just upgraded to prelude injectors with 8:1 fmu and i can'y get my car to idle with the inline pump on....and right now the fuel pressure is at 20psi....and i can't get it any lower with the b&m fpr ...so my question is how do you guys get the motor to idle with the bigger injectors + fuel pump???

 

What ECU are you using and what year Prelude did those injectors come from?

Sonny

 

prelude injectors... peak and hold or saturated? if they are peak and hold, you need a resistor box. just covering all bases here in case you didnt know that...

 

the injectors are peak and hold from a 92-96 vtec prelude

 

and i am running an 86-89 integra ecu for the zc motor

 

Is it me, or is your fuel pressure REALLY low ?

 

??? DO YOU KNOW IT IS AT 20PSI ???

The lowest I've seen pressures at with out the pin hole mod, is around 34psi.

do you have the fuel pres gauge?

 

First off, the fuel pressure you have is too low. 25 for 450's and 30'ish for 310s.
Second, the ZC already needs a resistor box, so that isn't a problem.
Third, you are checking fuel pressure with the vacuum line disconnected, right?

Randy

 

yea with the vaccuum line disconnected.....the fuel pressure is at 25psi with the line on..and if i go any higher it boggs the car....my msd coil has been arcing for a while so i'm going to try to replace the coil today to see if that helps....maybe i should try a bigger plug gap too

 

ok so i replaced the coil with a blaster ss external and checked the plugs and they're black....i think they might be fouled out the car runs....but these plugs are only 2 weeks old how can you tell if they are fouled or not?...or can i just clean them?

 

You have to check the gap on them to see if their fouled or not.

You need to DECREASE the gap, not open it up.

It will fire easier with less gap.

 

cool...well i hooked up the coil and the car definitely perfoms a lot cleanerbut it does the same thing when i turn on the pump.....my car has been idling real crazy lately sometimes the idle air screw needs to be adjusted because at idle it will rev up to like 1500 rpms then drop to 0 then up then to 0....well today i got home and i couldn't get it to stop doing that ****.....i even turned the screw all the way in to drop the rpm's all the way down and it still kept doing it..what gives? is there a sensor or somthing that also controls the idle on a crx? i think the car will stay runningwith the pump on if i could bump up the idle some. i knew it was low already because i was having rough idling a few weeks back and i took the screw out and cleaned off all the carbon and stuff.....then when i readjusted the idle after cleaning the screw i had to almost screw it all the way in just to get it to idle around 6-700rpms
-any thoughts?

 

The 92-96 Lude injectors are 330cc/min. The ZC's are (to the best of my knowledge) 240cc/min.

A friend of mine ran RC310's in his 2000 Civic Si (stock injectors are 240cc/min). The stock idle pressure on the Civic Si is 31-37 psi (factory spec). Since the 310's were ~30% larger than the stock injectors, his idle pressure had to drop by roughly the same amount. His car would throw a code 45 (too rich/too lean) if his idle pressure was any higher than 22 psi. Even at that setting, he verified with a scan tool that the car was still running a little on the rich side (short term/long term fuel trims were off a bit).

You need to find out the stock idle pressure for the ZC/86-89 Integra with the stock injectors and then do similar math to come up with an idle pressure that is in the ballpark for your new setup. Assuming that the ZC has 240cc/min injectors, the Prelude's 330's are (330/240) = 37.5% larger. Your idle pressure of 22 psi or so sounds about right, but my guess is that it is still too high, assuming that the ZC idles with around 35 psi of pressure.

Since you are using the Integra ECU, you should use the specs that are "expected" by that ECU. I have an 87 Integra Helms manual at home. If you want me to look that up for you, I can do that.

Sonny




[Modified by Sonny, 11:32 PM 5/10/2002]

 

man that would be great...i'm getting so aggrivated with this crap.. just want it to work

 

I'm running 370's with stock ecu and using the fields sfc to lower the fuel intake.. the car idles kinda rough soemtimes.. not always at 700rpm and give me the code 45 almost every other day.. sometimes goes into limp mode with the IAC code.. and sometimes runs like crap when i'm not on the gas and boosting...

i know of no way to fix it and dont want to jack something up by lowering the fuel pressure too much....

//waiting for xmas bonus for hondata//