Funny but a member in our local club has had nothing but trouble with the
CAS but it always generates a code.

 

 

 

 

Larry Alster

 

91 Miata  White Knight

92 Miata  Silver Bullet

92 Miata  Honey B

04 MSM MX-5 Whooosh

06 WRX STi Subie

 

From: [email protected]
[mailto:[email protected]] On Behalf Of Bell, Richard (GE
Energy Services)
Sent: Thursday, March 10, 2011 8:08 AM
To: Ken Bogart; [email protected]
Subject: RE: Non-starting 2001 help needed

 

I found this interesting post by Twiggy144 on miata.net forum. Going to try
this later today when I get home.

 

A faulty CAM pos sensor is hard to diagnose, it rarely triggers a CEL, but
on the other hand, knowing it is hard to troubeshoot, we should suspect this
part early in the diagnosis process, and unveiling it's failure becomes a
faster process.

The cam pos sensor sends a signal to the PCM, that will fire the spark
plugs, AND activate the fuel injectors.

It the engine cranks but does not start, first of all check the main relay,
the 30 amp INJ fuse, (both under the hood) and the 15 amp engine fuse (in
the cabin).

Next, check for spark at the plugs. If no spark, and no unburnt fuel can be
smelt coming out of the exhaust while cranking the engine, then strongly
suspect either the cam pos sensor, or the crank pos sensor.

I did these little tests on my 2002 to understand what the sensors control.


Test 1. Disconnected the cam pos sensor connector and attempted to start the
engine. Results: there was no spark, obviously the injectors were not
activated ( the cam sensor's main purpose is to synchronize the fuel
injectors through the PCM), but the fuel pump ran for three seconds, exactly
as it is supposed to. ( The PCM activates the fuel pump relay for three
seconds while starting the engine, to build fuel pressure in the fuel line.
After these 3 seconds, if no signal from the cam pos sensor is received at
the PCM, the fuel pump relay is shutoff. This is a safety system when the
engine is not running to prevent a possible fuel feed fire in the engine
bay). 


Test 2. Disconnected the crank pos sensor and attempted to start the
engine.Results: there was no spark, and the fuel pump did not run at all,
not even for the first 3 seconds. 


>From these tests, by listening at the humming noise the fuel pump makes, one
can diagnose if either the camshaft or the crankshaft position sensor is
faulty. If fuel pump noise is heard, the crankshaft pos sensor may be ok,
suspect the camshaft position sensor. 

 

 

From: [email protected] [mailto:[email protected]] On Behalf Of Ken Bogart
Sent: 10 March 2011 12:49
To: Bell, Richard (GE Energy Services)
Cc: [email protected]
Subject: Re: Non-starting 2001 help needed

 

Correction - the Cam Position Sender on the 2001 is top of the cam cover,
towards the front of intake side. It can prevent the car from running and
more likely to fail that the CAS located on the crank pulley.


Ken

 

On Thu, Mar 10, 2011 at 7:42 AM, Ken Bogart <[email protected]> wrote:

Fuel pump comes on for a few seconds when you turn the key to pressurize the
system. 

 

No spark / no fuel indicates the ECU is not receiving a signal from engine
rotation. 

 

>From my recollection, in a 2001, the Crank Angle Sensor is on the front of
the engine and controls spark. The Cam Position Sensor on the top back of
the engine controls fuel. No fuel and no spark point to the timing belt. 

 

 

 

Ken Bogart
-----------------------------------------------------
96 Montego Blue FFS Coldside (His)
97 Black & Tan (Hers)
90 Crystal White (sons)
------------------------------------------------------
http://www.miatacare.com
http://www.cincimiata.com
http://www.bcchallenger.org
MiataMail.com list owner 

On Thu, Mar 10, 2011 at 6:55 AM, Bell, Richard (GE Energy Services)
<[email protected]> wrote:

Battery charged up to 12.6V and cranked well so think that is OK. I will
check for cam belt today.

 

I'm just wondering what could cut power to the fuel injectors but still
allow the fuel pump to run?

 

Thanks,

Rich

 

From: [email protected] [mailto:[email protected]] On Behalf Of Ken Bogart
Sent: 10 March 2011 11:43
To: Bell, Richard (GE Energy Services)
Cc: [email protected]
Subject: Re: Non-starting 2001 help needed

 

Could be weak battery... but sounds like a classic broken timing belt. Can
you see the cam turning through the oil fill hole?

 

Probably not, but simple to check for. 


Ken Bogart
-----------------------------------------------------
96 Montego Blue FFS Coldside (His)
97 Black & Tan (Hers)
90 Crystal White (sons)
------------------------------------------------------
http://www.miatacare.com
http://www.cincimiata.com
http://www.bcchallenger.org
MiataMail.com list owner 

On Thu, Mar 10, 2011 at 4:23 AM, Bell, Richard (GE Energy Services)
<[email protected]> wrote:

Hi Folks,

I wonder if anyone can shed some light on my issue as I'm getting
nowhere at the moment. Car is a late 2001 and was running fine before
sitting for a week. Battery wasn't great and went flat, however, I
managed to get it back to full charge. Car cranks fine but refuses to
fire. After cranking, I pulled a plug and it was completely dry and
there is no spark when cranking with the plug against the cam cover.
However, I do hear the fuel pump run for about 0.5 seconds after I stop
cranking. I have no CEL and no fault codes logged. There is no key
warning light on to suggest immobiliser issue.

Can anyone suggest any possible causes? I'm going to borrow a crank and
cam sensor to see if they are causing issues as I read sometimes they
don't cause fault codes. But other than that, what else can I check? Can
someone point me in the right direction of some wiring diagrams for a
2001?

Thanks in advance,
Rich
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