Upgraded Injectors

[Eye8Pussies]

Since boosting, I've had some fuel problems and will also be picking up a wideband soon to get a better idea of my a/f.

I've got the 255lph HP pump in as well as an apr fuel regulator with rising fuel pressure with boost. I also have a new fuel filter as well, and on the gen3, there is no real need for a mod such as Jim's Fuel mod since it is a return-style fuel system. I will also be installing a fuel cooler soon as well (once it starts getting warmer outside). I will also be installing my SAFCII as soon as it gets warmer.

The problem though, is that even in closed loop, my car is running lean. So therefore, an SAFC will not solve my current problem by itself by any means.

So to help solve part of my problem (hopefully) , I am looking into getting some better injectors than stock. I know there is debate over the need for it at only 4psi, but you guys are all running better ecu's than mine since my obdII was the very first one to come out in 94 and it was also programmed quite differently than the gen4 and solara ECUs. That, and once I get all this figured out, I'm moving on to the 6lbs pulley. If that doesn't work out, then down to a 5.5 pulley.


So here's my question for people with upgraded injectors. I am looking for direct fit ones and I know that the supra ones fit. I am looking for something around the range of 315cc or so to a max of 330cc with a top feed.

This is where I get confused with the supra injectors.

Do I use the 7m-ge ones or the 2jz-ge ones??? I believe that the 7m ones are 310cc and the 2jz ones are 330cc? And do they both bolt-in, or only the 2jz ones?

Thanks!

[PDX SuperSolara]

Well there is easier and cheaper (not to mention better) ways to get more fuel into your engine than spending at least $700 for Supra injectors. I use stock injectors with 8 psi boost and lay down at least 275 HP to the rollers through an automatic. Sure I have noticed some differences in injectors over the past few years, but I'd be surprised if yours are the real problem. Since you already have a return style fuel system how about just raising the fuel pressure? An Aeromotive FPR will do the trick and allow increased fuel pressure with boost. The fuel mod I send out may benefit your system since it corrects the problem in the fuel filter and fuel lines and connections to the fuel rails. So I wouldn't rule that out. I would check fuel pressure at the rails and see if it goes down under power. More than a pound or two drop is a major problem.

[krook]

I would check fuel pressure at the rails and see if it goes down under power. More than a pound or two drop is a major problem.

just curious...how do you check fuel pressure at the rails?

[PDX SuperSolara]

To check fuel pressure requires a fuel pressure gauge and and a means to attach it. On most of the 1MZ motors I have seen, the stock fuel delivery pipe goes first to the rear bank and then up to the front bank, so you will want to attach the gauge to the front bank since it gets fuel after the rear bank has had it's fill, so to speak. Anyway, the banjo bolt on the stock front attachment point has to be modified on non-return style systems, or you can figure any other easy way to attach a gauge, depending on your set-up. But there is no fitting already on the fuel rail like on most American makes where it is simple to do. I got another Banjo bolt, drilled a hole on the end, and brazed a fitting to it that I could attach my fuel gauge to.

Once you have a gauge attached, run the fuel line on the gauge to inside the car and go for a drive so you can read fuel pressure as you accellerate hard. On my stock fuel system on the SuperSolara prior to modification I had about a 25% drop in fuel pressure at the front rail at full power. That is a very serious problem, or at least it was before I put in a full return style system.

Dialing up the fuel pressure is like turning up a garden hose, the nozzle on the end (like the injectors) will spray more water (fuel) for any given duty cycle, unless you run out of pressure, in which case you need a pump capable of delivering more pressure.

[Eye8Pussies]

Well there is easier and cheaper (not to mention better) ways to get more fuel into your engine than spending at least $700 for Supra injectors. I use stock injectors with 8 psi boost and lay down at least 275 HP to the rollers through an automatic. Sure I have noticed some differences in injectors over the past few years, but I'd be surprised if yours are the real problem. Since you already have a return style fuel system how about just raising the fuel pressure? An Aeromotive FPR will do the trick and allow increased fuel pressure with boost. The fuel mod I send out may benefit your system since it corrects the problem in the fuel filter and fuel lines and connections to the fuel rails. So I wouldn't rule that out. I would check fuel pressure at the rails and see if it goes down under power. More than a pound or two drop is a major problem.

only problem that I can see in my fuel setup at the moment is my fuel filter, since it's a stock fuel filter (aftermarket), since I already have an aeormotive fpr as well as a 255 pump, so fuel delivery and pressure should not be a problem.....unless something's drastically wrong.

And it also runs lean in idle, while the fuel is at 40+psi.

I'm going to take that model # that you gave me a while back for the fuel filter that you have in your kit and look it up.



but back to the original question though- do the 7mge injectors fit?

[PDX SuperSolara]

Yeah that fuel filter I supply has much better flow the the later stock filter because the later stock filter has a really bad outlet tube. The have it bent at a 90degree angle and the pipe is pinched so bad I'm suprised it can feed a stock motor let alone a S/C car. But that doesn't sound like the only problem you are having with fuel delivery since you are seeing lean running at idle. Remember that aftermarket intake air systems really can meter fuel differently than the stock air intake tube, my Injen setup with a true cold air intake has to run at -12% at idle or so much fuel goes through that it washes the cylinder walls and burns oil after a minute or so at idle. So if you have a non-stock intake be sure you check the fuel mix at various loads and RPMs. Yours may have the opposite effect depending on brand, and may need to be compensated for. There is really no reason you should be running too lean at idle otherwise, it certainly wouldn't be the filter causing it because if it was, the car wouldn't run at all off-idle.

[Eye8Pussies]

^ hmmm...that's a good point. thanks.

I will look into what you said as well, and in the mean time start fixing one thing at a time and see where it takes me.

First thing I'm going to do though is pick up a wideband so I have a real and exact idea of how lean I'm actually running.