increasing fuel delivery...

[tlcooper]

hey guys, what do you guys suggest as a way to increase fuel delivery from the cpi unit on a sonoma gt? I've installed a custom comp cam with these specs.

duration @ .050: 224/230
lift: .534/ /534
lsa: 114 w/ 4degrees of advance built in.

I know have a lean coniditon and am not getting the needed fuel at WOT. would an FMU work, I know its a half ass way but will it work even though I dont have any forced induction?

 

[BoostedSUV]

Re: increasing fuel delivery...

The lean condition you're seeing is most likely due to the tune and not fuel delivery. You can't just change a cam in a computer controller vehicle and expect it to run properly. A re-tune will be needed to accommodate the extra air and fuel needed for a bigger cam.

However, if you haven't already you should upgrade the fuel pump and fuel regulator. Add some adjustabilty to fuel pressure to increase fuel volume. I don't know much about the CPI motor but I would imagine the rules still apply.

 

[Injected1]

Re: increasing fuel delivery...

you could try this.. It took a while to do, not that difficult but it will definitely fix your fueling problems.
http://i244.photobucket.com/albums/gg17/syclone6969/EBAYSYLUNATI056.jpg

 

[tlcooper]

Re: increasing fuel delivery...

yea but the cpi unit's regulator is part of the unit. it cant be upgraded and yes I do have a hp fuel pump. so I was wondering is there a way to force more fuel through the stock injectors? is it possibly the tune holding me back, can I possibly tune the injectors to increase fuel delivery by making the injectors pulse width longer or increasing the duty cycle?

 

[midnightbluS10]

Re: increasing fuel delivery...

The CPI doesn't use actual injectors. It uses poppets connected to one central injector and is not very tuneable.

IIRC, the is an AFPR you can buy for the CPI system.

 

[tlcooper]

Re: increasing fuel delivery...

there is!!!!!! where? who makes it? where can I find an aftermarket fuel pressure regulator for the cpi unit?

 

[midnightbluS10]

Re: increasing fuel delivery...

I think cfm-tech sold them. I checked their website, but did not see anything CPI related. You may want to call/email them and find out for sure. I know that lindertech sells an updated regulator, but I don't think it's adjustable. It couldn't hurt to call them, also.

www.cfm-tech.com

http://www.lindertech.com/reconinj.htm

Have you checked the spider assembly and regulator to make sure it's not leaking or anything? I'd make sure all of that was in good shape first. Now that I think about it, I want to say that Vortecfiero on here figured out a way to bump the pressure up a tad when he had a CPI 4.3 in his Fiero, back before he did the syty intAke/turbo that he has now. PM him and ask.

 

[tlcooper]

Re: increasing fuel delivery...

yea I know of lindertech's unit. but as u said its not adjustable. man an adjustable FPR would solve all my problems. I'll call cfm-tech this morning and see if they offer an adjustable FPR for the cpi unit. Do you have any other thoughts on getting more fuel through the cpi system? what do u think about an FMU, I mean they come standard on most supercharger kits for the 4.3Ls.

 

[midnightbluS10]

Re: increasing fuel delivery...

I think FMU's are boost dependant, meaning they increase pressure based on reading boost so I don't think that would work. I edited my last post and added some more info, also.

 

[tlcooper]

Re: increasing fuel delivery...

gotcha, yes I've checked the cpi unit for leaks and its perfect, no clean spots in the manifold, no gas smell, or anything. but I will pm him as to how he got more fuel pressure, thx. if u have anymore ideas or advice pls let me know.