saskyrunner88

Hey tmcorbin good to see someone in the same boat as me haha well I just bought the tps sensor, expensive little devils, and I'm putting it on after christmas and I'll tell you how it goes. If you fix it before me make sure to let me know

TinMan

Are you still driving it?

saskyrunner88

No I quit driving it until I install the new tps

DupermanDave

Check for a banana or potato in the tailpipe yet?

saskyrunner88

Hahaha yes there is nothing in the exhaust

TinMan

I took the new Bosch 02 sensor out and put the old one back in. Seems to have taken all the lower end detonation away, still a little valve floating at top end. next time I drive it I will richen up the AFM and see if that takes away the top end lean condition. The exhaust is wide open so it would not surprise me if it needs some more fuel. Ordered a denso 02, wont be in until the 29th.

later
Merry Christmas

saskyrunner88

okay so i replaced both the 02 and the tps and am still having the same issues

85-in-va

i would check for a vacuum leak which can cause it to run lean, easy to check and least inexpensive, and the cause for the oil pressure drop is because when the manifold turns cherry red the oil starts to thin out because of the excessive heat and instead of having10w-40 its like having 0w-20

saskyrunner88

I know this is an old thread but I need help resolving this issue. Since I last posted the runner has got a new tps sensor, re machined exhaust manifold and full exhaust, no leaks. It has no error codes but still heats up cherry red any time I drive it for an extended period of time. The acceleration is terrible but it is a 22re so don't know if it's more then normal. Any help would be greatly appreciated

JohnnyCanuck

Wow that sucks to have this unresolved for almost 3 years. Check this thread: http://www.pirate4x4.com/forum/toyot...g-red-hot.html
good luck.

vasinvictor

iTrader: (3)

Does the 22re have a cold start injector that could be sticking open? What's fuel pressure look like?

Terrys87

iTrader: (1)

An old thread and I have tried everything on here and still getting a Cherry Manifold. 88 4runner 22re.

Things I have done.
No Check Engine Light but when I pulled codes I got a TPS error. I replaced the TPS. Old Part Number was 89452-20030, Toyota now uses 89452-20050 new from Toyota Parts East. It is set to specifications. No more errors and did try two other TPS to eliminate any bad parts.

AFM has 50k miles on it and passes test according to FSM and works on my 86 Runner.

Replaced O2 Sensor with Denso from www.sparkplugs.com and exact replacement.

All hoses are routed correctly and in great shape.

I have removed the Catalytic Converter to see if this is causing an issue.

I have cleaned the Intake System of all EGR carbon related build up. EGR is functioning.

Fuel System is cleaned from tank to injectors and back to tank.

Timing is set to 5 degrees with TE and E1 jumpered.

Denso Plugs, wires, cap, rotor are in great shape.

Timing Chain has 50k miles on it and no issues of being off a tooth.

Truck runs great for about 10 miles. It then loses power and I can open the hood and the manifold is Cherry Red. Let it cool down and then drive again and it runs great until it get hot again.

I am looking for suggestions but in the meantime I will check fuel pressure and see if maybe my fuel pump is getting weak an not putting enough fuel pressure to the injectors. I think I have a spare set of injectors and ECU to try and see what happens. Any other suggestions?

RJR

Could be an exhaust valve sticking open, or stretching slightly when warm such that it doesn't close fully, and letting hot gases out into the exhaust manifold.

Terrys87

iTrader: (1)

Thanks RJR... I did the head gasket and timing chain on this truck a few years ago and had the head serviced when it was off. I had suspected maybe a valve issue and hoping I don't have to get into looking at it just yet. I did do several more checks on the truck and so far everything looks great. When the truck is cold it runs great, but after it warms up or roughly 10 miles it starts losing power.

After running out of ideas, I finally took it to my local mechanic and he has a scanner. It came up with O2 sensor/circuit and Water Temp Sensor/circuit. I will go get the truck tomorrow and start checking those circuits out and see what I can find.

The O2 sensor was packaged well so I really don't suspect that it was damaged in shipping. I think I still have the old sensor laying around as it was not throwing any codes, but I thought I would change it as good maintenance. I will see if I have a bent pin or wire damage which I least suspect as it was easily installed and see what the old sensor does for me.

On the Water Temp Sensor, I have seen those get very dirty or it may even be failing as well. I have seen some problems that do not all ways throw codes. The mechanic I have used in the past with the scanner has found some things for me in the past that wont throw a Check Engine Light.

I am weak in electrical, I have a Digital Volt Meter but think I need to find a Analog Meter to check for voltage on the circuits??? Also wont these pulses be so quick and low volt, will I even be able to get a reading on a meter??? I half way understand diagrams and have a basic understanding of electric but not great enough for this kind of trouble shooting.

This is the first time I have had to get help on one of these motors on the home page but these problems are always a great learning experience. Below is what I have ran into in the past on the sensors and I doubt that I could be so lucky as it just needing a good cleaning. I will admit I have not cleaned these sensors in quite a while. It has been a couple of years since I cleaned them. I will be working on this problem in the next couple of days and will post what I find.

Any suggestions on tools that I could use to trouble shoot? I have used LEDs in the past for reading pulses but that wont work on the O2 Sensor. Also the 88s and newer trucks use 4 wires for the O2 Sensor so will need to start studying which wires go where and functions they do. 87 and older trucks use a 1 wire set up.

What I have found in the past.

I had to take two intakes and make one. Here are the dirty sensors. Cleaning temp guage one in between #2 and #3 cylinders has helped my temp guage to be more stable then jumping around.(Top Right).


Here they are cleaned. I just use a brass tooth brush and water to get them cleaned. The manual says to wrap the Cold Start Injector Time Switch (Sensor with Brown top)with plumbers tape. I do them all. I haven done it yet but will when I put the motor together.

RJR

It's possible the engine is running overly lean (due to a bad O2 sensor circuit), which causes slow burning of the fuel. That means the fuel is still burning when it's going out the exhaust manifold, causing the cherry-red symptom.

Depending on the sophistication of your diag connector, you can make some measurements with your digital meter which will tell you what the ECU thinks is going on mixture and O2 sensor wise. Post a picture of your diag connector and the pin labels and maybe I can be of some help. Unforutunately I don't have good documentation on the '88 diag connector.

Terrys87

iTrader: (1)

Thanks RJR..I will get a picture of the Diagnostic Connector in the morning. I just got the truck back.

Here are the codes he pulled.

21-O2 Sensor/Circuit
22-Coolant Temp Circuit
24-Air Temp Sensor.

I reconnected the old O2 Sensor and in ten miles it got cherry again. I have an 85 FSM and a Haynes Manual and they both mention the Air Temp Sensor but I am unable to find it in either manual.

I am sure I have some spare Water Temp Sensors. It is the green one that is located next to the brown Cold Start Injector Timing Switch. I have not checked the Water Temp Sensor yet and will be my next move.

In the past I have had the Cold Start Injector Timing Switch to fail and when it fails, a 22re will not start in cold weather. I think it is the temperature range is roughly 50 degrees.

I do not know the symptoms of a Water Temp Sensor failing unless it causes the Cherry Manifold. Looking at my 85 FSM, the Water Temps Sensor is in line with the O2 Sensor and offers feed back to the computer.

I will do some more searching on as to where the Air Temp Sensor is. The FSM does show how to test for the Air Temp Sensor at the computer but I still have not found where this sensor is and is actually the first time I have actually heard of it. I wonder if it located in the Air Flow Meter?

RJR

The air temperature sensor is part of the VAFM (Volume air flow meter). The temperature signal comes back on one of the lines on the VAFM connector. The diagram I have (for a '94) shows it on pin 7 of that connector. At the ECU it's pin 3 (auto tranny) or 1 (manual). It's labeled THA.

General rules of thumb for various sensors
- Coolant temp sensor -- as engine warms, it wants a leaner mixture because the fuel vaporizes better, so ECU will lean out mixture as coolant heats up.
- Air temperature sensor -- Warmer air has less density, so needs less fuel to mix with it. ECU will lean out mixture as air warms up.
- VAFM - more air obviously requires more fuel
- TPS - As throttle opens, air flow increases and ECU will enrich the mixture as throttle is opening to prevent stumbling on acceleration. ECU cuts off fuel above predetermined rpm when throttle is suddenly closed to prevent backfiring. ECU will enrich mixture somewhat at full throttle to maximize power.
- Knock sensor -- ECU attempts to advance timing until onset of pinging, and then retards slightly to avoid engine damage.
- O2 sensor. During normal cruise, ECU continues to tweak mixture to keep O2 sensor switching back and forth between 0V(lean) and 1V(rich) to optimize the mixture for the cat converter. O2 sensor is normally ignored at idle and at full throttle.

When everything is working properly, the ECU reads all these sensors, goes to a big lookup table, and figures out optimum ignition timing and injector timing for each engine revolution. When a sensor fails and gives bad data, the ECU will wind up in the wrong part of the lookup table and generate inappropriate fuel flow and ignition timing for actual conditions.

andykrow

I know you said you checked timing, but I've only personally seen this from severely retarded timing. Can you throw a different timing light on there and recheck? I've had timing lights go bad on me a couple times... That or your balancer could have shifted so your timing mark is off

Terrys87

iTrader: (1)

Thanks RJR... I have got to work on it a little bit today. This really has me stumped. I have several extra parts and swapped them out to see if anything would change and still the same results. I have an extra 88 computer and it did nothing. I swapped water temp sensors and still a cherry manifold. I took the AFM off of an 85 project that I am working on and still same results. I am going to post test of parts I have done just to help rule out what the issue could be.

Thanks andykrow.. You are right about the timing being retarded and causing a cherry manifold. I had a distributor bolt to loosen and it went to the maximum setting and went cherry quick. I helped another guy with the same issue also. I will try another timing light. I asked several guys if I could use one of theirs and was surprised at how many do not have one.

Terrys87

iTrader: (1)

Here is my 88 Diagnostic Port. I believe it is the same as the 89-94. I can try to get a better picture of it if needed.


I put the Water Temp Sensor in the freezer for about 30 minutes and then did resistance checks on it. At about 40 degrees it was 4.3k ohms as the temperature rose, the resistance decreased as it should. At about 70 degrees it was 2.5k ohms. I got the test from Haynes Manual page 4-11 Section 13.35. I have an 85 Factory Service Manual and the test are the same. Most wont have an FSM so will refer to Haynes where test are the same.

On 85 an 88s the Water Temp Sensor are the same.