TBIThrottle Body Injection discussion and questions. L03/CFI tech and other performance enhancements.
Welcome to ThirdGen.org!
Welcome to ThirdGen.org.
You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, at no cost, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, join the ThirdGen.org community today!
I've read a ton of threads on 305 to 350 conversions and am still stumped.... I converted to a 350 and a t-5. I replaced my injectors, knock sensor, spark control, and put in a "tbichip" for a 350 with a manual transmission. When I'm on the skinny pedal it does just fine, but at idle, (and when I push the clutch in) it just falls on it face. I've checked for vaccum leaks and cannot find a thing. I was wondering if I need to change the pressure regulator.... Everyone I've talked to says they didn't have any problems with their conversion.... This marrow is gonna die!
Jay and RIP
This ad is not displayed to registered members. Register your free account today and become a member on ThirdGen!
Sponsored Links
Registered users do not see this ad. Click here to register for free!
the only thing that i can think of about the car shutting off when you push in the clutch is the clutch saftey switch, is there a possibility that you hooked it up wrong and that it kills it? just a suggestion.
__________________
1991 Formula conversion, 5spd swap, 350tbi with open element, tbi chip, hooker headers, flowmaster exhaust, cat delete, modified throttle body
i never plugged it in but i tried to delete all the egr and accidently delete the map sensor so i figured it out and just had to plug it into a vaccum port on the throttle body
__________________
1991 Formula conversion, 5spd swap, 350tbi with open element, tbi chip, hooker headers, flowmaster exhaust, cat delete, modified throttle body
Quote: my air/fuel ratio gauge. Is that the one tied into NB02? It is not very reliable if so.
I dont believe it showing lean B4 dying is unusual. Did you datalog the event?
At idle you should be around 5-15 counts/steps on IAC. Zero steps is Ok but that requires the idle rpm to be controlled by throttle stop screw. Is your IAC functional? Stall saver should kick in and you would see the IAC counts to increase preventing stall. If I drop my rpm with TSS to a low # stall saver always prevents a stall.
I assume your BLM data is within + or - 10 of the ideal 128 during stall. If not you need to address that. NB02 can only do so much to correct A/F to stoich.
you just went way over my head.... my iac is reading 41 steps........ I upped my idle (via idle stop) and now it just kinda surges... If I disconnect my map sensors it actually seems to idle better....?
GM controls idle by IAC steps. Based upon coolant vs RPM. Say the coolant is 190F and commanded is 775 rpms. IAC will move in and out and keep it at 775 rpms. On a modified engine sometimes that is problematic as it swings pulsates. So an experiment would be to set idle speed low say 600. then move the throttle stop screw(like a carb) to set RPM at 775. You may need to remove cap/seal. Now ECU sees 775 and is happy. The IAC is now not able to control RPM and has no need to since at 775 as commanded. I set IAC steps at zero for idle as well. that allows max air flow past TB's and that is a good thing on atomization.
Does your mask allow OL idle? It may show as a flag OL-IDL. If so, You may want to give that a try as well at 14.0/1 to start or try 13.5/1. There is also a MPH qualifier to allow CL. That would keep it OL until you are moving in first gear. I think mine is set to 20 MPH.
I've been reading everywhere and now I'm not sure its a LO5. Its a crate 350 intended for a mid-80's suburban..... Heres where I'm at: my fuel pressure is good, however when I clamp off the return to check my regulator it idles like a champ.... I'm told: tbi's run between 10-13psi and when the return is clamped off it will jump to about 18-20... thats exactly what my car does, I just can't figure out why it runs so much better when the return stays pinched....???
OL = open loop (not using nb02 feedback) as runnin offOL tables for a predetermined AFR.
CL= closed loop running off the NB02 feedback an running stoich.
If you have a healty fuel pump I would expect the FP to increase as you pinch. keep in mind the reg does in fact pinch but not 100% and there is fuel retunring back to tank. lets say 12lbs is a partial pinch. what you see is normal.
I would say you need more fuel as you say it runs better with higher FP. consider running 15 lbs FP and give that a try.
