1998 Vectra stalling, MIL light on, but no fault codes in ECU memory

Hi

My 1.8L 1998 Vectra has developed a problem recently, not found
anything like it on the groups before.

Scenario 1: After a cold start.

Driving to work, suddenly feel the car hesitate, like a misfire, then
it picks up. About a minute later, the rev counter swings wildly
between 2000 & 3500 revs, the engine no longer responds to the throttle
& stalls (all dash light come one). I slip into neutral, turn off/on
the ignition, engine responds, dash lights go out except the MIL. MIL
stays on until journeys end. Problem does not occur again for the
remainder of the journey.

Scenario 2: After a warm start.

MIL comes on, but everything is fine.
No problems occur during the journey.

NOTE: after a long stopover, MIL light is off when started & problem
described in scenario 1 may not occur if journey is short.

So far, I have tried the paper clip method to read the fault codes,
there appear to be none. As a test, if I turn on the ignition with the
paper clip in place, but do not start the engine, I get the fault codes
for the camshaft/crank sensors flashed.

Is it possible for the engine to deveop a fault, but not store a fault
code in ECU memory?

Can some of the other systems (immobiliser/abs/etc) also illuminate the
MIL if they develop a fault?

This problem appears like the infamous IAC or TPS problem, except I've
had the IAC problem before & that usually caused the car to stall when
stopped at junctions (not at speed) & a restart would not cause the MIL
to stay on.

Not sure if this is connected or not, but I've noticed the engine seems
to stay warm for a lot longer than usual. The temperature gauge is
reading normally, but to me, the engine seems hotter, if I leave it &
start it after 30 minutes, the gauge climbs to normal temperature
quickly. I might be reading too much into that, however.

This problem might be connected to a journey I made about a month ago,
it was a hot day, got stuck in a slow moving tailback & the engine
really heated up. Not overheated, the electric fan came on several
times. Once I got moving again, I heard a whistling noise from the
engine bay, stopped to take a look, found nothing. Was driving to the
airport, so did not have time to look into it more.

Stall problem started happening about a week ago.

Anybody seen anything like this before?

Gerry

 

You dont mention if the engine misfires or looses power whilst the tacho is
jumping about, rather than just dying, but this definately sounds like the
infamous CPS problem.

Tim..

 

Well, it's hard to say what's really happening, the engine might be
still firing, I do see the power dropping, speed falling off.

As you probably know, when the engine dies, PAS dies too, so I have
about 10 seconds to get the engine going again before the steering
becomes very difficult. Yes, it's possible the engine is still running,
but usually, when all of the dash lights are on, the engines stalled.
Next time, I'll be able to make a better judgement, I'll just let it
coast to a stop (assuming it's safe to do so).

What's the CPS, or is that a typo, should it be TPS?

If it is the TPS, why does it die, then recover when the engine is
restarted & go on to work fine until the end of the journey?

Is there some way to fix it?

Gerry

 

Ok, replying again to myself

Looked on net for CPS = Crankshaft Position Sensor AKA crankshaft
sensor, Ok, I got it.

Yeah, I suspected this, was looking at it today, it looks to be a
ba$tard to replace, have to take the PAS pump out first, although some
web discussion seemed to say you could remove the exhaust heat sheild +
dipstick & do it that way. Hmm, there's a few Torx headed bolts, have
to buy a set of sockets.

I think you are correct Tim, it must be intermittent. It's strange how
they fail, do you know if it's a passive (magnetic pickup) or active
(hall effect) sensor?

Actually, this sounds like the exact same problem as on my wife's
Hyundai coupe, the crank sensor used to go open circuit when it heated
up. Used to work fine when it was cold or had time to cool, but if you
stopped the car when it was hot, there was no way to get going again.
Hard to believe such as simple failure could disable the car.

I bet the Vectra overheating episode caused it to begin the decent into
premature aging. Damned tailbacks.

Guess I'd better buy a replacement

Gerry

 

Actually no, CPS is camshaft position sensor.

CAS is crank angle sensor.

Both fail with frightening regularity on the ecotecs, although check the CPS
first.

Tim..

 

Is there a simple test I can do, because there are no error codes
stored, but I get the them if I turn on the ignition with the engine
off?

Was going to purchase a new CAS, but if it might be the CPS, then I'd
better be sure to buy the right part.

I can trace the CAS lead to a connector near the top right of the
engine bay, but I can't seem to find the CPS connector, it runs down
under the fuel injection.

I suppose I can start the engine, pull apart the CAS connector, see if
the MIL comes on, or is this a bad adea?

Gerry

 

Changed the crank angle sensor tonight, MIL light is still on.
Tried resetting the ECU, MIL light still comes on.

The CAS was definitely on the way out, the insulation was frayed &
missing from the leads at the point where it enters the sensor body.

However, a replacement does not appear to have fixed the problem.

During the week before I changed the CAS, the time to failure shortened
each day, eventually it just failed (I assume) as the MIL came on
permanently.

Plan to change the CPS tomorrow night, hope this fixes it for good.

Thing is, if the CAS was faulty, & the CPS was faulty at the same time,
I would expect the engine to refuse to start, or else stop
(inconveniently) every so often.

If I short ALDL pins 5 & 6, turn on the ignition, I get the flash codes
for CAS + CPS + ignition coils, which is what I would expect if the
engine is not running.

Get none of these when it does start, except the MIL illuminates after
about 1 second.

The engine is definitely rev limited at about 4200.

Gerry

 

Went to change the camshaft sensor tonight, using the procedure from
the following site (appears to be offline ATM)

http://vectra.no-ip.pl/~pepin/czujnik_walka/czujnik_walek_e.htm

Took a bit more effort, my Vectra has 2 pipes running between the air
filter box & the cambelt cover.Not sure if they are Air-con or PAS. Got
the cambelt cover off, the belt seems slack. I remember someone posting
previously that a slack cambelt can cause the MIL to illuminate.

I'm now concerned the belt has jumped a few teeth & the timing is out,
causing the MIL to light up & the revs to be limited.
With the cambelt cover off, the section of belt on the right is not
really pressing against the roller with any great amount of tension.
I can rotate the roller on the right side easily with just finger
pressure, where as the one on the left is tensioned too tightly.

Is there some way to check the tensioner is set correctly?

The cambelt + rollers + water pump were all changed about 22K miles
ago.
Not sure if the tensioner was changed, I could go & ask.

I suppose I can go ahead & change the CAS sensor anyway, but I suspect
htis won't fix the problem.
Is it easy to check whether the belt has slipped?

Gerry

 

my guess would be to get the slack sorted first, I would also surmise that
'if' the teeth had jump, you should be getting some additional problems as
well, rather than just limited revs.

I'd go ask if the tensioners were changed if you can confirm this, if not
change them and then restart your diagnostics,

slack will cause the cambelt sensor to give erratic readings.

mike

 

Job Done!!
Was the camshaft sensor all the time, replacement cured it.

Chris, took your advice & signed up to www.cavweb.co.uk.
Loads of good info there.

mikeFNB, found a "how to" on cavweb, cambelt change.I read through this
& found a section dealing with belt tension. My cambelt seems tensioned
ok.

Chris, I manually lined up the timing points on the sprockets, all were
in alignment, so no problem there.
Also, checked with the guy who did the cambelt last time, the tensioner
was changed, so no worries about it failing (touch wood).

So, everything back to normal again.

With regard to the ECU & failure codes, although my Vectra has an ECU
that will flash fault codes (paper clip trick), it does not seem to do
this when the engine is running. It will flash when the ignition is on,
but the engine off. However, that's of limited use.

Only people with Tech 2's in my area are main dealers, they have long
queues (2 week wait for testing is normal), so I won't be going near
them anytime soon. I believe the ECU will reset the stored faults after
25~30 starts (or if I feel like it, I can switch the ignition on/off
that many times).

The MIL is off, will do a proper run tomorrow, see if I can get above
4200 REVS.

Thanks for the help

Gerry