Bogging and dies

[Rockbottom78]

Hey guys. I just got my 78 c10 with a 5.3 lm7 and a 4l60e running and driving. I drove it around the block for an initial shake down. It seemed sort of boggy and seemed to lag. Was low on year old fuel so I figured it was that. Went to start it the next day and drive to the fuel station when it died in the driveway. Got the tank filled with fresh 91 octane. Started and idled better. Still lacking power once in gear and any load is applied bogs down to a stall out if I don't give it any gas... Any ideas!?
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[mongocanfly]

did you change the fuel filter? what about fuel pressure..have you checked that?

[Rockbottom78]

Originally Posted by mongocanfly

did you change the fuel filter? what about fuel pressure..have you checked that?

Checked fuel pressure this morning. 62 lbs right at the fuel rail. Good now. Must have been bad fuel or the fact that my trans was a liter low of oil. Thanks!
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[mongocanfly]

might want to go ahead and change that filter..especially since you were pumping old gas thru it..better safe than sorry
low trans fluid won't give the issues you had

[Rockbottom78]

Originally Posted by mongocanfly

might want to go ahead and change that filter..especially since you were pumping old gas thru it..better safe than sorry
low trans fluid won't give the issues you had

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[Rockbottom78]

I will have to throw a new filter in then. Your right trans fluid didn't have anything to do with it since it's back. I jumped the gun when I thought it went away... I have been told to check the throttle body isn't dirty on both sides of the butterfly. Or a bad o2 sensor possibly. My scan tool isn't throwing any o2 codes at me. Or any codes at all for that matter. I guess I'll start by cleaning the t/b and go from there...
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[mongocanfly]

might put some injector cleaner in your tank as well..

[BR3W CITY]

Check fuel pressure under some load as well, and see if it drops. When demand rises, the pump should be keeping up. If the pressured drops, then you might have a restriction, bad reg, or issue with the pump.

And as always, check for vacuum and exhaust leaks on any new swap. The ECM can account for a pretty decent leak on either side at idle, but under load from the trans sometimes they will bog. If your not running a full exhaust, then be aware that the o2's might be seeing clean air and throwing your trims way off without triggering codes.

Is this a stock engine, or is there motor work involved. If its cammed, you might need your tuner to bump up the load correction on the idle.

[Rockbottom78]

Originally Posted by BR3W CITY

Check fuel pressure under some load as well, and see if it drops. When demand rises, the pump should be keeping up. If the pressured drops, then you might have a restriction, bad reg, or issue with the pump.

And as always, check for vacuum and exhaust leaks on any new swap. The ECM can account for a pretty decent leak on either side at idle, but under load from the trans sometimes they will bog. If your not running a full exhaust, then be aware that the o2's might be seeing clean air and throwing your trims way off without triggering codes.

Is this a stock engine, or is there motor work involved. If its cammed, you might need your tuner to bump up the load correction on the idle.

Nice. I'll check fuel pressure under load as well. I still need to get exhaust built also. So it definitely could be the o2 sensors being so close to the end of pipe (collectors with a bung in it). That makes real sense as I'm slowing down from any speed the motor is falling in rpm. The lower the rpm the less exhaust pushing over the o2 gets worse reading lower rpm gets worse yada yada until stalled out. I guess I'm. It done building it yet! Also it is a stock motor with intake and headers. The only thing is the timing has been advanced slightly.
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[Rockbottom78]

Originally Posted by mongocanfly

might put some injector cleaner in your tank as well..

Thanks I threw a bottle in yesterday. Hasn't ran much with cleaner in tank yet though. I'm sure my 160k mile engine would enjoy a drink of injector cleaner ether way haha
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