So got a question about 4g63 n/a

[25psi_talon]

so i swapped a 4g63 n/a into my colt the donor motor was out of a 91 talon that ran flawlessly.... the problem im having now is that i can get my car to start... sometimes... but only when im on the gas... it revs fine but when i drastically let of the gas the car back fires and slowly dies.... but i can not get it to idle at all.... i have replaced my fuel filter, put a walbro 255 in and have all vacuum lines ran.... what could be my problem?

the only thing i can think of is my mpi relay is out of a 94 n/a

 

[doubleclutch99]

i would check the coolant temp sensor. see if you can get a logger on it to see if you can pull up any trouble codes. just a thought

 

[thomcasey]

You also need a different FPR. The 255 is too much for the stock FPR and can over-run it. THis will make you run real rich.

 

[doubleclutch99]

That's a good point. you should check your plugs to see if they are fouling out or loading up.

 

[agentorange313]

cant run a 255 with a stock FPR. if you want to keep the stock FPR find a 190 or an evo one and rewire it.

edit: sorry didnt see that someone posted about the FPR alread

 

[25psi_talon]

Ok turns out it's a stock fwd turbo fuel pump

That's a good point. you should check your plugs to see if they are fouling out or loading up.

And I just put new ones in like 3 days ago along with wires

 

[coty]

go to your local adavance auto and they will scan it for you

 

[25psi_talon]

go to your local adavance auto and they will scan it for you

WTF ummm the car can't idle it bearly can move on it's own? And it's not throwing any codes

 

[AllShallPerish]

What ECU are you running?

 

[25psi_talon]

What ECU are you running?

The 91 n/a donor cars ecu