RangerWill Posted March 10, 2013 Share Posted March 10, 2013 Little background, I have a 77 280z. Ive been working on for about 5 years between deployments and the Army moving me here and there. Not a lot done to the motor. Lots else where though. MUAH HAHA . - Shaved intake, ISK fuel rail W/ gauge, Fuel lap pressure regulator, 240SX TB, MSA 6-1 header, Fireball coil, Thunderbolt plug wires,MSA cold air intake, NGK plugs, new stock injectors ISSUE - Motor very hesitent to fire up after any lengh of driving. I could start it and then fire it right back up and it struggles. Has to have an all night cool for it to fire right up. Otherwise Im on the starter 3 times of about 10 seconds to get it to hit and fire up. Once it does it runs like crap for about 5 mins and the as normal. I have read and read posts hopeing to find the answer and thought I had with Heat Soak. Thinking my Fuel in the Rail was vaporizing and then not wanting to fire the car off. Not the case I believe. To combat this I installed a hot switch to my fuel pump and disconnected the normally driven wiring. My plan was to simply run the fuel out of the rail and in theory there would be no fuel to Vaporize. Once I was ready to start it up again, flip of the switch to once again pressurize the rail with some fresh fuel. Sounds to me like this would work. WRONG! Damnit...... haha. I was actually starting to fab up a heat sheild until my hot switch fuel pump idea. Since I know there is no fuel in the rail to Vaporize Im at a TOTAL LOSS.................................... So tired of my car running like a damn champ and then not wanting to start up. It just runs to well to think of the common plugs, points, cap issues. I need your help guys. Its driving me INSANE not being able to figure this out. Hell, Id even PAY $$$ to get this issue resolved. Yes, Its come to that. PLEASE HELP. haha. Heres a pic of my Beautiful BABY........................... Quote Link to comment Share on other sites More sharing options...
NewZed Posted March 10, 2013 Share Posted March 10, 2013 The fuel may not be there but the heat still is. Do you have any heat shields at all? Nissan put a lot of effort in to keeping heat away from the fuel system, from rail and FPR to injectors. Quote Link to comment Share on other sites More sharing options...
RangerWill Posted March 10, 2013 Author Share Posted March 10, 2013 No there's no heat shielding at all. Quote Link to comment Share on other sites More sharing options...
skirkland1980 Posted March 10, 2013 Share Posted March 10, 2013 (edited) By cutting the fuel pump you made your problem worse. Maintaining pressure in the rail is what you want. The fuel will boil at a higher temp when the pressure is higher, just like your cooling system. Also when you turn off your fuel pump with the engine running you're not completely purging the system of fuel. You're simply going to lean the engine out until it can no longer stay running. Edited March 10, 2013 by skirkland1980 Quote Link to comment Share on other sites More sharing options...
RangerWill Posted March 10, 2013 Author Share Posted March 10, 2013 I always pressurize the rail before attempting to start it. That's not the problem. Also that wouldn't explain why if I turn it off and immediately try to restart it it hesitates. There's no way it vaporizes that quickly. At I wouldn't think. Even if I don't run the fuel out of the rail the pressure will slowly leave on its own. From 40psi to 0 in about 10 mins. Quote Link to comment Share on other sites More sharing options...
RangerWill Posted March 10, 2013 Author Share Posted March 10, 2013 At least* I wouldn't think...... Gotta love that auto correct. Haha. Quote Link to comment Share on other sites More sharing options...
skirkland1980 Posted March 10, 2013 Share Posted March 10, 2013 Anyhow. You need the injector cooler to prevent the vapor lock that you are experiencing. Quote Link to comment Share on other sites More sharing options...
BluDestiny Posted March 10, 2013 Share Posted March 10, 2013 (edited) It should not bleed off pressure that fast. It takes my car about an hour to bleed off from 35ish psi. I have a similar setup (shaved n42 intake, fuel rail, and no heat shield) but I've never had that problem. I have the MSA 6-1 headers that are coated, but that's it as far as any kind of heat shielding. How is your fuel system routed? Edited March 10, 2013 by BluDestiny Quote Link to comment Share on other sites More sharing options...
NewZed Posted March 10, 2013 Share Posted March 10, 2013 Get the stock heat shields back on and you'll probably be back to heat soak only within a 20 minute period from 10 to 30 minutes after a hot shut-off, just like everyone else with a stock 280Z. Quote Link to comment Share on other sites More sharing options...
RangerWill Posted March 10, 2013 Author Share Posted March 10, 2013 I too have the coated MSA headers. Fuel is routed almost stock. Stock location of the fuel filter. From the filter running near the radiator to the fuel rail. After the rail it runs to the FPR mounted on the fire wall. Then returned to the tank. Quote Link to comment Share on other sites More sharing options...
Tony D Posted March 11, 2013 Share Posted March 11, 2013 Fuel pump check valve. Repair kit available on ebay from vendor Toolman's World. Installs at the back and keeps pressure on the rail. Second, make sure your FPR is working. Even with the engine off, as the fuel heats, the FPR bleeds off till it flashes to vapor, then the vapor vents off. A fuel prime solves it, as long as you know your fuel prime is getting FUEL into the rail and at the proper pressure. MAKE SURE the Cold Start valve is OFF when cranking---number one issue with extended cranking is CSV dumping excess fuel... Stating "it runs too well to think of the common things" is a dumb statement to make. I make my living on people with that attitude, and they show no lack of ire and vitriol when I come in, start at square one, go to the end of the book checking the basics, and afterwards can not repeat their problem. Best dispose of that notion immediately, or you will be in this issue for a LONG LONG LONG TIME! Quote Link to comment Share on other sites More sharing options...
RangerWill Posted March 11, 2013 Author Share Posted March 11, 2013 CSV is now nis-connected. Probably explains the fuel smell and white smoke on the hesitant start ups. Ordered some good heat wrap and blanket. Going to fab up a heat shield. Any suggestions on the shield? Quote Link to comment Share on other sites More sharing options...
Xnke Posted March 12, 2013 Share Posted March 12, 2013 Start with the factory design, and see if that works for you. if it doesn't, insulate the factory design. If that doesn't help, add more shielding, or spot cooling. Quote Link to comment Share on other sites More sharing options...
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