PROM Burned for 27 lb Injectors
 

Hi, everyone.

I had a TPIS Stage V Prom modified for use with 27 lb injectors and now I'm running rich (108 BLMs, 127 Integrator values) in Cell #6 during cruise conditions.

Other cells are rich as well, but not as much as #6. I figure that I'm about 20% rich right now.

What would be the effect of re-installing the 24 lb injectors I previously used?

Would the engine then be richer or leaner and by about how much?

Thanks for any help.

Jake

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1986 Corvette Coupe, 415 CID, Edelbrock 6073s, ZZ9

Why go trough the hassle of reinstalling injectors when you can just have the chip modified ? Or better yet modify it yourself https://www.thirdgen.org/messgboard/smile.gif

Thanks for the response.

Wish I could reburn it myself but I don't have the equipment or the knowledge.

A friend made the mods for me but he lives about a thousand miles away and I haven't been able to catch up with him lately.

Since I'm retired, time isn't a problem for me to swap injectors, I just wanted to know what to expect from the change back to 24 pounders.

I can do a hellofa lot of stuff, but burning PROMs "ain't" one of 'em.

Thanks,

Jake

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1986 Corvette Coupe, 415 CID, Edelbrock 6073s, ZZ9

JakeJr,

I use to run a TPIS Level V PROM that they 'custom programmed' for my setup. Well, the fuel curve was way off at idle. I had 108 BLMs just like you. This is the main reason that I got into the PROM programming ... because the fueling on my TPIS level V PROM sucked. Took me about a week and a half of reading up and ordering the equipment before I burned a PROM (actually several) that finally got my idle BLMs to 128.

Of course, this was on a Speed Density setup where they have to adjust the VE but didn't. I think that you have a MAF setup in which case this probably doesn't apply too much. Swapping in the other injectors (as long as they are rated at a lower lb/hr) will definitely bring your BLMs down. But, you'll want to watch out to make sure that you are not running lean anywhere else. Are you sure your friend programmed the chip correctly? What injectors did you use to have installed (brand and flow rating) and what injectors did you just install (brand and flow rating)?

Tim

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TRAXION's 1990 IROC-Z
Best Time = 12.244 @ 112.51mph (1.778 60' / 7.819@88.32mph in the 1/8)
All Natural. No Force. No Drugs. Stock Bottom End. Stock Body Panels.
Gunning for NA 11's after installing Hooker LT Headers and reducing weight.
-=ICON Motorsports=-
Moderator: PROM board at thirdgen.org

Ooops ... one small correction ...

installing smaller injectors will definitely bring your BLMs UP

Tim

Thanks, Tim.

You're right, mine is a MAF system, 86 Vette and I was originally running the stock GM 24 lb injectors which, as I understand it, are rated at 43.5 psi.

The one's I'm using now are TPIS 27 lb injectors and from reading their catalog, I believe they are rated at 40 psi instead of the 43.5

I've got some time on my hands so I'm going to swap them out tomorrow and see what gives.
I just didn't want to go through all the trouble only to end up richening the mixture even more.

I'll run some tests using Diacom and I'll watch out for the lean conditions you cautioned me about.

Thanks.

Jake -Not to be confused with my namesake.

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1986 Corvette Coupe, 415 CID, Edelbrock 6073s, ZZ9