i change the tbs as well

next up on the list of Z31 troubleshooting:

Did you check compression?

Send injectors out to be cleaned and flow tested?

Swap in a known good ECU?

Fuel pressure?

next up on the list of Z31 troubleshooting:

Did you check compression?

Send injectors out to be cleaned and flow tested?

Swap in a known good ECU?

Fuel pressure?

How many miles on this Z, please? Enough for the timing belt to have slipped a little?

Greg's suggestion of a compression check would disclose that.

Frank T

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1970 240Z

i dnt rember how many but i replaced the timing belt also replaeced the timing belt sprockets

all the injecters where replaced but the guy who had it b4 me so there good and i just did a comperssion test and every thing came ot good and my fuel pressure is good as well

OK, basics.

The only things an internal combustion engine needs to run well are:

1. proper air/fuel mixture
2. proper compression
3. proper spark at the right time
4. clear exhaust

It's really that simple. One (or more?) of those issues has gone wrong and is causing your problems.

Your mission, should you chose to accept, is to identify which one of them is working improperly, determine why, and correct it.

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1970 240Z

but i have checked all of these factors and the car still wont work right

(No cussing on this Club website, please?)

If all of your test results match the factory specifications, I would suspect your testing method. One of those factors is clearly wrong, or your car would be running perfectly.

One of my most-miserable Gremlins was vacuum leaks. If a vacuum hose is leaking, it lets outside air into the intake manifold on the vacuum side of the carburetors or fuel injection intake. That means you can test the airflow at the intake with good results, but the engine itself is getting more air than it needs, which makes the air-fuel mixture lean.

My test for leaky vacuum hoses was pretty simple: With the engine COLD but running, i sprayed some starting fluid around various areas of the engine. When the rpm jumped up momentarily, that meant there was an air leak in that area which was sucking air into the engine. Simply placing my thumb over the leak usually rewarded me with a better running engine and showed me what hose needed to be taped up or replaced.

Frank

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1970 240Z

I understand you are frustrated with your car but you need to relax a bit.

If all those items have indeed been replaced/tested and your testing methods are sound and reliable then there are two things left to look at:

ECU and/or CAS (crank angle sensor AKA your distributor)


Swap with a known good ECU, a used 87 n/a ECU typically goes for $75-ish shipped form a reliable seller.

good used dizzy's trade in the 50-90 range as well form a reputable seller or you can buy a new distributor for $160+

If you reply that you have tested your distributor then please highlight how and what readings you got.....

Hi Adam, what ever came of this?