- Thread starter
- #161
Yep, identical except for badges, cladding, amenities. Best way to search is by FZJ80.
No More High Idle on Cold Start (3 Viewers)
- Thread starter harrydunn
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- Thread starter
- #162
Cruiser is at my friend's shop today getting checked out. He's not going to bill for all of the diagnostic time if he can figure out what it is. Just point me in the direction of the repair. I'm convinced it has to be a small electrical problem.
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- #163
IAC tests fine (which we knew) but just doesn't appear to want to move as much as it should. He's testing each individual wire (4 signal wires) that run back to the ECU for continuity. The two 12-volt wires check fine. Just keeping things updated here.
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- #164
Well, IAC sensor wires are all fine all the way back to ECU. Does anybody know if there is any sort of sensor that would tell the ECU, "hey, we can't idle high right now."? A transmission sensor, etc?
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- #165
No real news to report this week. I've been examining my OBD1 scanner running data for anything weird and there simply is nothing. IAC does move as it sets to 49% when the engine is turned off. This is normal behavior and the right percentage. Upon startup, comparing it to @Zantier 's '94 LC, it should drop to about 39-40 % at cold start to maintain the high idle. Mine drops to about 25% right away. The saga continues. Until, next time...
Arabian Cruiser
Arabian Cruisers
Wow well done on effort.
Just read the entire thread.
I have the opposite happening as my truck revs to 3000 on start and goes down to 1100.
Then it goes up to 3000 and 2000 from time to time. It also goes so low the engine shuts off.
Was a real learning reading about all the possibilities related to idle. Will be going through each item.
Thanks again.
Just read the entire thread.
I have the opposite happening as my truck revs to 3000 on start and goes down to 1100.
Then it goes up to 3000 and 2000 from time to time. It also goes so low the engine shuts off.
Was a real learning reading about all the possibilities related to idle. Will be going through each item.
Thanks again.
- Thread starter
- #167
Search for the IAC o-ring trick. It's a band-aid fix sometimes for high cold start idle problems.
- Thread starter
- #168
Well, no dice. My friend is a well-known and knowledgeable mechanic and finds nothing wrong. He's confident he could fix it if I wanted him to start tearing into stuff but I'm not to that point. If it ran bad because of this, I suppose I would. I'm going to install my OEM hand throttle tonight and just use that on the really cold mornings when I want to bump the idle up a bit. Pretty excited honestly. I can see myself using it for other instances during the summer heat as well. Keep temps down when idling in Park and helping A/C efficiency at idle in Park. I may revisit this at some point. Thanks for playing.
Sorry to hear that. Behavior looks pretty much like mine, with the added twist that my idle occasionally drops when warm (accompanied by the IAC % going down below 20%). I do have the hand-throttle cable installed. As long as you are the only driver - not too much of a problem (don't pull on the cable, blah, blah). If your SO occasionally drives the Cruiser, however, consider that if you leave the hand throttle in, the vehicle may stall. If you leave the hand throttle out, the occasional high idle will be a surprise as the truck creeps forward. And if you let your SO use the hand throttle, be prepared to invest in spare hand throttle knobs. That's the case with my SO, at least. Maybe I should invest in spare SOs.
Hi. Do you have any photos of your engine bay?
Man I was very sad to see this thread drop off after 3+ years! Did you figure this issue out finally??
Any chance anyone's still around dealing with this issue?
I have something similar going on with my 2014 Sierra 1500 where it doesn't high idle at cold start but after driving it and letting it sit for 3-4 hours and then starting up it will be a high idle cold start like it should be. But if the truck site over night or my entire shift at work, then I get a low idle cold start.
I've cleaned TB twice, it looks brand new.
Battery voltage is kinda high at 15V when running.
Did an upper engine clean using a full can of seafoam with my truck running and Rpms held steady at 2000. Didn't really get any white smoke coming out at start up after doing that... Not sure if that's any need for concern?
Any chance anyone's still around dealing with this issue?
I have something similar going on with my 2014 Sierra 1500 where it doesn't high idle at cold start but after driving it and letting it sit for 3-4 hours and then starting up it will be a high idle cold start like it should be. But if the truck site over night or my entire shift at work, then I get a low idle cold start.
I've cleaned TB twice, it looks brand new.
Battery voltage is kinda high at 15V when running.
Did an upper engine clean using a full can of seafoam with my truck running and Rpms held steady at 2000. Didn't really get any white smoke coming out at start up after doing that... Not sure if that's any need for concern?
- Thread starter
- #172
Noop, never figured it out. My best guess is leaky intake when cold. Seals up when warm.
Damn no happy ending in the books then eh. Do you still have the truck?
Hi Harry I just thought I would chime in as I have had exactly the same problem as you for around 2 years now. I have a 93 FZJ80 Aus version but just like yours one day my cold start idle went from 1200rpm when cold straight to 650. It happened just after my mechanic had the rocker cover off to check the valve clearances, he did a clean of the throttle body at the same time. I have done heaps of things including swapping the IAC and various other sensors etc but nothing has worked. The only thing I found is that whenever i have reset my ECU (for example after disconneting the battery to do other work) the first time every time i start it up it goes back to 1200rpm on cold start. After that first time it then drops back down eventually to 650rpm after a few cycles. I figured the mechanic must of bumped something while doing the valve clearances and/or throttle body and unfortunately I havent figured it out yet but will post it up when I do
- Thread starter
- #175
Hi Harry I just thought I would chime in as I have had exactly the same problem as you for around 2 years now. I have a 93 FZJ80 Aus version but just like yours one day my cold start idle went from 1200rpm when cold straight to 650. It happened just after my mechanic had the rocker cover off to check the valve clearances, he did a clean of the throttle body at the same time. I have done heaps of things including swapping the IAC and various other sensors etc but nothing has worked. The only thing I found is that whenever i have reset my ECU (for example after disconneting the battery to do other work) the first time every time i start it up it goes back to 1200rpm on cold start. After that first time it then drops back down eventually to 650rpm after a few cycles. I figured the mechanic must of bumped something while doing the valve clearances and/or throttle body and unfortunately I havent figured it out yet but will post it up when I do
Great. Would love to get this figured out!
Hey Harry I just wanted to let you know that my issue with the cold start idle has fixed itself!
Yesterday I replaced the o-ring on my IAC valve as the old o-ring had perished and it had been on my list of things to do for a while. To mix things up, I installed a spare IAC valve I had from a 97 model. When I started the car it went back to the original cold idle (1200rpm) and slowly dropped back down to 650 once warm. I checked it again this morning just to make sure it was still working correctly and it was.
The only other thing I did was replace my TPS a few months ago after testing it and finding it was not to spec, I found that helped bring my warm idle down (as it had been slightly high for a while). I also resetted the ECU after replacing the TPS and . Unfortunately I don't have an exact fix but it could be a combination of TPS then ecu reset then IAC valve replacement (with new o-ring).
Also when I was driving around yesterday I noticed the IAC valve I installed seemed to control the idle better (smoother without fast drops) when the A/C cycled on and off and when dropping between gears and stopping (my 80 is a manual btw).
Anyways I hope this helps!
Dan
- Thread starter
- #177
Sold my 80 long ago and have been in 2 100's since then but I am glad you got it figured out! I had replaced IAC's TB, etc but no dice. Plan is to have another 80 at some point down the road for fun.
Thanks mate, I think I will sleep a little easier tonight. And thanks for posting up all the info in the first place and what you did to try and solve the issue, it was very helpful. We might see you back on this thread again when you get the next one
wow! great thread...amazing troubleshooting...i also have a '93 that recently lost cold high idle start...bummer on the ending!
- Thread starter
- #180
Well the good news is I have another 80 now! Ha. A 100 and an 80 as toys.
