rb25 cant start without take out fuel pump fuse

[doc_tai]

I just finished the swaping rb25 in the s13. I can't start it unless I take out the fuel pump fuse, crank it over about 7 or 8 times before it start then I have to put the fuse back before the motor die out. after it start it runs and idle just fine. For some reason it keeps flood the motor when I try to start it. I have walbro fuel pump and nismo fpr set at 43 with the hose off. So what can i do to fix it? Thanks

[rb25drag]

I have the same problem but only when my car warms up. If its cold it starts fine no problem, AS soon as it warms up it will flood it instantly. My fix was to wire a fuel pump switch in. But you might want to check the Water temp sensor. I have heard if its bad or is giving the wrong signal to the ECU then it will cause it to flood.

If thats the case you can do one of 2 options

1: get a new sensor2: Go to Radio shack and buy a potentiometer and splice into the signal wire to the ecu that allows you to adjust the signal going to the ecu.

[240z4u]

I have the same problem but only when my car warms up. If its cold it starts fine no problem, AS soon as it warms up it will flood it instantly. My fix was to wire a fuel pump switch in. But you might want to check the Water temp sensor. I have heard if its bad or is giving the wrong signal to the ECU then it will cause it to flood.

If thats the case you can do one of 2 options

1: get a new sensor2: Go to Radio shack and buy a potentiometer and splice into the signal wire to the ecu that allows you to adjust the signal going to the ecu.

Two thumbs up for janky work arounds!

Get the right sensor IF thats the problem. The FSM for the motor says how to test it.

Evan

BTW, won't cause flooding. It will cause a very rich condition.

[doc_tai]

just installed the wide band. It's very rich at idle 11.3. I'm gonna install safc and try lean it out at idle see to fix the problem or not. Anybody has pfc that wanna sell under $1000?

[rb25drag]

Check your timing first. If you set it between 15-20 degrees it should run around 15.8-16.8 AFR. After I bumped the timing it started running leaner at Idle. Might help you for the time being.

[sleeper101]

Check your timing first. If you set it between 15-20 degrees it should run around 15.8-16.8 AFR. After I bumped the timing it started running leaner at Idle. Might help you for the time being.

I agree!!! Check you timing first!!!

Wat is your Idle RPM?Are you running a FPR?

[doc_tai]

nismo fpr set at 43 with the hose off. I'm not sure what rpm it idle at( I dont think the stock tach is correct) that's another reason I wanna to install safc2. plus I only pay 100 bucks for it. what rpm you guys set timing at? between 800 to 1000 rpm?. Thanks alot for all the reply

[lilskyline240]

when you have the fuse pulled and its running. What happens when you hit the gas? Does it sputter out and die? What is actually happening here is your gas tank is sucking gas from the tank to keep it running. Its happened to me a couple times. One time i had a leaky injector. the other bad maf, the other bad ecu, and finally bent valves.

just my experiences. If it runs with the fuel pump fuse out. Try opening your gas cap and doing it again. it wont be able to suck fuel from the tank then

also do you smell gas in your oil?

[grenade180sx]

leaking injectors can cause your problems as well. and worst case hydrolock of the cylinders

check your O rings

[doc_tai]

It start without the fuse but I have to put it right back on to keep it running or it will die out. no leak. It runs and drives fine I even get on it no problem. But I remember when I change out the fuel pump the fuel tank gasket broken so I put silicone on it. That might be a problem. I already order a new gasket but it wont be here another week. Thanks

[lilskyline240]

i highly doubt thats your problem. but give it a try. try swaping out mafs with someone if your running super rich. also check your 02 sensor per the FSM

[doc_tai]

still cant fix the problem after install safc2. a/f ratio at ilde and drive around is 14-15, full throttle kinda rich 10.4 but it's all good. Not try to tune wide throttle yet. I'm gonna try get the injectors clean and flow to see anything wrong with it. I dont think it maf though plus I don't know anybody with rb25 maf that I can borrow. The safc knock pick up 19. Is that high or what? Thanks

[lilskyline240]

Is your TPS adjusted correctly? and a bad maf can cause a rich/lean condition. same with a bad 02 sensor. Did you try running your ecu codes?

[doc_tai]

one time it's throwing 13 (engine coolant temp) and that's it. I might change it out. Does the z32tt temp sensor fit rb25? Thanks

[lilskyline240]

that can cause alot of problems. Pretty much tellin the ECu that the car is too cold/hot causing it to add more fuel

[rb25drag]

YA thats going to cause your rich problem. IM not sure if that sensor will work or not. I personally like the potentiometer override. It allows you to adjust wat signal the ecu it reading. you can pick it up at your local radio shack for like $1

[lilskyline240]

search the sticky's for the part number.

[doc_tai]

I have the same problem but only when my car warms up. If its cold it starts fine no problem, AS soon as it warms up it will flood it instantly. My fix was to wire a fuel pump switch in. But you might want to check the Water temp sensor. I have heard if its bad or is giving the wrong signal to the ECU then it will cause it to flood.

If thats the case you can do one of 2 options

1: get a new sensor2: Go to Radio shack and buy a potentiometer and splice into the signal wire to the ecu that allows you to adjust the signal going to the ecu.

put a new coolant temp sensor from 98 240sx. The car starts everytime. Thanks again for all your help