gregnash
Anal Retentive Analyst
Ok so this is an on-going saga that has been happening with BeBe since I rebuilt the top end in 2015/2016. She is a 85 FJ60 with the original 2F in her, desmogged when I first got her due to the smog pump being seized.
Issue:
- Truck will idle high after it has warmed up. Talking between 900rpm and 1500rpm, just depends on the particular time no real consistency to it.
- Quick pump of the gas pedal MAY drop the idle, which has been set to about 650rpm, down to normal idle rpm or it could just drop down a little.
- Shifting while high idle is present will cause the idle to stay high during the shift. If clutch is pushed in the idle will slowly drop, but may "bounce" back a few hundred RPM. (E.G. drops to around 1k but will bounce back to 1200) Bounce may occur when quick pump happens, again inconsistent.
Example:
Can be leaving for work after the truck has warmed up for 5-10mins at normal idle, no choke and get to first stop sign by the house and all will be good. Then will continue to drive on my route and by next stop sign the idle will kick up to 1k rpm when the clutch is in (regardless of shifting or not). Quick tap of the pedal at the stop MAY drop the rpm, sometimes does sometimes doesn't. Next stop sign may see the idle return to normal, may go higher, may be slightly lower, never goes above 1500rpm-ish though.
This will continue regardless of how much I drive the truck, regardless of how many miles are put on the street vs. highway. This only happens with my carb as I had @HemiAlex stock carb that he lent me months ago, on there and never had this issue.
What's been done:
- Carb was rebuilt in 2016 when I had the top end apart with the proper Keyster kit from @cruiseroutfit.
- Stock ICS was found to be KIA during the rebuild (see build thread) and thus replaced with only aftermarket available at that time from CCOT. At this time was start of issue.
- Checked manifold gaskets, carb base plate gaskets and all surrounding areas for possible vacuum leaks but only found a small leak at the manifold, nothing that would cause this large of increase.
- Checked all vacuum line routing to ensure everything was proper and no cracked lines. Replaced where necessary.
- Carb was rebuilt again at the beginning of this year when I swapped Alex's carb in. Never exhibited these or any issues with his carb.
- Replaced cheap AC Pump in carb that comes with Keyster kit with OEM replacement from City Racer when rebuilding carb.
So last week I had time to swap the carbs again, putting mine back on. For the first day or so everything seemed alright but then the high idle issue started up again. No matter the adjustments that are made to the carb, it seems it will either idle like crap and keep a normal idle pattern (staying around 650-700rpm) or it will have this high idle issue. Thinking that it may be the aftermarket ICS from CCOT I purchased another aftermarket from CityRacer only to get it yesterday and find that it LOOKS to be the exact same make, NAKAMOTO.
Even with the new ICS the carb still has the same issue so now I need to figure out where to go next. Should I just start all over again, bring the timing back down to stock and start all over? In the past this has done nothing and being that the truck is desmogged I normally run at about 12-15*. I have everything for a high altitude vehicle as Carson City is at about 4500' and I regularly travel up to Lake Tahoe to go to the family cabin at over 6500' and then mountains being anywhere from 7k' to 8k' passes.
One thing I have not been able to find on here is a definitive "baseline setting" for the carb to start from after having done things like a rebuild. I have the fuel screw currently turned out 2 3/4 turns and she seems to be running quite happily there, FSM says to start at 2 and then go up. I know that JimC's write-up says to run at 3-4 but when I do it smells like she runs real rich. I know that part of my exhaust is shot and I am gathering pieces to replace it and the cat (non-oem as I upgraded to 2.5" exhaust from cat-back) in the next couple weeks here, hoping to get some work done on it this week.
I am a bit at a loss for this, it is something I have been fighting with for a while but can never seem to get the idle just right. Other than the high idle issue, she runs great, plenty of power (for a 2F with close to 200k on it) and has good compression last I checked (bout this time last year).
Issue:
- Truck will idle high after it has warmed up. Talking between 900rpm and 1500rpm, just depends on the particular time no real consistency to it.
- Quick pump of the gas pedal MAY drop the idle, which has been set to about 650rpm, down to normal idle rpm or it could just drop down a little.
- Shifting while high idle is present will cause the idle to stay high during the shift. If clutch is pushed in the idle will slowly drop, but may "bounce" back a few hundred RPM. (E.G. drops to around 1k but will bounce back to 1200) Bounce may occur when quick pump happens, again inconsistent.
Example:
Can be leaving for work after the truck has warmed up for 5-10mins at normal idle, no choke and get to first stop sign by the house and all will be good. Then will continue to drive on my route and by next stop sign the idle will kick up to 1k rpm when the clutch is in (regardless of shifting or not). Quick tap of the pedal at the stop MAY drop the rpm, sometimes does sometimes doesn't. Next stop sign may see the idle return to normal, may go higher, may be slightly lower, never goes above 1500rpm-ish though.
This will continue regardless of how much I drive the truck, regardless of how many miles are put on the street vs. highway. This only happens with my carb as I had @HemiAlex stock carb that he lent me months ago, on there and never had this issue.
What's been done:
- Carb was rebuilt in 2016 when I had the top end apart with the proper Keyster kit from @cruiseroutfit.
- Stock ICS was found to be KIA during the rebuild (see build thread) and thus replaced with only aftermarket available at that time from CCOT. At this time was start of issue.
- Checked manifold gaskets, carb base plate gaskets and all surrounding areas for possible vacuum leaks but only found a small leak at the manifold, nothing that would cause this large of increase.
- Checked all vacuum line routing to ensure everything was proper and no cracked lines. Replaced where necessary.
- Carb was rebuilt again at the beginning of this year when I swapped Alex's carb in. Never exhibited these or any issues with his carb.
- Replaced cheap AC Pump in carb that comes with Keyster kit with OEM replacement from City Racer when rebuilding carb.
So last week I had time to swap the carbs again, putting mine back on. For the first day or so everything seemed alright but then the high idle issue started up again. No matter the adjustments that are made to the carb, it seems it will either idle like crap and keep a normal idle pattern (staying around 650-700rpm) or it will have this high idle issue. Thinking that it may be the aftermarket ICS from CCOT I purchased another aftermarket from CityRacer only to get it yesterday and find that it LOOKS to be the exact same make, NAKAMOTO.
Even with the new ICS the carb still has the same issue so now I need to figure out where to go next. Should I just start all over again, bring the timing back down to stock and start all over? In the past this has done nothing and being that the truck is desmogged I normally run at about 12-15*. I have everything for a high altitude vehicle as Carson City is at about 4500' and I regularly travel up to Lake Tahoe to go to the family cabin at over 6500' and then mountains being anywhere from 7k' to 8k' passes.
One thing I have not been able to find on here is a definitive "baseline setting" for the carb to start from after having done things like a rebuild. I have the fuel screw currently turned out 2 3/4 turns and she seems to be running quite happily there, FSM says to start at 2 and then go up. I know that JimC's write-up says to run at 3-4 but when I do it smells like she runs real rich. I know that part of my exhaust is shot and I am gathering pieces to replace it and the cat (non-oem as I upgraded to 2.5" exhaust from cat-back) in the next couple weeks here, hoping to get some work done on it this week.
I am a bit at a loss for this, it is something I have been fighting with for a while but can never seem to get the idle just right. Other than the high idle issue, she runs great, plenty of power (for a 2F with close to 200k on it) and has good compression last I checked (bout this time last year).