95' 4runner 3VZE Myriad of problems

[Telepresence]

95' 4runner 3VZE Myriad of problems (SOLVED)

Before I start I have already searched the forums for the issues that are currently plauging my vehicle.

So lets start with the simple things first, I recently replaced the distributor, TPS, and the Oxygen sensor. Before I replaced the oxygen sensor the idle was up around 2000 - 2200 rpm. The new O2 sensor brought it down to 1200-1600 rpm. And the Old O2 sensor tested out bad when it was up to temp, So I know that fix worked good.

A few months ago I was trying to troubleshoot the rough idle of my 3VZE and noticed that the distributor was loose, the old cap's o-ring was dried out and had let some water in and rusted out the bearing. I replaced the entire distributor reset the ECU and retimed the engine. I really noticed the rough idle and it was very hard to set the base timing , I still cant set it to 15 degrees , it just keeps jumping around. There has always been throttle hesitation but the new distributor has made it even worse.

Now onto the TPS, The old unit tested out bad, which is what I thought was the problem with my trottle hesitation. Sometimes I press the gas and it took up to a full second for the engine to rev up or even react. I bought a new unit and installed it and calibrated it. but still the hesitant trottle persists and another thing to add occasionally it hunts for RPM between 1200 - 1600 RPM. and when in gear (5 speed manual) at low RPMs 900-1100 it gets jerky when I let off the throttle and let it idle down the road, and it starts hunting for RPM when in gear as well which makes it very hard and annoying to drive.

There are also some engine codes that I need to post but at the time of writing it is too late to go out to the garage and check the ECU for stored codes.

ANY help or speculation to what is causing these issues is very much appreciated, I'm tired of throwing parts at it and taking stabs in the dark. I'm at my whits end with this engine, I love the truck, but the engine had driven me bonkers and I plan to do a swap but for now I want to make it drive good.

 

[bearcat90]

Yeah, get the codes. Have you checked for vacuum leaks, spark plugs and compression? If it isn't one of those, possible the fuel injectors.

 

[Telepresence]

yes I have checked for vacuum leaks and found none, that was a few months ago though so it might be worth re-checking. Its got good compression and the spark plugs are new because I did the traditional 70K mile head gasket rebuild on it already ( that was 70K miles overdue). I replaced and regapped the spark plugs as well. and when I rebuild the engine 5000 miles ago the injectors tested out fine but they could also be plugged, but would that cause hesitation when I hit the throttle of over a second? it seems like it would be something on the sensor/electrical side of the engine.

When the engine is idling there is a slight misfire but the moment it gets up above 1200 it runs great, aside from the hesitation/ jerking issues forementioned.

Could the timing belt have skipped a cog on one of the cams as well?

 

[Telepresence]

I was just looking at some photos of the trottle body on a 3vze and was wondering, would a cap missing from the dashpot filter make any difference in throttle response, because it looks like the cap restricts air flow a little bit.

my dashpot filter has been missing the cap since I bought the truck but I thought nothing of it until now.

 

[Telepresence]

OK so I found the source of the jerkyness while idling in gear and the slow throttle response, and like you said Bearcat, it was a vacuum problem. The hose goes from the power steering pump directly onto the passenger side of the intake.

so this is what that hose fixed in a nutshell:

• Slow throttle response
• jerkyness while idling down the road in gear
• Allowed me to set the base timing easily

And the problems that still persist are as follows

• Exhaust smells rich
• There is still a slightly rough idle
• Engine is hunting for RPM between 1100RPM and 1500RPM
• When at speed in ANY gear if the gas is let off the engine drops about 100-200 RPM and slows the Truck down slightly in a jerking motion, this happens every time the throttle is let off so it is extremely annoying but not as bad as before the vacuum leak was fixed.

and the only code that the ECU had stored when I checked was for the speed sensor which has been neglected for a while now. My theory for the fix to the problems is that the TPS is out of adjustment or I got A bad unit from the store.

its always good to come out of the garage having fixed something though. That is the thing with me and this truck, alot of the times I never get anything fixed on it and it turns into a multi day/weekend ordeal.

none the less I still love the hell outta my 4runner.

 

[bearcat90]

What you pictured is the hose to boost the idle speed as to not lose giddy up at low RPMs while you're turning and the power steering system is under load.

Did you try to reset the timing after reattaching the hose? Does the idle speed and quality change after the engine has warmed up or is it consistent?

From the troubleshooting guide, it looks like throttle position and volume air flow meter are the computerized things to look at, while fuel delivery could also be a culprit. Since you're running rich, it's unlikely the pump is giving too much fuel, rather you're probably not getting enough air, causing the hesitation and poor idle.

 

[Telepresence]

OK, starting with the Idle speeds you are asking for.

After the engine was started at roughly 40 F it initially idled at 1725 and then went up to 2000 within a few seconds. Then it started to hunt for RPM between 1700 and 2000 before it was up to temperature.

I let it get up to temperature and it was still hunting for idle in between 1500 and 1700 this time. It was running ever so slightly rough but not more than it was when I bought the truck. Now that the vacuum leak is fixed it is no longer running rich and without getting input from the O2 sensor I cannot tell if it is running at the proper ratio but it smells normal again. The truck has also had a catalytic converter installed within the last year before the problems cropped up.

When I was backing it down the driveway to pull into the garage I noticed when I pressed the brakes the RPM dipped and was still hunting for RPM but this time between 1250 and 1500.

I proceeded to take the throttle body off to make it easier to test the TPS, I also sprayed out the vacuum ports and the intake with parts cleaner and compressed air to make sure there was nothing clogging any of the passages. When I was testing the TPS the only OHM measurement that would show up was between pins IDL and E2 and it was 12MEGA OHMS, nothing else would produce a reading even with the feeler guages in, I took the TPS off just to make sure and rotated it by hand to see if I could get any values to show up on my meter. I even switched to a different meter to check that it wasnt the meter. Still nothing showed up on the screen except for the previous reading of 12M Ohms. this TPS was new when installed and tested out fine when I installed it.

Tuned using this guide : Toyota 22RE Throttle Position Sensor

Although this is the second one that I had purchased because the first one was DOA and I returned it. So I went to another parts store and purchased a Duralast brand TPS which is the one currently in there. And now its Dead as well within only 3 months of putting it into the truck. And since I cant return it I decided to get a cheap unit from rock auto to see if the third time is the charm.

Sometimes I just hate the computer/sensors in this thing and i just want to swap in a carbureted chevy V6.:smashputer:

 

[Telepresence]

SOLVED

OK so I did a whole load of searching around and decided to troubleshoot the Auxiliary Air Valve. I followed this thread: Disable Auxiliary Air Valve? - Page 2 - YotaTech Forums

That brought the idle on startup back down to 1000, and after warmup it was around 900RPM and there was no more hunting for idle. The TPS is still in the mail and once I get it put in that is the last thing im going to be doing to this engine

Since I have plans to swap in the 3.4 and I dont really care about this POS engine I just plugged the hole with RTV silicone to put a bandaid on the problem until I can swap a new engine in.

Thanks for the help. and I hope this helps someone in the future :biggrin1:

 

[Griff007]

3VZE Issues

Well, i've also done my fair share of research and digging into the forums and while I have been able to fix a few issues, there is just one issues I am currently struggling with and it sounds very similar to your.

1994 4Runner, 4x4, 3.0, 187,000 miles, bought from original owner in Las Vegas, NV

Items already replaced:
EGR valve/vacuum modulator
fuel pump
fuel press reg
TPS
MAF
coolant temp sensor
nearly all vacuum lines (also rerouted according to FSM/forums/haynes manual)

**note** I also plugged that same AAV hole, but without success. In fact, the idle became worse and the truck ran like crap.

issue:
RPM hunts at 1800 and bounces between 1500-1800. If you give it more gas while it does this it jumps to 2500-3000 rpm. It does not and will not sit anywhere in-between this range (1800-3000 rpm). However... and for me this was the kicker, it runs and idles like a champ when it is cold. In other words, it only does this hunting (assuming this is the right term) while at operating temp.

It idles between 800-900 rpm without any issues at all. It drives down the road with no issues, although there is a slight hesitation when accelerating from a stop (as if it needs to kick down to another gear).

I am going to try to attach a video to help.

Any advice or help would be great! Thanks!

 

[Griff007]

Video of issue

https://www.youtube.com/watch?v=BW3MCcL1WxU&feature=youtu.be

https://youtu.be/9zChu6jrZpU

The second video is while the engine in cold and the rmps and truck seem to run like a champ.

 

[bearcat90]

[MENTION=150481]Griff007[/MENTION] Did you replace all the little vacuum hoses or did you check for vacuum leaks? Some other solutions I found for the surging idle pointed to vacuum leaks relating to the brake booster, one even from a leak around the idle speed screw. That was fixed with teflon tape.

 

[Griff007]

[MENTION=150481]Griff007[/MENTION] Did you replace all the little vacuum hoses or did you check for vacuum leaks? Some other solutions I found for the surging idle pointed to vacuum leaks relating to the brake booster, one even from a leak around the idle speed screw. That was fixed with teflon tape.

I checked for leaks before replacing the leaky ones and then replaced the ones that were dry or looked like they needed replacing. One of the lines I replaced was to the brake booster, but i only replaced the leaking portion, not the other portion of the line. I will look around the idle speed screw next. Thanks for the reply.