Sorry for the long explanation/ story but I feel it will illustrate my point better if I get a little long winded on this one.
I have been chasing a few issues with my 2009 GT500 for the last couple of months. I was having stalling issues right after filling up with gas. Pulled codes and it indicated purge valve solenoid. I bought a new one and a new charcoal canister purge valve too. That handled that.
I also had a bigger issue with the car being down on power the last several months. The car started running lean and nosing over at WOT. My A/F, which had been real nice and fat below 11.5 since replacing my failed Kenne Bell BAP with dual Lethal units, was going above 14 at WOT and DEFINITELY down on power. At first I thought maybe it was due to heat soak like last summer. But I had added a VMP triple pass HE without fans, then mid summer added the twin Spal fans with VMP's wiring harness. I also replaced the stock fuel pumps with a set I bought off of this site from a user that were supposedly "new in the box" but when I opened them, you could tell they had been in the tank and were used.. the sending unit is bad as well... but I digress...There was definitely still SOMETHING wrong and the car was down at least 100hp and running lean.
I was at a car show last weekend and a buddy with a Big Block '66 El Camino was there and we left together. He had an electric fan issue and his car overheated so he pulled over. I took him to the auto parts store in my car to get a new box of fuses so he could make it home. I began describing what was going on with my car and he said he had a friend with a built GT350 that was supposed to be 9 second capable but it was breaking up up at high RPM and down on power. Someone told him to unhook his stock radio and it solved his problem. His car ran like it should. That got me to thinking, my issues got worse since I installed those Spal fans. Hmmmmm....
Then later that night I was participating in the thread on here about the dual pass vs. tried pass HE, and was looking at YouTube video reviews of the VMP triple pass with dual fans. The guy I was watching had a '13 GT500 and he said his car was down on power and was breaking up above 4500rpm since the install so he unplugged the fans and it solved his problem .
A light went off at that point. I texted my mechanic and told him the 2 stories. I said that I thought maybe my alternator was weak and these fans were too much and we needed to get a higher output alternator like a 200 amp. He reminded me that we had left the key on overnight while working on the car back in the spring and ever since then if we left the key forward and the car not running for over 30-45mins or so, we had to use the jump box to start the car. We knew it had a weak battery and I was going to replace it when we got the other issues straightened out. He said that we should try putting a new battery in the car before spending $500 on an alternator and I agreed.. Well, I got a Napa Gold 36 month with 725 cranking amps and put in on Tuesday morning, the old battery tested bad, had less than 520 cranking amps whe we took it out, so it probably had a dead cell. The alternator tested with a multimeter saying it was putting out 14.6 amps at idle. I took the car out and WOW!! Better than ever before. I have put about 150 miles on it this week since changing the battery and this car is super fun to drive again. My A/F at WOT is nice and fat, the back end of the car will come out with a tap of the throttle, and it pulls like a freight train.
Moral of the story- when goofy things are going on, check your voltage. It could be something simple causing those sleepless nights.
I feel dumb but if this helps someone else I am glad my stupidity will pay off for whoever that is.
I have been chasing a few issues with my 2009 GT500 for the last couple of months. I was having stalling issues right after filling up with gas. Pulled codes and it indicated purge valve solenoid. I bought a new one and a new charcoal canister purge valve too. That handled that.
I also had a bigger issue with the car being down on power the last several months. The car started running lean and nosing over at WOT. My A/F, which had been real nice and fat below 11.5 since replacing my failed Kenne Bell BAP with dual Lethal units, was going above 14 at WOT and DEFINITELY down on power. At first I thought maybe it was due to heat soak like last summer. But I had added a VMP triple pass HE without fans, then mid summer added the twin Spal fans with VMP's wiring harness. I also replaced the stock fuel pumps with a set I bought off of this site from a user that were supposedly "new in the box" but when I opened them, you could tell they had been in the tank and were used.. the sending unit is bad as well... but I digress...There was definitely still SOMETHING wrong and the car was down at least 100hp and running lean.
I was at a car show last weekend and a buddy with a Big Block '66 El Camino was there and we left together. He had an electric fan issue and his car overheated so he pulled over. I took him to the auto parts store in my car to get a new box of fuses so he could make it home. I began describing what was going on with my car and he said he had a friend with a built GT350 that was supposed to be 9 second capable but it was breaking up up at high RPM and down on power. Someone told him to unhook his stock radio and it solved his problem. His car ran like it should. That got me to thinking, my issues got worse since I installed those Spal fans. Hmmmmm....
Then later that night I was participating in the thread on here about the dual pass vs. tried pass HE, and was looking at YouTube video reviews of the VMP triple pass with dual fans. The guy I was watching had a '13 GT500 and he said his car was down on power and was breaking up above 4500rpm since the install so he unplugged the fans and it solved his problem .
A light went off at that point. I texted my mechanic and told him the 2 stories. I said that I thought maybe my alternator was weak and these fans were too much and we needed to get a higher output alternator like a 200 amp. He reminded me that we had left the key on overnight while working on the car back in the spring and ever since then if we left the key forward and the car not running for over 30-45mins or so, we had to use the jump box to start the car. We knew it had a weak battery and I was going to replace it when we got the other issues straightened out. He said that we should try putting a new battery in the car before spending $500 on an alternator and I agreed.. Well, I got a Napa Gold 36 month with 725 cranking amps and put in on Tuesday morning, the old battery tested bad, had less than 520 cranking amps whe we took it out, so it probably had a dead cell. The alternator tested with a multimeter saying it was putting out 14.6 amps at idle. I took the car out and WOW!! Better than ever before. I have put about 150 miles on it this week since changing the battery and this car is super fun to drive again. My A/F at WOT is nice and fat, the back end of the car will come out with a tap of the throttle, and it pulls like a freight train.
Moral of the story- when goofy things are going on, check your voltage. It could be something simple causing those sleepless nights.
I feel dumb but if this helps someone else I am glad my stupidity will pay off for whoever that is.
