1997 1FZ Hiccupy idle and running rich (2 Viewers)

Joined
Feb 12, 2015
Messages
92
Location
Plano, TX
1997 FZJ80 - stock
250K total miles
60K miles ago - HG, new head, new everything "upper engine" besides intake/TB

Hiccupy idle and running rich. I describe it as hiccupy because it isn't stumbling, low, high, or even shaking the truck. You can only really feel it in your seat, and it's not 100% consistent.

I have owned the truck less than 96 hours, driven it about 150 miles, and had the first cold start in freezing weather, which has revealed *some* sort of small problem/problems.

I owned a very abused 1994 LC before that I rescued, drove for about a year, lost a place to park it, and sold it on.

I did NOT get a PPI, as I have previous experience with the 1FZ, the previous owner was meticulous, and kept great records and spared no expense on the truck. HG was previously done and there is paperwork to substantiate the work and PO's care over the last 10 years. I also did an exhaust gas test on the radiator, checked all fluids for signs of contamination, etc. - nothing out of order or out of place. As far as drivability...it is absolutely excellent,

EDIT: I also just noticed I have gas cap woosh. F.

My thoughts for potential cause thus far -
  • Small unmetered air leak in/around air hose from filter to TB (OEM air hose form 2017 - clamps look original though)
  • Something to do with the gas cap woosh.
  • Lazy O2 sensors (I believe original)
  • Ignition timing, cracked plug, failing plug wire(s) - (everything was brand new OEM in 2010, plugs were changed 2017+)
  • Vacuum leak (some hoses look new, some look OE)
  • Sticky/lazy injector
  • Fuel pressure fluctuations (no evidence of a fuel pump failing or being replaced, fuel filter done in 2010, 60K miles ago)
No blow-by, no CEL is set, no tailpipe smoking, all gauge readings nominal...

What else? Where to start?

I am very used to working on pure mechanical engine systems (diesel Mercedes, aircooled VWs, SBC) and also modern CANBUS systems - this combo of simple electro-mechanical/vacuum system without plug-n-play modular diagnostics is not easily understood by me.

Even though I have been thumbing through the FSM, I cannot figure out where to start.

Please help me with a starting point.
 
Joined
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Messages
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Location
Santa Monica, CA
None of what you describe strikes me as overly concerning. The slight wobble on idle is likely just the early MAF circuit trying to keep up at the extreme low end of its parameters. I believe @NLXTACY (Wit’s End) has a MAF upgrade that is supposed to help this.

As for running rich, is this only on start-up, or all the time? My truck smells like a NHRA pit garage for the first minute or so - till the engine reaches operating temp and the fuel maps shift.

If you just got the truck, I’d spend some more time with it before going too far down the rabbit hole.
 
Joined
Feb 12, 2015
Messages
92
Location
Plano, TX
Good thinking. I ordered a timing light last night. :)

I went full nerd and looked at the Toyota EFI troubleshooting guide, and rank scored my symptoms and potential causes and it looks like I need to check, in order:

  1. Timing
  2. EFI Problems (generic - their language not mine)
  3. Spark plugs
  4. Vacuum/Air leaks
  5. Idle Speed
  6. Compression

I ordered a kit to replace the factory air tube and some t-clamps in place of the dinky OE wire ones. My 1994 always had a slight hunting idle (and it would set a CEL from time to time) and it was caused by tiny air leaks coming in around the two ends of the air tube from MAF to TB...t-clamps finally solved it.

Also, my fusible links look very suspect. I am going to replace all of that (links, AM-1 block, nuts) as a precaution. It needs to be done anyhow.

Lastly, I am going to pull the glovebox and check for harness wiring rubbing up against/chafing on support brackets, just to eliminate any weird electrical gremlins as the source.

If after timing, air tube upgrade, and fusible links are done and it still has this uneven idle, I don't know. Smoke test it?
 
Joined
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Messages
92
Location
Plano, TX
None of what you describe strikes me as overly concerning. The slight wobble on idle is likely just the early MAF circuit trying to keep up at the extreme low end of its parameters. I believe @NLXTACY (Wit’s End) has a MAF upgrade that is supposed to help this.

As for running rich, is this only on start-up, or all the time? My truck smells like a NHRA pit garage for the first minute or so - till the engine reaches operating temp and the fuel maps shift.

If you just got the truck, I’d spend some more time with it before going too far down the rabbit hole.

Thanks for your input here! Very appreciated.

I kept trolling Mud last night and found the LandTank MAF discussions around the same topic. However, I went to order one and it shows Out of Stock at Wit's End. I definitely want to make that upgrade - even if it doesn't cure my entire issue. @NLXTACY - will they be back in stock sometime soon?

She's :pig: rich on cold startup, and it gets less rich and more normal as the engine reaches operating temp, so maybe this is just normal behavior and I am overly sensitive to it because I have been driving an electric car for the past 13 months, and not used to exhaust smells.

The more I inspect the vacuum lines, the more I believe it could be due for a refresh, including the lines to/from the charcoal canister. I visually found a hairline crack near the canister vacuum port. on that hose.

She's far too nice and strong for me to be overly concerned, and so I am going to take your advice and just spend more time with it before loading and firing the parts cannon. I work from home and she's not even my DD, so I have a little breathing room.

Lastly, @midfat - where do you order your OE Toyotas parts online? It has been a while since I have had a Cruiser and am out of the loop.
 
Joined
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Lastly, @midfat - where do you order your OE Toyotas parts online? It has been a while since I have had a Cruiser and am out of the loop.
When I first got my LC back in 2017, I ordered everything through @cruiserdan. But then he up and vanished like a fart in the wind - some lame excuse about retirement. :meh:

ToyotaPartsDeal.com or PartsSouq.com are always easy.
 

cruiserdan

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When I first got my LC back in 2017, I ordered everything through @cruiserdan. But then he up and vanished like a fart in the wind - some lame excuse about retirement. :meh:

ToyotaPartsDeal.com or PartsSouq.com are always easy.

That's interesting. I thought I retired in 2016. :)
 

mudgudgeon

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Please help me with a starting point.

Basics first.

I had similar with my 93 recently. I'm same as you, not really up to speed on all the EFI stuff.

Mine occurred after I changed plugs, leads, distributor cap and rotor, and advanced the static timing.
I checked, and rechecked this stuff, and put the time back to stock, but still had hiccups.

I just recently replaced the head gasket and while I was at it, replaced all rubber hoses on the engine.
Most were rock hard original OEM. Some where showing splits and cracks.

I replaced all vacuum lines, PCV valve (it was cracked and brittle) PCV hoses, intake hose.
I also replaced the injector harness clips as a couple were broken. I also replaced the oil cap.

My hiccups is now gone. I'm assuming I had a vacuum leak.

Replacing vacuum hoses with the manifold in place would be a PITA, but not impossible with patience and the right tools.

I purchased OEM hoses through Partsouq for all the specialised moulded hoses. I used Gates hoses for fuel, vacuum and basic heater hoses that weren't moulded to save a little $$$. I'm not OCD to the point were everything has to be OEM.



If you play with timing, make sure to jumper out the EFI timing advance at the diagnostic port.
Jumper between E1 & TE. You can use a paper clip, or a piece of MIG wire. On mine dielectric grease make it a little tricky to get a solid contact.

I am running with 9-10⁰ static timing. Pulls a lot harder, and no pinging or knocking.
 
Joined
Feb 12, 2015
Messages
92
Location
Plano, TX
Basics first.

I had similar with my 93 recently. I'm same as you, not really up to speed on all the EFI stuff.

Mine occurred after I changed plugs, leads, distributor cap and rotor, and advanced the static timing.
I checked, and rechecked this stuff, and put the time back to stock, but still had hiccups.

I just recently replaced the head gasket and while I was at it, replaced all rubber hoses on the engine.
Most were rock hard original OEM. Some where showing splits and cracks.

I replaced all vacuum lines, PCV valve (it was cracked and brittle) PCV hoses, intake hose.
I also replaced the injector harness clips as a couple were broken. I also replaced the oil cap.

My hiccups is now gone. I'm assuming I had a vacuum leak.

Replacing vacuum hoses with the manifold in place would be a PITA, but not impossible with patience and the right tools.

I purchased OEM hoses through Partsouq for all the specialised moulded hoses. I used Gates hoses for fuel, vacuum and basic heater hoses that weren't moulded to save a little $$$. I'm not OCD to the point were everything has to be OEM.



If you play with timing, make sure to jumper out the EFI timing advance at the diagnostic port.
Jumper between E1 & TE. You can use a paper clip, or a piece of MIG wire. On mine dielectric grease make it a little tricky to get a solid contact.

I am running with 9-10⁰ static timing. Pulls a lot harder, and no pinging or knocking.

All of that is SOLID advice!

How involved is it to get the manifold off? If it takes several hours of wrenching, drinking, and cussing to do it with the manifold in situ, and only 0.5-1 hour more, but with less frustration, I am definitely going to go that route. I'm not really scared of taking a lot of stuff apart and I am way worse with very fidgety jobs, especially at the moment due to recent shoulder surgery.

I have already identified a couple of generic hoses that look like good culprits, and I can get a PCV + PCV hose on the way stat. Is there a list of moulded versus non-molded hose? I was kinda hoping to go silicone (as I have on my Swedes for 4-5 years) for as many as possible. It looks like the most common hose ID is 3.5mm. What's the other common size if you know off the top of your head.

I am going to try and take it slow and just strategically knocked this down instead of firing of parts cannon.

Cheers!
 
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Location
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All of that is SOLID advice!

How involved is it to get the manifold off? If it takes several hours of wrenching, drinking, and cussing to do it with the manifold in situ, and only 0.5-1 hour more, but with less frustration, I am definitely going to go that route. I'm not really scared of taking a lot of stuff apart and I am way worse with very fidgety jobs, especially at the moment due to recent shoulder surgery.

I have already identified a couple of generic hoses that look like good culprits, and I can get a PCV + PCV hose on the way stat. Is there a list of moulded versus non-molded hose? I was kinda hoping to go silicone (as I have on my Swedes for 4-5 years) for as many as possible. It looks like the most common hose ID is 3.5mm. What's the other common size if you know off the top of your head.

I am going to try and take it slow and just strategically knocked this down instead of firing of parts cannon.

Cheers!
Don't do silicone. They are known to leak and be too soft.

You can buy OEM stuff from Toyota Online Parts | Genuine Toyota Parts | Toyota Parts Online - https://toyotaparts.mcgeorgetoyota.com/ and gather part numbers from www.partsouq.com
 

mudgudgeon

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I think it would be worthwhile removing the top part of the manifold.

I might still have the invoice with part numbers for all the hoses I used.

Vacuum lines are 3mm, 4.5mm, and some 6mm fuel hose
 
Joined
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Messages
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Plano, TX
I think it would be worthwhile removing the top part of the manifold.

I might still have the invoice with part numbers for all the hoses I used.

Vacuum lines are 3mm, 4.5mm, and some 6mm fuel hose
If you have your parts list handy, I would appreciate cribbing from your prior work.

If not, I can troll through the diagrams and buy what I need.

Appreciate the help thus far and will definitely be reporting back once I get to the bottom of it. Also, I am going to focus on one area at a time and note any improvement/further degradation so it's easier to pinpoint the root cause. Hopefully this thread helps someone else down the line.
 

mudgudgeon

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If you have your parts list handy, I would appreciate cribbing from your prior work.

If not, I can troll through the diagrams and buy what I need.

Appreciate the help thus far and will definitely be reporting back once I get to the bottom of it. Also, I am going to focus on one area at a time and note any improvement/further degradation so it's easier to pinpoint the root cause. Hopefully this thread helps someone else down the line.

Partial invoice below.

Includes all hoses for pcv, heater, bypass, intake, radiator. Some hose clips, and other random shît

I will qualify this list as being for an Aussie market '93.
There will be differences.


Screenshot_20210115-155922_Drive.jpg
 
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Messages
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Location
Ohio, USA
Thanks for your input here! Very appreciated.

I kept trolling Mud last night and found the LandTank MAF discussions around the same topic. However, I went to order one and it shows Out of Stock at Wit's End. I definitely want to make that upgrade - even if it doesn't cure my entire issue. @NLXTACY - will they be back in stock sometime soon?

She's :pig: rich on cold startup, and it gets less rich and more normal as the engine reaches operating temp, so maybe this is just normal behavior and I am overly sensitive to it because I have been driving an electric car for the past 13 months, and not used to exhaust smells.

The more I inspect the vacuum lines, the more I believe it could be due for a refresh, including the lines to/from the charcoal canister. I visually found a hairline crack near the canister vacuum port. on that hose.

She's far too nice and strong for me to be overly concerned, and so I am going to take your advice and just spend more time with it before loading and firing the parts cannon. I work from home and she's not even my DD, so I have a little breathing room.

Lastly, @midfat - where do you order your OE Toyotas parts online? It has been a while since I have had a Cruiser and am out of the loop.
I also sell a set of adapters for the "Ghetto Land Tank mod". less than $125 USD all in, and it works identically to Rick's overpriced aluminum tube. PM me if interested.
 

mudgudgeon

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I also sell a set of adapters for the "Ghetto Land Tank mod". less than $125 USD all in, and it works identically to Rick's overpriced aluminum tube. PM me if interested.

Not cool to come in and pimp your rip off product, and slag off another members product. Particularly when they are a member that contributes a lot to the landcruiser community
 
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Joined
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Not cool to come in and pimp your rip off product, and slag off another members product. Particularly when they are a beefy that contributes a lot to the landcruiser community
Not a rip off product... Rick wasn't the first to do it, and he wont be the last.

What he contributes is taking a lot of your money for a little bit of product, does that mean he's the only one allowed to contribute?

What will you guys think when I drop my supercharger kit before he does... Maybe he'll be ripping me off then...
 

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