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Thread: 350 Vortec wi th 454 TBI running pig rich

  1. #76
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    Quote Originally Posted by sturgillbd View Post
    With the engine idling faster than what is commanded, the ecm is going to bottom out the IAC. The ecm is also going to retard the timing trying to slow the RPM as delcowizzid stated. Have you found any more vacuum leaks? I just disabled knock, egr, and ccp in this bin. I also pulled 35% from the entire Idle VE table. Load this in your APU1 or burn to a chip after warming the engine up. Datalog and post the results. Most of your BLM's from the last log I looked at were at 90. This should help. I assume no responsibility from the use of this file. I recommend you look at the file and do a bin compare in TUnerPro to see what I changed.

    Brian
    Brian: Just got done running the 350 Vortec and setting the idle screw hidden behind the plug. Also advanced the timing and readjusted the idle RPM. It is running VERY GOOD. Thanks again for all the help. Now I need to undo the knock, EGR and CCP one at a time. Is it possible to send image of each of these which were disabled in TunerPro? That will get me to the exact spot in the list and adjust them back one at a time to see what the effect is on running the 350 Vortec. Need to bone up on data tracing and adjusting the VE tables. The idle VE is a little on the lean side, but I think I will leave it there for now. Won't do much to the off-idle VE table till the engine is in the pickup and test driven to record the parameters and then adjust from that point. This will not occur until Knock, EGR and CCP have been returned to their previous state.

    Rolly
    KW7RS

  2. #77
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    Quote Originally Posted by rsicard View Post
    Brian: Just got done running the 350 Vortec and setting the idle screw hidden behind the plug. Also advanced the timing and readjusted the idle RPM. It is running VERY GOOD. Thanks again for all the help. Now I need to undo the knock, EGR and CCP one at a time. Is it possible to send image of each of these which were disabled in TunerPro? That will get me to the exact spot in the list and adjust them back one at a time to see what the effect is on running the 350 Vortec. Need to bone up on data tracing and adjusting the VE tables. The idle VE is a little on the lean side, but I think I will leave it there for now. Won't do much to the off-idle VE table till the engine is in the pickup and test driven to record the parameters and then adjust from that point. This will not occur until Knock, EGR and CCP have been returned to their previous state.

    Rolly
    KW7RS
    Brian: I have found the Knock, EGR and CCP items that were altered. Don't bother sending any images as I will go to a previous bin and get the values. Thanks again.

  3. #78
    Fuel Injected! sturgillbd's Avatar
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    Did you ever datalog your running, driving vehicle? Did you ever test your timing light on that same vehicle? If I were you, I would narrow down a few possibilities. Test your timing light on the other vehicle with TunerPro connected to the ALDL stream. If it works as expected on your drivable vehicle, I would be suspicious of the aftermarket distributor. You could swap distributors and see if the problem follows the distributor.. Swap PCM's. See if the problem follows the PCM. Here is the first run of my 7427 TBI project. It was rich and overall ran like crap. This video shows the engine running with everything hot-wired and even used a jumper wire to start it. I had no switches, fuses or any kind of circuit protection. https://www.youtube.com/watch?v=IoyPCrM0nR8 During the first 20 minutes of running it after adding an adhoc cooling system to it, It killed a set of plugs. When I connected a laptop to it, with it running, the BLM was bottomed out at 90. It had a very pronounced surge at steady throttle and the rpm fluctuated between 500 and 1100 RPM at idle. After some minor idle VE adjustments, It starts, idles and runs great. When I set the base timing to 0 deg and reset the PCM, I glanced at the timing.with a light with it running. I don't have a dial back timing light but it was in the area where 20 advanced would be. That reminds me, I need to acquire a timing tape. I have not touched the open throttle VE table yet because there is no need until I can get the thing out and drive it at highway speeds to get data at varying loads and speeds. Check some of these points mentioned above and post what you find.

  4. #79
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    Quote Originally Posted by sturgillbd View Post
    Did you ever datalog your running, driving vehicle? Did you ever test your timing light on that same vehicle? If I were you, I would narrow down a few possibilities. Test your timing light on the other vehicle with TunerPro connected to the ALDL stream. If it works as expected on your drivable vehicle, I would be suspicious of the aftermarket distributor. You could swap distributors and see if the problem follows the distributor.. Swap PCM's. See if the problem follows the PCM. Here is the first run of my 7427 TBI project. It was rich and overall ran like crap. This video shows the engine running with everything hot-wired and even used a jumper wire to start it. I had no switches, fuses or any kind of circuit protection. https://www.youtube.com/watch?v=IoyPCrM0nR8 During the first 20 minutes of running it after adding an adhoc cooling system to it, It killed a set of plugs. When I connected a laptop to it, with it running, the BLM was bottomed out at 90. It had a very pronounced surge at steady throttle and the rpm fluctuated between 500 and 1100 RPM at idle. After some minor idle VE adjustments, It starts, idles and runs great. When I set the base timing to 0 deg and reset the PCM, I glanced at the timing.with a light with it running. I don't have a dial back timing light but it was in the area where 20 advanced would be. That reminds me, I need to acquire a timing tape. I have not touched the open throttle VE table yet because there is no need until I can get the thing out and drive it at highway speeds to get data at varying loads and speeds. Check some of these points mentioned above and post what you find.
    Thanks again. Very nice for sharing experiences. Had the same experience prior to you leaning out my near idle VE table. Have not datalogged running vehicle. Purchased an identical PCM for test purposes. May be the aftermarket distributor. Don't want to swap distributors from running vehicle. Need to purchase timing tape for running vehicle and then hook up APU1/TunerPro and timing light. Also can try the recently purchased spare PCM first to see is the ignition timing situation changes for the better. May have had a bad other spare PCM. When push comes to shove, may have to build a bench stimulator to try many different PCM binary adjustments. Should have done that from the outset. Then could have removed running vehicle PCM, run and record baseline and then compare another test PCM and make it somewhat similar. Would be nice to bench test and find out all the other variables affecting ignition timing. Need to shield run-in stand EFI wiring. Likely ignition noise getting into TPS, MAP, CLT input wiring. May have to fab shielding for spark plug wires also to cancel cross-coupling noise.

    Will try to get the engine run tomorrow with newly purchase PCM. Will let you know how it turns out.

  5. #80
    Fuel Injected! Loyd's Avatar
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    we had a the same problem with a 350 running 350 tbi on an adapter plate. there was a vacuum leak caused by the gasket set. replaced the plate, new gaskets and it ran much better. so make sure no vacuum leaks as the computer will sense low vacuum and put more gas. Good Luck

  6. #81
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    see where your map sensor volt are, most of the stock engines I have seen are .90-1.14 with the tps volts around 55-65

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