Idle Speed adjustment or is there more to it?

[Some1esle]

Ok, here's my problem, I'm sure someone else has had this... My truck model info in the sig.
I've done the grounding mod ( a bunch of 8 gage wire grounds from various pionts to the chassis. Then grounded the engine block, alt, neg post, and the coil/ignitor to the chassis with 01 gage welding cable/wire. I'm pretty sure that There is no grounding problem under the hood), I've replaced the oem air filter with the K&N. I've replaced the exhaust Y-pipe back with flowmaster cat, muffler, 2.25 in pipe between the cat and muff, then 3 inch tail pipe. I'm running two amps for my stereo, and a head until that has a built in amp. The amps are small and I don't think they are having a major draw. The stereo information is listed in the sig as well. I believe there may be a grounding problem with either (or all) the amps, or the head unit since at low volume I get a squeal or engine noise. This my be that the speaker wire is running along side the power, and RCA's for the amps...
Anyway, that is the information on mods done. Now to the real problem, The idle speed is about 500 rpms, and has stalled at a stop sign a couple times before. This is when the truck is warm, and with/without the A/C on.
Other symptoms include the lights dimming when the engine is at idle, then brighten up when the throttle is applied. the voltage gage is about 2/3rds to the top of the gage. measured at idle I show 13.7 volts. that's running with the battery disconnected measured pos ot neg, and connected to the battery measured touching the terminals, not he battery post. I never thought to measure across the posts. This is a relatively new problem like as developed over the last 1 - 1.5 months. the truck, with the exsiting mods, normally idled around 700 to 900, and would vary up and down between. now it's pretty steady at 500 - 600.
Now I may be thinking that a week battery may be the problem, other than that I don't know. Is my stereo to much for the alt, and has maybe drained/weakened it?
I hope I've just been though and not to confusing.
Thanks in advance...

 

[rustyrazor]

I'm not sure about the effects of the changes you made or what the stereo equipment would do but when I look at idle problems in general I have a few tricks that I like to try.

First check the timing, I would suggest using a timing light and setting the timing correctly. By doing this you can make sure that you get to the real root cause of the problem.

If you don't think that it's a big deal and just want it to idle higher you could loosen the bolt for the distributor and rotate it while the engine is running until the idle is where you want it.

Trick two. Usually if it's idling rough I'll throw in some new spark plugs. If your plug wires, cap and rotor are old you could change these too.

You already mentioned a new air filter and that would also be one of the things that I would check.

Tell me if any of these ideas help.

 

[854runner557]

There should be a idle screw on top of the throttle body. :biggrin2:

 

[Some1esle]

the plugs, wires, and cap are all toyota oem, about 5 months old.... not sure if that is the problem. They should last a lot longer than that. Also, should have memntioned has 203000 miles roughly, and new timing belt was at 162500.
Any chance that I've been running 87 octane.... I put some gumout fuel system cleaner in 3/4 tank to full bottle. It said that it treats up to 21 gallons. I did this yesterday, and with about 30 miles since it is idling aboiut 600 and pretty smooth. Should I be running higher octane... Possile that the 2200 mile highway trip two weeks ago dirtied it up?
I will probably scedule it for the toyota shop locally to make sure the timing is dead on...

not wanting to advance the timing, or anything like that... But my idle it up a hundred or so with the screw... BTW, which screw on the throttle body is that? I know stupid question, let the stupid answers roll, as long as one of them is the right answer...
Thanks in advance again.

 

[854runner557]

idle scerw

it is located on top of the throttle body, it is side ways facing u. It has toyota across the top of it.

 

[Some1esle]

Re: idle scerw

it is located on top of the throttle body, it is side ways facing u. It has toyota across the top of it.

Thanks. I'm pretty sure that the adjustment is just off.. I'll adjust it see what happens. then go from there.

 

[rustyrazor]

vaccuum advance

Since we're on the topic of idle speeds I'll tell you about a problem that I'm having.

My idle speed was a bit high after changing my timing chain and putting in new guides.

I pulled out the timing light and set the timing while it was idling. My timing was a little bit advanced so I adjusted it to "5 deg BTDC" like it said on my vehicle information lable.

The instructions tell you to race the engine a couple of times and then check the timing again so I did and low and behold the timing was advanced like crazy and the idle was up again.

So I checked out the users manual to see what this means and it says that I may have a leak in one of my vaccuum hoses.

I looks like I'll be setting the timing again after I find the vaccuum leak.

Here's where I have a question for all of you. An old "back yard mechanic" guy (my dad) told me a cheap way to check for vaccuum leaks.

This is how it goes:

Take a propane torch, like the one's you use for soldering copper pipes, and turn it on low without lighting it. Then run the tip of the torch along the vaccuum lines. If there's a leak the engine will rev up a bit.

I was wondering if this is something that I should try doing. I like my eyebrows the way they are right now, namely un-scorched, and I'm concerned about burning my truck to the ground.

Does anyone know a better way to check vaccuum hoses?

 

[4gone]

Re: vaccuum advance

Take a propane torch, like the one's you use for soldering copper pipes, and turn it on low without lighting it. Then run the tip of the torch along the vaccuum lines. If there's a leak the engine will rev up a bit.

I was wondering if this is something that I should try doing. I like my eyebrows the way they are right now, namely un-scorched, and I'm concerned about burning my truck to the ground.

Does anyone know a better way to check vaccuum hoses? [/B]

You can accompish the same result with WD40 or Carburetor cleaner Just spray the hoses where they connect and listen for increased idle.

I have a Vacuum gauge I use. It will also alert you to burned or sticking valves, fast or slow timing and improper air/fuel ratio on Carbureted engines.
Good luck

Arlen