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No Throttle Response

Flyboy207

Flyboy207

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Hello guys I'm back again,
I just spent a few hours installing a Profab turbo horn on my '02 LB7, and having connected everything back the way it was (almost), I found the boost/MAP sensor connector was too short to make it back to the sensor. :mad2:
So after a run to the parts store I got a new connector with a long pigtail and connected them (using "twist'n'tape" cause I was in a bind for time, but I thought it was solid) and fired my truck up. Nothing abnormal, sounded fine, no check engine light and no message on the dash. I let it run while I put stuff away.
Then I backed out of the lot and accelerated, except the pedal felt like it wasn't part of the truck, nothing happened when I pushed it! Even in park the engine just idled while I hit the pedal. I tried wiggling connections and replugging it, but nothing worked. :(
Eventually I had to get a ride home from a friend. I currently have two broken trucks, so any advice will help.
Thanks everyone!
 
So today I fired the truck up again and I had a check engine light. Plugged it in to the scanner and I got two P0107's and two P1639's. After untwist/untaping the three wires and securely soldering them together, still no change. I cleared the codes and tried again, still no throttle response. Again, a P0107 and a P1639. However I did find out that the throttle will rev up to about 1500 rpm if I completely bury it in the floormat, which may have been true before. It drives at maybe 7 MPH max. TPS maybe? Or still a lousy wiring job? Thanks again.
 
Sounds to me like you crossed 2 connectors. The barometric pressure sensor is mounted under he 2 bale connectors on my 01, but not sure if it is the same on an 02. You need to double check you have it hooked up correctly as the 5 volt reference for the baro and boost sensors is teh same one for the APPS, so if there is any wiring problems to the baro or boost sensors the throttle can go dead. Try unplugging the baro sensor and see if it will run then.
 
Yes, after unplugging the sensor and clearing the codes it runs just fine. Is there a problem with running it without the map sensor plugged in?
 
Flyboy207 said:
Yes, after unplugging the sensor and clearing the codes it runs just fine. Is there a problem with running it without the map sensor plugged in?
Click to expand...

Theres no MAP sensor on these, you have the barometric pressure sensor and the turbo boost pressure sensor. Which one do you have unplugged?(the one that is out in the open or the one that hooks to the intake) If it's the one just sitting out in the open then it will run in a form of limp mode without it hooked up. It determines which timing table to use, glow time, fuel pressure offset, and max fuel based off of the altitude reading. Without it the ECM will default to a safe level regardless of altitude which will limit the max fuel and run low timing. Sounds like you crossed the wires if unplugging it makes it run correctly.
 
The one I have unplugged is on top of the intake, right next to the intake heater, It has a little hose that runs down to a tiny hole in the pipe, right before the pipe bolts to the intake bridge. I believe it's the boost sensor. (I've been hearing all kinds of different names for this thing). I'm almost positive I have the wires connected right, but I can try them switched around.
 
Flyboy207 said:
The one I have unplugged is on top of the intake, right next to the intake heater, It has a little hose that runs down to a tiny hole in the pipe, right before the pipe bolts to the intake bridge. I believe it's the boost sensor. (I've been hearing all kinds of different names for this thing). I'm almost positive I have the wires connected right, but I can try them switched around.
Click to expand...

Sounds to me like you crossed the boost sensor and the barometric pressure sensor, and that is why the harness was to short after you did the intake horn swap.
 
That would make sense, but I don't think I unplugged a barometric sensor... I could trace where the wire loom went over the old turbo horn into the same sensor. Now I have a code for the boost sensor, obviously because it's unplugged. However, the MAP code is gone.
 
Howdy, I was having same issue. Mine was for some reason, the truck would be demanding 19k to 21k rail pressure at not quite a quarter throttle. After months of tinkering, new FPR, FPRV mod, filters, lift pumps, tuning, new fuel lines, sensors, skinned knuckles etc, on a whim just today, I unplugged the BARO sensor on driver side under radiator hose....truck no longer throws code, "P0093" and desired pressure will stay with desired..blows my mimd...but, I'm getting a P1017 code now that says my MAP or 'boost sensor" is not working, and according to the Edge monitor, my boost gauge stays at 12. Also, now, the truck desires less fuel rail pressure at the low end. Before, it was demanding 19k to 21k not even quarter throttle. Now it's more gradual as you get in the throttle. I'm gonna leave it like this. I have it on the "tow tune" on the edge programmer, and it will pull like a frieggt train now, NO LIMP MODE. no funny sounds, no smoke, etc. Blows my mind. Maybe someone can tell me why. Also, my overall EGTS are way down considering
 
I tried looking up code P1017 and all I can find is something to do with a reductant control module sensor. I'm not sure what that is but seems to have something to do with the emissions system. I am curious if your baro sensor was shorted 5v to ground causing your issue. I would say check with a vilt meter making sure you have +5 vdc on one of the leads to the baro and ground on the other. the third will be the signal lead going back to the ECM. if all checks out, replace the baro sensor and clear the codes. your baro works in conjunction with the MAP for the ECM to figure out boost pressures. essentially the baro reads outside air pressures and this can change depending on altitude. then the MAP will read the same inside the intake. the difference of the two gives the ECM what your boost pressure is.
 
Check to make sure your getting +5v to both sensors with the key on. it sounds like there is a sensor shorted to ground. we'd have to find a schematic on your truck to see what other sensors tie into that same 5v line but chances are both the baro and map will share the same line
 
one other think you can check, if you are able to display live data from the sensors with your scanner, see what they are showing and if they change with load on the engine and turbo spooling up. you should see a somewhat static reading from the baro, but you should see the map change as boost increases. a faulty ground can also cause these issues too. look for any ground wires around the harness. GM put small eyelet ground wires in various places on the engines. on the ground wire in the sensor connector, you can use a test light to positive on the battery and it should light up, BUT verify your working with the ground lead in the connectors. if you touch another pin that goes to the ECM, bad things can happen!
 
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