Problem after tune up

[kjphilippona]

I just replaced wires (ngk) plugs (ngk) dist cap and rotor button. I had a miss so i did an old test i learned back many years ago when i had my 260z. I disconnected on plug wire at a time, with #'s 1-3-4-5-6 the engine would change idle and run rough, straightening out when the wire was reattached. With #2 there was no change, there was a spark at plug and dist. cap. What do you guy's thing ?

[bobc]

Did you get a spark at the spark plug? That is, did you pull out the spark plug and connect it to the number 2 wire and ground it against something to see if you had spark at the plug? If no spark, did you try another plug to make sure it's just not a bad plug?

If you've tried two plugs and no spark, I'd suggest doing a compression test next to see what's going on with the #2 cylinder. Check valve settings, next if compression is good.

Just my thoughts,

Best,

Bob

[FastWoman]

Also check the #2 injector to make sure it's clicking. Often the electrical connection will get corroded.

[kjphilippona]

Thanks guy's i check out what you suggested. bobc, i only pulled the boot loose from the plug, i did not have my remote starter with me today. I will be bringing it home this week, she still sits at my mom's. Crazy thing FastWoman when i first got the wires replaced she would not run, checked my wires and plugs and #2 was black, the injector plug got knocked off. I need to replace all of the connectors they are cracked and barely hold on.

Edited November 5, 2009 by kjphilippona

[kjphilippona]

Think i have found my problem, me being a newbie, while cleaning all the oil and crud from this engine, i accidental got cleaner on the injectors and connectors and they are all green with corrosion.

[kjphilippona]

Got all conectors cleaned up and now she runs for a while and then just dies:tapemouth

[Pomorza]

How does she die? Sputtering or just plain old flat out death. (as in just shuts off).

Jan

[kjphilippona]

She does not sputter, just slowly idles down on shuts off:disappoin

[Pomorza]

I would first check the fuel pressure and make sure that it is where it should be. Secondly, make sure that while cleaning up everything you didn't happen to knock something off or disconnect something (I've done that), or you didn't get some of that cleaner on anything else fairly important. Varify that your timing is correct, could have been altered somehow when you were working on the car.

Start there and see where it goes.

Jan

Edited November 6, 2009 by Pomorza

[kjphilippona]

Thanks, i'll dive in tomorrow

[sblake01]

Did you get a spark at the spark plug? That is, did you pull out the spark plug and connect it to the number 2 wire and ground it against something to see if you had spark at the plug?

This is an old school test for points type ignition but I would highly recommend that you don't do it on cars with electronic ignition. It can cause spikes that will damage the ignition module. Use an inline spark check tool. Edited November 6, 2009 by sblake01

[FastWoman]

OK, you have a '77 -- one year different from my '78. I THINK the fuel injection is the same. Here's what you can do to test your injectors and their connections. (I did it yesterday on my own car.) BTW, it's up to you to verify you have the same configuration of system. I'm not taking any responsibility for anything you might blow out by following my advice.:

Pull off the driver's side kick panel. The fuel injection computer is underneath it. With your ignition off (!) pull the big connector off the front of the module. You'll have to push a little catch near the cable to release it. Twist it around, so that the connections are facing you. You're looking at the connections to all fuel-related devices in your car, including the injectors. As it hangs down (cable at top), you'll see a longer row of connectors on the right and a shorter row on the left. The connections are numbered from the upper right #1, to the lower right #18, and then from the upper left #19 to the lower left #35.

Now find or make a little probe you can use. One end will connect to ground, and the other end will be small enough to touch briefly to a contact ON THE CABLE SIDE of the connector. (I want to be clear -- leave the fuel injection computer alone. You're only testing at the big connector that clamps to it.)

Hook up a fuel pressure gauge, and turn on your ignition. You should see the system pressurize. Now use your probe wire to briefly actuate the individual injectors. Watch the pressure gauge to see if the pressure drops off. I would only touch/tap each connection BRIEFLY, as you want enough pressure to test all your injectors. Now, using the numbering scheme I described, you do the following:

Jumper the following to ground to watch for fuel pressure bleedoff:

Starting on the righthand side, 4th from bottom, and moving upwards:

#15 (cyl 1)

#14 (cyl 4)

Then starting on the lefthand side, 3rd from bottom, and moving upwards:

#33 (cyl 2)

#32 (cyl 3)

#31 (cyl 6)

#30 (cyl 5)

If they open and bleed off fuel pressure, then they're at least working. That doesn't necessarily mean they're working *well*.

If you think you might have a weak connection that gives you an intermittent problem, you can also measure resistance through the system. However, it's a bit more difficult. BTW, this is where your wiring is more likely to differ from mine, but resistance testing is pretty gentle -- nothing to blow up. Here's what you do:

Disconnect your battery.

Find your Electronic Fuel Injection Main Relay inside that big black box on the righthand side of the engine compartment -- the one that the fusible link boxes are mounted to. It has a rectangular 6-wire connector on it. Pull the connector loose. Contact #43 on the connector is the one you want. Clip one wire on any of the aforementioned injector connections on the EFI main connector, and probe each of the six connections to the relay. Only one of them will have any continuity. Now start measuring resistances between that one terminal and each of the six injector contacts. The resistance will include about 6 ohms for the dropping resistor, located beneath the brake master cylinder, as well as the resistance of the injector coil. I don't know what that resistance is, but you should have the same TOTAL resistance on all six tests. If you don't, then you might have issues with a connection or with the drop resistors. You can always pull the drop resistors to test them. Mine measured 6.5 ohms, but they are nominally 6 ohms each. Similarly, you can pull the connectors on the injectors and measure those individually. If you have extra TOTAL resistance that you can't account for, then you probably have a bad connection somewhere.

Whew!

I hope that helps.

Peace,

Sarah