OldMan50

I have been working through issues with my 4Runner one thing at a time. Poor performance, no power when she is first started, then ok power when she warms up. I changed the fuel filter, spark plugs, air filter then today set timing to 10 advanced. She has never had any issues idling, but after taking her for a test drive after setting the timing she won’t idle. She dies when you take your foot off he gas. I even returned the timing to what it previously was set to, no idle.

I am have trouble understanding how changing the timing would affect the idle? She doesn’t run rough when running.

Any incite would be appreciated.

scope103

Welcome to YotaTech.

Did you follow the procedure for setting base timing? (jumper TE1 to E1)

Do you have the sticker under the hood? Different engines (and years) have different base settings, so the sticker is where to start.

Can you get it to "idle" (around 750-850 rpm) by opening the throttle? You may have the idle speed set wrong.

OldMan50

I did jumper Te1 to E1 as the vehicle information sticker shows when setting the timing. I don’t see where to adjust the idle, but it idled fine before setting the timing.

OldMan50

I can hold the gas pedal down to maintain idle physically, but as soon as I let go of the pedal it dies.

2ToyGuy

You set the idle speed, once it's warmed up, with the Idle Adjust Screw. It's a relatively small screw, located under a cover screw cap. It's located on the top of the Throttle Body, left hand side as you face it. Close beside air tube coming into the throttle body, right in front the butterfly valve. The cover screw is a rather large screw. Unscrew it, and down inside is the smaller Idle Adjust Screw.

After 30+ years, it's a good idea to look at the o-ring on the idle adjust screw. Screw it down till it bottoms out, not real tight, just snug. Count the turns it takes, including the partial turns. Then unscrew it all the way out. There should be a small o-ring very near the bottom, just above where it narrows down to the needle on it's bottom. Just at the bottom of it's threads.
The o-ring is readily available from many sources. Mostly in o-ring kits. Available in auto parts stores, some hardware stores, Harbor Freight, etc. Put a new o-ring onto the idle adjust screw, and put it back into the throttle body. I always put a thin layer of Vaseline, or silicon dielectric grease, on the o-ring. It makes them last a lot longer before they get brittle and fall apart. It also makes a better seal.
Check the air passages for any blockage. A short squirt of carb cleaner, or even brake cleaner, into each air passage makes sure they're clear.
Screw the Idle Adjust Screw all the way down, and then back it out to where it was when you started. It may not be right, but it should be somewhere close. Then, with the engine warmed up, you can adjust the idle speed to it's required value. Then set the timing to 5° BTDC, with T1 and E1 jumpered. Stop the engine, pull the jumper, and check the timing again. It should be 12°, approximately. It will change slightly with a large number of variables. Temperature, altitude, etc etc.

Does my rambling help at all?
Pat☺

OldMan50

Yes it did! Thank you for the info! I was adjusting the idle screw cover, lol.

I think I have other issues though. It stammers under 1000 RPMs and my check engine light is not working. I am going to fix the check engine light, then replace the wires, distributor cap and rotor, and set the timing/ adjust the idle. If all that fails and I don't have codes that help, I'm going after the fuel system.

I am finding the Haynes manual is almost useless. Anyone know what the fuel pressure should be?

2ToyGuy

About 38-45 without vacuum applied to the pressure regulator, 33-37 with vacuum applied. Measured at the cold start injector. According to the FSM.
Does that help? Remember, the pressure regulator is at the back end of the fuel rail. The device up front is a "pulsation damper", used to keep the fuel pressure in the rail constant, even though the fuel pump pulsates the pressure.

Remember, also, never, ever reuse a crush washer. They will leak. Any time you screw down onto one, even a little, replace it. It's a good idea to have several of every size you might need on hand before you start. You will invariably need more than you thought you would. Never fails.
Also, the crush washers are malicious. If you only have one left that you need to install, it will leap, yes LEAP, out of your hand, fall down through the engine all the way down, and vanish. Literally disappear. Your truck can be sitting on a clean section of cement flooring, you will hear it hit, and it won't be anywhere to be found once you go to look for it. Not only are they malicious, they're magic, as well. You've been warned!

The trouble you describe could be a few things. The o-ring on the idle adjust screw being bad, ie: brittle and/or broken up, a clogged air passage on either side of the IAS, a non-functional IACV, the rectangular device under the throttle body with the large air line up to right below the IAS. Often the spring that opens/closes the air passage with the coolant temp fails, and the air passage doesn't operate properly. Finally, a clogged vacuum line. Check and clean all the vacuum ports on the throttle body.
Almost forgot, the BVSV. Verify it's operating correctly. If you need, I can post the portion of the FSM that's applicable in PDF format for you.

Good luck to you!
Pat☺

OldMan50

I can't thank you enough! It is very much appreciated. I will update when I work through each possible issue this week.

OldMan50

If you don't mind post that portion of the FSM? I think I need the FSM and not the Haynes.

2ToyGuy

You can find the PDF for the EFI system attached to this post. I hope it's some small help...

Good fortune, and keep us up-to-date!
Pat☺

OldMan50

Thanks again for all the info! I replaced the spark plug wires, distributor cap and rotor and found a hole in the EGR box that connects to the air box. I plastic repaired that, adjusted the idle and she is all good now!

2ToyGuy

Glad it's all fixed!

Now, and this part is both mandatory, and absolutely essential: Go out and enjoy your truck
These trucks seem to do better the more they get driven, so get out there and make your truck happy

Tale care!
Pat☺