Blueprint 400
 

I just installed a Blueprint 400 sbc with First Fuel Injection and 36lb bosch d3 injectors. The engine dyno'd at 474hp and 500tq at Blueprint. I can't seem to get rid of a rich cruise condition. Everything under 1600rpm is starting to look good. But above 2000rpm I'm way rich. I've been reducing and reducing the fuel in the VE tables but my blm's are still at 96. I've seen the pulsewidth at under 1.00 even with the rich condition. Everything was working fine before the swap. The car will be running smooth (120blm) for a few seconds then it jolts and goes to 96 blm.

I'm starting to suspect that the injectors can't flow any less. Is there something I need to do with the pw correction tables? I'm running a 7730 ecm, speed density. I changed the injector constant and cylinder volume when I swapped from the 350 to the 400. I had 24lb (27 according to Southbay) injectors with the 350.

Any help would be appreciated, thanks.

Re: Blueprint 400
 

Upload the Bin so we can take a look...

- Rob

Re: Blueprint 400
 

Here's the latest one.

Re: Blueprint 400
 

Do you have your Injector Offset sheet handy? Values seem a tad off in certain areas...

- Rob

Re: Blueprint 400
 

Id have to check but i recall a min pulsewidth value in there you could try but if its already commanding under 1, it shouldnt be that rich imo. I have run those injectors in a stock 305 before.

Being ok below 2000 doesnt make sense as higher rpm should be more fuel. Is it triggering a power enrichment? Low ve and high ve tables match?

If ve isnt changing it, i was thinking a power enrichment trigger but seems unlikely. I will have to look at the bin when i get a chance

Re: Blueprint 400
 

His injector flow rate also needs to be increased from 35% to 36%. The upper VE table needs to be put back to where you had it, you're taking too much fuel out after 1600-RPM. Upload that Injector Offset table that came with the Injectors whenever you can...

- Rob

Re: Blueprint 400
 

Here's a quick pic of the Bin, correct the Injector Flow from 35# to 36# just to get that out of the way, then confirm that the offset values are correct in the 3.2 and 4.8 range by uploading the offset doc, they seem very excessive in that area...

- Rob

https://cimg5.ibsrv.net/gimg/www.thi...1fe91b3c96.png

Re: Blueprint 400
 

Wow, I go out and cut the grass and I get a half dozen replies. This is great.

I don't have the offset values. The injectors came from Southbay. When I looked up the injector number it corresponded to a Volvo 35lb injector. That's why I put 35 as the constant. I did try go up to 38 but again, no change. I copied the Injector pw correction from 350tpi I thought. But now it's a little off.

Here are my datalogs from ALDL droid.

Re: Blueprint 400
 

Here's the injector: https://www.injectorplanet.com/produ...sch-0280155830

Re: Blueprint 400
 

Somebody in the comments section of the link you provided mentioned they used the Holley 36# offsets with success, and that the idle was very good with those injectors. Here are the Holley 36# offsets, see below. Not sure what to make of the 3.2 and 4.8 values found in your Bin, however they do match the $8D offsets from what I can see. I would try lowering those two though, make them match the 6.4 volt area, while leaving the 0.0 and 1.6 volt area alone. Just my two cents...

- Rob

https://cimg0.ibsrv.net/gimg/www.thi...3ac5bec979.png

Re: Blueprint 400
 

Dummy, dummy, dummy. I didn't realize I was using the extended VE table. And I was adjusting just the regular table. It's been a few years since I've had to do burn any chips and I forgot I had been using that table.

I did plug in the pw numbers you guys gave me and it's working well. I'm now about 10% lean. I can burn another chip at work on Monday.

Thanks for your help. Sorry to waste your time.

Re: Blueprint 400
 

Not at all.... what's important is that you found the cause, corrected it, and people learn from it. :thumbsup:

- Rob