well howdy, the crank shaft position sensor is some where near the front of the engine around the crank shaft, look for wires going to a device. they are normally a magnetic type sensor . its sole purpose is to tell the ecu what postion the crankshaft is at. What does not make sense is normally when they go out the vehicle will not run. best thing to do is find the wires going to the sensor and see if they are frayed or about to break. if so repair them. Just becasue the code says the sensor is the code that is normally where you start looking. its helps to diagnois the problem. wish I had my books to tell you exactly where it is.

Lance

 

Thanks for your help Lance. What actually did happen about a year ago was that the leads coming from the ECU thats housed in the plastic tubing ended up being frayed/insulation rubbed off exposing the lead by apparently rubbing against the frame from the vibration of the engine. The tubing ended up ripping and a wire was frayed (not broken) and everytime it touched the frame a fuse would blow and my vehicle wouldnt start. I ended up finding the short, taped up insulation on the wire and retaped the tubing and that problem went away (the fuse stopped blowing and the truck ran fine). Maybe that wire is the problem again. I'll try opening up the tape again and check the wire.....maybe its almost ready to break. Forgot about that. Thanks again.

 

Respliced the wire.......Check engine lite still on. I turn engine on and it idles for about 10 seconds (without giving some increased RPM and it dies). I found the Crank Sensor and traced it back an no obvious problems. I can turn the engine on and off as many times as I want and same thing (it'll idle for about 10 seconds after cranking the engine and it dies out.....after about 10 seconds immediately). Once I keep the idle up (foot on the accelerator) after cranking the engine (and lettting a couple of minutes) I can take my foot off the gas and it wont die out. It'll idle fine. Not real sure. You guys have been great.........Any other hints? As Lance mentioned..........I dont think its my Crankshaft sensor.............I've just ordered one (Crank Senor) anyway just to make sure I can prove the diagnostic code PO336 wrong (got a cheap one by the way) I'll let you know.......................but any other assistance would be great as I wait for the part to come in. Still driving the truck and dealing with starting problems...............idle for awhile problems go away w/exception of lite stays on............not real sure..........Sorry for the bible. What do you think. Lance, keep your head down while in the desert!

 

Have you tested the sensors?

 

lets see what the new sensor does but the simptoms you describe is not that of a CPS. now I am going to have to think real hard, I have seen this before so let me clear out the cob webs and Ill get back to you. Wish I had my sensor book. probably time to buy a updated one again anyway.

Lanc

 

Did some digging through the FSM. The P0336 indicates a bad timing belt. Basically the CPS is out because the timing between the cams and crank is off. When was the last time you replaced it, and if it has been replaced was it done correctly? Another thing that could be going on is that the shorted wires damaged the sensor causing it to send a bad signal.

 

Thanks again for the input guys. I think the last time the timing belt may have been changed was about Aug 04. I dont recall which belts I purchased but the problem at that time was I had a bad Crankshaft Pulley and I purchased it. The guy who help me change the pulley told me that if he was going to change the pulley he may as well change the belts at the same time. I looked at the receipts and it just says "Crank Pulley" and 3 belts. I went back through my old E-Mails and cant find the one indicating exactly which belts I ordered but I think one of the belts was the timing belt. That was shortly after getting to England and I think I had about 121K miles on the truck and now have 135K miles on it (I live close to work so havent put much miles on the truck in the past couple of years). I havent had a chance to test the sensor yet..........I just assumed that was the problem after I respliced the bad wire and the problem remained and the diagnostic machine punched out PO336 (the manual for the machine identified it as the Crankshaft Sensor).. Now that I have an idea of where the sensor is located I'll see if I can test it. If the sensor comes in within the next couple of days I'll just replace it and see if it clears the problem (I'll let you know the outcome). Somebody also told me it could be my "Cold Start Injector". Maybe thats next on my list......I dont know. Thanks again.

 

Lance, TcmaBoy:

Changed the Crank Sensor today and check engine lite still on. Same problem. Starts fine, check eng lite on, idles for 10 seconds and dies.....or if I put in gear while idle yet before dies by itselt it automatically dies. Next step ECU? Thanks for both your help.......been awesome. Checked timing belt while changing the sensor.......seems to be OK. Will continue searching......any suggestions?

 

it sounds like the sensor that checks for the engine temp is gone and is not raising the idle until it warms up. by the way you describe it. may be it is stuck in the hot position and there for casuing your problems. Just something to check without buying a new sendeing unit. whew internet was down for 4 days life sucks over here with out it but its up again.

Lance

 

it sounds like the sensor that checks for the engine temp is gone and is not raising the idle until it warms up. by the way you describe it. may be it is stuck in the hot position and there for casuing your problems. Just something to check without buying a new sendeing unit. whew internet was down for 4 days life sucks over here with out it but its up again.

Lance

I don't know about that. By the FSM the code indicates that the readings between the crank sensor and the cam sensor are out of spec. If the readings are off the motor won't run. Possible causes for this are a stretched timing chain, bad crank sensor, a bad cam sensor, bad wires, and bad ECU.

With a high mileage motor it could very well be that the timing chain is stretched, or the tensioner is worn, allowing the cam and crank to be just on the edge of spec. With a stretched chain the marks will still line up, but the motor is not timed. This is why timing chains/belts must be replaced by mileage, not by inspection. They can look fine, but there is no way to tell if it has stretched just by looking at it. When you rev up the motor the cams catch up to the crank, and the motor runs.

I've seen this problem on many high mileag motors. It is really noticable with older motors with distributers. The motor will knock like mad until the cams catch up which will allow the ignition timing to catch up. At 135K on the clock I would replace that chain and see if that helps things.

 

well just a thought to look at if you wanted, I agree with Tcmaboy, but if the ecu is failing then it could throw false codes. Follow Tcmaboys advice and since you are there go ahead and chang the water pump. or the next thing that will go will be the pump.

Good Luck

Lance

 

Thanks again. Both you guys have provided super info. Looks like I am down to the Engine Temp Sensor, ECU (dreading changing that $$$), Timing Chain (also $$$), Cam Sensor (I think I've eliminated the bad wires and the Crank Sensor). I also ordered a Water Pump for when I get in there to change some of this stuff. I guess I should be glad that I can drive it around but really need to get it fixed though. The truck is awesome and its been paid off for about 7 years so I dont want to get rid of it. Also dont need any ridiculous car payments. Will continue replacing until the problem goes away. Thanks again for both of your help. I'll write back in as soon as the check engine lite goes out and let you know what the problem was.

 

Check Engine Lite

Fellas:

Follow up.....I'm back stateside.........Brought my Tacoma back with me. Well, after chasing that Check Engine lite problem for a long time that was throwing out the code to replace my Crank Shaft Sensor I did the following. Just to recap: Changed my Crank Shaft Sensor (twice), Engine Module, sent my ECU in and it came back fine, traced all the wires from the ECU back into the engine and checked each one and did a few more things along the way one of the first things I did when my truck arrived was drop the truck off at a Toyota dealership (wish I could do it myself but Im not a mechanic) to check it out. The final result............The Timing Chain. They replaced it, check engine lite is not on anymore and the car doesnt stall out and runs great again.

Just thought I'd throw it out there for anyone else that may be running into the same problem. Thanks again TcmaBoy and Lance for your help. For some reason nobody wanted to touch my Timing Chain in England. The dealership up there told me that the Timing Chain wasnt the problem and if they went in there to change it and it didnt fix the problem than the job itself was going to cost me more than my truck was worth (they quickly followed that up with wanting to sell me new truck) My buddy that was helping me to do all the other stuff said that changing the Timing Chain was a little out of his league. In either case the the problem is fixed and the truck runs awesome.

Thanks again for your help.

 

Hello and Thank you Apocho1!!!

I know this thread is old but I am having a vary similar issue and I have not seen too much on timing chains. I have a 1995 Tacoma with 225K miles and I have never changed the timing chain.

I have a code for the cps and my truck will start and runs without hesitation but will only idle for about 30 seconds. Sometimes when it is warm, it will idle for awhile, other times when warm it will not idel at all when warm. Okay, so per this forum and other research I think it may be the timing chain.

Around 10 years ago I had the cat removed and went with a muffler and straight pipe. I have had a engine code, p420 ever since removing the cat, since obviously the sensors were not getting the right airflow.

I do not have the tools or resources to fix myself. Both issues cost about the same $1500 to $1700.

Any reason to fix the exhaust with a cat or should I just directly for the timing chain?

Update.

The truck will not start. Pretty sure that is has both to do with the p0420 code and probably a timing chain. Any advise to know for sure?