start and run problem
 

Hi I have been reading the forums while working on my 85xtra cab RE doing a rebuild of the frame plus chevy springs rear and rear toys up front.
Well to the problem it starts good but only runs about a minute then starts to stumble and by two minutes it has quit. I thought it would go away when I replaced the fuel tank and pump but no luck.
I have discovered that if when it starts you keep the key in the start position with a second person removing the wire from the starter solinoid it wll run ruff but continue to run.
If you let the key go it will lean out and quit

IS there a relay involved and if so where is it

Thanks for your help

Ok by leaving the key in the start postion will keep the starter turning out with the flywheel and if you keep doing that it will burn it up. The starter has nothing to do with your problem. Pull codes. Tune-up? You said it will run good upon first start up then after a few fines run rough and cut off? Sounds like a fuel problem. will it does this all the time no matter what or does it get to a point to where it will not start at all?

Starter Burn up
 

I Mentioned that we are disconecting the power to the starter solinoid so I believe that the starter will then disengage from the fly wheel is this not right.
I am not thinking it is a starter problem but rather the relay that controls the fuel at startup and run
This is the second fuel pump on it and it still acts the same.

thanks

Prop not the fuel pump. Does it stay running if you spray carb cleaner in one of the hoses in the intake?

I will try that

I have a manual but cannot find a listing for fuel pressure any where any idea what it is suppost to be

Between about 33-38 i believe.

jump the fuel pump, see if it stay running, if it does, look at the afm

afm ???

air flow meter

Is this the sensor in the air box

yes it is

I tried a different air box withthe same result
any other ideas

did not try jumping the fuel pump as I am not sure which side is hot
the blue or the whit red
thanks

just look under the cap on the diagnostic connector under the hood... jump terminals fp and b+...that will keep the pump running.

Thanks
will try when iam back away now
thanks again

Hi I have returned to the north land
For those that have any interest in aproblem like this
85 re motors due not have a diagnostic port so I deceied to take a gambel and find out what happens when hooking direct found blue wire to be the + and white red to be - immediatly was getting gas out the loose fitting on the line.
rolled the engine after tighting fitting and we have ignition
thanks to all for your thoughts

Good info on this thread, thanks.

The diagnostic connector on the 85 is on the drivers side fender well, close to the coil. It will be a green plug with nothing connected to it. If it is in good shape it will be in a rubber holder mounted to the fender. Only two wires on this connector and you take a paper clip, wire, or whatever to jump it out with the key on to pull the trouble codes.