Before we go into the bin, can you do us all a favor and take a picture of your tbi adapter? I want to see what you are using. There are some out there that are notorious for vacuum leaks. If it is the 1/4" steel plate or a thin aluminum plate, do the TBI mounting bolts protrude through it when the throttle body is mounted to it? If so, the bolts may be causing part of your issue.
What was the 4 letter code on the memcal you were using?
I found this when I first started my vortec tune .
http://gearhead-efi.com/gearhead-efi...0chip%2029.txt
The ve table got the idle /near idle richness in check -the ve table was a great starting point for me personally .Mine was black smoke rich at first .
Many thanks for the post.Originally Posted by zuk1972
Will get the 4 letter code of the memcals being used and post. Thanks ever so much for your patience.
Right now it is dark outside. Since you are in Stone Gap VA, you are 3 hours later than we. Will take the pictures of the TBI adapter and 4 barrel manifold and post them. The adapter is 1/4" steel and I hogged it out to 2" bore like are on the 7.4L TBI. Also hogged out the 4 barrel manifold to also accomodate the 2" bores. Need take it apart to photo, and also study carefully for leaks..Just thought about it, have not "T"eed into the MAP sensor hose to see what the vacuum value is. Purchased a new MAP sensor from Oreilly Auto Parts. It is a BWD made part. Made a bracket for it to Vortec 4 barrel intake. Just pulled the ECU from the stock 1995 Chev C1500 pickup and ran the Vortec on it also just as it came out of the pickup. Still runs PIG RICH. Now suspect the MAP sensor may be getting fooled by a vacuum leak and causing the rich running condition???
I suspect that you are still employed and working approx 8 to 5. Will have the photos posted for you.
Found the vacuum leak. Took the throttle body (TB) and adapter plate off an cleaned. Purchase new TB gasket and new 4 barrel 4150 gasket. Sealed both of them with Loctite 509 sealer. Ran the engine and it appears to be running fine. Need another run with TunerPro. Will have to hook up Innovate LM-1 Wide Band O2 to APU1 and record Wide Band AFR with other parameters.
Attached are photos of the TB and adapter plate as requested.
Thats good news. Its impossible to tune around a vacuum leak. Neat bracket you fabricated to take care of the throttle blade adjustment. Hopefully you are well on your way now.
The engine is running better. There is still something wrong with the ignition timing. A timing light on the balancer says zero to 10 degrees advanced. The TunerPro screen says something totally different. Need help with the ignition timing. Also the IAC comes up with a fault. Don't yet know what that is about. Log file attached.
Will play your log in tunerpro and have a look
Your throttle blades need to close more. Adjust your bolt to where it allows the blades to close more. You still are idling above the commanded idle rpm. The IAC is going to 0 counts at idle. That is your IAC fault. If you are positive you no longer have vacuum leaks, you will have to start adjusting your idle VE table. Your BLMs are at 90 in most places. Your bin is set to allow a minimum BLM of 90. You may look at the text file that zuk1972 posted the link to. You have to look at the VE table in the text file carefully because the taableis layed out backwars to what you will see in the bin for BJYL. I would get the tuning spread sheet and fill in the running average from the datalog you just posted and follow the explaination in this thread. http://www.gearhead-efi.com/Fuel-Inj...ng-VE-Fueling&
What are the specs on the cam you are using in this engine?
yes the iac is maxed needs throttle blades closed.where did the ecu originate from did it come with the TBI unit .with the writing on the top would allmost look like its maybe been modified for multi point injection .wording looks like injector driver mod and netres jumper on the memcal
I didn't see that picture when I looked last night. I viewed the pics from my phone and missed that. If the sense resistors have been jumped, it will be operating the injectors in saturated mode. Rsicard, Pull cover off of PCM and blue cover off memcal. Send pics of the internals.
ECU came from 1994 7.4L Suburban modded with Edelbrock batch port injection intake manifold. Need to remove jumpers, then use ECU as test subject on 350 Vortec with appropriate binary chip.
The camshaft being used is the LT-4 Hot Cam. Installed it and also installed new Crane Cams valve springs on the Vortec heads. Specs as follows. Understand what needs to be done to the VE tables. First need to get the ignition timing situation under control. What the ECU is commanding for timing has no relationship to what is being strobed on the balancer. Need help with that.
LT-4 Hot Cam Specs
Hot Camshaft (P/N 24502586) Specifications
Intake Exhaust
Lobe Lift 0.328” 0.328”
Valve Lift
@ 1.5 ratio 0.492” 0.492”
@ 1.6 ratio 0.525” 0.525”
Duration
@lash point 279° 287
@0.006 cam 272 281
@0.050 cam lift 210° 228°
Lobe Centerline 109° 115°
Lobe Separation 112°
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