ezera

Hello, I've lurked around on this forum years and its helped me a lot.

So heres the thing...

Drove my 92' Pickup 4x4 x-cab 3vze down to San Diego CA from Portland OR for Christmas and new years. The truck is completely stock except for 30x9.5r15 bfg ATs instead of 31s. 130k on the odo.

When filling up for gas or a food and bathroom break the engine would start up just fine but only idle at around 500rpm and would stumble/ sputter around and want to die. It would only do this when the engine was already warm. When it did this I could usually give it some gas and it then would idle fine. Shutting off and then restarting again would yield mixed results. No check engine indicator.

This doesn't happen everytime I start the engine when its warm.

Also, when I moved up to portland Jan 2013 with a lot of my stuff in the truck I got better gas mileage.

Some buddies and I we're thinking maybe an EGR problem or maybe vac lines.

Just wanted to hear if anyone has had any experience with this or had any pointers.
Thank-you!

94hiluxZE

I've got the same problem when I drive about 90 miles down to my dads house everything is fine but when I get there then try and drive it after its been parked for like 10 mins it idles really rough then dies or almost dies. If I give it gas it stays on and then idles normal. Im not super mechanical I can't figure it out.

kai32

I have this exact same issue with my 94, it also will smell heavily of gas when it does this. Just hopping on to see if anyone knows what this is.
My EGR, PAIR, and FPU vacuum lines were all mixed up and after putting them back into the correct places to get rid of the engine light the hot start issues starting happening.
Maybe something to do with the fuel pressure on a hot start?

Steve92yota

Had the same issues with my 22re, was my IACV (idle air control valve). Cleaned it out and ran better.

ezera

I think I'll try that this weekend. Looks like the IAC valve on the 3.0 is built into the throttle body. I hope removing that thottle body won't be too hard.

Edionne13

I would like to know the results my 3.slow does the same!

kai32

oh man, i just cleaned the TB when i was troubleshooting my EGR. hopefully i didnt mess that IACV up or something. id appreciate if you posted the results too!

Gamefreakgc

It's very difficult to clean it on the 3VZE, I've taken off the TB twice for various issues. I've just learned to live with it. Then again, with 285k I've learned to live with a lot.

There's no ill-effects of this one. If it bothers you that much, adjust your idle slightly higher to about 900 or 950 RPMs at idle and call it good.

Edionne13

That's a really good idea ill have to do that! Or would doing a few clicks to lean on the MAF have an effect to this?

Gamefreakgc

Doubt it, but you are changing the fuel supply by doing that so it might. I never adjusted the stock VAFM and never had too much of an issue. I've got a modded Supra one on right now and my idle is all over the place but I'm fine with that.


I just thought of something... if you removed the spoiler in front of the airbox it'll cause the issue you are describing. Once the engine's hot the heat saturates the engine bay while it sits off for 10 min, the engine sucks up hot air and will drop the idle. Just food for thought if you've change anything about your air intake from stock.

ezera

I've got one of those K&N clean and reuse air filters but i've been using it for a couple years now. The air intake is stock and not modded. When I was living in San Diego someone stole my catalytic converter. The OEM replacement california compliant cat is insanely expensive so I got a magnaflow CA compliant cat and welded that on; but that also was a couple years ago. Dunno if a bad cat would cause the symtoms i'm experiencing anyways.

Do I have to worry about air getting into the cooling system if i'm removing the throttle body and inspecting the IACV and the hoses going through it?

ezera

Alright. So I took off the throttle body today and gave it a good look over. When I detached the coolant lines going into the IACV a little bit of coolant spilled out. Hoses seemed unclogged. The whole TB didn't look too dirty and I took the cover off the IAC valve and that didn't look very dirty either. I cleaned the IACV and the throttle body with TB cleaner and I cleaned inside the plenum what I could reach. I didn't have the tool to completely disassemble the IACV so I got a pair of needle nose pliers and wrapped the end with a rag and pulled up on the IACV to make sure it wasnt stuck or anything and It moved just fine. Threw the new gasket on and reinstalled. At this point i'm doubting that the IACV is causing any issues. Mind you that I havent had the warm start trouble for a few weeks now. If I do have the warm start problems again I'm going to check out the EGR system. Next weekend i'm going to try and get a torch and check vacuum lines. At least I know now and had a good excuse to clean out the TB.

Before I took the TB out the truck would warm idle at around 800. After I put it back on and took it out for a test drive and got the truck up to warm operating temps the idle never went below 1k. I'm thinking I might have moved the idle screw accidently while cleaning the TB.

Before cleaning:





This summer the truck is gonna get some love. New OEM rotor and cap with spark plugs and wires for sure; maybe that will get my MPG back to 20 hwy.

TrailTrek2Fish

Hey guys,

I have the same idle issue. My engine is fully stock. When I'm in stop and go traffic, my idle drops to about 500rpms and the engine begins to stumble and surge. It behaves the same way on a hot start. If I don't rev the engine, the engine dies. But when I'm just putting' down the roadway or I stop every so often at lights and stop signs, the beast runs fine.

I thought it was the intake sucking in hot air built up under the hood in stop and go traffic but yeah, it wasn't.

I'd like your guys advice; PLEASE! I'm about a gas tank away from taking a sledge hammer to my engine. Well, not really, but yeah… Hahah!

Gevo

TrailTrek, what have you checked so far?

vacuum leaks
egr operation
and read the rest of this thread and search for others for many other things to check.

TrailTrek2Fish

Ooops, sorry 'bout that. I should've elaborated more. Prior to last night, I haven't really dug in there except for adjusting the idle screw on the TB. But in heavy stop and go traffic, that didn't even get me out of the woods. I still had to rev the engine to keep it from bonking out. Before diving deeper, I wanted to get more opinions based on the symptoms I provided. So…

Last night I cleaned out the EGR valve and the EGR modulator. The EGR modulator filter was understandably and obviously gunked up from years of usage. I replaced the filter with a small stack of gun bore patches that I cut down to size. It's just as breathable so I figured that I could try it out. The EGR itself was not visibly clogged up but I cleaned it out anyway with carb cleaner and manually actuated the valve with an awl to make sure it was still springy and not gunked shut. I'm gonna put him through his paces and see if any of those solved the problem.

If not, I'm planning on using an unlit propane tank to check for vacuum leaks. Then next down the line, I'll check the IAC by removing and cleaning the TB. I'll update you guys with my findings and/or photos of me busting my engine up with a sledge hammer. Hahaha!

Gamefreakgc

Your issue seems a bit different, since giving it gas doesn't return the idle to normal. I'm gonna say grab a multimeter and feeler gauge and test your Throttle Position Sensor on the back of the throttle body per the service manual specs:

http://personal.utulsa.edu/~nathan-b...93throttle.pdf

If it doesn't match up like it should, adjust it by loosening the screws and rotating the sensor (don't take it off unless you know how it goes back on!)

TrailTrek2Fish

Don't get me wrong boss. The idle speed did change when I adjusted the screw. It just wasn't enough in the HEAVY stop and go traffic. I'll check the TPS gap anyway.

Gamefreakgc

Yeah, adjusting the screw fixes most issues and has no ill affects so should be tried first. However, if you find your idle bounces around, there's something wrong. On a stock setup, the idle should stop at roughly 800-850 RPM every time. Idle it for a few min, still 800-850. Hot outside, still 800-850 rpm. Anything else means something's up and usually only gets worse until it threatens to stall the motor, like what yours is doing right now.

TrailTrek2Fish

So it wasn't the EGR or EGR Modulator. The journey continues…

Gamefreakgc

Have you checked the TPS? The TPS is responsible for putting the engine in "idle". If it is mis-aligned or not working, the engine will either enter "idle" too soon (when throttle is still open, causing power loss at lower RPM's) or too late (won't enter idle until very low RPMs, or never at all).

Seems like yours is not entering "idle", so the engine sputters and is all over the place when you come to a stop.