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Need a little help with a Silverado

 
Ismael Lasalle
I love my Chevy Chevette!
Posts: 3
Joined: 01/14
Posted: 01/21/14 04:58 PM

I have an 08 Silverado 1500-4.8 running 12# of boost, cam 216/220. Every since I put in the Pro Charger I have a little hesitation. When I turn my truck on and get ready to take off, it hesitate to a point the it wont accelerate. I stop and then it works fine until I shut it off again. Change the throttle body for the same one (87mm) and did the same thing. Change for a 90MM and got a little better but still doing the same thing. Can anyone let me know if have the same problem and how to fix it?  

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shyrgfuh70
V-6 Camaros rule!
Posts: 32
Joined: 01/14
Posted: 01/22/14 03:47 AM

HI, IF YOU DON'T GET AN ANSWER HERE I SUGGEST YOU TRY THE CORVETTE FORUM. They will likely have your answer. Just tell them you have a corvette too but need help with this, lol.

HAS IT DONE THIS ALL ALONG?

what is your compression?

try running without the charger and if the hesitation goes away try it again with around 6 lbs boost.

might be a computer prob.  

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wayne712222
My first time was in a Chevy
Posts: 245
Joined: 10/13
Posted: 01/22/14 09:49 AM

i would want to use a professional scan tool...

and monitor the accelerator position sensor voltages.. there are 2.. one that starts low and goes up to about 4.5 and the other that starts at 4.5 and goes to 0.5..

i would also want to monitor the throttle position sensor signal on the throttle body.. there are a matching pair of sensors there also..

next i would search out the ground connections

bat neg to the block
bat neg to the body
engine to the firewall
EFI harness to the engine..

and verify that they are all intact by taking them off and wire brushing them .. their mounting points..  and the underside of the fastener head..  then reinstalling them..

i have a voltage drop test for you to perform.. the 4 part test only takes a minute to perform..

engine running.. headlights on...  hand held digital volt meter set to 20 volts DC scale..

1. Negative battery post to the positive battery post.. 14.1 to 14.8 volts is expected.

2. Negative battery post to the engine block.. 0.04 volts DC MAX..

3. Negative battery post to the Body... 0.02 volts DC MAX

4. Engine block to the Body. usually at the firewall. 0.02 volts DC max..

if you get 0.00.. change the meter setting to 2 volt scale..

post results..

1._____

2._____

3._____

4._____


Its more than likely a ground issue.. where the computer harness is hooked up to the engine..  please run all the tests..

since you have had it all apart.. you will recall where the ground wires are..

the ground is not really a ground.. it is half the circuit.. and the side that supplies ALL THE ELECTRONS..   no ground or bad ground. you won't have enough electrons to operate the various devices..

there is also a small chance that your throttle body is set too far closed and is binding..
with an advanced scan tool and the engine warmed up and idling..
how many idle air counts to you have??? IAC..  you should have between 20 and 50 ..warmed up and idling.  

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Ismael Lasalle
I love my Chevy Chevette!
Posts: 3
Joined: 01/14
Posted: 01/22/14 03:44 PM

Thanks for the info. I'll do the test this weekend and see the outcome.  

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Ismael Lasalle
I love my Chevy Chevette!
Posts: 3
Joined: 01/14
Posted: 01/22/14 03:49 PM

It started with the installation of the charger. It was at 6# boost. Then I cammed it and went 12#boost. It got better when I installed the 90mm. The shop that did all the installation said it was the first timethat it has happened to him. We called procharger and the can't figure it out. I email a independed procharger guy and he said most likely is a tuning issue.  

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wayne712222
My first time was in a Chevy
Posts: 245
Joined: 10/13
Posted: 01/23/14 12:33 AM

this might help...

pay close attention to the

TP1
TP2
APP1
APP2
throttle actuator control percentage

i don't see the idle air control counts listed.. but this is a generic list and i don't do a lot of work on drive by wire stuff YET..

i have been doing electronic fuel controls since 1980.. the first models came out in 76..  and by 81.. they were all over the place..



Obd2scandatachart Zps65411833


This%20Might%20Help


This%20Might%20Help


this might help...

pay close attention to the

TP1
TP2
APP1
APP2
throttle actuator control percentage

i don't see the idle air control counts listed.. but this is a generic list and i don't do a lot of work on drive by wire stuff YET..

i have been doing electronic fuel controls since 1980.. the first models came out in 76..  and by 81.. they were all over the place..



Obd2scandatachart Zps65411833


this might help...

pay close attention to the

TP1
TP2
APP1
APP2
throttle actuator control percentage

i don't see the idle air control counts listed.. but this is a generic list and i don't do a lot of work on drive by wire stuff YET..

i have been doing electronic fuel controls since 1980.. the first models came out in 76..  and by 81.. they were all over the place..



Obd2scandatachart Zps65411833

Obd2scandatachart2 Zps6e93e7de  

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