Running rich, RPM's drop at 4000 and car dies, enjector 2 not firing

[tfsbecause]

I have a 1978 280z, stock car, no mods. It sat for about 5 years. I drained the tank, placing a fuel filter between the tank and the new fuel pump, changed the oil and flushed the radiator. I replaced the fuel injectors, spark plugs, wires, distributor cap and rotor. I also installed a new temperature sensor. I read it causes problems so I replaced it since it was only $15.

My 2nd cylinder is missing (wire's and plug are good, tested by swapping with Cyl 1 plug and wire, and they worked on cyl 1). The 2nd fuel injector isn't working, I hear no tick. I suspect I may need new connectors since they are in pretty bad shape. Any suggestions what kind? I have not checked the fuel pressure because I don't have a fuel pressure tester and limited funds.

It is running very rich, black smoke out and a strong gas smell. At idle when I rev it up to 4000 RPM's drop and the car dies. Since putting in the Water temp sensor I can keep it going if I back off and then pump the peddle. Any ideas where to start? I dont' have a lot of $$ To work with so need t spend it wisely. I need to get back to work and need this car.

I hope to start working on it more tomorrow. Any ideas? Please help.

I have the FSM and FI bible. just not sure where to start and not real experienced with electrical. Help! Thanks.

[tfsbecause]

Well I narrowed it down some. The continuity test came back no good for the Throttle switch, the air temp sensor and water temp sensor. No wonder I am running rich! Now to figure out where the currents broke. I hope it's just the connectors or bullets. Will have to figure out the air temp sensor and how to test it. Im not ever sure where it is, but will find it. Going back at it tomorrow morning, 4 year old in tow again. All the other circuits tested ok. Not sure what's up with FI 2, but it has continuity.

[Zed Head]

Looks like you're taking the right approach, with testing and fixing. The ECU uses a multitude of switches and sensors to determine the injector open time. They all have to be working right for the engine to run right. The best thing to do in the FSM is to combine the continuity tests with the values described later in the chapter for each component. No reason you can't measure values from the ECU connector also.

The air temp sensor is in the AFM. The throttle position switch (TPS) can be opened up and cleaned. The coolant temp sensor has a couple of bullet connectors over the manifold, pretty easy to find. It only takes a little moisture to stick an injector. Apparently the insides rust easily. I have unstuck an injector by tapping on it.

[tfsbecause]

Well the water temp sensor seems to be fixed, just cleaned the connection 5 or 6 more times, retested at the ECU and it has continuity.

No progress with the TPS/switch. There is still no continuity on the idle side at the ECU, the WOT is good (the same as when I first tested). The thing I don't get is why does it move when I increase the RPM? Has anyone had just one side not work? How do you test just one side? My test light is getting no reading anywhere...worked fine on the battery, 12.xx volts. I tried it on a known good wire and still nothing. I tried it with the ignition off and on, it didn't matter. I just said ef it and moved on to AFM. I kind of doubt the meters volt and continuity tests work and the resistance tests not working.

The AFM tests were all off (that is assuming my meter is good). I will list my readings and (what they should be in brackets). The fuel shut off switch pins 38 & 36 - 7 ohms (0). The AFM potentiometer resistance readings: Pins 6 & 8-400 ohms (180), Pins 8 & 9-200 ohms (100), jumpers melted so didn't finish the test. The Air Temp test also failed, Pins 27 & 6 - 0 ohms (1.75 guessing, I figure it's about 85 F out). So I gather there is noo fixing this? Is it time for a new AFM??

I also am in bad need of new fuel injector connections. It's amazing they don't fall off. What kind do you recommend? Plan to shop online tonight.

So is my TPS and AFM bad? Any other tests, repairs or things I should do before dumping $$ into parts?

[tfsbecause]

Will search the forums to see if I can find someone with similar issue(s). I have to get this car running asap.

[Zed Head]

Well the water temp sensor seems to be fixed, just cleaned the connection 5 or 6 more times, retested at the ECU and it has continuity.

No progress with the TPS/switch. There is still no continuity on the idle side at the ECU, the WOT is good (the same as when I first tested).

The AFM tests were all off (that is assuming my meter is good). I....The AFM potentiometer resistance readings: Pins 6 & 8-400 ohms (180), Pins 8 & 9-200 ohms (100), jumpers melted so didn't finish the test. The Air Temp test also failed, Pins 27 & 6 - 0 ohms (1.75 guessing, I figure it's about 85 F out).

I also am in bad need of new fuel injector connections. It's amazing they don't fall off. What kind do you recommend? Plan to shop online tonight.

So is my TPS and AFM bad? Any other tests, repairs or things I should do before dumping $$ into parts?

The resistance numbers of the AFM look right. 100 and 180. You might be able to figure out the air temp sensor if you have the AFM off. There's not much to it, plus a zero reading would make the engine run leaner, not richer. If you're testing the AFM at the ECU connector and you get bad results, the next step is to take the component off of the engine and test it. I assume that you were applying voltage and measuring but that test is more for fine-tuning the smoothness of acceleration, so probably not too relevant to your problem.

The TPS is not complicated either. Take the black cover off of the side and the connector off and retest it at the pins on the TPS. Find out of the TPS itself or the wiring and/or connections are bad.

You tested resistance for the AFM and the air temp sensor but reported continuity for the water temp. sensor. Resistance values are most important for the water temp sensor., continuity doesn't tell much.

Volvo or GM type EV1 connectors are nice because the spring clip stays on the connector. The others are good but you can lose the clip.

You haven't said if the engine runs better or worse than it used to. A "state of the engine" comment or two might give some more clues.

Edited November 4, 2012 by Zed Head

[tfsbecause]

Haha, point taken. There is still some black smoke, but much less. It is running better, but its missing on cylinder 2, which has spark and compression of 140. I think it's the connector. I hope so anyway. It starts right up, don't even have to hit the peddle. The idle is smooth at a steady 800 RPM. I adjusted it with the idle screw and whatever that other thing is called (sorry I am an older lady who likes tinkering with cars and do not know the names of all the parts. Too lazy to look it up at the moment. Damn it looking it up, don't want to be a slacker. It's the dash pot). Just tweaked it a little. Though the idle never was too erratic, maybe 50 RPM's. When this project started it was low and ran super, super rich, poured out black smoke and made you choke.

The AFM was off when I tested the pins. My results were 400 and 200. The 100 and 180 ohms were what they should been.

The ECU test showed no good for the air temp sensor. When I took the AFM off the ATS test results were 0 ohms and it should have been about 1.75 I am guessing. It should have shown something. From what I have read in the FSM the whole thing needs to be replaced. But I guess I am irrationally hoping it can be fixed .

The reason there isn't resistance results for the TPS and WTS is I couldn't get the meter to work. I set the meter on dc-v, penetrated the wire and got nothings. I tried a test light and nothing, even on known good wires. Pissed me off! I can't explain why I got no readings. It was pretty maddening. I didn't get any on know good wires either, like the thermotime. The meter tested my battery and the AFM fine so I'm pretty sure the meter works. I told you though I am not experienced with electrical. Yeah this should be fun right. **** now I am wondering if I had the ECU unplugged...idk. Would it make a difference? If I didn't need to use this car it wouldn't be such a big deal. But my POS escort has dropped valve seats in cyl 3 and 4 and is ready to go. I could probably figure it out how to remove the head, but don't have a garage to work in, but I digress.

So after the AFM is resolved I will try again to test resistance of the TPS and WTS. But what the hell am I doing wrong with this meter?? Ugg.

Will look into the FI connectors. Thanks! I found some with other connectors, for one the other end of FI harnass, for $55. But I would have to put the wires in. I've never done that, but can figure it out with a little help and some reading. If I can solder my laptop power supply plug in I can figure out that. I think. No I don't work on laptops usually. That is if they still have them. Thoughts on those connectors? I think there was also a WTS and TPS connectors in the pack.

[Zed Head]

I misread your post about the AFM. 400 and 200 aren't good. But I think that you may well be mis-uisng your meter. dc-v Would be a voltage measurement, not resistance. Maybe your 400 and 200 are millivolts, not ohms. And there's no reason to pierce the insulation on any of the measurements, the connectors are pretty easy to remove. I think that it might make a difference also if you don't disconnect the connector. With it connected you're measuring the ECU properties also.

The problems with the meter settings might also explain the burnt wires. I would look around for some instructions on how to use the meter and start over. Good luck.

[tfsbecause]

I will recheck but am pretty sure it was at the right setting for the AFM and that it's bad. I borrowed my dads meter and he doesn't have the papers so will google it. Should be able to find something. I pierced the wire near the bullet down stream with the meter and the test light. Well find the papers for this meter online. Should be pretty easy to find. Probably work on it again Tuesday after work.

[tfsbecause]

Actually I have the AFM here so will test that maybe tonight. The car's at my dad's and wont get there till tuesday.

[Elena]

"""Hey There...

I'd really appreciate if someone could suggest a good car mechanic and

car reseller... I have a Porsche that I would like to sell....

james elena"""

[sblake01]

^^Why is this person still allowed to post?