280zmn Posted December 25, 2011 Share Posted December 25, 2011 Recent new owner of a 1976 280z that's running super rich.. All my plugs are wet after sitting for a day! Smell of gas in oil also. I checked for leaking cold start and it doesn't seem to be leaking. I checked the injectors about a week ago and couldn't tell if they were bad stuck or leaking (I'm a newb to inspecting injectors) but they all looked fine to me. Didn't see gas leaking out of them that I could tell.. My throttle body has a wall of this liquid substance and smells like gas but feels like something else. I Assume that it's oil and gas mixed since I do not have a catch can. I have terrible gas mIleage and all my sensors and everything checked out good at the pin according to the efi bible. I'm stumped now... Could it just be a coincidence all 6 injectors are leaking? Or is there something else I could check? Any advice would be greatly appreciated! Merry Christmas to all! Thank you Quote Link to comment Share on other sites More sharing options...
rossman Posted December 25, 2011 Share Posted December 25, 2011 (edited) Make sure your engine temperature sensor connectors are clean and free of corrosion. There are two connections, one at the sensor and a bullet connector further up the harness. If they are dirty your car will run rich. Edited December 25, 2011 by rossman Quote Link to comment Share on other sites More sharing options...
rossman Posted December 25, 2011 Share Posted December 25, 2011 After reading your post again now that I'm awake , it seems like something more than just a dirty temp sensor. I believe that it's more of a gross fueling problem since all plugs are wet and I doubt that all injectors would fail mechanically open at the same time. Assuming the car is stock, I can think of a few things that could cause this problem. 1) Dirty engine temp sensor connectors as mentioned above. 2) Loose AFM spring tension. A super loose spring will cause it to run rich. 4) Stuck open or sticking AFM flapper. 3) Malfunctioning FPR. This would only cause the problem at idle. Also, you mentioned "catch can," does the car have a properly functioning PCV system? Tell us more about the car. Is it stock or has it been modified? Quote Link to comment Share on other sites More sharing options...
Tony D Posted December 25, 2011 Share Posted December 25, 2011 Keep in mind if the engine is cold, the COLD START INJECTOR will spray as long as the car is in the 'crank' position. You can easily flood the hell out of the engine to the point of wet plugs like this. Same goes for the loose thermal sensor for the ECU in the thermostat housing (or CHT depending on model/year...) REpair or check those items (I remove/clamp off the fuel to the cold start and disconnect the plug.), then crank over the engine with the plugs out---I tend to stick a propane torch flame in there and BOOM it out individually... then heat each plug till the electrode time glows red and the orange flame stops coming off it. Install quickly and try again. 9 times out of 10 the engine will then fire off and you can 'clean it out' by some judicious throttle work. If the manifold is particulary gunked up with PCV residue from 176,000+ miles of deposition then being solvent washed by a lot of gasoline, this process may take a while...and it's a prime time to clean the intake with Seafoam and then do an oil change! Good Luck! Quote Link to comment Share on other sites More sharing options...
280zmn Posted December 25, 2011 Author Share Posted December 25, 2011 I changed the Pcv valve a few days ago just for a piece of mind. That's the only thing I checked for the Pcv system anything else I should be concern about? I've cleaned all my sensors and got the proper reading down by the ecu pins for all my sensors so I don't think it's a sensor problem. I pulled out my cold start valve and crank the engine to see if it was leaking but it wasn't. I even squeezed the fuel line connected to it trying to force fuel out but it didn't so I think my cold start is fine. The only thing I can think of now is my fpr but I don't understand how it could cause all my plugs to be wet after it has been sitting. The plugs are dry after I drive the car but after sitting for a day it becomes wet. That's why I suspect something is leaking but had no luck finding the culprit. Quote Link to comment Share on other sites More sharing options...
280zmn Posted December 25, 2011 Author Share Posted December 25, 2011 Oh an my car is fully stock... For now Quote Link to comment Share on other sites More sharing options...
Tony D Posted December 26, 2011 Share Posted December 26, 2011 How long do you crank it to get it started? The longer you crank, the more the CSV pumps in. Unless they are dried put like I suggested, it could NE three or more days till they dry out to jump spark to the electrode. What you have now is wet fouled plugs. They WILL NOT fire the engine, so either dry them, or replace them and start checking from there. Quote Link to comment Share on other sites More sharing options...
rossman Posted December 26, 2011 Share Posted December 26, 2011 Plug the fuel line going to the cold start valve to check if that is the problem. Use starter fluid if it won't start without the valve. Quote Link to comment Share on other sites More sharing options...
Tony D Posted December 26, 2011 Share Posted December 26, 2011 If the car won't start without the CSV you got FAR more problems than wet plugs! It should start with a tad bit more of cranking, at most, without a CSV. After it starts, operation without a CSV is exactly the same. All the CSV does is provide a 'priming pulse' akin to squirting fuel down the stacks on a mechanical Hillborn or Enderle system. After the intital firing, atomization at the injectors sustains all fueling needs. Actually, there are some EFI Datsun/Nissans that did not come with a CSV if you look. It is not necessary for starting the car. At all. Ever. It really is an 'insurance holdover' from Gen1 Bosch Systems with the smaller EPROM. There is sufficient processor and memory in our Gen2 Licensed units to accomodate 'priming pulse' from the injectors, and it was incorporated in some vehicles (with no CSV Present!) The Gen3 did away with it forevermore. It was eliminated due to extended cranking causing hard starting and wet fouling issues in temperate climates when battery voltage was low, or other ignition issues caused extended cranking and flooded the intake with CSV-Supplied fuel. Quote Link to comment Share on other sites More sharing options...
rossman Posted December 26, 2011 Share Posted December 26, 2011 Thanks for the info Tony. That explains why I never had any problems without one. Quote Link to comment Share on other sites More sharing options...
Tony D Posted December 26, 2011 Share Posted December 26, 2011 LOL, yep..."that would explain it!" Quote Link to comment Share on other sites More sharing options...
280zmn Posted December 26, 2011 Author Share Posted December 26, 2011 Thanks for all the replies guys. I plugged up the CSV fuel line and took it for a drive. It starts up no problem without it so thats not an issue. I'm still getting bad gas mileage and can still smell fuel from my exhaust pipe.. But when I checked my plugs earlier it was not wet with fuel but they seem to be even more fouled up then they use to be before. Even my 1st spark plug which normally does not foul up is now fouled. My AFM looks new. And there is a sticker on it that said refurbished. My fpr looks pretty old so right now that's what Im suspecting it is. Either that or my AFM was not refurbished right.. I am going to leave the car sitting for a little longer to see if it starts getting wet again. Thanks for all the suggestions keep them coming. Quote Link to comment Share on other sites More sharing options...
NewZed Posted December 26, 2011 Share Posted December 26, 2011 Measure your fuel pressure. If you have a return line or FPR blockage (or connected backward) and an aftermarket pump, you could have up to 90 psi at the injectors. That will push a little extra gas through when the injectors are open. Quote Link to comment Share on other sites More sharing options...
280zmn Posted December 30, 2011 Author Share Posted December 30, 2011 After hrs of trouble shooting I find out that my cold start valve was causing the wet plugs and my fuel pressure regulator was causing me to run extremely rich. Just documenting this here, just Incase others who search this up run across the same problem. thank you everybody for the help Quote Link to comment Share on other sites More sharing options...
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