Quick question, when changing out chips, do you disconnect the battery every time?
Quick question, when changing out chips, do you disconnect the battery every time?
Looks like you're idling around 900 rpm with idle air control (IAC) counts at zero. You either have a vacuum leak, or need to close the throttle blades some on the TBI. With the engine fully warm and idling, IAC counts should be around 10 with the trans in park.
it's also worth mentioning that it wont start without my foot in the throttle, gotta rev it up a few times to get it to idle at all
in the beginning of your datalog, IAC went from over 60 with the throttle open slightly to zero, and the rpm did not change significantly. Go pull your air cleaner and put your finger over the IAC supply port with the engine running and see if the rpm decreases. If it does, and the IAC is at zero, there could be something mechanically wrong with the IAC.
New news! I had the wife crank the truck over and noticed what seemed like way to much fuel while cranking. I decided to change out the 65 lb/hr injectors, found one of the installed 180 out. The injector wasn't sealing at the O-ring until the truck was warmed up. this also explains some of the poor idle quality. I'll get new datalogs soon. I never would have caught this without the ability to datalog This is such a great tool.
You wouldn't want tp put smaller injectors in it and at the moment you are probably out of fuel by 3,500-4,000. That engine is going to want more like 20-24 psi.Originally Posted by DOCBAWRENCHTURNER
Okay, I'll throw the 65 injectors back in it when I get the chance. I have an AFPR, I wonder if my current pump has the stones to produce the kind of pressure
If its the stock TBI pump no, you can get a pump for a TPI or like I did and cannibalize a 96 and up sending unit for its pump. I run 18 psi on 80# injectors to my 97 vortec and had to change the spring out in my AFPR.
87 4Runner, 15" spring lift, 3" body, chevy vortec 355, 5.29 gears, 38.5x15.5x15" Boggers, 280hr, 16168625 running $0D
93 S10, 36x12.5x15 TSL's, custom turbo headers, 266HR cam, p&p vortec heads, $0D Marine MPFI with 8psi boost.
05 Silverado, 2' lift, 4" exhaust, Bully Dog programmer,
Delco EP241 seems to be a popular choice, thoughts on this pump?
I've run the TPI pump, the 96-97 Vortec truck pump, and now the EP377 which is the 94-95 BBC truck pumps good for 30psi. It is by far the quietest of the bunch.
89 K1500 Scottsdale 5.7L 5spd 3:42 RamJet cam Dart iron TBI heads 427 PCM swap
95 C2500 Cheyenne 6.5L turbo diesel 4L80e 4:10 DB2-4911 Manual pump conversion 0411 PCM trans control 2Bar COS
05 Outback XT 2.5L turbo gas auto
The Big Block pump is a great thought, I never even considered it.
I got the EP377 installed on Saturday (thank God for nice weather). I got the fuel pressure set @28psi. The truck seems to like that under heavy acceleration. but it's too rich while cruising. Looks like I get to learn more! Datalogs are attached, if anyone has any suggestions fire away! I think it;s actually acting like a pre o2 exhaust leak, but maybe i'm missing something else
Last edited by DOCBAWRENCHTURNER; 03-17-2015 at 06:45 AM.
It is pig rich. Try increasing the injector flow in the bin to 85 lb/hr and retry. Your O2 sensor swings well but the voltage is low; never getting above 700 mv. I don't know what's causing that.
Pig rich is right! but to be honest it's better than the corrupted factory tuning.
I got the injector constant where i think it needs to be fore regular driving and added a little more fuel for acceleration/tps. Cold starts kind of awful now though, seems OKAY once it's warmed up. I think it made more power under load when it had too much fuel. Any suggestions?
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