Well, i finally finished putting my project together but now I have another problem. The car would not idle at all when the fuel pump is on but when the pump is turned off, the car idles fine. Any suggestion on what the problem could be?

 

no fuel pump = no fuel

how could the car possbily be running fine

 

There's no way the car is running without fuel. If so, apply for a patent because you will be a rich man!!

lol

 

anybody???

 

Its obvious you have the switch flipped backwards. You have (on) means off and (off) meaning on as of right now.

Are you sure you have it wired up correctly ?

 

im sure the wiring is correct. When the switch is flipped on ON there is pressure reading on the gauge and when its OFF no pressure. So its not the switch wired backwards.

It was idling fine with stock injectors, then we switch off to 880cc before tuning. after that, it just would not idle when the pump is turned on.

 

What year is the car? Did you install peak hold injectors or saturated injectors?. Peak hold needs a resistor box. Saturated does not need a resistor box.

If they are peak hold injectors did you check the polarity of the two injector wires. Just to summ it up peak hold injectors the polarity matters.

Saturated it dont.

Check on that

 

The car is 1990 CRX. The injectors are peak n hold and we have a resistor box is installed for it.

 

fuel pump possibly pumping in reverse? or simply put, the fuel pump is sucking instead of pumping?
possible defect. would also explain why you get pressure reading but doesn't start? i don't no....hahah you got me with this trick. got another?

 

Ummmm... a car will not run without fuel.

The only possibility is that your wiring is incorrect and you think it's off when it's on.

 

This is when those Jebus people should come in and post there ****.

 

I've idled my gsr with the fuel pump fuse removed. I figured I was just an idiot, and pretended it didn't happen...

 

it will idle for 20 secs maybe at the most. I had that confuse me a couple of times in random parking lots. WTF?? WHY DID MY CAR STALL??!??!

 

only thing i can think of is that it is getting so much fuel it will not idle then the stored fuel in the rail is shooting off and it is staying on for a short period of time.

how long is is idleing for?

 

well there is usually pressure in the lines for about 30 mins after you park the car, as soon as that burns off it won't idle

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ProjectDarkBlack &raquo;</TD></TR><TR><TD CLASS="quote">well there is usually pressure in the lines for about 30 mins after you park the car, as soon as that burns off it won't idle</TD></TR></TABLE>

right, but if there is no pressure pushing the fuel out and the injectors are that big, i can only imagine that the fuel would some how seep through at each injector pulse just enough to keep the car idleing for a short period of time.

unless thats what you ment than nvm haha

 

i doubt that the pump is reversed because when its on "ON" position, its reading pressure. So it must be flowing properly. Its wired up according to the fuel pump relay. I had the car idling for about 3-4min with the pump off. So, im clueless on what the problem could be.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DSRxEMS &raquo;</TD></TR><TR><TD CLASS="quote">i doubt that the pump is reversed because when its on "ON" position, its reading pressure. So it must be flowing properly. Its wired up according to the fuel pump relay. I had the car idling for about 3-4min with the pump off. So, im clueless on what the problem could be. </TD></TR></TABLE>

Well we know one thing, the pump is not working after its switched off because the car does die 3-4 minutes after that.

Try turning your fuel pressure way way down and turn the car on with the pump on. Also try to get the car warmed up because the ecu will dump a bunch of fuel into the motor if its cold. Maybe put the stock injectors in, run it, then swap to the 880's.

And what program are you using to tune? You need to decrease the fuel delivery with those big *** injectors. when its warmed up i can see the car possible idling because the ecu will level out the a/f ratio as it gets warmer. but damm i can only imagine how much fuel is being dumped into the cylinder with the 240cc tune and a cold start. whew.





ps. i did some math, if your a/f ratio at idle is say 13:1 with the 240cc's, with the 880's you will be at approx 9.5:1 which is a 27% increase in fuel.

Add cold start to that and your dumping way way too much fuel into the motor.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DSRxEMS &raquo;</TD></TR><TR><TD CLASS="quote">im sure the wiring is correct. When the switch is flipped on ON there is pressure reading on the gauge and when its OFF no pressure. So its not the switch wired backwards.

It was idling fine with stock injectors, then we switch off to 880cc before tuning. after that, it just would not idle when the pump is turned on. </TD></TR></TABLE>


As already hit upon, its likely the car is getting too much gas while the pump is on. Injectors act differently from each other, especially when they're peak&hold injectors that are 3x the stock size and since the ecu was designed for saturated. Its been my experience that just scaling the maps won't get you dead nuts on the money. You need to scale the maps then try 15% more then 15% less and see what happens.

This is of course assuming you scaled the maps for 880cc's. I would hope you aren't that dumb.