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Re: '97 Previa RWD VERY HIGH IDLE Warm Engine
hi, I'm not sure if this might help. But I remember seeing an article a while ago, possibly on the yahoo group of the supercharged previa's getting black flakes in the coolant and blocking up one of the pipes where it t's off. I'll try finding the article, but here's a pic showing the pipe I believe it is. I used to have a 95 le s/c and the dealership could never figure out it's high idle in the cold.
Attachment 2242
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Re: '97 Previa RWD VERY HIGH IDLE Warm Engine
It was toyotanation actually. I asked the question a while ago. Attachment 2243
http://www.toyotanation.com/forum/85...le-previa.html
I hope it helps.
Re: '97 Previa RWD VERY HIGH IDLE Warm Engine
yea, i found the source of some black flakes in my coolant by the way ... while I replaced the big water hoses, I noticed that the black paint around the pipes ( guess TOY wanted them to look good?) that connect the hoses is just "Flaking" off. I rubbed all paint off pipe ends and connected hoses... Flushed the system real good afterword..thanks for info...." its what we do"
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Re: '97 Previa RWD VERY HIGH IDLE Warm Engine
OKAY! I had thought the fast idle had gone away miraculously but I was mistaken! So I replaceded fuel filter, replaced fuel pressure regulator, and even swapped out fuel rail with injectors (mine tested 17.2 each and FSM wants them around 14.2). So all in all I ended working EFI system over real good. Ended up replacing cold start injector, cold start time valve, coolant temp sensor, Egr modulator, hoses, PCV, TPS, and list goes on...(found 2 previa at U pull it and worked them over real good too, Yea used parts I know but they worked just the same...didnt remedy or worsen the symptom!) Anywho, after scratching my head over it I decided to check ISC again. I might have to replace ISC? and I was hoping the Previa were still at the bone yard. After removing throttle body for 3rd time, I ran across a sticking valve!! I dont know how I missed it the first time:wall:
but I caught the buggar this time... cleaned it really good till valve moved freely!! Reinstalled on 92 PREV and she definitely purrs. :dance2:
So now its up the coast I go! Heading up Atlantic coast!:fshn::sfr:
Its definitely BEER-THIRTY HERE!:drunk:
thank you everybody that chimed in.:wrthy:
Re: '97 Previa RWD VERY HIGH IDLE Warm Engine
Yeah, I think these 2 issues are MUST DO if you have a previa.
The black flakes and EGR clean out. I was so angry that the shop that did my motor ignored the manifold. It could have easily been cleaned out and taken cared of.
Re: '97 Previa RWD VERY HIGH IDLE Warm Engine
Glad to see it helped. :wave1:
Re: '97 Previa RWD VERY HIGH IDLE Warm Engine
I feel this is a must do for the Previa.
Clean out the IAC valve and put in the "flake filter".
IAC valve and "flake filter"
- Fram G15 inline filter - this for the flakes going into the ventilation tube.
- 2 small hose clamps for the filter.
- Throttle body gasket - 22271-76020
- IAC valve rubber gasket - 22215-76010 - gasket between the IACV and Throttle body
- IAC valve screws (set of 4) - 21821-25180 - holds the IACV to the throttle body
Re: '97 Previa RWD VERY HIGH IDLE Warm Engine
I believe the lowest one is the "Start Injector Time Switch"
Quote:
Originally Posted by
tbkilb01
thanks pdgizwiz,
had time tonight and checked into coolant temp sensor. I found 3 sensors on water outlet. removed top one and tested it hot and cold, passed resistance as per FSM... middle one just goes to temp guage. The lower one escapes me, couldnt find wrench to fit (bigger than 19mm)....and i could not find the sensor mentioned in FSM. so I started prev and disconnected upper one. It triggered code. Havent had any codes (so I was relieved to see one). I reset CU to see if it comes up again.. at least I know the upper Sensor works...:cnfsd:
lower one does nothing that i can tell...so far. any way to test the lower one you know of? its a water temp sensor for sure just not sure what it sends temp to...i may remove it to get toyota numbers off it and look on rockauto or Toyotaparts.com.
I'll let car heat up thoroughly tomorrow and disconnect it to see if any effect on prev.
again thanks for chiming in.
Did you have a HIGH IDLE problem...?
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Re: '97 Previa RWD VERY HIGH IDLE Warm Engine
Quote:
Originally Posted by
Jwsmsmith
I believe the lowest one is the "Start Injector Time Switch"
I believe your right, thanks...
However, my speedometer just stopped working and I'm thinking/hoping speed sensor?:cnfsd:
found picture:
Attachment 4994
Re: '97 Previa RWD VERY HIGH IDLE Warm Engine
hopefully it was the sensor that has gone bad
otherwise, the capacitors in the speedometer itself has gone bad.... that's relatively easy to fix for less than $10 (search for my thread)
Re: '97 Previa RWD VERY HIGH IDLE Warm Engine
Quote:
Originally Posted by
TheMAN
hopefully it was the sensor that has gone bad
I've replaced speedometer cluster, VSS and wiring to VSS. Speed still does not register. Computer problems?
Re: '97 Previa RWD VERY HIGH IDLE Warm Engine
Regarding the original problem posted in this thread I had exactly the same issue in my 97 AWD Previa: slightly high idle on cold start, increasingly fast idle as it warms up. Surging idle in Neutral, very fast idle in drive or park (or stopped in neutral). Undriveable.
I first tried the coolant temp sensor. Didn't change anything.
I next assumed it was the Idle Air Control, so I ordered a new one (off eBay! Huge mistake). I changed it, but got no improvement.
Digging further in, I took out the new IAC and bench tested both the old and new IAC valves. The old one was all gummed up with sticky carbon crap so it couldn't move freely, which I cleaned out with lots of carb spray and manual movement of the valve. Got it moving very freely. Then it bench tested properly.
The new one I ordered for cheap failed the bench test. One side of the circuit didn't work at all. It would open but not close, which is a recipe for a high idle! So it's going back for a refund.
Here's a GREAT article on how to test the valve so you KNOW whether it's the problem:
https://www.toyotanation.com/threads...valve.1676205/
Meanwhile, I re-installed the cleaned OE IAC. I also cleaned out the "T" junction clog with Qtips (very crapped up--see further up in this thread for details about this procedure) and then opened the other end (under the van) and blew out the coolant line with compressed air. While I had the throttle body out, I cleaned it thoroughly with carb spray as well.
Reassembled everything, and the idle is perfect. In the end, the issue was the gummed-up IAC, which is partially dependent on the T-junction flow to function. So if you're having this problem, I would go straight to testing and cleaning the IAC, and cleaning the T junction.
Re: '97 Previa RWD VERY HIGH IDLE Warm Engine
Quote:
Originally Posted by
aplarsen22
Reassembled everything, and the idle is perfect. In the end, the issue was the gummed-up IAC, which is partially dependent on the T-junction flow to function. So if you're having this problem, I would go straight to testing and cleaning the IAC, and cleaning the T junction.
Personally, I would start with the T-Junction. It's easier to get at and 9.8 times out of 10 will solve the problem.
On my left hand drive van, it had the high idle issue; cleaned the T-junction and it went away immediately. Not even 6 months later, the high idle came back. Second time around I not only cleaned the T-junction but also installed a filter between the junction and the IAC. The filter should collect any black flakes and prevent the junction from clogging in the future.
I am currently overseas, but I am going to do the filter mod to my right hand drive as soon as I get back!
If cleaning the T-junction does not solve the problem, then the IAC is obviously the next suspect.
Re: '97 Previa RWD VERY HIGH IDLE Warm Engine
I know this is an old thread but it helped me fix my van so I thought I'd chime in.
A few years ago I had a shop replace the headgasket and after getting the van back I've had nothing but problems. So much so that my friends and I had labeled it the "worlds most unreliable Toyota".
I've taken it to several different mechanics and they couldn't figure it out either. Symptoms were inconsistent but generally hard to start, would misfire/load up and the idle was all over the place.
You could start the van cold and let it idle, it would seem fine and then die for no reason. So I replaced the ICV. No luck.
Replaced the EGR valve and vacuum modulator, no change, engine temp sensor, plugs, new vacuum lines, fuel pressure regulator, removed and cleaned the throttle body and EGR/Vacuum ports, etc. I chased theories and replaced parts all over the van, even the charcoal cannister. For two years I toiled and could not solve the issue. Some things would make it better and some worse (like the new EGR Valve).
About two weeks ago I decided to mess with it again. I started reading forums and finding similar issues but none of the solutions solved it.
I had previously ordered a throttle body off of eBay which had a new ICV and TPS sensor on it. I found the guide in this thread to test the ICV and thought, well, might as well. So I removed it, tested the new one and it was good. I took the old one off the van (which I had replaced), tested it, and it failed. So I had been chasing the symptoms of a problem I thought I had solved two years ago.
I was both elated and frustrated at the same time.
So as I go to reassemble the van, I'm putting the spark plug cover back on the valve cover and the engine starts to stumble. I reach down and touch one of the wires and got a big shock! Turns out, there were tiny slits in the spark plug wires that was making it short out against the valve cover! You couldn't see them at a glance but upon closer inspection you could. So I replaced the plugs and wires and then discovered the distributor cap was LOOSE. At some point, someone had sheered off one of the three bolts holding it on and didn't bother to tighten the remaining two.
So I replaced the cap and rotor and snugged it down really good.
Now the van runs like its brand new. Its been such an oddessy for me over the last few years and I'm so relieved its fixed. It was this thread that lead me to the solution so I thank all of you who contributed.
There is a lesson in here that I should be learning as well, maybe check the obvious stuff first, put your hands on the parts, visually inspect, dont over complicate things... etc... One day I'll figure that one out too, lol.