I am not having difficulty , this is a new Code Scanner and it lists codes for the cars , trucks and Heavy trucks , the only code I am getting which I assume is why I do not get the 11 is the one that states that my high speed fuel pump relay is open , I have a HP Pump on frame rail with 2 LP pumps , one in each tank , pump is new , it only has one speed , on , so I disregard this right now , if there is a issue with ECM then maybe that is why it is being generated , I do not think so as it has applications in parenthesis , this is a very nice scanner and I think that this is probably just a broad compatibility function regarding the OBD 1 .
I am getting ready to go out now and check TPS for flat spot with ohm meter and will also check voltages to make sure in spec , the TPS does have slight adjustment that is possible , I do not think it is planned per say but it can be moved minutely one way or another , it was removed and re-installed on cleaning / rebuild , it may not have been installed the same way I did before , I loaded the potentiometer with the throttle closed , my friend that rebuilt it may not have done this , I will check .
If TPS is Ok then I will be removing ECM today and checking the PCB for the leaking caps or any other problems I may see , this truck does have some body work and new paint on drivers side quarter and door , and this is where ECM is , so outside of the obvious cap leaking issue there may be other damage never investigated , will post with results when I am done and let you know what I find , Thankyou

Also I am using the KOEO readout , but this scanner requires a warm up for the test , so you warm up , cut off , scanner loads info gathered , then key on , then re-checks ( I can hear the relays and such being tested ) , then key off , and then press for final results , the last one I did the scanner gave me an all clear , it did not give me the 11 but rather told me All Clear , No Codes Remaining .

 

Also , I would like to Thank all of you for your input , you are a great help , as I said , I am going to check TPS now , and if it does not have a flat spot with ohm meter I will check voltages and possibly recheck to make sure the potentiometer is loaded with throttle plate closed if voltage is off of spec , Thankyou All Again , I will report back soon , if I find no issues with TPS I will be removing ECM to investigate PCB

 

Fan-tastic !!!!!!!

May I utilize some of your knowledge later on in this thread, (depending upon what your visual inspection of your computer yields) in order to help some of the readers and/or "Google" searchers out there ???

It'll be basic stuff, not too over the top.......I promise.

Bob

 

Sure Bob
I am probably going to join here to support forum and also because you guys are a great help , I used to turn wrenches for GM over 20 years ago , I am no stranger to vehicles but input helps , especially from people that have been there and done that
You guys are great , so I would be more than willing to return the favor

 

I am going out right now , finally stopped raining , I will re-run code check and run the CM Test as well as check the TPS , Thankyou for the Link .

 

Ok , TPS is fine , closed throttle @ .997 / WOT @ 4.78 , also checked voltage progression , nice and smooth , double checked with ohm meter and the same result , no flat/dead spots and smooth progression of resistance from potentiometer .
Also re- checked fuel pressure as I have been running a cocktail in it to make sure injectors are clean , fuel pressure is still good , right where it has been since pump and filter replacement before rebuild

 

If memory serves me correctly, closed throttle voltage at the TPS should be about .06 volts, and wide open should be at about 5 volts.

I'm thinking someone has dinked with the idle set screw to try and compensate for "other issues".

I've been playing the TPS/vacuum leak "game" for a couple of weeks now.....it ain't fun.

Just my thought.

Bob

 

Your TPS closed throttle value is on the high side of what is recommended (0.6VDC to 1.00 VDC) but that is fine. The PCM will adjust for anything in that range. Do not start the futile quest to adjust the TPS to some magical value. The full throttle output voltage is what I would expect as well. VREF is rated at 5.00 VDC nominal voltage with a tolerance of +/- 3%. The output voltage from the TPS or any other VREF fed signal will never exceed VREF and will typically be in the range you stated.

So you now have pretty much eliminated the TPS as a root cause for the off-idle stumble. I still eye aftermarket TPS sensors with some suspicion, but for now you should be fine.

Personally I do not like your code reader readings, I prefer empirical numeric values. At least we now know what you are working with.

 

TPS Voltage range is 0.6v to 1.19v. Anything in between is fine.

One thing I would do for sure though with an off-idle hesitation is unplug the IAC valve, and see if it idles. With the IAC unplugged it should just barely hold a steady slow idle. If the idle stays up high, or the truck completely dies out then someone has messed around with the idle air screw.

Also what is the exact scan tool you are using?

The code you got translate to Code 96. Code 96 also means "Fuel pump secondary circuit fault". The computer monitors the fuel pump circuit power, and this code indicates that the computer is detecting low/no power on the fuel pump circuit. Guess what would cause a sudden bad hesitation and no power? Low power to the fuel pump.

 

Ok , I know I will get some rebuttle possibly but since the throttle screw just has a blank end and cannot be adjusted , I bent the throttle stop tab just a tad , now the voltage is sitting on 1V , I did this because normal wear and tear allow the throttle plates to close more than did when originally set and I feel that the throttle plate may have been closed a bit to much , after doing this I did notice an improvement , before I did that when you accelerate the rpm would dip below the standard idle and it would wander a little ( very little ) up and down , after doing this when I accelerate now it drops to idle and stops , no more minute wandering , this very well could have been part of the problem and TPS closed is still 1V , the adjustment I was speaking of is not any magic , it is just that when the screws are in sensor , it can be moved back and forth about a 32nd - 16th of an inch , so if I need to lower it unless it was installed unloaded , I can still drop it back probably a couple of tenths of a volt
Now I am going to Read the codes if any and will do the CM test , when I replaced the EGR last week I re-read for codes and all was clean and I erased the existing codes , so going to check now , be back in about 30 minutes .

 

The Code Scanner is an Innova 1203B , I bought it a month ago , it does everything but wash the dishes , although there was a one step up at that time that would do graphs and such but I was not interested for another 150 bucks , this one is computer updateable and I can print from it and such , it cam highly recommended , I got it when I got the truck so I would not have to deal with the flashing light mess , it does OBD 1 & 2 and covers 4 diff manufacturers .

Looking at the throttle stop set screw , it does not appear to ever have been moved but I will also unplug IAC and check that as well , I have personally checked the throttle body bushing for the throttle shaft and they are still without any play , I was rather amazed by that actually .

Be back in a few with results , Thankyou Everyone for your input , might just catch this ghost after all , if code scan is unproductive then I will remove ECM and investigate.

It still has the original map sensor on it , any chance that could be causing this ???? 20+ years old and it sat for 3-5 years as well .

 

Re read the post I made above yours again, I've added some stuff.

 

When I fired it up to check voltages on TPS I had Fuel Pressure Gauge on it , it was constantly stumbling off idle and no fuel pressure drop what so ever , does it monitor all three pumps or just the HP pump ?
I have even driven it with fuel pressure gauge on it and no drop ever even when experiencing this , I believe the code 96 was probably left on there from previous owner , as I have re-checked after the EGR replacement and none came back that time , all clear , I am going to check right now , I will be back shortly .
Thankyou

 

That code 96 may be from Continuous Memory. Switching between tanks with the engine running can erroneously trigger this code.

You have no code for a MAP sensor problem, as best we can tell with that fancy reader

But it never hurts to check it's output using a vacuum pump/gauge and a DVM that can read frequency. Here is what you should expect: Fuel Injection Technical Library » Manifold Absolute Pressure Sensor (MAP)

 

Another thought popped into my head....what color is the Ignition Control Module, black or gray? It should be a Push-Start style gray colored version. Many part manuals are wrong, you may have gotten the wrong one.

Weird odd-ball things can happen if you have the wrong one. Is yours a Motorcraft or aftermarket? It is highly recommended to avoid the aftermarket versions.....