The NOTORIOUS “Cranks but doesn’t start” experiment

[BamaDrewski]

There are lots of threads about 3rd gen T4R’s and Tacomas with 5VZFE engines that “crank but won’t start” and I had that issue develop on mine this past Friday on my way to work.

I did the usual stuff – cleaned the IAC, throttle body, MAF, checked the plugs, wiring, vacuum tubes, etc.

Was thinking it is the fuel pump (original pump at 325K miles and ordered all the stuff to change out the pump.) Doing research today however, I ran across something called the COR (Circuit Open Relay) and I am going to change that out first. (You must take the driver’s side panel off from under the steering wheel and it is located under the left-hand side of the relay/circuit box)

Stayed tuned and will let everyone know if it works!

Anyone ever heard of this and tried it? If so, did it work?

 

[Js'00imited4runner]

I followed all the same procedures that you did when I was experiencing stalling/hard to start issues I figured I would start with all the free diy stuff first then if that didn't fix the issue it was going to be more involved. My original fuel pump had 220k on it when it was on its last legs. A lot of people preach that a fuel pump lasts "forever" but if you really think about it they are a wear item just like everything else the only benefit of the toyota fuel pumps is they show signs of failure and don't completely leave you stranded just yet. Also changing the open circuit relays didn't fix the issue. Here are the threads I posted when I was experiencing the same issue.

Trying to figure this out *Solved*
^^^^^^^^^^^^^^^^^^^
When I was experiencing the problem and fixed it.

Easier way to check fuel pressure
^^^^^^^^^^^^^^^^^^^^^
How I diagnosed it checking the fuel pressure.

Good luck and I hope you get to the bottom of it!

 

[toyotaspeed90]

At start the COR mostly provides power to the ECU and the fuel pump. It's used at the "on" position to power the same pieces.

If you're thinking the COR then check for spark - if no power to the ECU while cranking then there wouldn't be spark.


Always check the basics -
Fuel (if worried about wiring or "is the pump on" you can jumper that in the diag port)
Spark
Compression

Everything can be tied back to those 3 things if the starter is spinning but the engine isn't starting.

(Example- problem is the ecu has no power. You will have compression telling you mechanically the engine is functioning, but you won't have fuel nor spark)

 

[BamaDrewski]

Thanks so much for the input. I suspect it is the fuel pump but I should be grateful I have gotten 325K+ miles out of the original fuel pump.

Rather than tackle this job, I am going to have the dealer do it. It costs a few more bones than I really have in my budget but hopefully they will do it right and back it up with a warranty.

This issue seems epidemic with older 5VZFE engines. However, in my case, it's the age and mileage (20 years old - manufactured in December 1999) and 325K miles.

Thanks again everyone! I love this forum!!!

 

[Js'00imited4runner]

Thanks so much for the input. I suspect it is the fuel pump but I should be grateful I have gotten 325K+ miles out of the original fuel pump.

Rather than tackle this job, I am going to have the dealer do it. It costs a few more bones than I really have in my budget but hopefully they will do it right and back it up with a warranty.

This issue seems epidemic with older 5VZFE engines. However, in my case, it's the age and mileage (20 years old - manufactured in December 1999) and 325K miles.

Thanks again everyone! I love this forum!!!

A few more bones? The whole fuel pump kit with filter is less than $100...That's a denso OEM replacement and wix fuel filter...What's the dealer gonna get to do the job? Just curious. Have you diagnosed that being the issue?
Hopefully the cost doesn't exceed the cost of the truck
just my .02. Anywho hopefully it all works out for you.

 

[nail bender]

I recently replaced the fuel pump on my 01. not a bad job at all and plenty of info/help on here. that is where I found out how to test things to make sure it was the pump. I did get parts from a toyota dealer. I would think the labor at a shop if it was a dealership or independent would be more than the parts.

 

[BamaDrewski]

A few more bones? The whole fuel pump kit with filter is less than $100...That's a denso OEM replacement and wix fuel filter...What's the dealer gonna get to do the job? Just curious. Have you diagnosed that being the issue?
Hopefully the cost doesn't exceed the cost of the truck
just my .02. Anywho hopefully it all works out for you.

You are right about the costs being higher at the dealer. I might just pay them the $90 diagnostic fee as I have so little time working as much as I do. That $90 would be money well spent (if they actually diagnose the issue) and then I could fix it myself when I get time. Thankfully I have a spare to drive in the meantime.

The dealer quoted $380+tax in labor....

I bought the Denso fuel pump kit for $88 (comes with everything except the gasket for the tank) The dealership (McGeorge wants $224 JUST FOR THE PUMP)

 

[Js'00imited4runner]

You are right about the costs being higher at the dealer. I might just pay them the $90 diagnostic fee as I have so little time working as much as I do. That $90 would be money well spent (if they actually diagnose the issue) and then I could fix it myself when I get time. Thankfully I have a spare to drive in the meantime.

The dealer quoted $380+tax in labor....

I bought the Denso fuel pump kit for $88 (comes with everything except the gasket for the tank) The dealership (McGeorge wants $224 JUST FOR THE PUMP)

Yeah that's somewhat reasonable but this time of year it stinks to take that big of a hit. Is your rig completely down? Or are you gonna have to get it towed to the dealer? If you want I can rent you out one of my fuel pressure test kits if you end up doing the work yourself. Do you have a OBD 2 scanner to know if its fuel/spark related? The only way to know if you don't have fuel pressure is to hook up right to the fuel system or test your electric resistance of power to the fuel pump under the backseat driver side floor hatch. But again I don't know if your completely dead in the water or if you were able to get it back home and have something else to run around for now which I read you do. You seem to be mechanically inclined I would use this as a opportunity to pick up some new tools/toys and add them to your toolbox and learn something from it. Yeah the denso parts lookup website is pretty awesome to find the correct parts for replacement. It took me roughly 2 weekends to get mine tore apart and back together. (Was waiting for parts).
But I didn't wanna order anything until I knew what exactly the problem was.
Curious to know how this all turns out! Good luck and have a good rest of the weekend. :snacker:

 

[BamaDrewski]

UPDATE: I paid to have my rig hauled to a good a reputable shop. Provided Denso fuel pump, strainer and gasket. It was changed out and STILL the "crank but no start issue". (I am seeing this pop up all over in a few recent threads)

So, the shop calls me and says two things; 1. The Ignition Control Module needs replacing and 2 the crankshaft sensor is bad.

I called BS on the crankshaft sensor as there were NO CODES on this and I know this.

With respect to the ICM (Or "igniter) as some call it, it makes sense. The shop wanted some $900+ to replace the crankshaft sensor and ICM. I said "no way" and had it hauled back.

From doing research, apparently the "ignition control module" dies over time with heat in the engine bay but does not throw a code (at least not in my case).

I have a used ICM on order and I also have a new fuel pump. Also, just for giggles, I had ordered a 2001 fuel sending unit thinking there would be no difference between a 2000 and a 2001. I WAS WRONG. The 2001 Fuel Sending unit does not fit on the 2000 year model and that part is no longer sold by Toyota for the 2000 T4R 3.4.

Thought this might provide some insight and help some of my fellow forum member avoid the same mistake. If the igniter works, I will chime in and let everyone know.

 

[TheDurk]

UPDATE: I paid to have my rig hauled to a good a reputable shop. Provided Denso fuel pump, strainer and gasket. It was changed out and STILL the "crank but no start issue". (I am seeing this pop up all over in a few recent threads)

So, the shop calls me and says two things; 1. The Ignition Control Module needs replacing and 2 the crankshaft sensor is bad.

I called BS on the crankshaft sensor as there were NO CODES on this and I know this.

With respect to the ICM (Or "igniter) as some call it, it makes sense. The shop wanted some $900+ to replace the crankshaft sensor and ICM. I said "no way" and had it hauled back.

From doing research, apparently the "ignition control module" dies over time with heat in the engine bay but does not throw a code (at least not in my case).

I have a used ICM on order and I also have a new fuel pump. Also, just for giggles, I had ordered a 2001 fuel sending unit thinking there would be no difference between a 2000 and a 2001. I WAS WRONG. The 2001 Fuel Sending unit does not fit on the 2000 year model and that part is no longer sold by Toyota for the 2000 T4R 3.4.

Thought this might provide some insight and help some of my fellow forum member avoid the same mistake. If the igniter works, I will chime in and let everyone know.

I wouldn't bank on that no code, so Crank Sensor is therefore good idea. The ECM is not very smart. So if no signal at all, I'd bet the ECM thinks the crank is not even turning, so it expects no signal from the sensor. Therefore it won't set a code. IIRC, code conditions are open, short, and voltage out of range. So if no signal, but not open or short, no code.

 

[LittleCaesar]

You should have checked fuel pressure. Don’t be a parts thrower.

Do you have spark? I have only usually seen crank sensors die while driving. But the igniter, sure thing. Unlike the American geniuses who put such right near the engine or over an exhaust manifold, Toyota has usually kept their igniters as far away from heat as possible for longevity.

[MENTION=10169]TheDurk[/MENTION] is correct in saying that as long as the ECM sees power and control for the sensor, it won’t throw a code.

Keep us informed.

 

[brillo_76]

I agree with [MENTION=10169]TheDurk[/MENTION] that our ECU are not very smart.

What the procedure telling you to check in the FSM when having this issue?

That's where I would start and prove and disprove each system is functioning properly. So you aren't just guessing and throwing money out the window.

Have you verified your crank sensor is good? The FSM has the testing process for that. How to test your ignition system etc. So you can get this rig issue figured out and cruising down the road again.



Sent from my SM-J337V using Tapatalk

 

[Dieselchessy]

I’ve had a crank position sensor fail, no code, crank all day and no start. Also no spark.
New sensor and started right up.

 

[plcfcng]

I would try to isolate if it is fuel or spark. To check if you have a fuel issue try pulling the air cleaner out and try a getting a can of starting fluid or taking the air hose of at the trottle body and poor/splash a couple of table spoons of gas into the throttle body. put it back together can crank it over if it runs for a moment then the problem is fuel if it does not them it most likely a spark problem. you can also pull a plug wire put a screw driver in that will stay in it with out damaging the wire have someone crank the engine over while keeping a metal part of the screw driver about 1/4 from some metal looking for a spark jump. This will allow you to focus on the half that is causing you problems. I don't know could your drive belt have broken?
:nerd:

 

[cahilc]

FWIW...

Fuel pump uses fuel for cooling. If you constantly run your tank dry will end having to replace more often. Keeping them covered and cool leads to longer life.

It's the old heat cycle vs life of electronic parts routine.

Cheers - Cahil

 

[JMat]

I had the same thing happen to me so my vote is crank position sensor and it's easy to diagnose if you have a scanner. Mine didn't throw a code, just wouldn't start one day and I used my Torque app to verify the issue. If when your cranking the engine and your scanner doesn't show any RPM it's the CPS. It should register somewhere around 200 rpm.

 

[brillo_76]

I had the same thing happen to me so my vote is crank position sensor and it's easy to diagnose if you have a scanner. Mine didn't throw a code, just wouldn't start one day and I used my Torque app to verify the issue. If when your cranking the engine and your scanner doesn't show any RPM it's the CPS. It should register somewhere around 200 rpm.

That's how I test mine. No 200 rpm. Crank sensors gone.

Sent from my SM-J337V using Tapatalk

 

[BamaDrewski]

There are lots of threads about 3rd gen T4R’s and Tacomas with 5VZFE engines that “crank but won’t start” and I had that issue develop on mine this past Friday on my way to work.

I did the usual stuff – cleaned the IAC, throttle body, MAF, checked the plugs, wiring, vacuum tubes, etc.

Was thinking it is the fuel pump (original pump at 325K miles and ordered all the stuff to change out the pump.) Doing research today however, I ran across something called the COR (Circuit Open Relay) and I am going to change that out first. (You must take the driver’s side panel off from under the steering wheel and it is located under the left-hand side of the relay/circuit box)

Stayed tuned and will let everyone know if it works!

Anyone ever heard of this and tried it? If so, did it work?

UPDATE: Thanks for all the input! I changed out the crankshaft position sensor and the ICU (igniter). Cranked right up! I ended up getting a fuel pump thinking that was the issue but I am fine with that expense as mine was original with 325K+ miles on it. I do notice it cranks much easier now so perhaps the pump was on its last legs......With respect to the crankshaft sensor replacement, I went with DENSO and saved some money for what is the same part sold by Toyota.