RORERI: A JDM 1992 ST185H-BLMVZ

Tippo

Well-known member
That's the cleanest tank I've ever seen come out of an ST185. I would clean it all off and repaint while it's out. Then get a gasket kit from GT4-Play. iirc they have the bolts as well. Everything else looks like it's in great shape.
 

Roreri

Active member
Yeah it is really clean, isn’t it?

I went ahead and ordered those gaskets—one for the fuel pump holder and one for the filler tube. You gotta love the shipping costs: 28 Pounds!

So, since I have some time I’ll go ahead and paint the tank. There was some rust on the inside. Is there anything I can do to treat the tank interior that I ought to do since it’s out?
 

Tippo

Well-known member
Roreri":3t77se3n said:
Yeah it is really clean, isn’t it?

I went ahead and ordered those gaskets—one for the fuel pump holder and one for the filler tube. You gotta love the shipping costs: 28 Pounds!

So, since I have some time I’ll go ahead and paint the tank. There was some rust on the inside. Is there anything I can do to treat the tank interior that I ought to do since it’s out?

I just hot-water pressure washed mine out. Soap and then water to rinse it out. Once it was clean, I dried it out completely with a vacuum and time. Definitely don't use a sealer or anything if the tank is clean, that's a disaster waiting lol. For the outside, I treated mine with flex-seal rubber after a few coats of chassis paint. Did the trick for sure!
 

Roreri

Active member
Right on! It’s hugely helpful to be in a dry climate for this. Once I get the rust dust out, it will dry clean and quick.

The gaskets are said to be arriving on the 12th so not such a long wait.
 

Roreri

Active member
When I got the Lorelei, it had an interesting lug nut setup. Each wheel had four BBS hex headed lug nuts, and a special lock nut that required a key that didn't come with the car. I missed that in the inspection, as I was focusing on many other matters, but that's an important point in a pre-purchase inspection.

Anyway, when I changed out tires almost immediately after purchase (another aspect of inspection that I am now wiser on--they looked good but were not good), the locking lug nuts had to be removed forcibly. The shop replaced these with a random no-name lug nut.

Since then, one lug nut came loose and is now aside a road somewhere.

Wishing to regularize the lug nuts, I purchased a set of BBS steel lug nuts--these guys here: https://store.bbs-usa.com/collections/w ... t-sets-257

Here's the difference between the new lug nuts and what's on the Lorelei:

Lug Nut Weight Comparison.JPG
Clearly, the BBS lug nuts that came with the Lorelei were super lightweight models. The difference of 32 grams per lug nut adds up to 640 grams--1.4lbs of that sometimes overemphasized and legendary "unsprung weight. The previous owner thought it worth pursuing, obviously.

Maybe I'm a fool, but I went ahead and got a set of 20 ultra lightweight lug nuts from N75 Racing: https://n75motorsports.ca/products/ultr ... wheel-nuts

N75 Lug Nuts.JPG
All told, these weigh 270 grams, as compared to 1040 grams for the BBS steel lug nuts. 1.7 lbs difference. Will it make a difference? Maybe. Car gear is fairy dust and promises. Of course I'll let you all know how they work out.
 

Roreri

Active member
The fuel pump assembly and filler pipe gaskets arrived from GT4-Play, a whole weekend ahead of schedule!

I went and got a pack of stainless steel wire ties, a can of DupliColor Toyota 202 Black, and a pack of shrink wrap. My intent was to use the wire ties to secure the fuel pump to the fuel pump bracket, and to use the shrink wrap to add an additional layer of protection over the wires to the newly installed fuel pump. I planned to clean the tank and then paint it another layer of black.

Cleaning went well. The tank was as close to immaculate as I could expect from a thirty year old tank. I did however dump out almost a pound of rust from inside the tank (417 grams, or .92 lbs). The paint was in such good condition I felt it extraneous to add another layer of paint to the tank exterior.

The fuel pump was next. I cut the new rubber hose to length, installed it onto the bracket, placed the the clips onto the hose without releasing the tension on them, installed the new pump, attaching the new hose to the top pipe of the pump, then installed the rubber base and filter, installing the spring clip to keep the filter on, and then released the tension on the clips on the hose. I used the wire ties to secure the new fuel pump even more securely to the fuel pump bracket. I then re-attached the power cables after cleaning the leads again. The shrink wrap went unused—the wires I deemed in good enough condition without reinforcement. I set the new gasket to the top of the fuel pump assembly and re-attached the assembly to the fuel tank.

New Fuel Pump 9 SEP 2022.JPG
Clean Fuel Tank 9 Sep 2022.JPG
That tank is in damn near perfect condition--well, uh, and lighter too now that it's minus a pound of rust.

I inspected the old pump. I tapped the old pump’s fuel filter on my workbench and a fine dusting of rust fell out of it. I considered it entirely possible that the fuel filter might have been clogged, and impeding the flow of fuel. I'll hold onto this pump and check the flow rate sometime. It could be of use to some needful allTrac-er down the line--maybe even me!

Old Fuel Pump and Rust 9 Sep 2022.JPG
Heading back down to the garage after supper to lift the tank back up, secure it, and re-attach the lines and filler pipe. If I hurry I might be able to test my work tonight, or certainly tomorrow morning.
 

alltracman78

Active member
DON'T USE TEFLON TAPE ON A FLARE FITTING.
OR ANYTHING EXCEPT METAL PIPE THREAD.

That pump is toast. I started wondering about rust in the tank. The pump is full of it inside.
If you had that much rust inside it may start rusting again. Keep it as full as possible.

Careful with plastic and gasoline. Gas is a solvent. Can dissolve plastic. You don't want that in your tank.
 

alltracman78

Active member
The guy with the jumper is on FB on the 5th gen parts group. Mike Morris?

Wrenches only squeeze together in one direction. Depends which side of the fitting your facing. Whatever you're loosening should be rotating counterclockwise (unless it's LH thread, like on a turbo shaft).

DON'T RUN THAT GAS THROUGH YOUR 2 STROKE. IT'S FULL OF RUST AND 2 STROKE GAS (WITH OIL) LUBES THE ENGINE. You're going to be running rust all over the bearings and piston.

Gas is a solvent also goes for paint and rubber paint. May or may not dissolve it.

You may or may not be able to tighten that fitting enough. It's pretty beat up. Make sure you check it carefully.
If you CAREFULLY file it down a little you may be able to get a 13mm on it. IIRC a 1/2 is slightly smaller than a 13mm. If the 1/2 is bigger that may work better than the 13. Or 14.
Once you KNOW it's not leaking may be a good idea to cover it in grease so the bare metal doesn't corrode. Don't know how much it will in Colorado, but still.....

Sorry for the caps, had a few whiskeys tonight.
 

Roreri

Active member
The caps are fine--a good warning is a good warning. I asked, so I hoped for an answer. I wish I had a couple of belts of whiskey in me, after my evening's doings.

I got the tank wrestled back up, the fuel filler pipe re-attached--gotta love those little bolts in the back--and the fuel lines re-attached.

The flare nut for the hard line was a son of a bitch to get started, but get it started I did, through dint of not giving up.

Tomorrow I get some fuel and try it out.

I'll dispose of that dirty fuel.
 

Roreri

Active member
Okay...long story short, the Lorelei's performance issue was not solved by installing a new fuel pump.

I got the hardline flare nut lashed down and it's solid. The flare nut is an embarrassment now and someday I ought to have it replaced, but it's secure.

I was hopeful, but...on the check ride I observed the same disturbing fuel pressure drop and lean conditions as before.

Further, I filled the tank to the click stop, and it leaked as before--the new gaskets did not solve that issue. Maybe it's the bent tube gasket--which I did not replace but only reconditioned with AT205 Reseal. I did figure out through putting in an initial 5 Gallons plus 13.4 Gallons at the local gas station that it's 18.4 Gallons to the click stop. My old procedure of adding 10 Gallons at 1/4 tank is probably the way to go.

When I got back, I did a voltage drop test and here's what I got:

Voltage Drop FP and B+ Jumped 10 Sep 2022.JPG
With FP and B+ jumped at the diagnostic box, I saw pretty severe voltage drop--2.375 volts on average across two different multimeters. I found this difficult to believe which is why I did it twice, but my observations bear it out: While driving, I never at any time see the rich conditions and power that was routine even a couple of months ago. Any time I attempt to go WOT and achieve boost, the mix goes lean and fuel pressure drops. I can, however, drive at vacuum or zero boost just fine. It's like I have my 1991 Celica ST all over again--only worse.

Voltage drop of 2.38 volts is verified or at least further evidenced by a check of the voltage at the terminals and the voltage in the pump circuit. 14.55 volts minus 12.17 volts equals 2.38 volts.

Voltage at Terminals and Voltage to Pump 10 Sep 2022.JPG
As bad as that is, the voltage drop with the fuel pump relay installed is horrific:

Voltage Drop Comparison Fuel Relay In 10 Sep 2022.JPG
Though the readings were not consistent between multimeters, they were taken at different times and under different conditions. Both are terrible and the observed driving performance is what you would expect: Awful. Like, turn around at the end of the block and come back home bad.

However, voltage drop is not the whole of the story, I believe. I rigged up a direct line with 14G stranded automotive wire from the battery terminals to the fuel pump harness in the rear compartment, and set up a switch on the line in the cabin. The pump draws 12.3 volts when switched on without the motor running, and 13.13 volts at idle. I didn't do a voltage drop test with this setup--tonight. It's basically like a kill switch. I turn the pump on, it pressurizes the system, I turn the motor over, and we're off. I can definitely hear the new pump whining away back there, what with the rear seats down. The original pump was much quieter or at a frequency my military grade hearing could not pick up.

I took the Lorelei on a check ride with this situation in place and performance was better. I still observed leaning out under boost, but I could achieve mild boost--2.8psi--at 14.5:1. Pushing more resulted in leaning out and fuel pressure dropping. I have been running the same test loop throughout all of this, and I live on a bitch of a hill--I was able to motor on up it, at least, when I've had difficulty finding the right throttle setting before.

So, my thoughts? The fuel pump is only part of the issue. I think one, I need to address the fuel pump wiring harness, and two, I need to investigate the fuel pressure regulator. Possibly, a new fuel relay might help. Hell, until I look into it, it might be the entirety of the issue!

Grounding was another possibility I was advised to check: I have checked grounding and while I have not visually inspected every ground wire strap, I've touched the multimeter to various points and combinations and every reading is within what I've read is correct.

The work continues...
 

Roreri

Active member
I'm shopping for a fuel pressure regulator that will work with a Gen 2 3S-GTE.

The OEM part (Toyota 23280-74070) is not available.

Does anyone have any advice to give on this topic? I'm looking to hook something into the stock fuel rail. I am not looking for a large pressure increase from the 42psi standard.
 

Tippo

Well-known member
Roreri":2k8jbdz0 said:
Okay...long story short, the Lorelei's performance issue was not solved by installing a new fuel pump.

I got the hardline flare nut lashed down and it's solid. The flare nut is an embarrassment now and someday I ought to have it replaced, but it's secure.

I was hopeful, but...on the check ride I observed the same disturbing fuel pressure drop and lean conditions as before.

Further, I filled the tank to the click stop, and it leaked as before--the new gaskets did not solve that issue. Maybe it's the bent tube gasket--which I did not replace but only reconditioned with AT205 Reseal. I did figure out through putting in an initial 5 Gallons plus 13.4 Gallons at the local gas station that it's 18.4 Gallons to the click stop. My old procedure of adding 10 Gallons at 1/4 tank is probably the way to go.

When I got back, I did a voltage drop test and here's what I got:

View attachment 1
With FP and B+ jumped at the diagnostic box, I saw pretty severe voltage drop--2.375 volts on average across two different multimeters. I found this difficult to believe which is why I did it twice, but my observations bear it out: While driving, I never at any time see the rich conditions and power that was routine even a couple of months ago. Any time I attempt to go WOT and achieve boost, the mix goes lean and fuel pressure drops. I can, however, drive at vacuum or zero boost just fine. It's like I have my 1991 Celica ST all over again--only worse.

Voltage drop of 2.38 volts is verified or at least further evidenced by a check of the voltage at the terminals and the voltage in the pump circuit. 14.55 volts minus 12.17 volts equals 2.38 volts.

View attachment 2
As bad as that is, the voltage drop with the fuel pump relay installed is horrific:


Though the readings were not consistent between multimeters, they were taken at different times and under different conditions. Both are terrible and the observed driving performance is what you would expect: Awful. Like, turn around at the end of the block and come back home bad.

However, voltage drop is not the whole of the story, I believe. I rigged up a direct line with 14G stranded automotive wire from the battery terminals to the fuel pump harness in the rear compartment, and set up a switch on the line in the cabin. The pump draws 12.3 volts when switched on without the motor running, and 13.13 volts at idle. I didn't do a voltage drop test with this setup--tonight. It's basically like a kill switch. I turn the pump on, it pressurizes the system, I turn the motor over, and we're off. I can definitely hear the new pump whining away back there, what with the rear seats down. The original pump was much quieter or at a frequency my military grade hearing could not pick up.

I took the Lorelei on a check ride with this situation in place and performance was better. I still observed leaning out under boost, but I could achieve mild boost--2.8psi--at 14.5:1. Pushing more resulted in leaning out and fuel pressure dropping. I have been running the same test loop throughout all of this, and I live on a bitch of a hill--I was able to motor on up it, at least, when I've had difficulty finding the right throttle setting before.

So, my thoughts? The fuel pump is only part of the issue. I think one, I need to address the fuel pump wiring harness, and two, I need to investigate the fuel pressure regulator. Possibly, a new fuel relay might help. Hell, until I look into it, it might be the entirety of the issue!

Grounding was another possibility I was advised to check: I have checked grounding and while I have not visually inspected every ground wire strap, I've touched the multimeter to various points and combinations and every reading is within what I've read is correct.

The work continues...


What a PITA, but sounds like you're on the right track. Doesn't hurt to replace the fuel pump as it definitely looks like it had some nasty buildup in it. Aside from that, the relay ore regulator is my bet. Unless there was a short/grounding or some rodents, unlikely a wire harness is no good. That would be a last resort for me. Mirum has a similar fuel delivery issue on lean condition, but it's most likely the ECU on that.
 

Roreri

Active member
I have a replacement fuel pump relay on order and will try that.

I took a drive today, and monitored the pump current. Started out at 13.64 volts, and this slackened throughout the trip to 12.9 volts by the end of an hour cruise.

I strongly suspect that the fuel pressure regulator innards have given out, and the FPR is allowing too much fuel back to the tank--it won't allow pressure buildup to the injectors. That's my hypothesis. I mean, on top of the fuel pump being voltage starved.

I just need some advice on what aftermarket FPR and hardware I ought to collect up to effect the correction.

I have done a shitload of work on this bad boy and corrections there have been none.
 

underscore

Well-known member
I'm a bit tired at the moment but isn't the larger voltage drop with the relay installed normal operation? From my understanding at low load the relay feeds power through the resistor, resulting in less voltage across the pump and less flow. Then at higher load it bypasses the resistor so the pump sees full voltage.
 

Roreri

Active member
I guess I’ve been tired too. That is eminently sensible. At idle I suppose something like that would be expected. It’s just that it doesn’t kick in the higher voltage when needed—at least from what I’m observing in driving.

I’ll have a new fuel pump relay on Tuesday evening, so I’ll see…
 

Roreri

Active member
With some help from a fellow allTrac-er I found out about this solution: https://racerxfabrication.com/mr2-celic ... or-adapter

RacerX Bosch Fuel Pressure Regulator Adapter.JPG
It allows the use of readily available Bosch 3 and 4-Bar FPRs, but does require some work to mate the return line output to the return line.

RacerX offers the option of a 3Bar or 4Bar FPR with it. The sole review said that he used an adjustable Bosch FPR. This guy from ECS Tuning: https://www.ecstuning.com/b-ecs-parts/a ... 198501blk/

Adjustable Fuel Pressure Gauge ECS Tuning Part Number 5705.JPG
Now...this would be a $254 parts bill.

Given that a non-adjustable Bosch fpr adds $45, that means $130 extra for adjustable and an inline fuel pressure gauge.

Alternately, I could try an Aeromotive 13109 for $209--hell, $164 from Aeromotive's Amazon store or Summit: https://www.amazon.com/Aeromotive-13109 ... B000CFSL1I

Aeromotive 13109 Fuel Pressure Regulator.JPG
But I am told that I would need about $XX in hardware to make this one work with the stock fuel rail...

Thoughts?

Option One: RacerX Bosch FPR Adapter and Bosch 3 or 4 Bar FPR. $124

Option Two: RacerX Bosch FPR Adapter and Bosch Adjustable FPR. $254

Option Three: Aeromotive 13109 Adjustable Fuel Pressure Regulator. $164 (plus $XX in additional hardware)

EDIT: The problem was not corrected by a new fuel pump relay. I assume I have two functioning fuel pump relays now, for whatever good that does me.

After weighing all of the factors, I've decided on the RacerX Bosch Fuel Pressure Regulator Adapter and the 3 Bar Bosch FPR. First, it will be the easiest to install. Second, it is the least cool factor option. Third, the cost is right.
 

alltracman78

Active member
This is what I was getting at when I mentioned you didn't understand what you were doing with the voltage drop test. You understand how to do the test in general, but you don't understand what it's doing or how to use the answers you're getting.

The point is to
A - see if you have a problem in the circuit
B - if you do have a problem, narrow it down til you find the specific problem(s).

If you find a problem in the circuit you have to keep breaking the circuit down and testing parts of it until you find exactly where the problem is.
Basically, you check the whole circuit. Then you break it in half and check each half. Then break each half down into half again. ect ect.
You don't need to break it down exactly in half; use natural points at connectors and/or connections.

Underscore is right, you should have some voltage drop outside of the pump with the FPR in "normal" mode. That's the FPR sending power through the FP resistor.

Your best bet to check the circuit is get one of those jumpers I mentioned so the FPR circuit is always in "power" mode. This removes the resistor from the equation completely. Makes it easier.

Once you have the FPR bypassed you check the circuit and if the voltage drop is too high (say anything above .2v or so) then you need to start breaking the circuit into smaller sections and checking each smaller section individually. This will narrow down exactly where the voltage drop is so you know exactly what to replace or repair.



I'm going to try to break some of this down specifically for your car.
First off I wouldn't worry (yet) about the voltage drop with the FPR.
Let's start easy(er) and go with the voltage drop when you jump FP and B+.
You shouldn't have any voltage drop here. There are no relays. Just wires and connectors. It helps that the wire is all the same color.

It is possible there are several bad connections or problems that are combining here. So don't skip any section(s) if you find one that has a high voltage drop. Keep checking the rest. The only time you can skip is if you check a section and it has no voltage drop. If you find no voltage drop in a section there's no need to break the section down further.
Also, I'm going off the US wiring diagrams. JDM is similar, but there may be some differences.
I'm going to assume you know how to locate the wiring connectors as well as which pin is which in the connector. If not you need to learn. Only going to type so much. :p

As you are breaking this down into segments you're going to be checking connectors that join 2 different wiring harnesses together. These will be some of your "break" points. It doesn't matter which side of the connection you back probe, as long as you use the same side to for both checks. If you use one side of the connection to check one segment and the other side to check the other segment you won't be checking the center of the connection and the pins and crimps for the connection itself.
I know that's a clumsy explanation, I can't think of a better way to explain it.

Key on.

1 - First break point is going to be at the DIAG box. We're going to separate the B+ side and the FP side.
-One MM(multimeter) probe on the positive battery terminal, the other on B+ in the DIAG box. If it isn't basically zero you have a problem in the B+ wiring. Hopefully not because there's a bunch of wires and splices in this circuit. Goes all through the engine harness plus some chassis stuff in the front. Will be a PITA.
-One MM probe goes to the FP port in the DIAG box, the other goes to the blue/black wire at the FP(Fuel Pump) connector. Should be basically zero again, but I'm guessing it won't be.

2 - Now we're going to break the FP part into sections. Engine harness and (several) body harnesses.
-Leave one probe on FP in the DIAG box. Other one goes to the IG2 connector (It's one of the 2 large harness to harness connectors attached to the outside of the ECU. White? I know JDM has this.). Find the corresponding blue/black wire and check. This is one single wire in the engine harness.
-One probe on the FP connector, blue/black wire, other probe on the IG2 connector blue/black wire.

3 - Breaking the chassis harnesses up. This is where I don't know how close the US wiring is to the JDM. So you may have to get creative. Though I'm guessing it will be on the same side because the FP is on the L side of the tank, so the wiring probably runs down the L side of the car for both US and JDM.
-One probe in blue/black wire on the chassis side of IG2, other probe in blue/black wire of IF1. On US spec this is in the drivers kick panel (L side where the large relay/fuse blocks are). Don't know if it will stay on that side or be on your drivers side (RH). This is your dash harness. Could be problematic because this harness is where FP splices into the regular pump circuit. Possible the splice is corroded.
-One probe on blue/black IF1, other probe on blue/black FP.

4 - Breaking up the last 2 chassis harnesses.
-One probe on blue/black IF1, one probe on blue/black BP1, which should be at the rear quarter panel. Roughly the side of the rear seat. This should run from the kick panel along the rocker panel to the rear seat area. One single wire.
-One probe blue/blak BP1, one probe blue/black FP. One wire that should run along the L rear quarter panel area to the fuel tank.

Couple more notes.
We didn't check across FP and B+ with the jumper installed. It's possible that was a bad connection.
This also doesn't check the wiring inside the fuel tank, it only checks to the pump connector at the top.
If you go to check the actual FP circuit, with the relays and all, you only need to check from IF1 (connection at the kick panel) to the battery. The circuit separates at that splice in the dash harness I mentioned above.

Hopefully that helps some.
And wasn't too detailed.
 

alltracman78

Active member
underscore":1ki61v42 said:
I'm a bit tired at the moment but isn't the larger voltage drop with the relay installed normal operation? From my understanding at low load the relay feeds power through the resistor, resulting in less voltage across the pump and less flow. Then at higher load it bypasses the resistor so the pump sees full voltage.

100% Correct
 

alltracman78

Active member
Roreri":2dzmf9vb said:
I guess I’ve been tired too. That is eminently sensible. At idle I suppose something like that would be expected. It’s just that it doesn’t kick in the higher voltage when needed—at least from what I’m observing in driving.

I’ll have a new fuel pump relay on Tuesday evening, so I’ll see…

The relay should bypass the resistor at WOT.
Which you can tell by the ECU going from closed loop to open loop.
Unless it's already in open loop because of cold start or a problem.

I know I keep saying this, but once again, another reason to slap that jumper in there. Gets rid of that question.
 

alltracman78

Active member
Roreri":289eav2q said:
With some help from a fellow allTrac-er I found out about this solution: https://racerxfabrication.com/mr2-celic ... or-adapter

View attachment 2
It allows the use of readily available Bosch 3 and 4-Bar FPRs, but does require some work to mate the return line output to the return line.



EDIT: The problem was not corrected by a new fuel pump relay. I assume I have two functioning fuel pump relays now, for whatever good that does me.

After weighing all of the factors, I've decided on the RacerX Bosch Fuel Pressure Regulator Adapter and the 3 Bar Bosch FPR. First, it will be the easiest to install. Second, it is the least cool factor option. Third, the cost is right.


I have zero experience with that. But the specs mention standard thread. Everything on our cars is metric. Every now and then you can mix the 2 and it will work. Just be careful because this is fuel.

FWIW I would have selected the same as you.
 
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