Ok so i just finished a 3 month long rebuild (didnt have much time cept rarely on weekends) i went all motor again running 10.5-1 cp's and a bunch of other things. This is the 3rd motor ive been on, i kept burning pistons and found out i was running way to lean. After taking my pistons over to my mechanic friend he decided it had to be the injectors. So i upgraded to 310cc injectors with a walbro 255lph pump. I go to start the car up and she starts fine. But a heater hose came off so we shut it down and reconnected it. After doing that the car wouldnt start well at all. It would start and then die, and after about 5 or 6 tries we could finally get it up to idle and it would fun fine. After taking the advice for break in we let it idle for an hour and shut it off to cool completely. So we then go to start it up again for the next hour and it wont start. Same story, we eventually get it started. The car will start and idle at about 200 rpms and try desperately to stay running and die, eventually it will make it to the regular idle. We pulled the plugs and they were drenched, like you could see the fuel on them, not like they were wet, almost like they would drip. Also we have arround 50 psi of fuel pressure at idle. Now, im not turbo so im thinking this is way to much pressure and that the engine i just flooded because of this. Any other ideas as to this problem? i have a pressure regulator that im going to put back on and dial down the pressure to try and lean out the problem. But other than that i dont know. The engine is pretty well modded, full msd ignition, head kit, crane stage 2 cams and gears, and the usual intake, 60mm throttle body, full exhaust, basically the only stock parts are the crank and rods and those are balanced. Also the car is idling real high, at about 1200 or so, and theres a mopar performance ecu in it, my thoughts were that the ecu is trying to compensate for the bigger pump and injectors and is idling high so that it wont stall but im not sure, any help is appreciated!

lower the idle pressure to 40-42psi and you should be okay. also, may wanna check for some vac leaks if your idling a little higher than normal...

what vac lines should i check? any that i should pay particular attention to, thanks for your help

um... you need to find a way to leanout your idle,lol 310;s are too big for non turbo apps, plus with the stock fp.

doesnt our stock 235's make the car run rich anyway
i mean they flow enough fuel for at least 8 psi of boost
and i put 270's in and still run 10:1 at 10psi of boost

so i would have to agree that 310's on a non turbo is not an answer

fire your mechanic
put the stock injectors back in
and look to other problems

Originally posted by baxsom
doesnt our stock 235's make the car run rich anyway i mean they flow enough fuel for at least 8 psi of boost and i put 270's in and still run 10:1 at 10psi of boost so i would have to agree that 310's on a non turbo is not an answer fire your mechanic put the stock injectors back in and look to other problems

disagree. you just need something adjustable to lower yuor fuel pressure. i would suggest leaning it down to around 35-42psi and then maybe getting an afc to lean it out a little more. just make sure all your vac lines on the back of your intake manifold are tightened down and good stuff.

alright cool guys thanks for all the input, theres no way im going back to the stock injectors not after burning 2 different sets of pistons from being too lean, so ill just turn down the pressure and go from there thanks for the help.

ok so i put in the pressure regulator, and found the disconnected vac line, the idle is good now but its still hella rich. The car will start perfect when i put new plugs in it, but after i shut it off it wont start again and stay on, it will start and run at 200 or so rpm and eventually die. How can i lower my idle fuel pressure? Theres just way too much fuel going into it at start up, also i cant just go back to stock injectors, those are the stock ones just ported out. The size is going to be good so im not going to go smaller, i just need a way to lean out the idle fuel mixture, anyone know of any ways i can do that? My pressure regulator hooks up to the fuel return line and i really didnt notice it doing much of anything, any help is greatly appreciated, this thing is really pissing me off.

Mopar ECU? :wary

I'm curious about your situation here. The only things still stock on my all motor build right now are the fuel system (completely untouched from tank to rail) and the cam gears. I run 10.5:1 Venolias, Crower 2s and an AFX/R ECU. Never had any problems with idle quality. There really is no need for injectors as big as you are using now. The ECU is seeing a reduction in vacuum at idle from the cams and adding more fuel. We run pig rich to begin with, so I'm thinking there might have been other issues resulting in your previous forged coasters. The Mopar ECU is news to me. I've never bothered to read that thread above and have not heard of anyone using such an ECU in a 2GNT.

As far as I've read (and been told) on this site, with stock injectors, Crower 2 cams, and a stock ECU, you would need an SAFC to trim out some fuel at idle or bog and die due to flooding, which it seems you have right now. Could be that your ECU is nothing more than stock... :shrug

this guy is running NA with 310cc injectors and a walbro 255
and is wondering why he is rich


there is no way a NA motor will ever need bigger than the stock injectors


on a stock fuel system you cant turn down the pressure

it doesnt say what you are using for fuel management
ie vortech, aeromotive, stock etc
but that 255 will overrun a stock one something fierce

did you try getting a new fuel filter

or not using that mopar ecu

what about just swapping out to the stock fuel pump, what would that do? would there still be too much fuel due to the bigger injector size? And to reply to the other guy, the ecu does do a lot, because i had the car running when i installed it, it changed the power curve and advanced the timing a bit, pretty good part in my opinion. gave me power a lot sooner in the rpm, anyway the fuel pump swap any ideas on what it would do? Oh and i have a remote mount pressure regulator that bypasses the fuel return line, thats the only kind of management im running, im thinking im going to need a afc.

now i am confused
you said you had a remote mount fpr that bypasses the return line

the return line is where the fuel pressure regulator should be mounted

also is your car a 95 with the stock fpr and return line on the rail or a 96+ with the fpr and return line back by the tank

if you dont have the return line hooked up and flowing it will cause way too much pressure

thats what i meant, the fuel pressure regulator is hooked up to the fuel return line, and yes mine is a 95 with the stock fpr on the fuel rail, hope this helps

Originally posted by allmotorgs
And to reply to the other guy, the ecu does do a lot, because i had the car running when i installed it, it changed the power curve and advanced the timing a bit, pretty good part in my opinion. gave me power a lot sooner in the rpm,

Unless you have dyno charts to back that up, I'm calling butt dyno calibration issues. The only post on this forum talking about the Mopar ECU actually installed on a 2GNT (although a 95MTX) is made by a complete idiot who has no idea what he's talking about and there would be, at best, wiring issues surrounding the install. If you simply picked up what you were told was a Mopar ECU and installed it without any research or harness modification, then there are a half a dozen potential issues which could show themselves.

Your first course of action should be to replace the mystery ECU with a stocker and get your massive headwound Harry fuel system reverted back to stock as well. If you ran lean on stock injectors and burned your shit up, I'm thinking your old injectors were dirty and clogged. Simple fact of the matter is, you're dumping excessive fuel. Your fuel system is overkill.

i did actually have the dyno curve to back it up, and the feel of the car was changed, i got power in places never had before, on the dyno i started to get power way eariler in the rmps than before. Anyway, im swapping out my fuel pump, going back to the stock one, as for injectors they were cleaned a few times thinking they were just clogged but they were not, the entire fuel system was checked over and over for clogs and waht not, but everywhere constant pressure was held, this was the reason for going to a bigger injector. Im doing the pump swap today ill let you all know how it goes

Originally posted by allmotorgs
Im doing the pump swap today ill let you all know how it goes

Please do. We all motor types need to stick together. :thumbsup

Originally posted by baxsom
there is no way a NA motor will ever need bigger than the stock injectors

I disagree. Just no one has taken NA far enough. On a stock fuel system, the stock injector good up to about 180 to 200hp. Now I'm not saying a 2.0L will need 30 lb'ers, but the stockers will only take you so far. Especially for the midrange where she likes to get a little lean. If some one built a high compression, not 10.5:1 but actualy high compression 12.5:1 range, fully built motor etc. The Neon guys who are pushing over 200 hp are running 24lb'ers.

The reason you can get so much out of them for turbo apps is you are running the injectors at around 95 psi fuel pressure under boost.

Exile Racing Technologies
http://www.exileracing.com
Go that way, really fast, if something gets in your way... turn.

also, i just remembered this, about a month ago i met a guy up at the drag strip in bithlo running a 13 sec civic coupe all motor. He had a gsr integra motor in it with crower stage 3 cams and the rest was built, he was running 370cc injectors and was fine, he also had a stroker kit making his engine 2.0L. So at the same displacment and relatively same compression ratio, i think he had like 11:1 or something, he was running even bigger injectors than my 310cc's and was fine. Oh and i swapped out the fuel pump back to stock, not a big difference but did have slightly lower fuel pressure. Any other ideas, see what happens is that when i have let the car sit for a couple of hours, letting everything dry out, it will start right away without a problem, run a little rough idle for about 15 sec and then smooth out running perfectly, now when i try and drive it or turn it off and start it again it dies, its flooded. I dont know where to go from here, im thinkin backing down on my injectors getting some 235cc's or something like that, but my problem is my previous engines have all blown due to leaning out way to much, the last time i even broke a piston and burned the other two down to the rings on the injector side.

Well im listening to everyone on this forum and taking your advice, i just ordered 24lb/hr injectors and they will be here friday so ill just hope they work out, my fuel pump is also back to stock, and ill post again when i swap out the injectors, i just gotta say thanks to all you guys for helpin out, everyone replies so quickly and gave me great feed back, i feel that i know a lot about my car but am still learning and this site is a great thing, hell im only 17 now, by the time im 21 just think of what ill know. Keep up the good work and because i have a dsm im sure ill be posting again with another problem. Thanks

Originally posted by allmotorgs
...i feel that i know a lot about my car but am still learning and this site is a great thing, hell im only 17 now, by the time im 21 just think of what ill know...

By the time you're 21, you'll realize how much you didn't know vs how much you thought you knew.

if you want to know about the car, read the archives and FSM like a novel.....

Originally posted by allmotorgs
...my problem is my previous engines have all blown due to leaning out way to much, the last time i even broke a piston and burned the other two down to the rings on the injector side...

Did all this happen while using that Mopar ECU?

**EDIT**
Oh, and Brian, check out what I found in the link in his sig:

So, it's not a mystery machine ECU. P5007034 is the actualy part number for the mopar ECU for a 1995 model. But are the wires the same from a 95 neon to a 95 eclipse?

no, the first motor blew before it, the second blew after it

also about the ecu, its just a performance upgrade that you can get through mopar, same as the venom one basically from my understanding which is limited mind you.

Originally posted by allmotorgs
same as the venom

I would hope that it's more than the Venom. Pretty much everyone agrees that thing is crap. Interesting that you are actually running that Mopar ECU, though. I have to give you credit for making it work. Since you have some time before your new injectors show up, why not pander to us with what it took to get that thing to run. Any issues? You got the one for a 95, installed it in a 95, right? Any issues (aside from burning up your shit)? LOL.

As for the ECU it mostly just plugged right in, had to wire somethings but it was pretty straight forward. As for driving it, it made the car feel a whole lot more peppy, raised the rev limiter to 7600, made power at a lower rpm. What it does or is supposed to do is advance the timing a bit, due to this you have to run premium fuel, but running 10.5's i did that anyway so it wasnt a big deal. But it was definitley a good upgrade, the car never ran any hotter, only hotter for me cuz we accidentally missed a wire that controled the ac, but fixed it. In the words of brad who first found it, it puts power in places it wasnt before, also he laughed when he told me i was certainly unique. First off, im an idiot for doing NA and not turbo, and to top it all off i have a neon ecu controlling the car in my eclipse.

heres a site selling it, ive found better sites detailing more accurately what it does but heres a basic idea...http://www.modernperformance.com/dcx/mopar_pcm.shtml

Ok i missed the delivery today but, im going to pick up the new injectors tonight!, and ill put them in, and of corse im expecting some sort of problem so ill post after i have them installed...

Ok i just swapped in the smaller injectors, car starts great, runs great, thanks for all the help, but will the stock fuel pump handle the bigger injectors? There not that much bigger only 24 lbs. but the stock one should handle it right?

stock should handle the 24's ok because with a stock fpr you arent going to need the really high fuel pressures that a rising rate fmu will require

the 24 lb injectors are only like 10%ish bigger than stock so the standard ecu can correct for any problems in mixture at normal fuel pressures

while you are doing all this fuel stuff
you did remember to change your filter right?

yeahp sure did :thumbsup, thanks for the help guys!!

How much did you pay for that mopar ECU? Did you have to rewire the plug at all? If not, it may be an idea for us 95'ers. I saw the ECU a long time ago, but never bothered because it was for a neon.