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Ford 30 lbs.hr. inj on modified 91 L98

Ethan

Well-known member
Joined
Jul 14, 2001
Messages
68
Location
Elgin Tx. USA
Corvette
1991 L98 Coupe
Just fired up engine with new Lt4 hot cam was setting timing and engine just seemed to be getting richer and richer untill it died.Ran great at first then just started loading up and would not clear out.The car has adj. regulator and kind of ran rich stock without mods. I know I need to check pressure any suggestions .Mods are as follow. Lt4 hot kit,Ford 30 inj.,high flow intake,runners,plenum,52mm throttle body,adj. fuel regulator,coolent bypass,160 degree thermostat,k@n,underdrive pulleys,2400 stall,Bosche +4 plugs. The car has sat for 9 months fuel kinda smells bad.
 

69MyWay

Well-known member
Joined
Jul 3, 2001
Messages
4,364
Location
Auburndale, Florida
Corvette
1969 Killer Shark
Ethan,

Just a few basics, but did you hook the PVC tube and valve back up?

Have you checked all sources of vacuum including the couple of hoses that come off the throttle body?

There is a large one on the passenger side that must be hooked back up just to the rear and below the oil breather tube.

Make sure the temp sensor is hooked up under the plenum and the other small vacuum off the driver side bottom of the throttle body.

If the vacuum is not on the MAP sensor, it will run super rich.

Finally, check to make sure the knock sensor is plugged all the way in.
 

Ethan

Well-known member
Joined
Jul 14, 2001
Messages
68
Location
Elgin Tx. USA
Corvette
1991 L98 Coupe
Ford 30 inj.

Everything you mentioned is good.Maybe adj.reg has failed or oxygen sensor.Going to get pressure gauge first to test it. Thanks
 

Ethan

Well-known member
Joined
Jul 14, 2001
Messages
68
Location
Elgin Tx. USA
Corvette
1991 L98 Coupe
Ford 30 inj.

Ok hehe what do you need to make combustion?Whell turns out I needed gas after 9 long months evaporation took its toll to the gas tank runs now but still rich getting code 15.Took it down the road with 2.59 gears runs like a bat out of ---- .Feels alot better with hot cam but need to check pressure too rich or maybe needs custom chip with motorsports injectors.? Oh well at least it now runs.
 

-=Jeff=-

Well-known member
Joined
Feb 2, 2001
Messages
909
Location
Bartlett, IL. (Chicago Suburb)
Corvette
1990 ZR-1
Ethan,

Are you running the Stock PROM with 30# injectors? If so, you stated they are FMS 30# which act like 32# on the Chevy.

I have 30# injectors on my 89 L98 but I have the PROM injector constant set to 32# and I don't have the rich condition like you are seeing. I would recommend changing the Injector constant to 32# and you should be okay.

Also with that cam you may want to invest the the PROM Burning equipment and tune the car yourself.
 

69MyWay

Well-known member
Joined
Jul 3, 2001
Messages
4,364
Location
Auburndale, Florida
Corvette
1969 Killer Shark
Ethan,

Are you running a heated O2 sensor?

If not, you might really want to consider it. This will really help you get the car dialed in and running lean.
 

-=Jeff=-

Well-known member
Joined
Feb 2, 2001
Messages
909
Location
Bartlett, IL. (Chicago Suburb)
Corvette
1990 ZR-1
69MyWay said:
Ethan,

Are you running a heated O2 sensor?

If not, you might really want to consider it. This will really help you get the car dialed in and running lean.

Well if he has the O2 in the stock location he may be okay..

I think getting the injector constant adjusted will help tremendously
 

Ethan

Well-known member
Joined
Jul 14, 2001
Messages
68
Location
Elgin Tx. USA
Corvette
1991 L98 Coupe
Ford 30 inj. on modified L98

Thanks I was planning to get Ed Wright at Fast Chips to burn one it has stock oxygen sensor in stock location figured it was injectors not compatable with factory computer.
 

-=Jeff=-

Well-known member
Joined
Feb 2, 2001
Messages
909
Location
Bartlett, IL. (Chicago Suburb)
Corvette
1990 ZR-1
Re: Ford 30 inj. on modified L98

Ethan said:
Thanks I was planning to get Ed Wright at Fast Chips to burn one it has stock oxygen sensor in stock location figured it was injectors not compatable with factory computer.
If you are willing to learn it.. you can buy the buring equipment and burn the PROMs yourself. Getting a "Custom PROM" is not always set for your exact car.. Just a suggestion
 
V

vetsvette

Guest
I've heard good things about the ford injectors but with your mods it sounds like 30# is a little large to me. Just my .02
 

Ethan

Well-known member
Joined
Jul 14, 2001
Messages
68
Location
Elgin Tx. USA
Corvette
1991 L98 Coupe
Ford 30 inj. on modified L98

Thanks for your help. Went with bigger injectors for maybe 125 shot of NOS or supercharger later on ( You know blow or go or is it blow up HeHe)If you can Jeff give me some info on PCM software.The net has a few sights Tuner Cat and TuneitLt1 edit. Thanks Ethan
 

-=Jeff=-

Well-known member
Joined
Feb 2, 2001
Messages
909
Location
Bartlett, IL. (Chicago Suburb)
Corvette
1990 ZR-1
Re: Ford 30 inj. on modified L98

Ethan said:
Thanks for your help. Went with bigger injectors for maybe 125 shot of NOS or supercharger later on ( You know blow or go or is it blow up HeHe)If you can Jeff give me some info on PCM software.The net has a few sights Tuner Cat and TuneitLt1 edit. Thanks Ethan

Ethan,

I use Tunercat and also WinBin to edit my files..

I have an old Needhams PB10 for burning PROMs, but I have heard good things about the EMP10/11 and the pocket programmer
 

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