First Post! New FZJ80 Owner... Looking for some expert idle advice! (1 Viewer)

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Dayton, OH
Hey everyone! First of all thanks for reading. After years of lusting after owning an 80 series. Several months ago I finally did it - 1996 FZJ80! The past couple months I've been slowly been trying to get my cruiser road worthy again after the previous owner neglected it. After doing the valve cover gasket, PHH, "tune up", other various coolant hoses, etc. etc. I'm finally getting down to the wire.

I'm sure to someone this may be kind've a dumb question but I'm kinda stumped, haha. Long story short I'm having some serious idle issues. Somedays it idles just fine. However, lately it's idling insanely high in park/ neutral. As of today, it was even pretty high (slightly above 1000 rpm) in drive. Last week when it was driving pretty normal the check engine light for the TPS came on. I thought maybe that could be the answer so I did end up replacing that. My throttle cable seems pretty worn and I've tried adjusting it to the best of my ability but I actually just went ahead and placed an order for a new one. (should come in later this week)

Before when the truck was idling semi-okay I messed around with this screw against the throttle diaphragm (not sure if that's exactly what it's called...) right below the TPS. However, now it's not even touching it as show in the video below.

I guess my question is how exactly is this related to the idle itself (Kind've a dumb question I know...) and what should be my next step?


Thanks in advance guys! I've been pointed to this forum a handful of times and I'm glad I finally joined. Hopefully I can get some direction of where to start dumping my money next, haha!
 
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Hey everyone! First of all thanks for reading. After years of lusting after owning an 80 series. Several months ago I finally did it - 1996 FZJ80! The past couple months I've been slowly been trying to get my cruiser road worthy again after the previous owner neglected it. After doing the valve cover gasket, PHH, "tune up", other various coolant hoses, etc. etc. I'm finally getting down to the wire.

I'm sure to someone this may be kind've a dumb question but I'm kinda stumped, haha. Long story short I'm having some serious idle issues. Somedays it idles just fine. However, lately it's idling insanely high in park/ neutral. As of today, it was even pretty high (slightly above 1000 rpm) in drive. Last week when it was driving pretty normal the check engine light for the TPS came on. I thought maybe that could be the answer so I did end up replacing that. My throttle cable seems pretty worn and I've tried adjusting it to the best of my ability but I actually just went ahead and placed an order for a new one. (should come in later this week)

Before when the truck was idling semi-okay I messed around with this screw against the throttle diaphragm (not sure if that's exactly what it's called...) right below the TPS. However, now it's not even touching it as show in the video below.

I guess my question is how exactly is this related to the idle itself (Kind've a dumb question I know...) and what should be my next step?


Thanks in advance guys! I've been pointed to this forum a handful of times and I'm glad I finally joined. Hopefully I can get some direction of where to start dumping my money next, haha!
Odds are it's your throttle cable as you described.

Hopefully you bought OEM, as many folks here tried to save a few bucks and go the cheap route, only to find out it doesn't fit well.
 
Joined
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Odds are it's your throttle cable as you described.

Hopefully you bought OEM, as many folks here tried to save a few bucks and go the cheap route, only to find out it doesn't fit well.
I did end up going OEM! Through ToyotaPartsDeal. Part #78180-60280. I'm really hoping that this helps. At this point I'm willing to try anything, haha.
 

Swbkrn2003

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I did end up going OEM! Through ToyotaPartsDeal. Part #78180-60280. I'm really hoping that this helps. At this point I'm willing to try anything, haha.
I had the same problem. Check the rubber connector from the air cleaner to the Throttle body for cracks or if uts brittle. Change throttle cable. Replace all vacuum. Lines, get a new gas gap, check your fuel tank filter, brak booster hose. Did all this as part of base lining, solved my idol issues.
 
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I had the same problem. Check the rubber connector from the air cleaner to the Throttle body for cracks or if uts brittle. Change throttle cable. Replace all vacuum. Lines, get a new gas gap, check your fuel tank filter, brak booster hose. Did all this as part of base lining, solved my idol issues.
I did get a new intake hose and replaced as many vacuum lines as I could find! The brake booster hose looks to be okay, but I’ll have to add that too the list.

The gas cap does seem to let out a lot of pressure (you can hear it) when opening it. Is this because the cap itself isn’t venting or is there more to that? I’ll have to add that one to the list as well. 🤙🏻
 
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I did get a new intake hose and replaced as many vacuum lines as I could find! The brake booster hose looks to be okay, but I’ll have to add that too the list.

The gas cap does seem to let out a lot of pressure (you can hear it) when opening it. Is this because the cap itself isn’t venting or is there more to that? I’ll have to add that one to the list as well. 🤙🏻
If the gas tank is hissing when you open the cap, you have a charcoal canister (CC) issue. Many here change it to a VC120 as the OEM unit is NLA. You need to do this before you end up with the cracked gas tank as well.

If the throttle cable doesn't fix it, then you can look into cleaning the IAC valve. (Idle Air Control) it's under the intake manifold.

Also consider a new Oil Fill cap for the new seal.
Hopefully when you did the VC gasket, you also did the spark plug tube seals and the PCV valve grommet.
I also did the PS reservoir cap in order to eliminate just one more leak.
 

Swbkrn2003

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I did get a new intake hose and replaced as many vacuum lines as I could find! The brake booster hose looks to be okay, but I’ll have to add that too the list.

The gas cap does seem to let out a lot of pressure (you can hear it) when opening it. Is this because the cap itself isn’t venting or is there more to that? I’ll have to add that one to the list as well. 🤙🏻
Its the fliter located in the engine compartment. Replace it if you have excess pressure had that problem too. Plenty of articles on replacement the OEM part is Not available but you can get other ones that work search VC-120.
 
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If the gas tank is hissing when you open the cap, you have a charcoal canister (CC) issue. Many here change it to a VC120 as the OEM unit is NLA. You need to do this before you end up with the cracked gas tank as well.

If the throttle cable doesn't fix it, then you can look into cleaning the IAC valve. (Idle Air Control) it's under the intake manifold.

Also consider a new Oil Fill cap for the new seal.
Hopefully when you did the VC gasket, you also did the spark plug tube seals and the PCV valve grommet.
I also did the PS reservoir cap in order to eliminate just one more leak.
I'll have to look into replacing that CC then it sounds like. It's definitely hissing like a snake when I stop to fill up! Great to know... Already learning so much on here.

I did clean the IAC valve to the best of my ability when I had the throttle body off for doing the valve cover gasket. Is it possible that it's just bad as a whole then maybe, if the accelerator cable doesn't fix it? I feel that the closer the engine gets to operating temp, the higher the idle gets.. Not sure if this is a direct symptom of the IAC valve being bad or or not.

Spark plug tube seals, and PCV grommets/ valve were all done when I had it all off! I've been trying to do as much as I can "the right way" when working on this thing so far so I don't have to take it all apart again, ha!
 
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Its the fliter located in the engine compartment. Replace it if you have excess pressure had that problem too. Plenty of articles on replacement the OEM part is Not available but you can get other ones that work search VC-120.
On it! Looks like I'm going to put in an order for one today. Seem's like a very easy little project.
 
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Since no one has asked -
Did you set the new TPS per the fsm?
Using a multimeter and feeler gauges?
I originally didn't (set to x% at idle per obdii) and it had a stumble/weird idle.
Redid the correct way last weekend and it's like driving a new truck.
 
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Since no one has asked -
Did you set the new TPS per the fsm?
Using a multimeter and feeler gauges?
I originally didn't (set to x% at idle per obdii) and it had a stumble/weird idle.
Redid the correct way last weekend and it's like driving a new truck.
No, I actually have not yet. Once my new cable comes in this week and I get that all squared away I'm going to take some time to do it the right way. My throttle itself doesn't ever break up or anything which is good. It's super smooth and linear power it just likes to idle really high, haha. Either way, I know I need to take the time to do that.
 
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No, I actually have not yet. Once my new cable comes in this week and I get that all squared away I'm going to take some time to do it the right way. My throttle itself doesn't ever break up or anything which is good. It's super smooth and linear power it just likes to idle really high, haha. Either way, I know I need to take the time to do that.
Tps being set incorrect would tell the ecu you are NOT at idle and hence do weird things.
It's much much easier with the throttle body off the truck for what it's worth. Worth the extra effort and a gasket.
 
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Tps being set incorrect would tell the ecu you are NOT at idle and hence do weird things.
It's much much easier with the throttle body off the truck for what it's worth. Worth the extra effort and a gasket.
100% going to have to do this next then. I did replace the gasket when I had it off to do the valve cover so it still should be in good shape hopefully.
 
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100% going to have to do this next then. I did replace the gasket when I had it off to do the valve cover so it still should be in good shape hopefully.
I've reused that gasket before and its technically got a crush section to it. I'd recommend replacing it every time you take it apart, but thats the OCD in me. Mine is getting replaced soon.
 
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I've reused that gasket before and its technically got a crush section to it. I'd recommend replacing it every time you take it apart, but thats the OCD in me. Mine is getting replaced soon.
Nope, I'm the same way. I'll be replacing it also, then. Good to know! Thanks brotha!
 
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I had the same problem. Check the rubber connector from the air cleaner to the Throttle body for cracks or if uts brittle. Change throttle cable. Replace all vacuum. Lines, get a new gas gap, check your fuel tank filter, brak booster hose. Did all this as part of base lining, solved my idol issues.
I am currently dealing with the same issue too, been chasing it for months and it won’t pass emissions -it started with no CEL with 1200 RPM idle and progressed. It’s now at 1k-1100 RPM idle and is now throwing code 25 (it was throwing a 25/26 combo prior) and I did EVERYTHING listed in previous posts and then some (mine is a 94 and I had a bad PAIR valve) so I just pulled my throttle body again and tested my IAC and this time around everything was in spec except B2-S4 (44.8 Ohms) while every combo was within spec (22 ohms) so I think I finally found it. This time around I did the battery test to the IAC and the actuator didn’t move but rather clicked and barely budged.
 

ppc

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This time around I did the battery test to the IAC and the actuator didn’t move but rather clicked and barely budged.
The IAC is a stepper motor. You are not going to see it move and yes it moves very little as you test each terminal in sequence only feel it as it generates torque. The high resistance measured between B2-S4 may be a possible problem but I would assume the ECM would be able to compensate for that.
 
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Well... replaced the throttle cable today. While it seems that it’s not sticking as hard and revving more freely it’s definitely still not right..

On the first startup after replacing it, it’s still revving high and was going up & down as shown in this video...
After shifting into drive it did go down to about 1000 RPMs. After driving it around and getting it up to temp it did lower a bit to 800-900 RPMs at idle. However shifting it back into park or neutral it still is going back up to about 1000-1100. Better but not great.

I have a feeling cold starting it again it’s just going to either do what was shown in the video or shoot straight up to 2500-3000 RPMs again...Anyone have suggestions as to what my next step should be? Thanks guys!
 
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Have you checked your oxygen sensors? Look for air leaks around the bung hole. Check they are tight. Check the wires for wear. Check the connecter to the main wiring harness. Wiggle the wire to see if this changes the idle.
 
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Well gentleman... the plot thickens. After letting it sit all day while I was at work I tried starting it up and it won’t idle at all! Had to give it gas to stay from bogging out. Even after driving it around up to temp it still didn’t really want to hang on to any sort of consistent idle 🤣 Triple Locked ‘96 up for sale soon... haha....
 

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