95 Camry Ignition problem hard to start

Clive > wrote in news:2B
:

> In message
> >,
> Mark > writes
>>it will usually catch after several seconds of cranking but it used to
>>start immedialy, now it needs to crank for a while and I can see the
>>spark is late due due the iGT pulse being wide...
> Surely the width of the pulse in direct related to the cranking speed,
> so the slower the speed, the larger the dwell angle.



That's counter-intuitive, actually.

The coil needs a certain number of milliseconds to saturate. That number of
milliseconds is constant, regardless of engine speed. One drawback of the
old points-and-condenser system was that actual coil-charge time varied
with engine RPM (shorter at high-rpm). Modern electronic systems do not
have this issue.



--
Tegger

Tegger wrote:
>
> Clive > wrote in news:2B
> :
>
> > In message
> > >,
> > Mark > writes
> >>it will usually catch after several seconds of cranking but it used to
> >>start immedialy, now it needs to crank for a while and I can see the
> >>spark is late due due the iGT pulse being wide...
> > Surely the width of the pulse in direct related to the cranking speed,
> > so the slower the speed, the larger the dwell angle.
>
> That's counter-intuitive, actually.
>
> The coil needs a certain number of milliseconds to saturate. That number of
> milliseconds is constant, regardless of engine speed. One drawback of the
> old points-and-condenser system was that actual coil-charge time varied
> with engine RPM (shorter at high-rpm). Modern electronic systems do not
> have this issue.

Doesn't really matter if the system is electronic or mechanical you
still have the same limiting condition that there is only so much time
for switching between cylinders. If you want to extend the time to get
complete coil saturation at high RPM you need multiple coils instead of
one coil for all the cylinders.

-jim


>
> --
> Tegger

On Feb 16, 8:57*pm, Clive > wrote:
> In message
> >,
> Mark > writes>it will usually catch after several seconds of cranking but it used to
> >start immedialy, now it needs to crank for a while and I can see the
> >spark is late due due the iGT pulse being wide...
>
> Surely the width of the pulse in direct related to the cranking speed,
> so the slower the speed, the larger the dwell angle.
> --
> Clive

Clive,

yes I am starting to think you are correct...

At cranking speed the RPM is very low and the pulse widths (dwell)
and rep rate all seem to get longer and shorter proportionaly with
RPM. Above a certain RPM around 1500 the dwell time seems to be
fixed and no longer gets shorter as the RPM increases. I am starting
to think this is totally normal and has nothing to do with the
problem. The car seems to be fine now, running and starting so I will
wait and see. I was able to scope the Ne and G pulses out of the
distributor pickups while cranking (with them disconnected from the
ECM and connected to my scope so the car did not start of course) and
they looked normal.

So right now the problem could be anything and I will have to wait for
it to happen again.

Mark

*I was able to scope the Ne and G pulses out of the
> distributor pickups while cranking (with them disconnected from the
> ECM and connected to my scope so the car did not start of course) and
> they looked normal.

Were you able to scope them with the ecm connected?
If you did all your scoping with the ecm disconnected... the ecm may
tighten up the signal during cranking...
Either way, there is some excellent factory toyota stuff he
http://www.autoshop101.com/
that may be of use to you.
Have you looked at iant.net? Much better source of the kind of
hardcore tech you may need.
HTH,
Ben

Mark > wrote in
:


>
> So right now the problem could be anything and I will have to wait for
> it to happen again.
>



A couple of suggestions:

1) Have you checked the voltage though the primary feed to the coil while
cranking? Do you see 6V? 8V? 12V? Other?

2) have you actually LOOKED at the spark being produced while cranking?
By that I mean: pulling a plug wire, sticking a spare plug into it, holding
the plug body to a handy ground, and operating the starter. In a dark
garage, or at night, the spark--even when cranking--ought to be very snappy
and purply-blue.


--
Tegger

problem #1 solved, the IAC was stuck, I cleaned that out and idle is
now good most of the time.

But I'm pretty sure one of the ignition sensor pickup coils inside the
distributor is intermittent, (I'm not taking about the HV ignition
coil, I'm talking about the low level reluctor wheel pickup coils).
They are known to get flaky with temperature swings, I want to be able
to trust this car, so at this point I need to replace these.

Problem is I can't seem to find them for sale anywhere.

I know I have the option to buy a distributor, but I just need the
pickup coils.


Any sugestions.

thanks

Mark

Mark > wrote in news:8ee538e3-a690-437e-b562-
:

> problem #1 solved, the IAC was stuck, I cleaned that out and idle is
> now good most of the time.
>
> But I'm pretty sure one of the ignition sensor pickup coils inside the
> distributor is intermittent, (I'm not taking about the HV ignition
> coil, I'm talking about the low level reluctor wheel pickup coils).
> They are known to get flaky with temperature swings, I want to be able
> to trust this car, so at this point I need to replace these.
>
> Problem is I can't seem to find them for sale anywhere.
>
> I know I have the option to buy a distributor, but I just need the
> pickup coils.
>
>
> Any sugestions.
>
> thanks
>
> Mark
>
>


1) Have you checked the voltage though the primary feed to the coil while
cranking? Do you see 6V? 8V? 12V? Other?

2) have you actually LOOKED at the spark being produced while cranking?
By that I mean: pulling a plug wire, sticking a spare plug into it, holding
the plug body to a handy ground, and operating the starter. In a dark
garage, or at night, the spark--even when cranking--ought to be very snappy
and purply-blue.



--
Tegger

On Feb 18, 3:24*pm, Mark > wrote:
> problem #1 solved, the IAC was stuck, I cleaned that out and idle is
> now good most of the time.
>
> But I'm pretty sure one of the ignition sensor pickup coils inside the
> distributor is intermittent, *(I'm not taking about the HV ignition
> coil, I'm talking about the low level reluctor wheel pickup coils).
> They are known to get flaky with temperature swings, I want to be able
> to trust this car, so at this point I need to replace these.
>
> Problem is I can't seem to find them for sale anywhere.
>
> I know I have the option to buy a distributor, but I just need the
> pickup coils.
>
> Any sugestions.
>
> thanks
>
> Mark

OK,
Car seems to run without hicupp if I connect the E1 TE1 test points so
it is in base timing mode. Its hard to start but it will run without
intermittent.

Also I put it in ECM test mode where is sets codes without delay. It
set a code 31 twice in that mode, which is MAP sensor. I monitored
the signal voltage out of the MAP sensor and it is appears perfect, I
was watching it on a scope even while the car stalled.

When it cranks and won't start, there is spark, and it tries to start
but backfires, I think this fit with an intermittent timing
problem.

When its running, it runs perfectly, so the base timing is good,
something seems to happen in the ECM or one of the sensors to throw
off the timing. The MAP sensor can do that but the voltage look
correct.


Questions:
Does the ECM ignore the MAP sensor when the ECM is in base timing
mode with TE1 jumpered to E1?

I'm suspecting an intermittent problem with MAP wiring to the ECM or
the MAP circuit in the ECM.

To Tegger, I'm looking at the spark on a scope and it looks exactly
the same when the car is running perfectly and when it's cranking but
won't start. I have no reason to suspect weak spark, but the spark
timing is highly suspect.

thanks

Mark

> Also I put it in ECM test mode where is sets codes without delay.
> It
> set a code 31 twice in that mode, which is MAP sensor. I monitored
> the signal voltage out of the MAP sensor and it is appears perfect,
> I
> as watching it on a scope even while the car stalled.
>

And where did you monitor this from? The MAP sensor itself?

There would be wires going from the MAP sensor to the ECM as well as
connectors. Perhaps there is a loose or poor electrical connection or
a wire is grounding out to a sharp metal object.

A diagnostic code for a sensor means there could be a problem with the
sensor and/or a problem with the wiring from that sensor to the ECM.

A *nasty* problem is that someone stuck a too large test probe into a
female connector and that terminal no longer gets a good grip on the
male pin.

On Feb 20, 10:03*am, "Bill" > wrote:
> > Also I put it in ECM test mode where is sets codes without delay.
> > It
> > set a code 31 twice in that mode, which is MAP sensor. *I monitored
> > the signal voltage out of the MAP sensor and it is appears perfect,
> > I
> > as watching it on a scope even while the car stalled.
>
> And where did you monitor this from? The MAP sensor itself?
>
> There would be wires going from the MAP sensor to the ECM as well as
> connectors. Perhaps there is a loose or poor electrical connection or
> a wire is grounding out to a sharp metal object.
>
> A diagnostic code for a sensor means there could be a problem with the
> sensor and/or a problem with the wiring from that sensor to the ECM.
>
> A *nasty* problem is that someone stuck a too large test probe into a
> female connector and that terminal no longer gets a good grip on the
> male pin.


Bill,

I monitored the MAP sensor output directly on the wire right next to
the MAP sensor. I agree with you, the next step is to monitor the MAP
voltage right at the ECM. I removed the glove box then ran out of
time yesterday. That will be the next step.

But it's starting to look like an ECM issue. I ordered a cheapie on
EBay.

Mark