Idling and starting issue

[ahoppj]

Hey ladies and gents.

just recently had this problem starting that I go to start the truck and it’ll turn after a couple goes. Idles high then it slowly idles down then turns off. Any ideas?

 

[Vbb199]

Carb? Tbi?

Also welcome lol.

I'm in Salisbury.

 

[ahoppj]

Carb? Tbi?

Also welcome lol.

I'm in Salisbury.

4 brl carb

 

[Vbb199]

Have you tuned the idle screws yet?

 

[ahoppj]

Have you tuned the idle screws yet?

sure haven’t

 

[Taylorb27]

Sounds like you may have developed a vacuum leak. Big enough to need idle mixture screws adjusted. It's firing off the accelerator pump shot and once that runs out it leans out so bad that it dies.
If your timing is right start by turning the idle mixture screws out a half turn then see how it responds.

What carb is on this?

 

[ahoppj]

Sounds like you may have developed a vacuum leak. Big enough to need idle mixture screws adjusted. It's firing off the accelerator pump shot and once that runs out it leans out so bad that it dies.
If your timing is right start by turning the idle mixture screws out a half turn then see how it responds.

What carb is on this?

I also did just replace the valve covers and replaced the pcv valve with a breather. Could that be it ?

 

[ahoppj]

Or I just need to adjust the screws because I took out the pcv valve hose

 

[Taylorb27]

I also did just replace the valve covers and replaced the pcv valve with a breather. Could that be it ?

Just make sure the pcv hose isn't dry rotted or anything and that pcv, although new, works like it should. Also make sure the grommet that the pcv goes in is still sealing as it should.

If you're concerned about that just cap off that port and run it. If it runs fine that's your issue, if not, hook the hose back up after checking it out and look elsewhere

 

[Taylorb27]

Oh sorry I read that wrong, you replaced it with a breather. I personally recommend you put the pcv back in. And make sure you capped the port or plugged the hose that went to the old pcv

 

[Taylorb27]

If you left the pcv port or hose open that is a major vacuum leak

 

[ahoppj]

If you left the pcv port or hose open that is a major vacuum leak

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[Taylorb27]

The arrow is pointing to around the area where that pcv hose should hook up, as I'm sure you know. Make sure that is capped since there isn't anything running to it

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[ahoppj]

Alright I plugged it up and now it’s just idling really low... who wants to give me the tutorial on the isle screws . I could look it up on you tube but I’d rather talk to you guys

 

[Taylorb27]

Alright I plugged it up and now it’s just idling really low... who wants to give me the tutorial on the isle screws . I could look it up on you tube but I’d rather talk to you guys

I'd recommend you get a vacuum gauge and do your fine tuning. For now you can just bump up your idle speed slightly to get to where you want it.

Basically on the mixture screws I start by bottoming the mixtures screws out and then backing them off 2.5 turns. Start the engine and get it to temp. Then look at the vacuum gauge and adjust in or out until I get the highest vacuum I can on the gauge.
This is assuming your timing is on where you want it. Then after this recheck timing again