RORERI: A JDM 1992 ST185H-BLMVZ

simple

Member
Re: Colorado

I left crowded Denver and went out to the desert. Everyone has a van, truck, or SUV in my group. Only a few of us have cars anymore and they don't get used much. Like I said, more fun having handlebars.


d2a3c87bb09f510cefe4ee2096c9366c.jpg
 

Roreri

Active member
Ah, yes. That other lifestyle.

That picture shows up HUGE and cut off in your post. Had to switch to mobile style to see it.
 

Roreri

Active member
It's almost spring and like many, the warmer temperatures and nice weather has got me moving on some improvements to my ride.

Waiting on Parts

Carbon Micro System in Latvia said they would be doing assembly of the carbon fiber hood I put on order in early December and a carbon fiber radiator grill. I'm told they're absolutely worth the wait. So, probably that will arrive mid April.

I put in an order with Feal and they told me it will be 4-6 weeks for them to build a set of Feal 441s for me. So, probably that will arrive in early May.

A/C System Refurbishment

Since the accident last November pushed the components at the front of the car in a bit, I've had a lingering concern that the ac condenser or the fittings up front had been compromised. Today I went and had the system checked out and charged. It held pressure. I know it will leak, slowly, over the course of the next couple of weeks, but if it doesn't leak any more than it did before, then I'll know I can go ahead with replacing the compressor and condenser dryer and union o-rings and it will probably be made right.

Intermittent Hesitation and Loss of Power

Intermittent hesitation and loss of power continues to be a problem. It's drivable, but it can be unpleasant. It's never straight up stranded me. It happens at seemingly random times. Sometimes it doesn't cut out. It's less pronounced and happens less when there's more gas in the tank. I'm right at a half tank in this video showing the problem.

https://youtu.be/I6_uumzJWY4

Last night I replaced the 30 year old Yazaki ignition wires (which had coiled steel around them as a heat shield--very retro cool actually) with new Denso ignition wires. Old as those OEM Yazakis were, they were not the source of the problem. I could change out the distributor cap and rotor. You never know. Though I really doubt those are the problem.

30 Year Old Yazaki Ignition Wires.JPG
The fuel pump is the actual likely culprit, as the AFM shows a fuel starved situation before and when I lose power. From what I know about how fluids and pumps work, the pump is helped out when there's more gas in the tank. Frankly, I been putting it off as I'm not looking forward to dropping the tank and seeing what's going on down there. I put a Denso unit on order today and pulled the aluminum gas tank rally shield off. It's looking pretty good under there, actually. The previous owner did me a solid and a half with that rally shield, because I was really not looking forward to dealing with a bunch of rotted bolts.

Gas Tank Without Rally Shield.JPG
I'll use this thread as a guide for how to go about the work once I have all the parts. PB Blaster and patience will be my friend.

viewtopic.php?f=7&t=38442

If that doesn't solve it...

There was a guy a long time ago that solved intermittent power loss and bucking by correcting a broken solder connection in his AFM. I could pull the AFM and crack it open.

It's been mentioned that leaking ECU caps could be a problem. I could try and pull the ECU on Monday.
 

Tippo

Well-known member
Roreri":19024608 said:
It's almost spring and like many, the warmer temperatures and nice weather has got me moving on some improvements to my ride.

Waiting on Parts

Carbon Micro System in Latvia said they would be doing assembly of the carbon fiber hood I put on order in early December and a carbon fiber radiator grill. I'm told they're absolutely worth the wait. So, probably that will arrive mid April.

I put in an order with Feal and they told me it will be 4-6 weeks for them to build a set of Feal 441s for me. So, probably that will arrive in early May.

A/C System Refurbishment

Since the accident last November pushed the components at the front of the car in a bit, I've had a lingering concern that the ac condenser or the fittings up front had been compromised. Today I went and had the system checked out and charged. It held pressure. I know it will leak, slowly, over the course of the next couple of weeks, but if it doesn't leak any more than it did before, then I'll know I can go ahead with replacing the compressor and condenser dryer and union o-rings and it will probably be made right.

Intermittent Hesitation and Loss of Power

Intermittent hesitation and loss of power continues to be a problem. It's drivable, but it can be unpleasant. It's never straight up stranded me. It happens at seemingly random times. Sometimes it doesn't cut out. It's less pronounced and happens less when there's more gas in the tank. I'm right at a half tank in this video showing the problem.

https://youtu.be/I6_uumzJWY4

Last night I replaced the 30 year old Yazaki ignition wires (which had coiled steel around them as a heat shield--very retro cool actually) with new Denso ignition wires. Old as those OEM Yazakis were, they were not the source of the problem. I could change out the distributor cap and rotor. You never know. Though I really doubt those are the problem.


The fuel pump is the actual likely culprit, as the AFM shows a fuel starved situation before and when I lose power. From what I know about how fluids and pumps work, the pump is helped out when there's more gas in the tank. Frankly, I been putting it off as I'm not looking forward to dropping the tank and seeing what's going on down there. I put a Denso unit on order today and pulled the aluminum gas tank rally shield off. It's looking pretty good under there, actually. The previous owner did me a solid and a half with that rally shield, because I was really not looking forward to dealing with a bunch of rotted bolts.

View attachment 1
I'll use this thread as a guide for how to go about the work once I have all the parts. PB Blaster and patience will be my friend.

viewtopic.php?f=7&t=38442

If that doesn't solve it...

There was a guy a long time ago that solved intermittent power loss and bucking by correcting a broken solder connection in his AFM. I could pull the AFM and crack it open.

It's been mentioned that leaking ECU caps could be a problem. I could try and pull the ECU on Monday.


I did this not too long ago, but I put in a Supra TT fuel pump. It's not actually as bad as it seems.

viewtopic.php?f=44&t=53834&start=15
 

grip-addict

Active member
17 afr under accel is way too lean. You definitely have a fueling problem.
Hit me up when you get around to doing the fuel tank and I can offer some pointers. The biggest one I have is to use flare wrenches and to make sure you don't f up the flare fitting between the tank and the line. The nut that's on the tank is static and does not move. Only the line side actually rotates.

And I'm a firm believer in upping the power line to the pump. The tiny wires that Toyota used in the factory barely check the box. Have you modified your pump wiring to run at full voltage constantly yet? Sorry if that's already covered in this thread.
 

Roreri

Active member
Thanks Tippo for the encouragement! My background in the trades is as a carpenter not a mechanic so this is old dog, new tricks territory for me.

Yeah grip-addict it was no mystery when I saw it at 17 and then the power cut out. Was pretty glaring that the motor wasn't getting fuel. Part of why I got the wideband air fuel meter as a diagnostic tool.

We talked a bit about this problem back in November. At the time there were a variety of possible issues. I've not taken care of some things, which I will take care of before I go into a tank drop. To include:

Cap and rotor (I was lazy and didn't do these when I had the intercooler off last night, so I'll do that tomorrow)
Checking grounding strap at back of motor
Fuel filter (I have one on hand--need to get flare wrenches for this)

Thanks for the pointer about the flare wrenches and the tank side nut not rotating--I bet some of these have been torqued unnecessarily over the years!

I'll also consider running a thicker gauge power line to the pump. I'll have to dig into to which wire and how to run/route it. How about this...I ought to run that thicker wire to the pump and see whether that fixes it. Wouldn't it be hilarious if what the problem was was an old and corroded wire somehow?

To trick the fuel system to run full voltage all the time, you just bridge +B and FP in the diagnostic block right? I've done that and the problem persisted. I'll do it again.

I had this exchange with a friend of mine who used to be a Toyota Tech:

"I still have this weird flutter when at less than a half tank. It's funny. I don't dare fill it to the click stop because it will vent through the can/leak. Nor can I let it get less than a half tank because hesitation and stuttering. I'm good from half to 7/8 full."

"You could have a leak in the rubber line in the tank pump that gets uncovered and draws air."

The thing that's so frustrating is this car CAN go if you lay your foot down. But sometimes it WON'T go. An intermittent problem like this is a real hassle. Thanks for all the help. I'm tracking it down.
 

underscore

Well-known member
Do you have any pictures of the fuel tank skid? Those mounting brackets look nice and hefty so I imagine the skid is too, and I'd love to try and copy it.

Your pictures and Tippo's pictures are throwing me for a loop now too. I was under the impression there was a drain plug in the gas tank, but clearly there isn't.
 

grip-addict

Active member
Ahh I remember that other thread now, thanks for reminding me.
I think you're on the right track with the fuel filter. I'd do that immediately before trying to troubleshoot anything further. 17 afr is too lean and that could be causing engine damage. It will definitely if it's that lean and under boost.
Do you have any mechanic shops near you that you would trust to do the fuel filter swap? I'm thinking like a mom and pop shop that has been around since forever.
 

Roreri

Active member
Underscore, I've taken a couple of photos and will set you up with a separate root post on the topic over in How To.

Grip-addict, I do know a shop that sorta fits that bill. They're not a mom and pop shop but they're the shop the old timers here in the neighborhood association take their trucks to. I've used them for my 1999 F-150 and they're good people.

I'm curious why you recommend I take it in for a fuel filter change. The instructions in the BGB look pretty straight forward. Though I know that it's possible to screw it up. Is is that possible? Per this it presents as a pretty easy task: viewtopic.php?t=51523
 

Roreri

Active member
Now I know why you asked if there's a reliable mom and pop garage I can take it to for the fuel filter. It was not a pretty easy task. Besides being really rather hard to get to, the bottom compression nut does not want to open, and is unresponsive to PB Blaster--so far. All I have done is render it undriveable now, because the metal washer for banjo nut on the top will not re-seal now that it has been opened.

Flare Wrench on Compression Nut at bottom of Fuel Filter.JPG
Tomorrow is another day.
 

grip-addict

Active member
Ahh yeah age has just loctited it in there for you so it doesn't leak! :D

When I do the job, I usually get at it from the top. I put a wrench on the bottom nut that's on the filter and then stick the flare wrench on the flare nut and squeeze both wrenches together. I find I get more tq this way. I think I had to use both hands when I did it on my father's Camry as it'd been so long since the last swap.

Just triple check that you're turning the nut the correct way and that you aren't twisting the hardline. That's the biggest risk here imo. If the line gets damaged... It sucks. A lot.

The washer between the banjo and the filter is just a copper guy you can pick up from any hardware store nuts/bolts section. I just have one of those 15 dollar sampler packs from Amazon since my turbo is seemingly always coming off and the oil fittings use the same kind of copper crush gasket. If you need to get it back together, just grab some of those and tq the banjo bolt back down to factory spec. And make sure it's not leaking fuel of course :) bridging the pins in the diagnostic box is a great way to pressurize the system to check for leaks without actually having to run the engine.
 

Roreri

Active member
After repeatedly approaching the task of replacing the fuel filter, being certain sure that I was wrenching the right way, and failing to budge that bottom union/flange nut, I resorted to throwing cash at it.

Thankfully, I was able to figure out why the banjo nut at the top wasn't sealing. There are two washers. The bottom washer had fallen down into the engine bay and I spotted it. So, at least I was able to drive it to the shop.

If you don't do it yourself, expect to pay for two shop hours to see it done. Humiliating, for I would have thought I would be able to see this done myself. But, that is compensated for by the fact that it's done, and two, that was a tight place to work, so money well spent in my opinion.

New Fuel Filter 22 March 2022.JPG
Some observations:

1. It idles a bit smoother than before, and about 100rpm higher (EDIT: Illusory, because under AC load)
2. If I stay off boost, I observe no overly lean conditions or cutouts.

Next will be the fuel pump.
 

grip-addict

Active member
I don't think it's embarrassing at all. This is one of those jobs that looks easy on paper, but one slip-up can turn it into a much much worse job, very quickly. Just ask my younger self...

Still getting 17 AFR's when putting the engine under load?
At least you know the job did need to be done since the behavior sounds a bit better.
 

underscore

Well-known member
In my mind if it took a shop 2 hours to do it then it would've been a royal PITA to DIY so the money was well spent. Now you know when the filter was last done and that it's not all siezed together should you decide to DIY next time.
 

Roreri

Active member
Oh, yeah, certainly. I was seriously worried about tweaking that fuel line.

I haven't placed the engine under serious load. I took it on a 30 minute drive, keeping it at 0cmHg or less (no boost). It behaved well. We'll see tomorrow. I'm driving it to work.

And yeah, underscore. If you look at the photo, there's a bolt on the bracket that's like torturous to get to, like a 10 degree twist per wrench turn. Would have taken a lot of effort to get to. So, costly, but it's done.

EDIT: Drove the 10 miles to work under non boosted conditions this morning (23 March). Aside from the relatively more sedate performance, it was solid. No cut outs, no stumbling. It ran a little lean, idling and running at 14.8-15.

It’s returned to idling at 550-600rpm. I was mistaken. Under AC load it idles at 750-800rpm, dropping to 550-600rpm.

Fuel pump parts are on their way.

FURTHER EDIT: Then I take it out for a short drive for lunch and it wants to idle slightly rich, initially 13.5 but slowly rising over the course of a minute to 14:1. If I rev to 1000 rpm it settles at 14.7 +/- .1 and if I go to 2000rpm it goes to 15.5, then when I let off it hangs at 15.2 then drops to 14.2. And then I try it again, and I get different results. It’ll give me rich mixes sometimes when under non-boost loads. Other times not. It’s inconsistent to be sure. This is some Click and Clack the Tappet Brothers level stuff.

It is no cooler but humidity is up as it’s raining a bit. It’s a bag of mysteries, for sure. I wonder if the narrowband O2 sensor is going.
 

Roreri

Active member
I recorded the twenty km drive home. Kept it almost always off of boost. I'm curious what your thoughts are.

https://www.youtube.com/watch?v=-jUq_VJpbps

00:08 Starts right up. This has never been a problem. Idles low at 550. Nice rumble but bothersome to a purist like me--I would prefer the to spec 800 +/- 50rpm.

00:30 Settles in at 14.2:1 Air to Fuel Ratio.

00:45 Immediately goes slightly lean (mid to high 15s) as I ease out of the parking garage.

01:20 Goes quite lean (higher than 16) as I get out onto the street, but settles down to the high 15s.

01:50: Settles to 14.6:1at a stop sign.

02:30: Hangs out slightly lean at 14.9:1 while cruising at low speed.

03:53: Oil Temp reaches 100 degrees F

04:15: Lean as I merge into traffic and put a moderate load on. Varies from 15:1 with momentary spikes into 16s.

06:22: Coolant temp reaches 105 degrees F.

07:08: Spike to 17:1 while under light load, then drops to 14.8:1 as I let off the gas and stays there as I continue to gain speed.

08:20: Momentary (8 second) spike to high 15s, but settles back down to 14.8:1

08:37: Lean as I increase speed from 95km/h to 115km/h

09:30: Settles in at 14.8:1 as I accelerate from 115km/h to 125km/h

10:16: Lean as I accelerate in 2nd gear through a curve, reaching 16s momentarily but mostly 15s.

10:26: Good acceleration near boost load, 60 to 95km/h in ten seconds, near stoichiometric ideal. Oil temp reaches 150 degrees F.

11:14: Lean as I apply light load in a curve, and merge onto the expressway--mid 15s to mid 16s.

12:33: Settles down to 14.8:1 as I cruise at 100km/h.

13:10: Goes lean (15s) as I apply light load, accelerating from 100km/h to 120km/h in 12 seconds.

13:37: Lean again (mid 15s to mid 16s) as I apply light load, accelerating from 110km/h to 125km/h.

13:45: Settles down to bouncing around 14.8:1 as I continue accelerating from 125km/h to 150km/h in 14 seconds.

14:42: Stumbling as I merge onto surface streets.

16:00: Take off from stop light. Nominal AFR. Oil temp reaches 176 degrees F, Coolant reached 185 degrees F.

16:30: Pull up a hill. Some stumbling, but it settles in to 14.7:1.

16:52: Coolant reaches max temp for this trip at ~200 degrees F.

17:45: Coasting clutch in downhill. Idling at 14.9:1.

18:00: Cruising at moderate load. 14.7 to 14.8:1.

19:13: Acceleration 75km/h to 100km/h in 16 seconds. Bouncing around 14.7:1.

19:52: Take off from stop light. Nominal AFR.

20:58: Oil reaches max temp of 195 degrees F.

21:50: Destination reached. Idling at 14.9:1.

25:10: Started back up. Idling at 14.8:1 and 14.9:1.

As I listen, I'm struck by a couple of things.

One, wow, that suspension is rough. Really looking forward to the Feal 441s, which I hope will tone that down.

Two, it doesn't sound clean. I can definitely tell it's microstuttering, just from the engine tone.

I am considering these possibilities:

1. Bad distro? I have a cap and rotor on hand.
2. Bad O2 sensor? Could be feeding bad data to the ECU.
3. Bad fuel pump? I have a Denso unit on hand now.
4. Failing ECU. This was mentioned earlier as a possibility.
5. Failing AFM. Perhaps. I could do continuity tests and crack it open and inspect.
6. Clogged Fuel Injectors. Perhaps. I ran a can of fuel injector cleaner through it at the end of October/beginning of November. I could run another can of fuel injector cleaner through it.

I checked for air leaks with throttle body cleaner. No leaks.

No Check Engine Lights.

I made certain sure the gas cap was on tight.

I put the fuel pump on the GT-Four. In the spirit of mechanics everywhere I charged 2 hours labor.

Fuel Pump On The Celica.JPG
 

grip-addict

Active member
man, i'm sorry to hear that there are still issues.
If you see >14.7 but you're not touching the throttle and you're letting the RPM's wind back down, then I wouldn't worry about it as there is a fuel cutoff point.
Seeing >14.7 under any load is bad though, and it sounds like that's still happening.

Swapping your distributor cap and rotor are really easy to do, just keep track of which wire goes where (new cap should be numbered, but make sure before you embark). Ignition shouldn't cause you to go lean though, this still sounds like a fueling issue to me.

unplugging the o2 sensor entirely should just cause the engine to run super rich. It might be worth trying this just to see what happens.

The intermittent part is weird. If it was my car, I'd be working on #4 next and check out the ECU. When caps start to leak, the pos/neg poles inside start to change position and the output is really unreliable. viewtopic.php?t=52355 touches on the process. I know some of the other forum members have had to "re-cap" their ECU recently, so it would make sense that all of the (running) cars would need it at some point around now. My chassis is a '91 and I had to redo the caps on the tach 2 years ago as they weren't doing their job right and the needle would just bounce around aimlessly.

If you choose to go down the fuel pump path next:
https://www.harborfreight.com/basic-fue ... 64939.html if you want to spend another afternoon on it :) this does at least come with the correct banjo bolts; you shouldn't need to buy anything extra to test.

If you open up the AFM, I definitely recommend doing some searches here on the board first. There are some screws on it that undoing will break the AFM. I bet there's a BGB test using a multimeter and checking resistance though.

If you want to get your injectors cleaned, you can have them done at witchhunter.com for about a hundred. You could always have one injector that's running real shitty but the others are fine...
The only downside is that you'll need to replace some of the injector gaskets and that'll add in some cash and waiting @ the toyota parts counter.

ECU is where my mind goes next as maybe you'll be able to see visible leakage from the caps. I think you've earned an easy win like that at this point.
 

Roreri

Active member
Thanks much. I'll get on the ECU and distributor cap and rotor today.

This morning, curious about whether the O2 sensor could be to blame, I unplugged the O2 sensor. I am 99 and 94/100 sure that this is the plug (the darker grey one dangling down in front of the alternator on the wire coming from, well, the O2 sensor on the downpipe). If I'm wrong and there's another plug I’m supposed to be disconnecting please let me know.

O2 Sensor Plug.JPG
Engine started right up, and as it settled in to idle at 13:1, I was hopeful that it would run richer, but it didn't. It was probably just running rich under cold start. After a couple minutes, I turned off the ignition and started again, hopeful that the ECU was just trying to get its feet under it or reset to base maps or whatever. But, no dice. Worse performance than before.

Headed back home, garaged the GT-Four for the day and drove the F-150 in.
 

Roreri

Active member
Distributor Cap and Rotor Replacement

As a friend of mine said: "It will last as long as you keep giving her all this love." Damn straight. Disappointed that unplugging the O2 sensor didn't force the engine into a rich condition, I dug into the thirty year old distributor cap and rotor when I got home from work.

I did a pre-changeout idle test. It wanted to idle in the 13s, settling down to 13.5:1

I didn't have to take off the intercooler. I marked all the wires with stripes: I, II, III, IIII. A useful mnemonic is odds in the front, evens in the back as you're looking at it.

The distributor cap was a little funky to get loose. 8mm hex for the one toward the firewall, 7mm hex for the one toward the front bumper. Who willingly sets that up like that? Toyota trolling me. Had to use a long socket in my hand to get that more constrained 7mm screw out. Anyway.

Then for the rotor. No surprise, the 3S-GTE is notorious for tight spaces. I had a short cross tip screwdriver so I could get at one of the screws. I resorted to a dual sided cross tip bit that was short enough that I could get down into the nest of wires and tubes to get the other screw loose. Thankfully nothing was seized up and I didn't strip anything. Just the standard litany of wishing there was a little more space in the engine bay.

Old vs New.JPG
I installed a new Intermotor distributor cap and a new Bosch rotor. These went on easy. All in all about a 45 minute job, with me being extra careful. The rotor was about to go.

Condition of OEM Denso Rotor.JPG
My guess is that it just got brittle and the recent stresses cracked it. Plus, look at that corrosion. I can easily imagine all kinds of problems this was causing, even though it's hard to connect ignition problems with a lean condition.

Performance Testing:

It fired right up after installation. As the ECU hadn't reset after battery disconnection, it idled at 12.2:1. I took it on three 13km loops--close to an hour of driving all told over two hours.

The first loop was immediately promising, with it running slightly rich under light load (low 14s). Then, in short order, it was like the ECU kicked in and said "I know what I need to do, I need to lean this shit out," and went to 14.8 to 15:1 at idle. And then, at non-boosted loads, it wanted to stay right there, just above stoich. if I can trust it. I gave it the beans a couple times and the ECU bumped up the mix appropriately:

7psi, up to 11.3:1 AFR
8.5psi, up to 12:1 AFR
8psi, up to 12:1 AFR

The second loop was similarly promising. The ECU had established 14.8:1 as its comfort zone by this point. I observed a couple of minor lean spikes. I gave it the beans again and the ECU responded appropriately.

8.5psi, up to 12.1:1 AFR

As I was getting low on fuel, I decided to fuel up before a third loop. My theory that perhaps more fuel in the tank might mitigate a weak pump, or maybe the low fuel was somehow not getting to the pump really didn't show out. Idle AFR read just above stoich. Seemed to still occasionally while cruising lean out for a moment then correct, but the ECU and EFI system was willing to fuel when a serving of beans was ordered up:

8psi, up to 12:1 AFR
8.5psi, up to 12.1:1 AFR
8.5psi, up to 10.6:1 AFR: https://youtu.be/_r0SalwkKR8?t=612

Performance was much improved. So much so that I set aside pulling the ECU, and focused on these test runs, then reviewing performance and confirming. It's irritating that it wants to idle at 14.8 to 14.9:1 indicated. The more I think about this, the more I think it could be the sensor reading slightly lean. It's located down low after the downpipe. Occasionally the AFR will trend lean but it's hard to know whether that's me coming ever so slightly off throttle while cruising or my foot slipping after hitting a bump or what.

It would be nice to have a way to just set a slightly richer base condition. There are ways to do that. Eventually. The S-AFC the previous owner installed is useless. I can set it richer, but the ECU immediately says nope and wrestles the AFR back to what it wants.

Next Step: ECU inspection.
 
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