High mileage T100 T-Shooting - What Should I do

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Aug 10, 2016
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Atlanta, GA
Team,

I got myself a 2wd 1997 T100 v6 3.4l 5vz-fe for cheap. It has lots of miles on it. 387k to be exact. I bought it knowing it has a few problems as it has some Check engine lights on it. I am going down the list to get the CEL's fixed.

CEL were
#1. P0107 System to lean (Fixed).
#
2. P0302 Cylinder 2 Misfire detected (Currently fixing) and need advise
#3. P0405 - Evaporative Emission Control system pressure sensor. (Did not t-shoot yet till i fix CEL #2)


CEL #2 - Is what I am working on now - Cylinder 2 Misfire - The engine being old with 387k miles is on the low end of the compression for this engine. All of the cylinders were between 150-140 lbs psi of compression. So I thought okay lets do a Leak down test for cylinder 2. After doing that I did not find a severe drop in pressure in #2 cylinder, like only 5-7% drop in pressure, but I did hear air escaping from the Oil cap. I did not see any more air noises from anywhere else. Not exhaust, not Intake, no air bubbles from radiator. So I assume I am getting pressure loss from the worn piston rings. I have also swapped the ignition coils, wires and put in new spark plugs with duel tips.and still have Cyl 2 misfire. So I assumes it was the fuel injector which is why I did the compression and leak down test. BTW I am seeing very little white smoke coming out of the engine during start up. Very little and it goes away within 3-5 seconds of starting the engine. No blue smoke at all. I am however getting some water droplets coming out of the exhaust pipe. BTW I did see other Cylinder misfire code come up when CEL #1 was not fixed like Cyl#3 Cly#6 misfire. But its only Cyl #2 now after the fix.

Other symptoms I see - Oil leaking from camshaft/valve area. In fact the engine likely needs another valve cover gasket which I can replace as well. I also see significant oil dripping. B/c the engine is so oily I am not zero down on if its oil pan or valve cover gaskets that are leaking.

---->>> 1) So my question is should I just junk this engine and look for another used one? b/c I am just going to have oil burning? I can technically replace the #2 fuel injector to get the engine code to go away. But I am wondering if the worn piston rings will be a problem? and why bother and just find a good used engine?

---->>> 2) If I do need to get an engine is there any place to buy a decent used engine with 180-220k miles on it somewhere?

My inclination is to fix the fuel injector in #2 and see how it runs and then make a decision. Any advise would be appreciated.


BTW here's how if I fixed - CEL 1 System to lean Code - main issue which was fuel trims (FT) where off the charts STFT and LTFT where running lean. (STFT was +20-25%, LTFT +20-25%), O2 sensor bank 1 was not responsive showing around 0v most of the time due to the fault. Another major symptom - The truck would start up when cold without any problems. But It would not start up if I started the warm engine after 10 min of engine being off. I think basically b/c of the FT the cylinders where getting flooded with fuel causing the issue with restart. Additionally I did see other Cylinder misfire code come up when this was not fixed like Cyl#3 Cly#6. But its only Cyl #2 now.

After much troubleshooting I swapped the fuel pump + fuel filter and my issue with FT are resolved. (STFT is not -4 to +5%, LTFT -2 to -5%). I also has small vacuum leaks that I fixed with swapping the rubber hose. There is a small leak where my passenger manifold meets the exhaust pipe. But I think it will be okay at the movement.

Troubleshooting steps for CEL 1 - Did a few things. I cleaned out Mass airflow (MAF) sensor which is working fine. Cleaned out the throttle fully including taking it out and cleaning the IAC valve with carb cleaner. I also has small vacuum leaks that I fixed with swapping the rubber hose. There is a small leak where my passenger manifold meets the exhaust pipe. But I think it will be okay at the movement. Checked PCV valve was shaking freely.

BTW P0302 Fix - This Cly 2 misfire was fixed by swapping the #2 cylinder fuel injector. I bought a generic one from Advance auto. It worked no prob.

CEL #3 - After fixing the P0302 where I fixed the lean codes and the misfire I got 2 Codes - P0441 and P0450.
The fix for this was swapping the Vapor Pressure Sensor (VPS). Both codes were fixed. The VPS is the sensor that has the 3 pin connector and only 1 rubber hose. Also for this truck the VPS was not being manufactured by Toyota. So I googled online where people who have 4runner/Tacoma swapped VPS from other Toyota VPS from V6 cars. I dont know if V6 VPS is needed but since its a similar engine I choose to go with V6 VPS. I found used VPS on ebay which worked just fine. I got mine for <$30 bucks. I am sure if you look you get one between $15-45 bucks.
 
Last edited:
Joined
May 27, 2011
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Have you tried moving the #2 injector to another cylinder? Say, swap #2&6 out, clear CEL, and fire it up to see if the misfire follows to #6.

Are you going to do the motor swap or have a someone do it? If you were going to do it you could just as well overhaul that engine. New crosshatch in the cylinders, new rings, new rod bearings, new gaskets all around, etc. May come out a little cheaper and get another 300k miles.
 
Joined
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Messages
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Location
Atlanta, GA
Yeah I did the swapping of the Injection coils from 2 to 6. Even after swapping No. 2 still showed misfire. So I dont think its the coils. Also as I mentioned I put in new spark plugs. The NGK ones.

I guess I'll Youtube overhauling an engine. I have done all the work. Although I have never overhauled I am willing to learn.
 
Joined
May 27, 2011
Messages
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Location
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Yeah I did the swapping of the Injection coils from 2 to 6. Even after swapping No. 2 still showed misfire. So I dont think its the coils. Also as I mentioned I put in new spark plugs. The NGK ones.

I guess I'll Youtube overhauling an engine. I have done all the work. Although I have never overhauled I am willing to learn.
I redid the 1.8t out of my Jetta years ago. It seemed like an impossible feat but it wasn't too bad. I created a spreadsheet of torque specs and took it one day at a time. Ordered up everything I knew I needed and had the parts sitting in my garage before I started. Harbor Freight shop crane and engine stand were back savers.

The dumbest thing I did not do was label the wires to the engine. There are a bunch on a German motor and several have the same connector. Scotch tape and a sharpie will save hours of guessing. Wouldn't hurt to even cow tag them with numbers and have a notebook of what it is. You can paint things on it while it's out, delete exhaust recirc stuff easily, etc.
 

ToyotaMatt

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here is my 97 day i bought new

captains chairs too
 
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