86 s-10 stalling / falling on its face

[motorsports12]

i have an 86 s-10 2.8 v-6 with a stalling type issue - it stalled out going down the road the other day - it then started but stalled again and eventually wouldnt start again - thinking it might be a fuel related issue (even though the fuel seemed to be spraying ok) or a spark related issue i changed the fuel filter and the cap and rotor (the spark plugs and wires were changed late last fall) - i also changed the valve idle air control and charged the battery - the truck started after a few tries probably getting the fuel from the tank back thru the filter and to the engine - sitting there idling it was running pretty good - i was even able to rev the engine with no faulter - i got in it to move it and as soon as it put it in gear and pressed the gas pedal it fell on its face - it would spit and sputter trying to move it from one place to the other - when i finally put it in park it would still fall on its face - nothing like when i first put everything on it and started it

could it be the fuel injectors?
could it be the throttle body itself?
is it something different?

any ideas or help would be appreciated

[MT-2500]

Originally Posted by motorsports12

i have an 86 s-10 2.8 v-6 with a stalling type issue - it stalled out going down the road the other day - it then started but stalled again and eventually wouldnt start again - thinking it might be a fuel related issue (even though the fuel seemed to be spraying ok) or a spark related issue i changed the fuel filter and the cap and rotor (the spark plugs and wires were changed late last fall) - i also changed the valve idle air control and charged the battery - the truck started after a few tries probably getting the fuel from the tank back thru the filter and to the engine - sitting there idling it was running pretty good - i was even able to rev the engine with no faulter - i got in it to move it and as soon as it put it in gear and pressed the gas pedal it fell on its face - it would spit and sputter trying to move it from one place to the other - when i finally put it in park it would still fall on its face - nothing like when i first put everything on it and started it

could it be the fuel injectors?
could it be the throttle body itself?
is it something different?

any ideas or help would be appreciated

You need to check for lose of fuel pressure and lose of spark.
Also post back vacumn readings at idle and at 2K RPM.

HOW IS BASE TIMING?

Any check engine ligts or codes?

[motorsports12]

are there any cheap ways of checking these ... i dont have a fuel pressure tester or a vaccum tester and dont know i can afford 40-50 per tester

i got to thinking could spark plugs even cause this issue - they are new plugs and gapped according to the spec sticker

[MT-2500]

Originally Posted by motorsports12

are there any cheap ways of checking these ... i dont have a fuel pressure tester or a vaccum tester and dont know i can afford 40-50 per tester

i got to thinking could spark plugs even cause this issue - they are new plugs and gapped according to the spec sticker

Spark plugs can cause a hrd start but not quiting on the road.

A vacumn gauge is not over 5-10 dollars and tells you many things.

Most parts places rent loan and sell fuel pressure testers.

A paper clip will tcheck for codes.

A screw driver can be used to check for good hot blue spark.

[motorsports12]

ok here is what i have for now - i checked the codes and it comes back with a 34 (vaccum sensor or map sensor) - my hayes manual says the map sensor voltage is too low and the ecm will substitute a fixed map value and then uses the tps to control fuel delivery - a guy i work with said it could be the tps sensor before i checked the codes - should i replace both

also (and i am not sure if this has something to do with it or not) but the battery loses its charge from overnight - so i wasnt able to put a vaccum test on it other than pulling one of the vaccum lines and pumping air in it which it held but that was only one line i checked - but could something be pulling the battery down causing loss of power to other things such as a map sensor or ecm or tps or even fuel injectors

any help is appreciated

[MT-2500]

If battery is going dead overnight get that fixed first.

After getting it started clear code and see what comes back and run the vacuum test with a vacuum gauge.,
Post back readings.
Check and confirm god fuel pressure.
also if quiting check for lose of fuel pressure or lose of spark when it quits.

[motorsports12]

any ideas what the battery issue could be - the battery is less than a year old - i will work on the vaccum fuel pressure and spark

thanks for all your help

[MT-2500]

Originally Posted by motorsports12

any ideas what the battery issue could be - the battery is less than a year old - i will work on the vaccum fuel pressure and spark

thanks for all your help

Check the amp draw on battery engine off with a volt/ohm/amp meter.
Should be no more than 25 milliamps, or 0.025 amps.


Try unkooking battery over night and see if battery stats up unkooked.
If so you have to much amp draw on some circuit.

Let us know what you fund

[motorsports12]

ok here is what all i have done and i think it is fixed - i really think what it boils down to for the stalling/falling on its face issue was old gas - what i did was put octane boost in the tank and i was able to drive it once it made it to the throttle body - i went ahead and ran some tests though and found some other issues

vaccum pressure was 17-18 psi running
fuel pressure was 10 psi running (ended up buying a tester)
i replaced the pcv valve
replaced several broken vaccum lines (test was ran after hoses were replaced)
i put about 3 gallons of 92 octane in the tank along with lucus fuel stabelizer
also had the battery tested ... it was ok
had the alternator tested ... it failed - replaced it
sprayed the throttle body with cleaner
changed the plugs

i really couldnt tell you where the real issue was - i do know the truck had been sitting for about 8 months with no new fuel put in it and in ohio weather which is cold and snowy right now - the only think i come out of this was probably there was bad fuel and the alternator needed replaced

thanks mt - all your advice and information is definitely appreciated

[MT-2500]

Originally Posted by motorsports12

ok here is what all i have done and i think it is fixed - i really think what it boils down to for the stalling/falling on its face issue was old gas - what i did was put octane boost in the tank and i was able to drive it once it made it to the throttle body - i went ahead and ran some tests though and found some other issues

vaccum pressure was 17-18 psi running
fuel pressure was 10 psi running (ended up buying a tester)
i replaced the pcv valve
replaced several broken vaccum lines (test was ran after hoses were replaced)
i put about 3 gallons of 92 octane in the tank along with lucus fuel stabelizer
also had the battery tested ... it was ok
had the alternator tested ... it failed - replaced it
sprayed the throttle body with cleaner
changed the plugs

i really couldnt tell you where the real issue was - i do know the truck had been sitting for about 8 months with no new fuel put in it and in ohio weather which is cold and snowy right now - the only think i come out of this was probably there was bad fuel and the alternator needed replaced

thanks mt - all your advice and information is definitely appreciated

You are welcome and thanks for posting back how it went.
Glad you got it running good.
Good luck with it.