My Z is Sick, i need help quick!!!

[280zx 2by2]

i do have oil in the car. i checked it before i checked the compression. the oil smelled really bad, not like regular oil smell, i almost threw up. i am about 100 miles past my oil change mileage though.

 

 

wont oil smell like that if i gets water in it? i have a few oil drip pans outside and they have that sour water/metal/oil smell

[woldson]

If he is running very rich with an older car the amount of fuel in the oil from cranking may be a bit excessive.

When I say search I am refering to the search function above. That was when the light really went on for myself, than I really started to play around with my car.

[S130Z]

i realized my battery was low when i ran my compression test so that would have an effect on my compression reading. is there any way to check for fuel delivery to an individual cylinder?

[woldson]

Have you read the efi bible?

besides a compression test, what is all the trouble shooting you have done and the results?

 

The problem is that you have really not given anyone enough information to even give a resonalbe trobleshooting guess.

[S130Z]

so i unplugged the number one injector, the idle slowed down to about 350 rpm, then i unplugged the number 5 injrctor and the idle went back to normal. i listended to the injectors with a screw driver to check for the click and they all clicked, and then i listened to the manifold and it had the same noise coming hrough the screw driver so i dont know if i herd the sound of the injector or just the engine running.

[280zedx]

Adam, just to clarify your injector troubleshooting...you unplugged #1 injector and it dropped to 350rpm (which is what it should do if that injector and cylinder are working correctly), you then unplugged #5 and the RPM went back up to normal?

couple of questions/comments:

-When you pulled #5 injector clip off had you put #1 back on? This needs to be done so you have a benchmark of "normal". As well, for the life of me I can't understand how an engine's rpm would return to normal by pulling off an injector clip.

-Clarify what happened with each cylinder when you pulled off (and put back on) the injector clip. (They should all have had the same effect as #1, noticable drop in RPM which means running on 5 cylinders)

-Also note how it is idling as is, (rpm #, choppy sounding, water/smoke from tailpipe, etc).

 

Hopefully with a clearer description of your troubleshooting so far we can help.

[S130Z]

well the thing about this is that i unplugged all the injectors at once, oddly enough, the car still ran, exactly the same. i checked the plugs with a test light and there is signal comming from all of them. i guess my injectors are stuck wide oppen and i actually had raw fuel comming out from my exhaust. looks like i might have found my problem.

[woldson]

Ok I will say what!!!!!

"i unplugged all the injectors at once, oddly enough, the car still ran".

 

You have done soo well,,, ummm..... please elaborate.

[m4xwellmurd3r]

it sounds like all of his injectors are stuck WIDE OPEN. causing it to dump fuel constantly

that would explain a lot of things haha.

that would also explain the horrible oil smell. and possibly the lower compression numbers if the cylinders got washed out

[Daeron]

at one point you mentioned pulling plug wires to no effect; I think you said cyl 1 and 4 were firing but the others, by that test, were not.

 

Is this still the case? If so, after attempting to run, or running, what do the spark plugs from the NON firing cylinders look like when you pull them right after shutdown? Are they covered in fuel?

 

I do not think that the engine would run at all with all six injectors stuck wide open; that makes no sense, it would be completely flooded out.

 

Your "dropped" compression numbers could mean literally nothing; if atmospheric pressure was higher the day of the first test than it was the day of the lower test, you would EXPECT to see lower numbers across the board. On the other hand, it COULD indicate that you are washing your cylinder walls with fuel.

 

Have you found the EFI bible yet? It has great troubleshooting flow charts that direct you to the tests you need to run, in the order you shuold run them, for a number of give problems. I would first suggest reading that book thoroughly (first section, just read through twice. Then, skim through the testing procedure section, then read through the first section again, and read the tests with your car and its problems in mind.)

 

If you want to "think outside the box" regarding the book, or if you have read and tested and are STILL stumped, you might try disconnecting the fuel pump power supply, and removing each injector one at a time, holding it in your hand while the engine gets turned over to see if it is physically functioning. All six injectors test out, and you get good signal, then its time to check fuel pressure... but ALL of that is contained within the book.

 

 

 

This book is not TITLED "The EFI Bible," that is just the label that the Z-car community have given to it because it is THAT comprehensive, and THAT vital to knowing this FI system. It is a simple, simple, SIMPLE computerized system designed and built in the EARLY 70's and quite frankly, all you need to do is RTFM and everything becomes clear. If the components pass all the prescribed tests, the bottom end is intact (140 across the board should run like a champ) and you give it good fuel and spark, then the car WILL start and run.

[m4xwellmurd3r]

he didn't pull the spark plugs, he pulled the injector plugs.

[Daeron]

he didn't pull the spark plugs, he pulled the injector plugs.

 

at one point you mentioned pulling plug wires to no effect;

 

i had the car running and unplugged 4 of the 6 plugs after i cleaned them and the car ran the same as with all them on. but when i pulled the cylinder closest to the fire wall the car stalled out. and i know i am gettting spark through the wires cuz they shocked me soo bid i bled.

 

Replace those wires. Try running the car and the dark and see how many places your spark may be arcing out to... bad wires leaks just like bad hoses.

 

i pulled the connectors off the fuel injectors one by on and the only cylinders that seemed to be effected by this was numbers 1 and 4

 

but cylinder 6 seemed to be firing according to the "pull the plug wires" diagnostic?

 

Something isn't right here, and wandering around in your engine bay, haphazardly looking at various subsystems for your problem is not going to pinpoint it.

 

 

 

New start. Get fresh plug wires, clean all six plugs, re gap them, and check for spark at each plug (yes, I mean pull the plugs, one at a time, and with the plug wire connected to the plug and the plug grounded on the valve cover, crank the engine and look for BLUE spark at each plug.)

 

If you do not get good, blue spark, then get new plugs. NGK BPR 6ES

 

Blue spark at all six plugs? Good. Again, even compression numbers around 140 WILL run perfectly fine.

 

Now run through the tests in the EFI bible.

http://www.atlanticz.ca/zclub/techtips/efisystem/280zfuelinjectionbook.pdf

Make sure that you run the component checks at the ECU end, AND at the component end. Testing say, the Throttle position switch.. it may go from idle, to run, to WOT and work perfectly fine when testing at the sensor, but if there is a break in the harness to the ECU then it will still behave badly. Testing at the component checks the component, testing at the ECU plug tests the vehicle's wiring as well.

 

 

 

Let us know which test solved your problem.

[S130Z]

i will post up when i install the new injectors and we can go from there. by the way thanks for the link to the efi bible.

[greygears]

Check your grounds. This system is very sensitive about it’s grounds. All the grounds between the manifold and the body must be clean & tight. Check your fuel pressure. It should be around 34 to 38 psi. Any more than that, check your fuel return line for blockage and check your fuel pressure regulator. Check the bellows between your airflow meter and your manifold. Any kind of leak here will cause problems. Good hunting.

[S130Z]

so i got new injectors, i used 300zx injectors witch are 20cc larger, and replaced the fuel filter to be safe and to my surprise it ran quite smooth and did not smoke. i let it idle for a few till it warmed up and then gave it some gas. it revved up and then backfired. confused i reved it up again and it backfired two more times and then started to run rough again and smoke. after messing with the TPS and wondering why it did this i reved it again and then it backfired through the intake. it began to run like before the new injectors and still ran with all the injectors unplugged. baffled i shut it off and left it alone. i also noticed that my ground wire that is connected to the idle hose bracket( this ground is smaller than all the other grounds) is barely hanging on.

[Daeron]

Take a multimeter, set it to DC voltage, put the ground probe on the ground terminal of the battery, and take the hot probe and touch the fuel rail, the intake manifold, any piece of metal that might somehow be connecting to the injector.. even if in a convoluted way. If you find any voltage registering like this, then something somewhere is shorting out.

 

In the meantime, you have gone from a poor/will not run situation, and installed LARGER injectors (MORE fuel) when you were already apparently running rich (did you ever check to see if the spark plugs were wet?) and you decided to fix this by installing LARGER injectors than what the ECU expects to be there, thus delivering MORE fuel than the system would have been before you "fixed" it. So, it runs richer than it did before?

 

Please, verify that the AFM output signal is within range and properly calibrated, that the throttle position switch is located properly, and that the coolant temperature sensor is being read right. These three tests take an hour for the most inexperienced novice to figure out how to do and complete, and twenty bucks says it finds your problem.

[Careless]

have you tested the original injectors?

 

just take two wires, and give them a shot straight off the battery. if they click, they're probably unstuck. if they don't, then someone probably tinkered with them.

[S130Z]

so i got around to messing with my car and i giggled around one of the grounds i thought might be bad and when i moved it i heard a clicking sound like it was coming from my injecotrs, i tried to start it after tightening the ground and then it wouldnt start. it was kinda dark so i coulndt check my fuses and i had no flash light at the time.

[kralcniloc]

i just ran the compression test and all my cylinders sat at around 140psi. the last time i checked them they sere at 178psi

 

Check the Timing chain or tensioner, because if the chain somehow slipped or if the tensioner failed, i will severely retard your timing which will cause a compression loss on all cylinders. and it could cause a poor running situation.

[S130Z]

i got time to mess with my car again and i cheked everything over, clean plugs, crainked it with the plugs out, eliminated my idle bypass screw and relocated that odd ground wire. i cranked it up, and it ran smooth as butter. i drove it down the road and it was still burning oil so i started to change the oil, drained it(the oil was 1/2 gas 1/2 oil) and it started to rain to im stopped for the moment.