93 300zx N/A Dumping fuel out exhaust after cleaning engine

[zcar93na]

Ok, i'm new on here, but i have been doing some research and have came up empty handed... About 2 months ago i bought my 300zx, #5 fuel injector was bad. So i replaced all 6 injectors, and got it running. It ran great until the other day i degreased the motor, now it dumps a fog of fuel out the exhaust when i start it up, and it gets worse if i rev the engine. I know that sounds like an injector o-ring is pinched just letting gas dump into the cylinder, but it never did this until i washed it. Did i short something out, or spray water into something i shouldn't have? Any help is greatly appreciated. Thanks, jacob.

[ChristianKustomz]

Hi there. I own ChristianKustomz Automotive & Performance Tuning and specialize in these cars so I may be of some help.

It's a little difficult to diagnose a problem without seeing the car but I can offer some suggestions. First would be are you sure it's fuel coming out the exhaust? Does it have a color like, a clear mist, blue, white or black smoke? When you start the car does it idle fine or does it miss? If it misses does it eventually go away or does it stay like that? Do you hear either a gurgle sound or a whistling sound while it's running? Anything else you can add would be great.

[zcar93na]

it's white smoke, and there's no doubt that it's raw fuel, it's all you can smell. I don't know of any weird sounds, but it does miss occasionally and then clears up. If it helps any, the fuel pump keeps running after i shut the car off, and it keeps running like it's not building pressure, i have to disconnect the battery to make it stop.

[ChristianKustomz]

First thing I would do it get an OHM's reading on the injectors. They should read about .012 if they are functioning correctly. Next check your fuel pressure. It is possible for the FPR to have gone bad. Sometimes the fuel dampened can cause issues too. Anyway check the fuel pressure; it should read Around 43.5 to 44 psi. If that's ok then next check the O-rinds to make sure the seals have not blown out. Next I would check the injectors themselves to make sure they did not die. Some shops can test the spray on te injectors to see if they spray or dump fuel out like water from a can. Lastly I can tell you a fuel pump should not be running constantly. If it is, it's a strong indication your FPR took a dump. I just had a modified 1994 Dodge Stealth at my shop 2 weeks ago with the same problem. The FPR was bad so I replaced it and she was running like a champ again. Personally from what you have told me it sounds like the FPR. Be careful though not to confuse the FPR with the fuel dampener. They look similar but they are not.

[zcar93na]

I replaced the FPR and the damper, ohm tested the injectors, then I found some wires with a short and part of the harness was melted together. I replaced all of that with a harness from my parts car, and it ran fine. It took about 15 minutes for all of the gas to burn out of the cats, but everything works fine now.lol

[ChristianKustomz]

Good. I am glad everything worked out for you. It was good you replaced the FPR and the dampener at the same time. I forgot to mention to do that. That took care of your running fuel pump. As far as the wires are concerned its common for these to corrode and what not. Glad to help.

[300ZXttZMAN]