Hello everyone. I am in need of some assistance again and I have not been able to find what I am looking for using the forum search tool (looks like there are a lot less pages than there were the last time I visited the site). The issue I am having is I hooked up my laptop today on my tbi conversion because the truck acts like it runs out of fuel when I give it over about 10-15% throttle but only after it is warm. Anyways, the only thing I saw that stuck out was my desired tps value was 1% at idle but the pcm was picking up a 0% tps value. I am sure this is not completely normal but I am not sure what is causing the problem. Also, I wanted to ask while I have a post up, I pulled two plugs the other day to make sure I wasn't running dangerously lean. My #2 plug showed a little leaner than it should have but nothing major. I also pulled my #8 plug and it showed ridiculously rich but yet it is on the same intake runner as my #2. I thought at first if it was on a seperate runner, I would pull all injectors that were on the same runner as #8 and if they were all rich I would have figured an injector balance issue but obviously this isn't the case so any suggestions on this? I know this isn't completely related to the PCM (as far as I can tell so far) but I don't want to start multiple threads. Any help would be greatly appreciated.

 

I will suggest the ECU learns the position of the TPS. I use throttle stop screw to set idle with commanded idle under what is set with TSS. All I ever see in datalog is zero when thottle is not depressed. I think GM sets ECU that way to make TPS sensor position non adjustable in relation to t blades. My guess.

 

Ok Ronny, I am going to restate what I think you said so I am sure I understand you. So you are saying to set the actual tps % with the desired tps % by means of the idle stop screw? If that's the case, that is simple enough.

 

I can place throttle blades at throttle closed anywhere I wish with TSS. My logs always show zero% with foot off pedal. I believe the GMECU learns quickly. Maybe key on engine off it learns beginning point. My hunch.

Quote: my desired tps value was 1% at idle but the pcm was picking up a 0% tps value

I never read there is a desired %% of TPS at closed throttle. It is always zero.

One can idle with IAC control of say 10 steps at idle and engine will idle at commanded speed(say 650rpm) OR one can set commanded to say (600rpm) set IAC at zero steps for idle and idle on TSS at say 675. That is how I am set up. a week ago I was idleing off IAC control and I did not care for result. Seems better off TSS for me.

 

Forgive me if I sound ignorant for asking ronny, but what is TSS? If I know what this is an abbreviation for I will be able to understand what you are saying much better. Thanks for the help so far.

 

Ron says:I use throttle stop screw to set idle with commanded idle under what is set with TSS. TSS=throttle stop screw

somewhere here is a complete list of acronyms.

There are hundreds.

 

Ron, in response to:

"One can idle with IAC control of say 10 steps at idle and engine will idle at commanded speed(say 650rpm) OR one can set commanded to say (600rpm) set IAC at zero steps for idle and idle on TSS at say 675. That is how I am set up. a week ago I was idleing off IAC control and I did not care for result. Seems better off TSS for me."

Are you saying to go and redo the desired idle speed in the chip and then set the tss to idle about 75rpm higher than what the chip is set at? I don't care much for iac control either and I thought I had an article book-marked about how to idle without iac control but I cannot find it.

 

Many will suggest that idleing off the commanded idle in chip is better than off a TSS(like a carb). I found that idleing off TSS works better for me. Now I will admit I did that to stabilize an idle that may in part be to lack of a perfect tune. My situation may diifer form yours or others. I have a set up with large inj's at 12.5 lbs FP controled with VAFPR. I already did the necessary changes in reducing prop gains in .bin. I idle 18 deg SA. I idle OL on rich side of 13.3/1(ext is clean). In order to idle on TSS the commanded idle needs to be set under TSS controlled idle. It is for me. As engine starts cold it is at 1200 rpms and gradulayy drops per the cimmand idle in ,bin intil it sees a CI that is less than TSS idle and ther it sits controlled by TSS. Pretty smooth.