Extremely High Idle...

[LuvNLife]

You've got multiple issues here, but none are a deal breaker. First, download these:

http://www.edelbrock.com/automotive/misc/tech-center/install/1000/1406.pdf

http://www.edelbrock.com/automotive/misc/tech-center/install/1000/1404_manual.pdf

You mentioned the electric fuel pump firing up. I can't see your entire engine bay, but Edelbrocks really don't like any more than 5-5.5 pounds of fuel pressure, so you may need a fuel pressure regulator to step down the pressure - just don't buy the crap plastic Mr. Gasket one.

When you started it after 2 days and the idle went high, well, this is supposed to happen - it's the electric choke doing it's job. If the choke idle is too high, read the manual and it'll show you how to back it down; simple adjustment.

One other carb related thing. Look at the diagram in the manual, and you'll see 2 vacuum ports - one timed (or ported), one full. You want the distributor vacuum advance hooked to the full vacuum port.

Timing. Assuming the 350 is a relatively stock or mildly built, 4 degrees is way too little. With the vacuum advance disconnected and plugged, set the timing to 12 degrees, lock down the distributor and reconnect the vacuum; that's a very safe number. After doing this, you may need to adjust both the idle RPM and the air and fuel idle mixture on the carb. Again, in the manual it's a very simple process, but you need to be gentle seating both the air and fuel needles all the way in before backing them out.

If you still have audible detonation at 3K after the timing adjustment, I believe you've got an issue with your distributor.

jerry

 

[Ashton84W]

You've got multiple issues here, but none are a deal breaker. First, download these:

http://www.edelbrock.com/automotive/misc/tech-center/install/1000/1406.pdf

http://www.edelbrock.com/automotive/misc/tech-center/install/1000/1404_manual.pdf

You mentioned the electric fuel pump firing up. I can't see your entire engine bay, but Edelbrocks really don't like any more than 5-5.5 pounds of fuel pressure, so you may need a fuel pressure regulator to step down the pressure - just don't buy the crap plastic Mr. Gasket one.

When you started it after 2 days and the idle went high, well, this is supposed to happen - it's the electric choke doing it's job. If the choke idle is too high, read the manual and it'll show you how to back it down; simple adjustment.

One other carb related thing. Look at the diagram in the manual, and you'll see 2 vacuum ports - one timed (or ported), one full. You want the distributor vacuum advance hooked to the full vacuum port.

Timing. Assuming the 350 is a relatively stock or mildly built, 4 degrees is way too little. With the vacuum advance disconnected and plugged, set the timing to 12 degrees, lock down the distributor and reconnect the vacuum; that's a very safe number. After doing this, you may need to adjust both the idle RPM and the air and fuel idle mixture on the carb. Again, in the manual it's a very simple process, but you need to be gentle seating both the air and fuel needles all the way in before backing them out.

If you still have audible detonation at 3K after the timing adjustment, I believe you've got an issue with your distributor.

jerry

Holy crap! Wow honestly never would have thought of that! Start simple and work your way up. So on my old K10, I had the same exact carb but it was disconnected electric choke wise. Simply put it was wired open so it made it a pain to start at times. Haven't really delt much with the electric choke as I'd rather do it myself. Never in a million years would it have crossed my mind that the choke may need to be adjusted to compensate for proper idle. That's the first thing I'm looking at thank you! Just goes to show my inexperience!

I'll see what's up with fuel pressure closely. My plan is to get gauges for just about everything there is as I want to k ow everything that is going on. I see what you mean also with the ported vacume and the full vacume. I'm assuming the full vacume kinda does a bypass on emissions and kinda sorta gives off a small change in vacume for the timing? I'm currently hooked to ported so I'll change that up.

Now I got my timing from the sheet under the hood in the engine bay just before the fan shroud. I specifically asked if it would be different between a 305 and 350 as that's what originally came in the truck. I also asked if it would differ any on a mildly built engine as I did not know. Obviously I was misinformed. Now is it 12 BTC or ATC? I seem to remember most street engines do not run on one of them but cannot remember exactly. Adjusting the carb I'd be slightly apprehensive about but should it be needed I'll find a way.

Once more thank you oh so very much! Good to know that there are SOME knowledgable people out there as most of the guys are on this sight!

 

[Ashton84W]

Also another update, took the truck to a shop with someone slightly more knowledgeable than me
What has been discovered is that the valves need to be majorly adjusted. I was told that they needed to be from the previous owner but apperently these were horrendous! One side was to tight and the other way to loose. So loose apperently that one of the rods was becoming stagnant and basically not moving? if I remember him saying so correctly. The mechanic seems to be pretty trustworthy and knows his stuff so I'll take his word on it. Should be getting the truck back tomorrow. If everything is running top notch and all is buttoned up, I'll keep the truck. Let's hope this issue is solved and not just bandaged. Keep ya updated and I'll make sure to do the test y'all had recommended for sure. On a side note, here's some pics of my old K10...

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[78C10BigTen]

Holy crap! Wow honestly never would have thought of that! Start simple and work your way up. So on my old K10, I had the same exact carb but it was disconnected electric choke wise. Simply put it was wired open so it made it a pain to start at times. Haven't really delt much with the electric choke as I'd rather do it myself. Never in a million years would it have crossed my mind that the choke may need to be adjusted to compensate for proper idle. That's the first thing I'm looking at thank you! Just goes to show my inexperience!

I'll see what's up with fuel pressure closely. My plan is to get gauges for just about everything there is as I want to k ow everything that is going on. I see what you mean also with the ported vacume and the full vacume. I'm assuming the full vacume kinda does a bypass on emissions and kinda sorta gives off a small change in vacume for the timing? I'm currently hooked to ported so I'll change that up.

Now I got my timing from the sheet under the hood in the engine bay just before the fan shroud. I specifically asked if it would be different between a 305 and 350 as that's what originally came in the truck. I also asked if it would differ any on a mildly built engine as I did not know. Obviously I was misinformed. Now is it 12 BTC or ATC? I seem to remember most street engines do not run on one of them but cannot remember exactly. Adjusting the carb I'd be slightly apprehensive about but should it be needed I'll find a way.

Once more thank you oh so very much! Good to know that there are SOME knowledgable people out there as most of the guys are on this sight!

If you have your electric choke hooked up make sure you leave the air cleaner on when you adjust it. Sounds dumb but makes a difference. I had a hell of a time with mine keepin it running and idling, it was a combo of dirty carb and out of adjustment choke. I would pull the air cleaner and adjust it and put it back on and it would always change how it ran. Took alotta frustration and swearin but i finally got it.

 

[LuvNLife]

Now is it 12 BTC or ATC?

It's before TDC...

Good find by the mechanic on your rockers being adjusted too tight (and loose). He was probably referring to one of the pushrods being so tight, it wouldn't spin freely like they all should. Sounds like you're heading in the right direction!

 

[Ashton84W]

It's before TDC...

Good find by the mechanic on your rockers being adjusted too tight (and loose). He was probably referring to one of the pushrods being so tight, it wouldn't spin freely like they all should. Sounds like you're heading in the right direction!

It's like day and night. Got the truck back today and wow, the adjustments done by him made a complete difference. Cost me $150.00 but was worth it as it needed to be done. Fixed a couple other small things also. Defiantly a good find.

 

[1987 GMC Jimmy]

That's a good price! Glad you got it fixed. Does this mean you're keeping it?

 

[Ashton84W]

Alrighty so I've found the issue which is amazingly so simple I completely looked over it. The high idle of course was caused by the electric choke which I am not to familiar with and therefore didn't think of it. I was thinking along the lines of a vacume leak or incorrect timing. The issue with that was that the choke was being the RPMs up to 2,500 at first start. Way higher than what is needed and wanted for it to warm up. Thanks to @LuvNLife i figured out the way to solve this also. I would have done it myself but when mentioned to my mechanic he said hell do it for free in the morning if I can leave it again overnight. He will adjust it toMorris on a cold start for me. After that she should be ready to rock and roll again. I'd post a vid of the start up but I do t think the website will let me. I'll let ya know how it goes tomorrow. Here's some pics I took of the engine bay also.

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Anybody know the reason as to why there are two batteries? There isn't a radio or system in there- not to say that there hasn't been one before. I thought only the diesels came factory with two batteries? Somebody put one extra on there somewhere along the lines?

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Pretty clean I'd say so myself...

 

[Ashton84W]

That's a good price! Glad you got it fixed. Does this mean you're keeping it?

I'll let ya know tomorrow. If so then it still needs a lot of work as the front leaf springs are kinda facing the wrong way:-0 suspension needs some love overall and interior will get redone along with some body work and paint. Also needs the left tank in and eventually some good jamin tunes. Unfortantly I just got a speeding ticket today for rocking out a little to hard so I may have to hold myself back on that one

 

[Ashton84W]

That's a good price! Glad you got it fixed. Does this mean you're keeping it?

Keeping it for now. Thanks for all the help guys. I'll be back in sure with more questions later on!

 

[Snoots]

Sounds like you're on your way!
Too bad about the ticket. Never had one myself. Well, no more than 12. I think. I lost count.
Nice lookin' ride you have there. I don't blame you for keeping it.