hard start, low idle on 93 4runner
09-26-2009, 04:50 PM
#1
hard start, low idle on 93 4runner
Nothing catastrophic but annoying; not every time but every other time or so, hard start (crank for 4-5 sec plus) and won't come to life without a little pedal and then even after driving, at idle, rpms drop to about 350-400 and the motor shakes. Pretty annoying when stopped on an incline in traffic and you have to feather the gas with a manual transmission; I only have 2 feet....
Wondered if anyone else has had the same issues and what the problem was. Somewhere in the owner's manual it says to hold rpms at 1500 for 10 sec and then let off and that corrects the problem but no dice. (I have the 3VZE engine btw)
I was going to start checking sensors to see if there are any bad ones left; just replaced the front o2 sensor with no changes other than better gas mileage and tested a few others. Still need to check the IAC valve/sensor
Wondered if anyone else has had the same issues and what the problem was. Somewhere in the owner's manual it says to hold rpms at 1500 for 10 sec and then let off and that corrects the problem but no dice. (I have the 3VZE engine btw)
I was going to start checking sensors to see if there are any bad ones left; just replaced the front o2 sensor with no changes other than better gas mileage and tested a few others. Still need to check the IAC valve/sensor
11-11-2009, 09:59 PM
#2
I'm having the exact same problem with my 91 PU 3VZE. Sometimes (less often) I have the opposite problem though, where she'll start on the first crank but the idle sits way too high and never comes down.
Searching on here seems to point at a throttle body problem, possibly some kind of a coolant clog/buildup in there. This is all pretty new to me, so I'm just repeating what I've read.
Any seasoned vets know a possible fix?
Searching on here seems to point at a throttle body problem, possibly some kind of a coolant clog/buildup in there. This is all pretty new to me, so I'm just repeating what I've read.
Any seasoned vets know a possible fix?
11-12-2009, 02:18 AM
#3
been a little while since my original post and can't remember exact order of events but, the low idle problem hasn't been as bad lately but still around. I pulled the throttle body apart because I couldn't find the IAC sensor only to find out my manual was wrong or my engine just doesn't have one; it's simply a valve and other than ensuring that there was good flow for the coolant I didn't accomplish much other than cleaning the throttle body (again). might be worth checking though for any low/rough idle, there's a bypass valve that's hard to get to without pulling the TB and I think cleaning out that helped.
Also replaced the PCV valve only after 2.5 hrs of work, had to remove about 30 hoses and EGR and the entire intake manifold to get to it. even then the rubber grommet was so old and hard i had to cut it out piece by piece and took 3 men and a horse to pull the thing out; almost lost a piece down the cover but saved it. recommend putting an extension on it like i read on another post (can't find it now) using flexible ss water hose and replace it often to avoid the pain of an old PCV grommet.
while I had the intake manifold off, I used an entire can of TB cleaner and cleaned it out (I hate EGR). Just pulled the one off my tacoma for S/C install and it was perfectly clean (00' and no EGR).
might be worth checking fuel filter too, haven't done that yet on my 4runner. just changed the one on my tacoma as it was easy to get to and it was a PITA. The 4runner FF is way up under the driver side towards the engine and next to the exhaust and behind a piece of the frame so it might take some work.
bought new NGK plugs but haven't had time to install yet, if I find out anything else that makes a difference I'll post it here.
and one more ramble before I post this....
put DevilsOwn alcohol injection in the 4runner (2gph nozzle) running a 50/50 mix after a couple gallons of dH2O and it adds to the power and helps clean the engine; had it on my tacoma for about a year and saw at least a 15% HP increase if not more in addition to about 50 more miles on a tank of gas. I have it a few inches before the TB and the voltage controller is hooked to the TPS for a signal. After installing this, I haven't noticed low idle as bad but until I get new plugs in I'm not convinced I've done much to fix it yet.
Good luck, this engine is a rough one to work on (and I'm not a mechanic by any stretch) but patience usually pays off
Also replaced the PCV valve only after 2.5 hrs of work, had to remove about 30 hoses and EGR and the entire intake manifold to get to it. even then the rubber grommet was so old and hard i had to cut it out piece by piece and took 3 men and a horse to pull the thing out; almost lost a piece down the cover but saved it. recommend putting an extension on it like i read on another post (can't find it now) using flexible ss water hose and replace it often to avoid the pain of an old PCV grommet.
while I had the intake manifold off, I used an entire can of TB cleaner and cleaned it out (I hate EGR). Just pulled the one off my tacoma for S/C install and it was perfectly clean (00' and no EGR).
might be worth checking fuel filter too, haven't done that yet on my 4runner. just changed the one on my tacoma as it was easy to get to and it was a PITA. The 4runner FF is way up under the driver side towards the engine and next to the exhaust and behind a piece of the frame so it might take some work.
bought new NGK plugs but haven't had time to install yet, if I find out anything else that makes a difference I'll post it here.
and one more ramble before I post this....
put DevilsOwn alcohol injection in the 4runner (2gph nozzle) running a 50/50 mix after a couple gallons of dH2O and it adds to the power and helps clean the engine; had it on my tacoma for about a year and saw at least a 15% HP increase if not more in addition to about 50 more miles on a tank of gas. I have it a few inches before the TB and the voltage controller is hooked to the TPS for a signal. After installing this, I haven't noticed low idle as bad but until I get new plugs in I'm not convinced I've done much to fix it yet.
Good luck, this engine is a rough one to work on (and I'm not a mechanic by any stretch) but patience usually pays off
11-12-2009, 02:23 AM
#4
also forgot, if high idle like that there might be a faulty engine coolant temp sensor or a clog somewhere in your coolant system. I would check that in addition. I just bought some toyota long life coolant and some cleaner and plan on flushing the system as it's been a while (radiator blew up on me last summer). could be multiple issues going on at once
07-01-2010, 01:51 PM
#5
thought i'd follow up with this awesome thread in case anyone else stumbles across it... doesn't seem likely...
cleaned TB again and replaced spark plugs and did some general cleaning and she runs fine now; no issues at all. I did the ISR mod which makes some awesome noise at idle and adds only a little bit of throttle response but thats it. I also have been running 92 octane for some time now as it seems retarded not to these days; back when gas was 87 cents/gal 20 cents more for high test was a lot; now that it's $3, 20 cents doesn't amount to difference and the extra mileage more than pays for this minute difference. Also have been using lucas fuel treatment religiously for a couple years now.
Anyway, the one thing I noticed that changed my rough idle issue was the last time I cleaned the TB, I cleaned out the bypass port on the lower right inside and a bunch of crap came out; after doing this, the problem ceased. seems kinda stupid but apparantly that was the only issue. I guess there's no doubt that the butterfly plate is closing all the way!
hope this helps someone out
cleaned TB again and replaced spark plugs and did some general cleaning and she runs fine now; no issues at all. I did the ISR mod which makes some awesome noise at idle and adds only a little bit of throttle response but thats it. I also have been running 92 octane for some time now as it seems retarded not to these days; back when gas was 87 cents/gal 20 cents more for high test was a lot; now that it's $3, 20 cents doesn't amount to difference and the extra mileage more than pays for this minute difference. Also have been using lucas fuel treatment religiously for a couple years now.
Anyway, the one thing I noticed that changed my rough idle issue was the last time I cleaned the TB, I cleaned out the bypass port on the lower right inside and a bunch of crap came out; after doing this, the problem ceased. seems kinda stupid but apparantly that was the only issue. I guess there's no doubt that the butterfly plate is closing all the way!
hope this helps someone out
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