savageskaterkid Posted July 9, 2006 Share Posted July 9, 2006 A couple weeks ago I decided to take my car to a mechanic to get some leaks fixed and see if they can figure out my problem for why the car runs while warming up but dies when its at operating temps. I got the leaks fixed already(the PITA leaks that are more of an annoyance then hard to fix). But my running problem is bugging them too. They were trying to convince me that the pump I am using is worse then the N/a Z pump. The MSD 2225 isn't the best, but I would highly doubt it is inferior to the Z's stock pump. After I convinced them that its a better pump, they thought it may be the wiring. Now, i've been f'ed by mechanics who thought it was this, then thought it was that........and it turned out to be the thing I told them to fix in the first place-although many, many dollars later. The real question is, could the stock fuel pump relay and wiring cause the MSD to drop fuel pressure after warmup? After warmup the return line needs to be clamped shut basicly for it to continue to run. Quote Link to comment Share on other sites More sharing options...
Twizted Posted July 9, 2006 Share Posted July 9, 2006 I would get away from stock wiring. There have been numerous situations resolved by direct wiring and puting in your own relay. I know that mechanics (especially Nissan ones) try to go back to factory whenever they have no freakin clue. Their logic, well if it worked once it'll work again... The factory pump is a decent unit tho, just not a very good choice when your going to be doing upgrades. How are your injectors? And what PSI are you running both before warmup and after? Good luck Quote Link to comment Share on other sites More sharing options...
savageskaterkid Posted July 10, 2006 Author Share Posted July 10, 2006 Everything worked with the stock pump, it just wasn't very adequate for the turbo, the injectors all pulse and the car revvs fine, but once it warms up, thats it. I haven't tuned the pressure just yet. Quote Link to comment Share on other sites More sharing options...
TimZ Posted July 10, 2006 Share Posted July 10, 2006 The real question is' date=' could the stock fuel pump relay and wiring cause the MSD to drop fuel pressure after warmup? After warmup the return line needs to be clamped shut basicly for it to continue to run.[/quote'] So if you clamp off the return line when it's in this state, how much pressure do you get at the fuel rail? What is the voltage at the pump, both cold and hot? Quote Link to comment Share on other sites More sharing options...
savageskaterkid Posted July 11, 2006 Author Share Posted July 11, 2006 I actually have no access to the car now, its all in the mechanics hands. But today I was told that the pressure the pump was putting out was 100psi, and all that is needed is 40psi. Now my question is how can the car run when cold at that much pressure, but not when it warms up? They ordered an FPR for me, I need one anyway, so its not a loss to me. Would the 100psi cause the car to run really rich when it warms up, and act as though its getting no gas at all? Quote Link to comment Share on other sites More sharing options...
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