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90 pickup 3VZE rough idle, rattling... air noise problem

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90 pickup 3VZE rough idle, rattling... air noise problem

Old 09-28-2015, 11:07 AM
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Question 90 pickup 3VZE rough idle, rattling... air noise problem

Hi

I have a 1990 Pickup SR5 Ext. Cab 4WD 3VZE.

I am trying to fix some of the power issues I have with my truck which I think may be related to my rough idle and rattling. I played with the idle screw a little bit but while I was able to bring it up from 500 to 800 after adjusting the screw, it does seem to go down after a while. That by itself kind of puzzles me. Note that I live at about 6000 ft in case that information is relevant XD.

Oh and I just replaced the spark plugs and wires yesterday which didn't help. I plan on adjusting timing next week.


A friend mentioned it could be a vacuum leak and found some nice diagrams and tuto's that will prove handy.


I wanted to ask you one question though, when I start the engine and idle I can definitely hear some air noise, which could be an air leak. The sound is coming from the under the dash, pedals area. I can't really hear it when I am driving because of the noise from the engine that's probably covering it.

After a quick look I don't think there is any vacuum line that is running remotely close to the area I am hearing the air noise. But I may be wrong.

Have you guys ever heard anything like I am describing?


Thanks
Steve





edit: Here's what's been done so far:

* 9/27/2015: Replaced spark plugs, checked gap
* 9/27/2015: Replaced spark plugs wires
* 9/28/2015: Played with idle screw. Affects RPM but still runs low when cold
* 10/03/2015: Adjusted timing back to stock (10 Degree) but it seems the truck is running worse that way
* 10/04/2015: Checked timing in diag. mode and normal op mode and I can't really see any difference, which doesn't seem normal to me
* 10/04/2015: Found a vacuum leak in the break booster (internal), found one at a junkyard and will replace it soon
* 10/04/2015: Couldn't take the ECT out (no socket deep enough) but checked the resistance it reads normal
* 10/11/2015: MAF sensor cleaned up and dead after reinstall, engine won't start. Start but stalls when MAF is unplugged
* 10/11/2015: No error code reported by the computer
* 10/18/2015: Reman MAF not received, old one still dead
* 10/18/2015: CSI is sprinkling when cold and trying to start the engine
* 10/25/2015: Reman MAF installed and works. Replaced Air Cleaner, old one had a hole in the bottom of it; probably reason of some of the problems
* 10/25/2015: Replaced the O2 sensor
* 10/25/2015: Vacuum gauge installed, measured 12 in.Hg with leaking brake booster installed
* 10/25/2015: Timing moved back to roughly 15-degree
* 10/30/2015: Replaced the ECT sensor
* 11/01/2015: Cleaned up the TB and checked the TPS
* 11/01/2015: Replaced the Brake Booster, and measured only 14 in.Hg
* 11/08/2015: Oil change. Replaced oil filter
* 11/14/2015: Replaced oil pressure sending unit
* 11/14/2015: Replaced the EGR valve
* 11/14/2015: Replaced most vacuum lines
* 11/15/2015: Replaced some parts of the intake
* 11/15/2015: Checked the ECT resistance on the ECU side (THW-E2) and it measured ok
* 11/22/2015: Cleaned up the TB and the IAC valve
* 11/22/2015: Replaced/readjusted the TPS
* 3/21/2016: Passed SMOG with flying colors
* 4/20/2016: Replaced CAT
* 5/14/2016: Cleaned injectors w/ Red Line SI-1

Planning on doing:
* replace broken TVV
* seafoam the vacuum system
* add CRC additive to gas to clean up the injection system
* add aftermarket gauges (oil, water, vacuum)

* Replace PCV valve
* Test the cylinder for compression



pic of the truck:

Last edited by zytra; 05-15-2016 at 07:01 PM.
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Old 10-03-2015, 11:18 AM
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Hi guys

I just adjusted timing. Found that it was a little past 15, and I brought it back to 10. Averaging of course as it oscillated a bit.

Made sure it was at normal temp and that idle was as close to 800-900 as I could.

Doing this, making sure it was hot enough before starting the process I learned something.

Cold start it was idling 500-600 tops.... Once warm tho idle was already up 1100 rpm so before I checked timing I turned the idle screw to get it to 800-900 or so. Then did timing. Bringing it from 15 to 10 also brought the rpm down a little but not much. I'll check the rpm on a cold start tomorrow but I think I must have some temperature gauge problem somewhere.

I bought a new ECT and just realized it's gonna be a pain to replace. Maybe I'll measure the resistance at cold tomortow before I take it out.

What do you think?
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Old 10-04-2015, 04:24 PM
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Ok, some progress but getting even more puzzled at this point :/

This morning I took the hood off to access the ECT. Not sure if the wire was already damaged or not but after pulling the connector off I found that one wire was broken. I fixed it with some high temperature wires soldered in place, heat shrink. Clean enough. I measured the ECT and it checked out (same value as the replacement I bought). I didn't have a socket deep enough to clear the plastic housing on the connector so I did not replace it. Reinstalled the wiring. Cold started the engine and it was as low as usual... 500-600 rpm. So either the wiring's got some problem further down, or I maybe it's something that's causing this low rpm issue.

I took her on a short test drive and it felt pretty good going downhill, however the way back was a real nightmare. I had to go into first where I usually climb up fine in second. And even in first I had to clutch it out - it really felt under-powered more than ever. Part of the reason why I am digging into this is that I think I should have more power. Well whatever I did made it even worse.

I was able to make it home, checked timing again and although the distributor was solid, I read something close to 15 again. I checked it with both E1/TE1 jumper in and without jumper and pretty much the same value in both cases...

I was tempted to move it back to wherever it was but with these readings different from my last adjustment I wasn't sure what to set it to.

The only other I could think of would be the spark plugs. When I did them, I found the original ones to be all in the .038-.040"... while the new ones were all .032" out of the box. And I got brand new wires as well...


Maybe the only "good news" is that I finally found a vacuum leak! I told a friend the symptoms (air noise in the cabin, but the noise would go away from I hit the brake and also slightly increasing the engine RPM (from the sound of it). That friend then told me to take the vacuum line off the brake booster, to plug it and to run the engine. I did that and the air noise I could hear from the cabin was gone! So... that booster must have some internal leak I suppose (spraying the booster with carb cleaner didn't show any leak). My friend is gonna look for a new booster at the junkyard and we'll go from there. But I got that noise since day 1 (over a year ago) so I don't think my newest power issues are related to that, especially after playing with plugs/timing).


conclusions: adjusting timing made it worse (unless it's something else I did but what? Plugs? I don't think so). And I found a vacuum leak on the booster.

Not the best day I tell you that haha.

if someone's got any advise I'm all hears!

Last edited by zytra; 10-04-2015 at 04:33 PM.
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Old 10-04-2015, 07:25 PM
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Okay I am no pro but I have messed around a little bit with my 2 3vze's. Had the same issue with a low idle and turn it up then drop again. I also had a warm up bog that just lasted for about 10-15 seconds when driving off a cold start. Anywho I changed the o2 sensor and it fixed my bog and also fixed the dropping idle problem as well. Just throwing it out their for you to test the waters. Good luck bud
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Old 10-04-2015, 07:43 PM
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Thanks man
I picked up an O2 sensor which I still need to install! I'll let you know if that fixes it!
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Old 10-05-2015, 04:14 PM
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I also looked at some pages showing how to pull out trouble codes from the ECU so I will do that maybe that'll put me in the right direction. Also picked up a vacuum gauge, tubing and Tee connector to get some readings and possibly this will help doing some troubleshooting based on the gauge behavior. And I will also clean up the MAF...

http://www.troublecodes.net/toyota/t...up-or-4runner/
http://www.imperialclub.com/Repair/F...auge/index.htm
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Old 10-09-2015, 11:38 AM
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Any idea what's a good spot to connect my vacuum gauge?
I suspect any of these 1/8" ID tubing would do? picking it up with a T connector..
but if there's a better way let me know
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Old 10-10-2015, 08:27 PM
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Hey guys

note getting much love here hehe hopefully it'll pick up

I've edited the first post with what I've done so far and what I plan on doing in the next few days.


Today I picked up a brake booster at the junkyard, will vacuum it tomorrow to see if it holds before I try to install it in.

I need to find the part numbers for:
- gasket that seals master cylinder to brake booster
- o-ring that's on the master cylinder


Any chance would know where I could find these toyota P/N? I'll call the dealer if not.
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Old 10-11-2015, 08:02 PM
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Today I had planned on cleaning my MAF sensor and then on readjusting timing back to ~ 15 where it was before I brought it back to 10/stock.

So I cleaned the MAF sensor up thoroughly with MAF sensor cleaner and went onto reinstalling it. And then impossible to start the engine. Hard to say if it's my last week's timing of 10-degree that didn't like the cold start (it was adjusted as usual at normal op temps), or if it's the MAF (I may have killed it while cleaning it? though I was being careful). Anyway, unplugged the MAF sensor and the engine starts before quickly into a stall. Plug it back in, nada. Did that a few times. Same results.

So ordering a new MAF sensor now.

edit: oh and I checked for CEL and none. I was expecting to see 2-3 codes, and not a single one.

Last edited by zytra; 10-11-2015 at 08:09 PM.
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Old 10-12-2015, 09:02 AM
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When cleaning the MAF, did you use spray that was specifically made to clean it or something else? Also when cleaning, especially if its the original, all you need to do is unplug it and take the intake off, nothing more then spay some MAF specific cleaner through it then let it dry.

The replacement your getting is it Denso or after market? Some users here have posted saying that after market MAFs don't work as well as OEM ones.
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Old 10-12-2015, 09:14 AM
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Hey,

I was going to grab this one:
http://www.partsgeek.com/17z9kq9-toy...ir+Flow+Sensor

it's a bit cheaper than others but yeah I don't think I want something that doesn't work right.

As for my "dead" one I took the air filter off and the MAF sensor with the first duct (it was easier to take disconnect the duct on the engine side rather than the MAF side), the connector was of course disconnected. I used MAF sensor cleaner bought at oreilly. Sprayed the electrode thoroughly and let it sit for a while before remounting it all. I couldn't see the inside but I was concerned that some cleaner got to the internal wiring and shorted something, I don't know. Not sure if a short there would cause some problem or just some intermittent acting (if so maybe drying over night would solve the problem, I don't know).

I'll post a picture shortly.
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Old 10-12-2015, 09:16 AM
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Old 10-12-2015, 09:19 AM
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FYI pics were taken before cleaning.

I also noticed that one of the hose (you can see it on the first pic behind the MAF sensor) was not clamped and came out very easily, so that could have contributed to some non-metered air going into the engine, I'm not sure.

Also, my air cleaner assembly (black box sitting next to the MAF/Air filter) was kind of loose, never noticed that but it was held with some zip ties through a hole into the plastic housing of the cleaner. The plastic bracket that bolts onto the metal brackets and MAF was broken, so I think I'm gonna pick up a new one as well.
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Old 10-12-2015, 09:23 AM
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It is possible something got shorted or just gave out. Also a reman might not be bad as it should be just a rebuild of your denso one. Is your pickup a 4 wheel drive, SR5 and standard or extended cab?

Last edited by Janos01; 10-12-2015 at 09:25 AM.
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Old 10-12-2015, 09:27 AM
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it's a 90 4WD, SR5 ext. cab
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Old 10-12-2015, 09:35 AM
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Originally Posted by zytra View Post
it's a 90 4WD, SR5 ext. cab
Thanks for that. Tried to see if Denso themselves carried the MAF still but no luck. I would go ahead and get that reman one you post the link for. As it is rebulit, it should be fine as it is/was a denso.
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Old 10-12-2015, 09:49 AM
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thanks a lot, I will do that today, hopefully it'll get there before the week-end!
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Old 10-15-2015, 02:52 PM
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looks like I won't have the MAF before monday :/
but I'm still going to give it another shot, who knows maybe some MAF Cleaner wasn't dry and was shorting some of the wiring. If I can start the engine and play again with timing I'd be happy!
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Old 10-19-2015, 11:40 AM
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Reman MAF just got here today.
Still tried the original one yesterday and same result so it really died it wasn't that it was still wet or something. Or maybe I killed it by replugging it before it was completely dry. Hopefully I didn't damage the computer.
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Old 10-25-2015, 06:17 PM
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Hey guys,

Here's a nice update.

* Received reman MAF, replaced the dead one. I had picked up a new Air Cleaner (I didn't like how mine had a zip ties to hold it in place). Turns out, my air cleaner had a huge hole in the bottom which I didn't know about. So I am really glad I had bought a replacement! After installing everything, the engine started right up! The engine seems to be running a little higher (700-800) on idle which is nice, however once warm it would idle at about 1000 rpm... And that's with the idle screw closed all the way.

I have finally found a 19mm socket deep enough to replace the ECT so I will do that next week-end, maybe mine is gunked or something (I already checked the resistant and it reads the same as the new one I bought).

* Once warmed up I readjusted timing back to 15 degree in diag mode which seems to be running better than at 10 degree... I checked it outside of diag mode and it read the same.

* I installed a vacuum gauge (with my leaking brake booster still not replaced) and read about 12 in.Hg which is tad low. However, no weird oscillations I could see.

* I also replaced my O2 sensor.


Wish I had some time to test it a little longer but it still seems I made some progress today. The engine seemed to run better just from the sound of it.

I have to smog it within a couple weeks so hopefully I am close.


Next week I need to take care of the ECT, and inspect/replace the TPS.
If I have time I'll install those VDO gauges I picked up (oil pressure, water temp, vacuum and voltage - my stock oil pressure gauge is dead, water temp is hit or miss...).




hole on the air cleaner unit as seen from the bottom... I didn't know about this one!!




new air cleaner and reman MAF installed




~ 12 in.Hg of vacuum (idle). that's with my leaking brake booster installed..






that's the O2 sensor I took off the truck
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