Fuel pressure and tune changed??
06-21-2016, 10:56 PM
#1
Fuel pressure and tune changed?? I'll try to keep this short. I had my car tuned a month ago.A ctsv if it matters.
The car has a Maggi and it didn't make numbers I was expecting.I towed it to the tune.I never drove the car before getting it tuned.I drove it home and wasn't impressed with the performance.Acceleration was lazy and flat.
I called tuner.We had issues with knock sensor being pegged at low rpm,s. We talked a little and I told him it threw a low voltage code on knock sensor.
I ordered new sensors and harness but before I installed them the fuel pump died. I have only drove the car probably 250 miles since tune.
The fuel pump was replaced at caddy dealer under a recall. I picked the car up and drove it 10 miles and when I was sitting at a light the engine started to miss.I didn't really mash it because I was being followed to return my rental car.
The car did feel very sluggish.
So I was thinking that dealer flashed computer for updates. I had a note taped to the steering wheel,a copy in an envelope with the key that was dropped in the key Dropbox and the next morning I called service and told the not to flash computer because of the tune.
I picked up car on a Friday before closing.I called dealer and asked if the computer was flashed.After checking they reported it wasn't.
Now the big question...Would it make a difference if the car was tuned with possibly a weak pump and then when pump was replaced the output changed the amount of fuel to cylinders? It seems to have 2 cylinders missing according to a snapon scanner. The plugs only have less than 300 miles on them...the cars exhaust smelled like raw gas.
Going to replace the knock sensors and harness tomorrow plus I ordered a new coil just in case.One code was primary circuit on the cylinder that was missing the most...weird things went bad so fast. Car ran fine besides not as strong as I felt it should have been.Fuel pump craps out now all this. Thanks. Sorry for the long read.
Ps..just an old fart and not really up on this tune and stuff.😁
The car has a Maggi and it didn't make numbers I was expecting.I towed it to the tune.I never drove the car before getting it tuned.I drove it home and wasn't impressed with the performance.Acceleration was lazy and flat.
I called tuner.We had issues with knock sensor being pegged at low rpm,s. We talked a little and I told him it threw a low voltage code on knock sensor.
I ordered new sensors and harness but before I installed them the fuel pump died. I have only drove the car probably 250 miles since tune.
The fuel pump was replaced at caddy dealer under a recall. I picked the car up and drove it 10 miles and when I was sitting at a light the engine started to miss.I didn't really mash it because I was being followed to return my rental car.
The car did feel very sluggish.
So I was thinking that dealer flashed computer for updates. I had a note taped to the steering wheel,a copy in an envelope with the key that was dropped in the key Dropbox and the next morning I called service and told the not to flash computer because of the tune.
I picked up car on a Friday before closing.I called dealer and asked if the computer was flashed.After checking they reported it wasn't.
Now the big question...Would it make a difference if the car was tuned with possibly a weak pump and then when pump was replaced the output changed the amount of fuel to cylinders? It seems to have 2 cylinders missing according to a snapon scanner. The plugs only have less than 300 miles on them...the cars exhaust smelled like raw gas.
Going to replace the knock sensors and harness tomorrow plus I ordered a new coil just in case.One code was primary circuit on the cylinder that was missing the most...weird things went bad so fast. Car ran fine besides not as strong as I felt it should have been.Fuel pump craps out now all this. Thanks. Sorry for the long read.
Ps..just an old fart and not really up on this tune and stuff.😁
06-22-2016, 01:58 PM
#2
May I assume this is a V1? Let's go with yes.
I think you are pushing it on a stock fuel pump with a blower. Not saying it can't be done, but geez I would call that risky if anything. A DW300 and hot wire kit from RaceTronix is pretty cheap insurance here. It occurs to me that the tuner should have seen issues with fueling at higher RPMs if the pump was that far compromised.
It is possible that you have too high of an expectation for the car, but I find it hard to believe you would call a V8 with a PD blower, manual transmission, and 3.73 gears "flat" or "lazy." I would think more like "whiplash."
Best bet is to get this thread moved to or repost in the V1-specific forum; several guys in there with similar setups that can set you straight. I'm still heading for N/A in my V...for the moment.
Here:
https://ls1tech.com/forums/cadillac-...2007-gen-i-68/
I think you are pushing it on a stock fuel pump with a blower. Not saying it can't be done, but geez I would call that risky if anything. A DW300 and hot wire kit from RaceTronix is pretty cheap insurance here. It occurs to me that the tuner should have seen issues with fueling at higher RPMs if the pump was that far compromised.
It is possible that you have too high of an expectation for the car, but I find it hard to believe you would call a V8 with a PD blower, manual transmission, and 3.73 gears "flat" or "lazy." I would think more like "whiplash."
Best bet is to get this thread moved to or repost in the V1-specific forum; several guys in there with similar setups that can set you straight. I'm still heading for N/A in my V...for the moment.
Here:
https://ls1tech.com/forums/cadillac-...2007-gen-i-68/
06-22-2016, 10:22 PM
#3
Hi Mercier,
Yes you are correct.V1.. I think I may have not painted a clear pic of the problem.Car has had this Maggi for years.Ran good before. Few people knew the car and told me.The guy that wrecked it before I bought it told me..
Maggi comes with a fuel pump booster..what ever that is..I think I am figuring things out or at least guessing.We pulled Maggi off and changed knock sensors.Got same code after..Changed a coil for a fault on G coil..still have same code.When I drove car the nite the fuel pump went south it poured rain.That is the first time I drove the car in the rain. The car was hit right in the computer.It damaged a couple wires on puter plug.I repaired those and thought I was golden.It looks like I may have a plug problem on the computer..maybe moisture in the connection..The computer plug was cracked but I figured it was ok...I have a feeling this is a good place to start.
Yes you are correct.V1.. I think I may have not painted a clear pic of the problem.Car has had this Maggi for years.Ran good before. Few people knew the car and told me.The guy that wrecked it before I bought it told me..
Maggi comes with a fuel pump booster..what ever that is..I think I am figuring things out or at least guessing.We pulled Maggi off and changed knock sensors.Got same code after..Changed a coil for a fault on G coil..still have same code.When I drove car the nite the fuel pump went south it poured rain.That is the first time I drove the car in the rain. The car was hit right in the computer.It damaged a couple wires on puter plug.I repaired those and thought I was golden.It looks like I may have a plug problem on the computer..maybe moisture in the connection..The computer plug was cracked but I figured it was ok...I have a feeling this is a good place to start.
06-23-2016, 07:00 AM
#4
A fuel pump booster(brand name: "Boost-a-pump") gives higher voltage to the fuel pump than is naturally in the car's electrical system to increase fuel pump output over stock. This over drives the pump, generally by a significant margin - 20%+. If that or the wires to that were damaged, you would instantly lose pump output.
It does sound like you still have a PCM or wiring issue.
It does sound like you still have a PCM or wiring issue.