1992 KA24DE Rough Idle problem/Dumping raw fuel out the exhaust

[240sxracer20]

I have a 1992 Nissan 240sx wthat has been giving me fits. It started out with a misfire on the #3 Cylinder. It turned out to be a bad injector circuit in the computer so I replaced it with a different computer. Then, I began having problems with the idle. The car eventually began flooding itself out. I have replaced the fuel injectors, fuel pressure regulator, fuel rail, coolant temp. sensors, distributor cap, plugs, and checked the timing. Now, the car starts fine when cold and runs good at RPM except for an intermittent exhaust backfire(minor), however, after the engine warms up it slowly loses its idle and lopes between 300-1000 RPM. If you give it gas, it will stumble for a split second but once you get above 1200 RPM it seems to be OK except for the intermittent backfire. When you let off the accelerator it wants to die when its trying to find its idle. The plugs now have gone from being full of gas to having carbon on them when you pull them out. I don't know what else to try and would appreciate any help you might be able to offer. I have not replaced the O2 sensor and am hesitant to spend any more money without some direction. The car is actually raced on a dirt track so the exhaust system has been removed in front of the Catalytic converter. Anyone with any ideas?

Last night I went back to the drawing board and started checking my grounds after reading the forum posts. I found that I had forgotten to install the nut on the underside of the fuel rail near the pressure regulator. I assume this is the fuel rail ground so I went ahead and put it back on. When I went to start the car it was like it was flooding again. I tried for a while to start it unsuccessfully and when I looked under the car, the undercarriage and ground behind the exhaust are covered in raw gas! I am at my whits end, PLEASE HELP!!!

[dkdeleon68]

are your injectors seated in properly? sounds like your injectors aren't installed properly

[NISTECH]

What kinda readings are you getting off your airflow meter? Are you able to adjust base Idle at all?

[240sxracer20]

I have never attempted to adjust the idle. I figured that since it had been idling properly prior to all this starting taht it was OK. I don't have the proper equipment for getting a reading off my airflow meter. If you have any idead on show to check these for a shadetree mechanic I would be interested in hearing them.

[navysnail]

you can check the airflow meter with a multimeter

[NISTECH]

Even the shade tree mechanic these days understand and have mutimeters. They are an absolute neccesity in todays autos.

[240sxracer20]

I have a multimeter and would be able to check it that way, does the car need to be running though, I can't even get it to start in its current condition. Also, what voltage readings would I be looking for and will it be constant or would it fluctuate with throttle?

[NISTECH]

you should see 12 volts on one wire, less then .2volts on another wire and the signal wire will be around 1.3 to 1.5 volts at idle and will increase as you give it throttle. check the first 2 with the key on engine not running. then check the other wire while cranking the engine if it gets up around the 1.3 to 1.5 volts it is likely ok.

[240sxracer20]

I'll try that thanks. Would a bad MAF cause the car to dump raw gas out of the exhaust?

[NISTECH]

yes if its running so rich it cant burn all the fuel.

[240sxracer20]

OK, I do know that before it quit starting all together, when you would unplug the MAF, it wouldn't idle at all so I thought that it must still be working but I must have been wrong.

[navysnail]

you dont unplug it to check it, you can use a small pin to pierce the wire, then use the multimeter against the pin to measure it. put a pice of electrical tape over it after your done

[240sxracer20]

I will try that tonight, if the MAF is OK, is there anything else I have missed that could be a possibility

[NISTECH]

well the initial respone about the injectors sealing properly was a thought but the problem was not evident imediatly after replacement so I am not thinking thats a problem. could be coolant tmep sensor as well.

[240sxracer20]

I replaced the coolant temp sensor with one out of a different motor which is when it started to get better. I thought I was pretty close for awhile!

[navysnail]

check the connector of the coolant temp sensor for corrosion, if it is, then you need to replace the harness part for it

[240sxracer20]

When I replaced the sensor everything looked clean, the end of the old sensor had some buildup on it but nothing major.

[navysnail]

may sound like a dumb question, but you checked the codes on the ecu right

[240sxracer20]

I haven't checked the codes in the last day or two but every time I do it flashes 5 short/5 long which I assume means 55 or no problems. If that is not what it means let me know