85 305 in a k1500 - wont idle after smog removal

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bbgbouncer

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f it does come down to using the new Edelbrock, you will need an adapter to mount it to your Quadrajet intake manifold.
Thanks. I did not get one of these. It is ordered now.
 

mtnmankev

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And IF you use the Edelbrock, make sure to get a good fuel pressure regulator, those carbs are very sensitive to too much fuel pressure and will flood.
 

bbgbouncer

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update on the truck. The shop (Sam's) worked to track down vacuum leaks first. They did find that the EGR valve, on the top of the intake by the carb, was leaking at the gasket on a two sides. I guess when I took it off I damaged the gasket. even with all the vacuum lines plugged and leaks resolved the carb would not idle. since I already had a replacement it was decided to spend the time to replace verses rebuild the existing one.

That being said once the new carb was on the truck idled again. They tuned the carb. then adjusted the timing. Timing was 12 degrees this was causing a hesitation after 2300 rpms. They advanced it to 22 degrees.

So far the truck has been running like a champ for a week. Cold starts at 5am, no issue. when warm the idle is low and smooth.

I want to thank everyone for taking time to respond to the thread and offer help and suggestions.
 

Bextreme04

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update on the truck. The shop (Sam's) worked to track down vacuum leaks first. They did find that the EGR valve, on the top of the intake by the carb, was leaking at the gasket on a two sides. I guess when I took it off I damaged the gasket. even with all the vacuum lines plugged and leaks resolved the carb would not idle. since I already had a replacement it was decided to spend the time to replace verses rebuild the existing one.

That being said once the new carb was on the truck idled again. They tuned the carb. then adjusted the timing. Timing was 12 degrees this was causing a hesitation after 2300 rpms. They advanced it to 22 degrees.

So far the truck has been running like a champ for a week. Cold starts at 5am, no issue. when warm the idle is low and smooth.

I want to thank everyone for taking time to respond to the thread and offer help and suggestions.
Sounds like they were setting timing with the vacuum advance still connected. Those numbers sound right for vacuum advance connected to manifold vacuum. Glad they got it sorted out, its unfortunate your carb got messed up somehow.
 

scrap--metal

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So far the truck has been running like a champ for a week.
Keep it running like a champ for years to come!

Glad to hear its back on the road again.
 

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Put it back on , duh.

Well some folks don’t have the time nor inclination to piddle around keeping 40+ year old emissions technology working. Some of us didn’t have that amount of patience 30 years ago even!
Nothing wrong with being simple in this regard.
There are a lot of good running, no headaches, no emissions controls 70s and 80s vehicles out there. I’d hazard far more than those with emissions intact.
If one has the inclination to keep the factory systems all operational, great, good on them. But I have to give the nod to the simplicity of, well, simple.

That said what @SirRobyn0 said about the 305 being “different” seems to make sense to me and then it’s all about what the best or easiest path to success is.
In the meantime, I’ll continue enjoying our ‘86 with the simple approach.
Maybe even have time to tune the carb one of these years although I’m not convinced it needs any tuning.
 

SirRobyn0

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Well some folks don’t have the time nor inclination to piddle around keeping 40+ year old emissions technology working. Some of us didn’t have that amount of patience 30 years ago even!
Nothing wrong with being simple in this regard.
There are a lot of good running, no headaches, no emissions controls 70s and 80s vehicles out there. I’d hazard far more than those with emissions intact.
If one has the inclination to keep the factory systems all operational, great, good on them. But I have to give the nod to the simplicity of, well, simple.

That said what @SirRobyn0 said about the 305 being “different” seems to make sense to me and then it’s all about what the best or easiest path to success is.
In the meantime, I’ll continue enjoying our ‘86 with the simple approach.
Maybe even have time to tune the carb one of these years although I’m not convinced it needs any tuning.
Interesting to bring this up now. But ya, even for a guy like me who believes the 80's higher compression 305's really were build for the emissions and control devices to be in place. Sometimes you just can't have it all. These are 40 year old trucks and some stuff is out of production or very hard to get and work arounds must take place which is fine, but most work arounds are not going to perform like the factory intended and will have some side effects. Take me for instance, I'm running without my ESC because the PO took some pieces off that I'm having to source replacements for. In the mean time I've figured out a compromise with the timing to prevent ping, but still have some advance. But rest assured my work around is not as good as the factory ESC, but if better than nothing. IDK, these 305's behave differently to emission removal and changes than other GM engines both SBC & BBC I think.
 

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IDK, these 305's behave differently to emission removal and changes than other GM engines both SBC & BBC I think.
I recall you saying this in a previous post. And I don't know what or why that is, but teh crazy useless info I recall and never thought nothing of until now, is the number of GM (and ford) engines I recall owning or working on in the late 80s/early 90s that either had non functional emissions parts or removed altogether. Most vehicles in the upper midwest had the first round of stuff rust up or rust off inside of 10 years back then. So deleting stuff back then was already somewhat common. I really don't recall ditching all the junk, plugging vacuum lines up and maybe worst case throwing a vac advance distributor in them being a problem. EXCEPT 3 particular vehicles all GM trucks, all 80s squarebodys and all 305s. 2 were my dads, an 85 and then an 83 afterwards and 1 1982 that I was responsible for at work. I don't recall specific issues other than it seemed those trucks were harder to get to run right or had issues vs 350s and big blocks.
 

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I recall you saying this in a previous post. And I don't know what or why that is, but teh crazy useless info I recall and never thought nothing of until now, is the number of GM (and ford) engines I recall owning or working on in the late 80s/early 90s that either had non functional emissions parts or removed altogether. Most vehicles in the upper midwest had the first round of stuff rust up or rust off inside of 10 years back then. So deleting stuff back then was already somewhat common. I really don't recall ditching all the junk, plugging vacuum lines up and maybe worst case throwing a vac advance distributor in them being a problem. EXCEPT 3 particular vehicles all GM trucks, all 80s squarebodys and all 305s. 2 were my dads, an 85 and then an 83 afterwards and 1 1982 that I was responsible for at work. I don't recall specific issues other than it seemed those trucks were harder to get to run right or had issues vs 350s and big blocks.
I don't really know. Maybe it's the higher compression ratio, the cam they choose and maybe the bore and stroke? I honestly don't know why, I'm just speaking from what I've seen, when I say they are different and react different. People reason that they should behave like a 350, when desmogged or equipment changes are made because they are both SBC, but they just don't.

I think we can agree it's pretty much common knowledge that a lean mixture can spike cylinder temps and potential cause pinging, but I've run into 305's running rich that liked to ping. Makes no sense to me, but they are sensitive to having the right fuel and timing.
 

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I don't really know. Maybe it's the higher compression ratio, the cam they choose and maybe the bore and stroke? I honestly don't know why, I'm just speaking from what I've seen, when I say they are different and react different. People reason that they should behave like a 350, when desmogged or equipment changes are made because they are both SBC, but they just don't.

I think we can agree it's pretty much common knowledge that a lean mixture can spike cylinder temps and potential cause pinging, but I've run into 305's running rich that liked to ping. Makes no sense to me, but they are sensitive to having the right fuel and timing.
I'm pretty convinced its the cylinder head design combined with the huge quench area that you get with the factory piston setup. The old motor in my truck was a 350 block with small valve 305 heads and a comp cams 270h stick in it. It was a gutless wonder and pinged like crazy all the time. I had to get the timing just right to keep it from pinging and it still sucked. I didn't do any of that, it came that way and I didn't figure it out until the motor finally destroyed itself. The new motor with a small quench area(due to shaving .020" off the deck), 9:1 compression, and mildly ported 882 heads drives great and has zero detonation issues at all.
 

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I'm pretty convinced its the cylinder head design combined with the huge quench area that you get with the factory piston setup. The old motor in my truck was a 350 block with small valve 305 heads and a comp cams 270h stick in it. It was a gutless wonder and pinged like crazy all the time. I had to get the timing just right to keep it from pinging and it still sucked. I didn't do any of that, it came that way and I didn't figure it out until the motor finally destroyed itself. The new motor with a small quench area(due to shaving .020" off the deck), 9:1 compression, and mildly ported 882 heads drives great and has zero detonation issues at all.
I think that just might be it! Regardless it's not a really good design. I mean I think the 305 gets an overly bad rap it doesn't fully deserve. I've certainly seen them go the distance, but they have some unusual peculiarities for sure.
 

Bextreme04

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I think that just might be it! Regardless it's not a really good design. I mean I think the 305 gets an overly bad rap it doesn't fully deserve. I've certainly seen them go the distance, but they have some unusual peculiarities for sure.
You could always put some nice hot heads on yours and let us know if it makes it ping less ;)
 

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