Guest jjohart Posted March 17, 2004 Share Posted March 17, 2004 Hi, I just got my Z back from a reknowned Nissan service center over 60 miles away, and they basically shooed me off, telling me they could spend hundreds of dollars without a direction to go on with my intermittent restarting sputter/stall issues (when the car is fully hot, idled a couple, shut down, and restarted 10-20" later). They also said they didn't have a fuel mix measurement device, and that my car seemed to be a bit "rich". What kind of service shop do I seek out for this? A fuel injection specialist, or a private racing shop with a dyno? How can I make the car run more lean? This is an 83 280ZXT, 50K miles, with intercooler added, which makes this problem worse. The dealer said it might be some sort of fuel puddling in the intake. I find it ironic that if I pop the hood everytime I stop the car, this problem doesn't happen! Thanks J Quote Link to comment Share on other sites More sharing options...
Phantom Posted March 17, 2004 Share Posted March 17, 2004 It sounds like you have a case of vapor lock. Your engine is boiling the fuel in the fuel rail when you are sitting parked. If you let it sit longer, or shorter, that won't happen - right? Do you have your exhaust heat shield in place? Do you have the fuel rail blower assembly in place with your engine? If youo'll thoroughly shield your fuel line - or insulate with a high temperature insulation your problem will go away. It should also go away if you have the blower installed and operational. "Renowned" dealership? If they were they would be able to work on a Z more than 10 years old. Most dealerships can't work on any car that doesn't have a computer hook-up anymore. Call around your area for a private repair shop that "specializes" in japanese cars especially if you see one that mentions "Datsun". that is where you will find the guy that was trained by the factory 25 years abo and actually knows how to work on your car. At least your dealer was honest with you. I went into the one that sponsors our Z club here in the local area to have some work done on my '77 280Z. they told me that they had no one trained on the car, had no service manual on the car, and probably didn't have the parts. Really makes you feel loved, doesn't it? Quote Link to comment Share on other sites More sharing options...
280Zen Posted March 17, 2004 Share Posted March 17, 2004 When this problem happens do you hear the fuel pump get louder? Quote Link to comment Share on other sites More sharing options...
Guest jjohart Posted March 17, 2004 Share Posted March 17, 2004 Phantom: the injector fan is operational, but is factory set to come on when car is 219F, which doesn't happen around Boston this time of year, but would seem to be too high for the injector fans to make a difference. YES, it definitely gets better if time span is SHORTER or LONGER. I am wondering if there's a simple way to get that injector fan to come on at lower temps..someone sent me a whole thermostat kit, but would the fan come on at lower temps if I wrapped the probe in an insulating foam/tape or something? Some other quick fix? Zen-no, the fuel pump doesn't get any louder, and fuel pressures tested within normal limits when the car was hooked up to a pressure gauge and left to sit for an hour (e.g lost 2 lbs). Thanks John Quote Link to comment Share on other sites More sharing options...
Tim240z Posted March 17, 2004 Share Posted March 17, 2004 Maybe there would be some way to have the fuel pump set to run for a while after the engine shutts off, thereby cooling down the lines with 'fresh' fuel. Alternately, wrap all of the engine bay fuel lines with heat shielding tape: http://store.summitracing.com/partdetail.asp?part=THE%2D14002 Quote Link to comment Share on other sites More sharing options...
280Zen Posted March 17, 2004 Share Posted March 17, 2004 the injector fan is operational, but is factory set to come on when car is 219F So the injector fan is designed to kick on when the temp reaches 219F?? I thought the fan only kicked on after the car was turned off. John Quote Link to comment Share on other sites More sharing options...
Guest jjohart Posted March 17, 2004 Share Posted March 17, 2004 Yes, as far as I've been told by factory techs, and folks familiar with it elsewhere on this list, it would be malfunctioning if it came on while the car was running! John Quote Link to comment Share on other sites More sharing options...
280Zen Posted March 17, 2004 Share Posted March 17, 2004 I wondered about that, I always thought it would be a good thing for it to kick in and run while the car was on, especially if the temp was high. I'd have to do a test to see if mine is working at all. Quote Link to comment Share on other sites More sharing options...
Phantom Posted March 17, 2004 Share Posted March 17, 2004 280zen - Fan running while engine is running is waste. Fuel flow through the rail to the injectors will stay cool enough to not boil. It's only when it sits and doesn't move that enough heat soak can occur to boil the fuel. jjohart - You can go to the electrical board and see if someone can help out with wiring in a lower temp thermostat switch. You might also consider relocating the sensor to a spot that sees the heat sooner. You didn't answer as to whether your exhaust manifold heat shield is still in place. I assume it is? Another option would be to replace the sensor with a switch that has a timer that turns the fan on for about 10 minutes every time you turn the car off. That would be overkill but it would do the job. Now - the real question - what is not working or been changed? The fan has done the job on Z's for over 20 years. Works great on my '83. It was running in the 50° garage last week. THat tells me something has changed from the original Datsun design. Quote Link to comment Share on other sites More sharing options...
Guest jjohart Posted March 17, 2004 Share Posted March 17, 2004 Hi. I am sure that the intercooler, open element K and N filter, and related plumbing changes have been the culprit in my car's increasing incapacity to dissipate heat effectively (air around the engine bay). There's no doubt in my mind that all that plumbing blocked a considerable amount of air flow space to atmosphere, adding to the problem. The Z tech speculated that it could be a bit of fuel "pooling in the intake" when the car's shut down...I have no idea if that is what is getting in the way, but let's face it, just like a patient with limited lung capacity in a hospital bed breathing from a tube has a good chance of getting "purified" air when the systems are monitoring them, but an increased chance of having complications when made to go back on breathing air under stress without the active monitoring and hose, my Z had those injector fans as a design band aid of heat issues with Z's! Similarly, my intercooler set up is helping the car to perform well by aiding it's intake when the car is running and moving, but I suspect its mass and band-aid design (i.e not from stock parameters) means it shows it's impact on the fuel boiling/vapor condition especially when the car's off and subject to the whims of heat with all the added plumbing. Sorry about the ranting metaphor. I just wish the mechanics in my area would take my situation seriously...I've replaced temp sensors, fuel injectors, done fuel pressure and ignition tests, but I knew all the long that this problem, while slightly present before the intercooler (noticed it in fall briefly, but never went through a summer with this car), was more likely a simple test of adding more ventilation/wrapping the fuel lines, as some on this site have suggested! Now if I could only show you the crappy clear heat dryer hose the I/C installer used to connect the BOV to the turbo outlet..it's come off it's Home Depot tension clips 3X, leaving me stranded, yet the installer told me "oh, we have to make a new intake to do a metal pipe set! SURE! I'll save this for a new topic when I can get a JPEG of the underhood situation! John-83 280ZXT Quote Link to comment Share on other sites More sharing options...
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