2002 5.3 engine loss of power?
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From: Friendsville, Tn
2002 5.3 engine loss of power? Thanks in advance!!! I'm new to the LS which I have a Bouncer with a 2002 5.3 LS from a Silverado 1500. Had issues with the charging system, would not charge the battery, if you charged the battery up it would run great for 20 mins start missing and die? Got a replacement alt for a 2002 chevy silverado, same thing happend, like the alt was not charging battery? I was told I needed more amps to run my rad fans, trans fan & elect fuel pump. Got another alt with higher amps 130 (carquest listed), this time it ran fine but the battery did come down some but not enough for it to miss and die like before? So I thought more amps was helping and the amps on my guage was showing it putting out 10-11.2 amps which I was told was still low? Ok so I was looking for more amps and got a new Mechman custom Alternator 250 amp GM 4 pin Self Exciting. This seems to have fixed my charging problem, the battery stayed up and the gage was now showing 14 amps under load. Here's my problem, immediately after that my engine has lost power, still runs good but didnt start as quick, didn't idle as good and idled at a little lower rpms, would not rev as fast as before and is considerably slower accelerating? Im not sure what to check now, it ran awesome before the alt change? Thanks for any help on this? Bryan
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From: Friendsville, Tn
Both Alts I returned so I can't try them. Haven't tried running any codes yet? Someone told me the new 250 amp alt may be sending to much voltage to the mass air flow sensor that a diode may need to be installed to drop the volts back down? I know nothing about that? I need to hook it up and check for codes I guess? I'm going to a competition in the morn so I'm out of time, was hoping it would be something simple? Thanks and I'll keep checking back to see any responses. Thanks a bunch for any ideas or solutions?
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From: Friendsville, Tn
could the battery be bad but everything electric, light, rad fans, trans fan and fuel pump all still work fine? The LS is running good just sluggish and down in acceleration? Thanks
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From: Friendsville, Tn
Well I feel a little dumified, my LS in my buggy lost power because when I installed the new Mechman high amp alternator I accidentally got a zip tie on one of the injector wires and when I pulled the zip tight it unplugged the 1 injector so that's why it lost some power! We did the water test which I'll share cause it works! Started the LS up and let it idle, took a cold water bottle and poored a little water on each header tube 1 at a time, each one sizzled and dried immediately except one, the one that wasn't firing! It was cold to the touch and the water didn't dry immediately so from there we found the unplugged injector. Thanks
" Someone told me the new 250 amp alt may be sending to much voltage to the mass air flow sensor that a diode may need to be installed to drop the volts back down?"
What the hell is a need for a 250 amp alt?
Diodes for the MAF?? A new one.
As for the alt not working... Is the PCM alt control removed?
What the hell is a need for a 250 amp alt?
Diodes for the MAF?? A new one.
As for the alt not working... Is the PCM alt control removed?
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Thread Starter
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From: Friendsville, Tn
I know that seems like alot of voltage for what I have but since installing it it's done great!! I have a few friends that run this same alternator on there comp rock bouncers and love it, one of them recommended it so I called Mechman Alternators, Knox. Tn and they built me one while I waited. I'm happy!!!
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From: PDX-OR-USA
No matter what current rating,, alternators should put out the same voltage within a couple tenths of a volt or so.. The 250 just has more headroom for load. Different alternators can take a different RPM to totally come on and provide juice to the system. Thats the most common fail I see on offload rigs, too low of RPM at idle to get the field excited.. and 1 wire alternators are the worst about it..
You can buy 16V alternators for some applications and a special battery but in general on a modern engine should not be needed until your running a really high current ignition.
I have a cheap harbor freight thermal gun I use at the track to make sure all the cylinders are firing before a race..
You can buy 16V alternators for some applications and a special battery but in general on a modern engine should not be needed until your running a really high current ignition.
I have a cheap harbor freight thermal gun I use at the track to make sure all the cylinders are firing before a race..
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From: Friendsville, Tn
Thanks PDX for the good info. Everything is working great so i'm not messing with it, Lol. I know Mechmann Alternators built mine to work better at higher rpms since I'm normally wide open!! Just the way I like it!!! Thanks for all the info Everyone. Bryan
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