Complicated issue. Crank no start.

2002 tacoma 3.4 prerunner double cab

Ok so.. a couple weeks ago I noticed my truck was misfiring. I already had the CEL light on from o2 sensor. So I stopped by orileys and got the codes read.

P1135 air / fuel sensor heater malfunction bank 1 sensor 1.

P1130 air / fuel circuit bank 1 sensor 1

P0125 insufficient coolant temperature for closed loop control

P0304 cylinder 4 misfire

P0303 cylinder 3 misfire

P0300 random multiple misfire

For some reason... I didn't even notice the coolant temp sensor even though I took pics of all the codes.

I rarely drive the truck and when I do I usually don't go far.

I decided to order parts on Amazon to tackle the misfire. I bought oem spark plugs, spark plug wires, 3 coils. Valve cover gasket, and plenum gasket.

One day after work I decided to try changing the coils while waiting on the other parts to come in. When I did and test drove it, still misfiring and then I started hearing a pop under the passenger side floor.

I figured the cat was bad... the 02 sensor had been replaced before around 2 or 3 years ago when I first bought the truck and the check engine light for the 02 sensor has been back on for at least a year.

I figured I might as well order a new cat. My parents rav4 years ago started misfiring really bad because the cat so i wasn't sure if that was part of my problem. I ordered 2 oem 02 sensors, and both walker cats. I looked under my truck and saw the condition of my muffler and exhaust pipes and said fuck it might as well replace the whole thing.

A few days later I tear the top of my motor apart so I can fix a leaking valve cover and replace the spark plugs and wires.

As soon as I pulled my first valve cover I was in shock.... the truck has 140k miles, I've owned it for a few years and I bought it with 130k miles. I've changed the oil 3 times since I've had it with synthetic.

Under my valve cover it looked like someone baked a cake and left it in the over for a week burning... I couldn't believe the truck was even running... it wasn't even sludge it was charcoal. I wish I took pictures...

I spent days... with picks and a vacuum. degreaser, brake parts cleaner, diesel, toothbrushes.... basically anything I could find to help break all that up with...

Oil was all inside my air intake and my throttle body...

Back to amazon... ordered pcv valve and grommet.

It's been about a week and I had my entire exhaust taken apart. And cleaned up my engine as much as possible. It actually looked really good by the time I was done.

Then comes yesterday. I took some extra time cleaning the valve covers, plenum and throttle body. Then I painted all 3 and painted some of the brackets and cleaned up some rust. I treated all my bolts with ospho to remove rust from them as well. It was getting late so I don't know if it was exhaustion or a cheap harbor freight torque wrench... it was set at 5 ft pounds and on my last bolt... I cracked the valve cover. Slapped some rtv over it and hope it holds until I get a replacement. I move on and tried to put the next valve cover on and I literally shattered the plastic protector for the wiring harness. I literally said fuck this I'm going to bed. It was about 2am...

Then comes today. I got a few hours of sleep and get back to it. This morning everything went smooth. Everything got put back together. Minus the exhaust. I drained all the nastiness from my motor. Changed my oil filter and was doing an engine flush. I used 4 qts napa brand oil, half a small bottle of engine flush, and about a qt of diesel.

She started right up. Misfire gone.

I let it run for 30 mins and that when I just noticed the coolant temp on my dash wasn't working... even though I had seen the code a week or so prior...

I drained it. Changed the oil filter and started a 2nd flush. While the truck was running I decided to finish cleaning up the engine bay and covered everything with foam engine degreaser and then sprayed it down with a hose. The truck ran for 15 mins then it back fired and shut off....

I drained the oil, changed the filter. Filled to spec with just royal purple and tried to start.

It now only cranks...

I'm confident all nuts and bolts, all vacuum lines, both grounds and my spark plug wires are all accounted for.

I tried starter fluid, no start. I pulled a spark plug wire and put in one of its old spark plugs and got no spark.

I thought... maybe it's the back 02 sensor because I just cut the wire and thought it might be shorting out... so I put my entire exhaust back together and replaced both 02 sensors.... crank no start...

I was to orileys and bought a cheap code reader and it won't even connect...

Is the coolant temp sensor causing it to not start?

Did I blow my motor?

Maybe it's the crank shaft or cam shaft pos sensor....

Maybe it's the fuel pump...

Let me know your thoughts...

 

I figured...... is probably your problems

 

I’d have to look at the diagrams.
But I’d start with why the scanner won’t connect with the truck.
Power and grounds is the first thing I would look at.

 

I'm thinking something got water in it and shorted or lost connection, does your check engine light come on with the key on?

 

You say you had the throttle body off?
Check the EB Ground

 

@Dm93 Man I wish I had your electrical knowledge. Maybe one day. TW should pay you for the amount of times you've helped other people out.

 

I have to go in to work today and the truck is at my parents house so I can't check the ground until later today.

I didn't think any thing of it when the code reader wouldn't work. I thought it was because it was a cheap 20 dollar code reader on the discount rack at orileys.

Later today I'll disconnect the ground and wire brush where it connects because I did paint the plenum.

I will also try and get a different code reader and see what happens.

I'll report back tonight.

 

Based on the symptoms you've described, there are several possible issues that could be causing your crank no start issue. Here are a few things you can try to diagnose the problem:

1. Check the coolant temperature sensor: The fact that the coolant temperature sensor code came up and then the temperature gauge stopped working could indicate a problem with the sensor. If the engine control module (ECM) doesn't receive the correct coolant temperature signal, it could prevent the engine from starting. Try replacing the sensor and see if that solves the problem.
   
   
2. Check the spark: If you're not getting any spark, it could be a problem with the ignition system. Check the condition of the spark plugs, wires, and coils, and make sure everything is connected properly. You mentioned that you replaced some of these components, but it's possible that there's still an issue. You could also try using a spark tester to see if you're getting spark.
   
   
3. Check the fuel system: A problem with the fuel system could also prevent the engine from starting. Check the fuel pump, fuel filter, and fuel pressure regulator to make sure they're working properly. You could also try checking the fuel pressure to see if it's within the manufacturer's specifications.
   
   
4. Check the timing: If the engine is out of time, it could cause a crank no start issue. Check the timing belt or chain and make sure it's still in good condition and properly aligned. You could also try checking the timing with a timing light.
   
   
5. Check for codes: If your code reader won't connect, it could indicate a problem with the ECM or the communication lines. Try checking for any blown fuses or loose connections in the wiring harness. You could also try using a different code reader to see if that works.
   

Based on the symptoms you described, I don't think you've blown your motor, but it's always possible. Try going through these steps to diagnose the problem and see if you can get the engine to start. If you're still having trouble, it might be best to take it to a professional mechanic for a diagnosis.

 

In addition to the above…

Check the EB1 ground first. Take the ground harness off and wiggle each wire individually where it enters the ring terminal. These have a tendancy to break internally. These grounds ground the PCM, and many other important electrical components. While at it verify the ground strap from the P/S cylinder head to the firewall.

If you have had a marginal battery and have cranked it over and she has not started, a low voltage conditon exists and this by itself will cause bizzare codes. Same thing with flaky grounds. Write the codes down, clear them, put a good battery in her and see what codes comes back.

 

My dad just called me. He borrowed a code reader from the auto part store.

P0340 camshaft position sensor a circuit (bank 1 or single circuit)

Guess the cheap code reader I bought was just a pos...

So I'm about to head to the store and get a new camshaft sensor and coolant temp sensor.

I'm hoping this is the culprit... just kinda weird so many things happened all at once. Just a couple weeks ago everything was running fine.

 

Did you verify the timing belt is still on it and the cam sensor is plugged in

 

Oh... that's not good.
Looks like something caused the cam to lock up, shearing the pin and bolt off.

 

That's what it's looking like. I tried my best to get all that gunk out and vacuum everything. I knew a flush would be risky.

 

Ok... so now I'm faced with the question... is this repairable without rebuilding the entire motor? I've done motor swaps but nothing internal to a motor. I'm sure I can replace the cam but I am concerned it would happen again. My best guess.. the oil pump got clogged from the sludge I was attempting to clean out.

Not sure my best course of action. I could do a motor swap but I'm not prepared to drop another 3k into this atm

 

With that much sludge under the valve covers I'm wondering if one of the valves was hanging up in a guide, stuck open and smacked a piston possibly? Or maybe the camshaft just decided to seize up