erratic rough idle - p/s leak & noise - sensors

[beubanks]

Hi, I've lumped a few things together.. what seem to be the remaining problems in my 87 2WD Automatic...

main problem:

erratic rough idle.....or an intermittent random misfire (as my mechanic friend who's been working on this van put it)
the EGR valve doesn't seem to be leaking, and this only happens at idle.. speed or load don't effect it.... one thought is that it's the fuel injector...maybe there is a clog? Any thoughts?

second issue:
have installed new rack and new power steering pump, but the pump continues to make a sort of harmonic whiney sound, especially when cold... and, when the steering is turned all the way left or right, fluid leaks out and burns off, but I can't see from where. the hose from the res to the pump is new, but I"m not sure my friend replaced the others (but also didn't mention they needed it)... there is also a slow leak when the van is stopped... seems to be collecting on the hose next to the coolant outtake hose and then spreading from there to the frame so it's hard to trace. The pump itself has no visible or touchable fluid leaks... and works fine...

third issue:
most of the sensors on the radiator cap are missing or broken, where can I find these? I pulled a few off a camry at a junk yard that looked workable, but haven't tried them yet as i'm a little hesitant to pry off the old ones. The temp sensor works, but the other 2 (or 3, as it seems like there are 4 in total) are not connected or not there...
I'm thinking this could also be a source of the first issue...particurlay the vacuum sensor/hoses which are non-existant...

Please let me know if photos or even a sound recording might help any of you consider this stuff.

To be clear, the van runs/drives really well, have put about 4k on it since I bought it in NC in January, and i've taken quite a few trips around the Northeast with no problems. It also just idled around manhattan traffic in 100 degree weather all day yesterday with no real problems. Planning a cross country trip in august and I'd feel better about it with the above resolved or understood..


thanks

[timsrv]

I'd start out by checking codes. This may not help but it's always a good thing to do when tracking a problem. To learn how to read codes CLICK HERE

Random misfires are usually caused by a vacuum leak. Check the rubber hose that goes from the back of the intake manifold to the metal line on the firewall. Make sure it doesn't have any cracks.



Also check your air tube. They tend to tear near the throttle body end and on the back-side (where it's hard to see). To check for this start the van and while it's idling grab the tube and squeeze it. If the van stumbles or stalls then the tube is leaking air. A leaking air tube will make the van run bad because the air flow meter needs to monitor ALL the intake air to function correctly.

Here's a picture of a really bad air tube:



Even one that's just barely cracked will make the van run bad......especially when in gear at low RPM or at an idle. This is because the engine torques to the side when it's in gear.........and this sideways torque makes the crack open bigger.

The power steering noise could be a plugged up filter in the reservoir. HERE'S a thread that explains it.

A bad ECU temp sensor will make the van run like total crap, here is a picture of it's location:



I'm guessing that's not it because the description "random misfire" is a bit too mild to describe a bad temp sensor . If it's bad you should pick-up an associated trouble code when it's in the diagnostic mode. There is also an ohm test you can do that's outlined in the FI section of the service manual (just to rule it out). The other sensors on the filler neck won't make it run bad. Not sure if Camry stuff is compatible. I guess if it fits and tests within van specs then you could probably use it. Tim

[beubanks]

Thanks so much for these details. I'm going to dig in and I'll check back with results. So it's okay to try some sensors out if they look the same? no harm done......?

[timsrv]

So it's okay to try some sensors out if they look the same? no harm done......?

Sure, but I'd at least check them with an ohm meter 1st. The on-line manual gives values for the sensors. I'd want to know they're in the range before wasting time with them. Tim

[Deesh]

Ah ha! My rough idling is because of a cracked air tube, exactly like in the photo. Stoked to have finally gotten to the bottom of this!

[timsrv]

Yeah, these air tubes have been responsible for many rough idle/hesitation problems. This was the 1st real head scratcher I had with my van (the 2nd was a bad injector connector). I fussed around with it for months before I found the cracked air tube . Of course that was before the van forums were around. Glad we're here now . Tim

[Deesh]

Decided to see how long a mended air hose will hold up, at least until I order a new one from Toyota. Here's what I did (I'll update after some heavy driving to let y'all know how well it holds up).

1. removed the air hose, located and cleaned the cracks.
2. glued the cracks closed with JB WELD Plasticweld 2 part epoxy
3. after the epoxy was cured I wrapped the cracked and suspect joints with high heat "insulating and sealing wrap" tape
4. popped it back in.

I started the van and my rough idle is gone even when fussing wit the air hose, earlier if I touched it at all I the van would immediately shutter and almost stall.

Here are some photos...


supplies


here is the main crack

wrapped this missing chunk with tape upon reinserting it, seems to be airtight...


here is the piece after applying epoxy and tape (kind of did this in the dark, just noticed it's a little sloppier than it could be)

all put back together

I'll update with the longevity of this fix, I could see it working out for quite a while but who knows


This forum is saving me one headache at a time, thanks!

[okalex]

Just curious, is this still holding up?