5.7 won’t start-blows air back through TB

[Jared Jackson]

I understand. Yes, I’ve sprayed starter fluid in carb throat. I have a audio file I’d like for you to hear but I cannot figure out how to upload it. I can probably email it to you.​

I wouldn't be TOO concerned about intake noises, at the moment. They can make some "gulp/hiss" type sounds when you open up the intake tube and listen to the engine stop/start.

Since you said it did drive for a few days and then stopped again, it really sounds like you have an intermittent failure point somewhere. You mentioned you have spark, how did you check? How many spark plugs did you pull? When you added "fuel" down the throttle body, did it try to fire off? Have you pulled the cap and rotor at the rear of the engine and checked for water?

 

[SuperTramp]

I wouldn't be TOO concerned about intake noises, at the moment. They can make some "gulp/hiss" type sounds when you open up the intake tube and listen to the engine stop/start.

Since you said it did drive for a few days and then stopped again, it really sounds like you have an intermittent failure point somewhere. You mentioned you have spark, how did you check? How many spark plugs did you pull? When you added "fuel" down the throttle body, did it try to fire off? Have you pulled the cap and rotor at the rear of the engine and checked for water?

https://www.dropbox.com/s/jbsoqrbb73ozru9/5.7 Starter Fluid -won't Start-Wes.m4a?dl=0

The above file is a recording of the engine. I was mistaken in that you can hear it start up and this is when I was spraying the starter fluid in throat, but it only started once for the 4 times I tried. I only checked one plug but will now check them all; I have not checked cap and rotor but will now.

 

[SuperTramp]

I just now checked the link to the recording and it worked for me

 

[Jared Jackson]

I just now checked the link to the recording and it worked for me

Since it did fire off when you added carb cleaner down the throttle body, I would lean more toward a fuel delivery issue than a spark issue. Are you getting any codes?

 

[SuperTramp]

Thanks Jared. I follow your suggestions and be back in touch.

 

[SuperTramp]

Acr

Since it did fire off when you added carb cleaner down the throttle body, I would lean more toward a fuel delivery issue than a spark issue. Are you getting any codes?[/QUOTE

Actually it did fire off and ran (in the recording) albeit rough, for about 25 seconds. I do not have any codes but will pay specific attention for that. What about mass air flow sensor (or whatever proper name is) it’s in the tube at throttle body that leaded to air intake) ?

 

[Urambo Tauro]

Hold up. So it sounds like we are finally on the same page about what it means for an engine to "turn over". But that thing about it only turning over "when it wants to" (post #3) sounds like a big clue here. Maybe it does have other problems as well, but if it won't even crank over sometimes, then I think we need to address that first. If there's an electrical problem somewhere causing that intermittent no-crank issue, then it might be affecting other parts beyond just the starter.

Have you checked voltage down to the starter, as well as the ground path? Could have a bad connection somewhere.

(Oh, and please don't hide any modifications that have been made to the truck. I know you said "all original", but you also said "carb" , which doesn't ring true on a '98 truck.)

 

[Jared Jackson]

Hold up. So it sounds like we are finally on the same page about what it means for an engine to "turn over". But that thing about it only turning over "when it wants to" (post #3) sounds like a big clue here. Maybe it does have other problems as well, but if it won't even crank over sometimes, then I think we need to address that first. If there's an electrical problem somewhere causing that intermittent no-crank issue, then it might be affecting other parts beyond just the starter.

Have you checked voltage down to the starter, as well as the ground path? Could have a bad connection somewhere.

(Oh, and please don't hide any modifications that have been made to the truck. I know you said "all original", but you also said "carb" , which doesn't ring true on a '98 truck.)

diagnosing no-start issues sight unseen are always fun!

I read into it as it would always turn over, but not always fire up and drive off.

 

[Jared Jackson]

Acr

Well... if it's running on carb cleaner... it will run rough as it is not a perfectly timed and measured spray directly into the combustion chamber.

 

[CrustyJunker]

Riddle me this. Take a video or have a someone watch the serpentine belt when you crank on it. When it puffs back out the intake, does the motor spin backwards after it stalls or struggles to start?