if i get those injectors and fuel pump and run it with my stock ecu will it run ****ty?

it's my understanding that it would run too lean, and who knows how long it would take the stock ecu to figure it out. I wouldn't risk it, if you need the pump and the injectors, you need proper engine management.

Cheers,
Joel

Originally posted by punkrocksailor
it's my understanding that it would run too lean, and who knows how long it would take the stock ecu to figure it out.

Why would it run lean??? The STi injectors flow about 25% more than the stock ones so your car would run very rich when in open loop. In closed loop I don't know how well the stock ECU would be able to cope. Your car would run ****ty without tuning.

yes, the STi Injectors flow more, but the same currents do not apply, someone more wise than myself needs to step in here and give the technical reasons why. I think it has to do with the ecu still thinking it has the stockers, so it gives the regular signals not revised ones for bigger injectors. I only know this from experience though. I had a ford focus hatchback that I used for auto-x and when I put in cobra R injectors before my ecu was modified to run them I ran lean as hell. then I got the ecu fixed and a supercharger and did really really well.

FWIW,
Joel

what if i reset my ecu after installation of the injectors and pump?

well, I don't think it will work, you can try it with your own car, but I sure as hell wouldn't go through it all again.

Cheers,
Joel

p.s. if you do try it, make sure you have an a/f meter or an EGT and the second you start running lean, turn the car off and pull the injectors. Good Luck

Injectors are controlled by electrical pulses. These pulses are controlled by the ECU. Flow has nothing to do with it if hte computer doesn't know it can do it. For instance, your stock injectors usually run around 80-85% capacity. You put in the STi ones without engine management, they will probalby only run at around 60%. That is where tuning comes in. You want your injectors to run around that 80% or so range. I'm not so sure if you would run lean or rich, just wouldn't be getting the full potential of the fuel system. Are you running a different turbo? If you are, you really really want to tune your car. Then, you will most likely run lean. That will lead to other problems and can lead to engine damage. If you can hear the pinging noise, then you know. Some people don't mind the pinging thinking it just part of having more horsepower. Just picture what pinging is for a second and maybe it will scare you into fixing it. If you don't know what pinging is, here you go. When you run lean, you get really high cylinder temperatures. What ends up happening is there will be these 'hot' spots along the cylinder wall. Now, what these hotspots will do is ignite fuel entering the combustion chamber before you want it to. These ignitions can happen as the piston is going up or down, but not at the top dead center where it should. So, you get this combustion at the wrong time that wants to force the piston back down, but it can't. So, the only movement it can do is shake violently from side to side. That pinging noise you hear is that banging of the piston against the cylinder wall. Hope this helps.

thanks, i dont have this set up yet but i want to get like a new turbo and i guess i will wait till i have everything to put on the ejectors like ecu and ****

Originally posted by punkrocksailor
yes, the STi Injectors flow more, but the same currents do not apply, someone more wise than myself needs to step in here and give the technical reasons why. I think it has to do with the ecu still thinking it has the stockers, so it gives the regular signals not revised ones for bigger injectors. I only know this from experience though. I had a ford focus hatchback that I used for auto-x and when I put in cobra R injectors before my ecu was modified to run them I ran lean as hell. then I got the ecu fixed and a supercharger and did really really well.

FWIW,
Joel

Actually the electrical properties of the STi pinks are identical to the stock injectors. The only difference between the two at all is the hole pattern in the endcap. So, if you just put them in with no real engine management, they will run 25% richer all things being equal. If you have a larger turbo, then it depends on how much larger. Either way you will have major idle problems with larger injectors.

Originally posted by BAN SUVS
Actually the electrical properties of the STi pinks are identical to the stock injectors. The only difference between the two at all is the hole pattern in the endcap. So, if you just put them in with no real engine management, they will run 25% richer all things being equal. If you have a larger turbo, then it depends on how much larger. Either way you will have major idle problems with larger injectors.


Exactly what I thought. When in closed loop the ECU would be using the O2 sensor for feedback and it might run (though not too smoothly) and in open loop it'll just be way too rich. In any case you will see a substantial loss in performance until you get it tuned.

I ran PE 800cc injectors and a stock ecu for about 3,000 miles without a problem. However, I never boosted.

I don't know from experience, but I have read that if you follow the proper ECU reset procedure after installing the pinks, the ECU has enough ability to adjust to the pinks and will run and idle ok....It can take 7-10 days for the ECU to adjust.
To do the re-set.... from a cold start...let the engine idle WITHOUT TOUCHING THE THROTTLE AT ALL......let it idle untill the fans cycle on/off once....do not touch the throttle....Turn the car off...remove the key....re-start the car and go for a drive easing the throttle slowly to WOT...DO NOT 'STOMP' the throttle to WOT!!!!!!!!!
It may buck and snort some ...but it will eventually learn the trim settings for the larger injectors....It may not be perfect...but it should work.....YMMV...

If I remember right running rich for too long could kill your o2 sensor.

Ban Suvs or anyone else How does the walbro pump work compared to the stock pump? Does it start at the same pressure and ramp up higher or something else?

the Walbro raises fuel pressure, and is also capable of flowing a higher volume of fuel at high fuel demand without a huge increase in pressure.

Originally posted by curbait
If I remember right running rich for too long could kill your o2 sensor.

I agree with Ban. Running rich can and will do other things as well. Fouling your spark plugs is one of them among other things.

Running too rich will also "wash" oil of the cylinders leading to ring wear. Not good.

I don't think the Walbro will raise fuel pressure. The fuel pressure regulator controlls fuel pressure. The Walbro is better suited to keep up with the pinks when they really start flowing.

One more thing to note, running very rich will cause excessive fuel dilution of the oil. The solution is to simply change the oil more often (around 3k miles should be more than plenty, but the only safe way is to have an oil analysis done).