89 Jeep Cherokee Won't Start - No Fuel Injector Pulse

Hey,
actually Help!

Here's my symptoms:

1. Cranks fine
2. Lots of good spark
3. Timing was set TDC on compression stroke.. verified twice.
4. Fuel Rail is pressurized
5. Crank Pos Sensor functional (as far as we can tell)
6. Map Sensor Functional (voltage too the sensor)
7. Throttle Position Sensor is functional

Big clue is the following and explains why its not firing:

We stuck a Noid light on two or three injector plugs and
there's no pulsing to the injectors. This explains the lack
of starting. But WHY??? What could cause the fuel injectors not
to be pulsed.

We haven't done a compression test but we've got a professionally
built long block so I'm not sure it needs to be done...

Any thoughts or insight would be appreciated..
HELP HELP HELP

Thanks

James

Check the Cam Position Sensor (inside the distributor). There's this
vague recollection that if that fails it inhibits the injectors.
That's the thing that tells the computer where in the two revolutions
you are to determine TDC for #1 cylinder since it can't tell the
compression strke from the exhaust stroke using just the crank
position sensor.

On Tue, 10 May 2005 14:07:26 UTC sevensixtwo_fmj (AT) hotmail (DOT) com wrote:

Hey,
actually Help!

Here's my symptoms:

1. Cranks fine
2. Lots of good spark
3. Timing was set TDC on compression stroke.. verified twice.
4. Fuel Rail is pressurized
5. Crank Pos Sensor functional (as far as we can tell)
6. Map Sensor Functional (voltage too the sensor)
7. Throttle Position Sensor is functional

Big clue is the following and explains why its not firing:

We stuck a Noid light on two or three injector plugs and
there's no pulsing to the injectors. This explains the lack
of starting. But WHY??? What could cause the fuel injectors not
to be pulsed.

We haven't done a compression test but we've got a professionally
built long block so I'm not sure it needs to be done...

Any thoughts or insight would be appreciated..
HELP HELP HELP

Thanks

James

--
Will Honea

There is a ballast resistor out on the drivers side fender near the rad
that controls the power to the fuel pump.

Do you hear the pump hum when the key is first turned on?

When was the last time the fuel filter was changed? It is on the frame
rail just in front of the tank, drivers side.

The pump also needs a ground which is supplied via the mesh strap from
the rear of the head to the firewall. I test that by putting a booster
cable from the battery negative tot he firewall to see if they start
then.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

sevensixtwo_fmj (AT) hotmail (DOT) com wrote:

Hey,
actually Help!

Here's my symptoms:

1. Cranks fine
2. Lots of good spark
3. Timing was set TDC on compression stroke.. verified twice.
4. Fuel Rail is pressurized
5. Crank Pos Sensor functional (as far as we can tell)
6. Map Sensor Functional (voltage too the sensor)
7. Throttle Position Sensor is functional

Big clue is the following and explains why its not firing:

We stuck a Noid light on two or three injector plugs and
there's no pulsing to the injectors. This explains the lack
of starting. But WHY??? What could cause the fuel injectors not
to be pulsed.

We haven't done a compression test but we've got a professionally
built long block so I'm not sure it needs to be done...

Any thoughts or insight would be appreciated..
HELP HELP HELP

Thanks

James

He says the fuel rail is pressurized and has no injector pulse - can
you think of anything besides the cam sensor that would inhibit the
injectors but not the spark? I assumed that the fuel pressure stayed
up during cranking. That long crank to start the Renix MPI 4.0 like
ours appears to be due to waiting for the #1 tdc pulse before putting
fuel to the cylinders. This also sounds a lot like the recall for the
'87 XJ/MJ where the Cam sensor leads were breaking off at the
distributor.

On Wed, 11 May 2005 18:03:11 UTC Mike Romain <romainm (AT) sympatico (DOT) ca>
wrote:

There is a ballast resistor out on the drivers side fender near the rad
that controls the power to the fuel pump.

Do you hear the pump hum when the key is first turned on?

When was the last time the fuel filter was changed? It is on the frame
rail just in front of the tank, drivers side.

The pump also needs a ground which is supplied via the mesh strap from
the rear of the head to the firewall. I test that by putting a booster
cable from the battery negative tot he firewall to see if they start
then.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

sevensixtwo_fmj (AT) hotmail (DOT) com wrote:

Hey,
actually Help!

Here's my symptoms:

1. Cranks fine
2. Lots of good spark
3. Timing was set TDC on compression stroke.. verified twice.
4. Fuel Rail is pressurized
5. Crank Pos Sensor functional (as far as we can tell)
6. Map Sensor Functional (voltage too the sensor)
7. Throttle Position Sensor is functional

Big clue is the following and explains why its not firing:

We stuck a Noid light on two or three injector plugs and
there's no pulsing to the injectors. This explains the lack
of starting. But WHY??? What could cause the fuel injectors not
to be pulsed.

We haven't done a compression test but we've got a professionally
built long block so I'm not sure it needs to be done...

Any thoughts or insight would be appreciated..
HELP HELP HELP

Thanks

James

--
Will Honea

I 'think' in another group some Jeep 'mechanic' insists that our renix
will start and run without the cam sensor even plugged in?

I had injector failure and it was a bad ground strap from the body to
the engine. Some things can steal a ground, but not all. Once the
starter is cranking, it can not leave enough juice to get around to
everything and fire up the computer if it has bad connections.

Mike

Will Honea wrote:

He says the fuel rail is pressurized and has no injector pulse - can
you think of anything besides the cam sensor that would inhibit the
injectors but not the spark? I assumed that the fuel pressure stayed
up during cranking. That long crank to start the Renix MPI 4.0 like
ours appears to be due to waiting for the #1 tdc pulse before putting
fuel to the cylinders. This also sounds a lot like the recall for the
'87 XJ/MJ where the Cam sensor leads were breaking off at the
distributor.

On Wed, 11 May 2005 18:03:11 UTC Mike Romain <romainm (AT) sympatico (DOT) ca
wrote:

There is a ballast resistor out on the drivers side fender near the rad
that controls the power to the fuel pump.

Do you hear the pump hum when the key is first turned on?

When was the last time the fuel filter was changed? It is on the frame
rail just in front of the tank, drivers side.

The pump also needs a ground which is supplied via the mesh strap from
the rear of the head to the firewall. I test that by putting a booster
cable from the battery negative tot he firewall to see if they start
then.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

sevensixtwo_fmj (AT) hotmail (DOT) com wrote:

Hey,
actually Help!

Here's my symptoms:

1. Cranks fine
2. Lots of good spark
3. Timing was set TDC on compression stroke.. verified twice.
4. Fuel Rail is pressurized
5. Crank Pos Sensor functional (as far as we can tell)
6. Map Sensor Functional (voltage too the sensor)
7. Throttle Position Sensor is functional

Big clue is the following and explains why its not firing:

We stuck a Noid light on two or three injector plugs and
there's no pulsing to the injectors. This explains the lack
of starting. But WHY??? What could cause the fuel injectors not
to be pulsed.

We haven't done a compression test but we've got a professionally
built long block so I'm not sure it needs to be done...

Any thoughts or insight would be appreciated..
HELP HELP HELP

Thanks

James

--
Will Honea

I'll see your Jeep 'mechanic' and raise on 1988 MPI manual <g>.
There's was a fairly long section in there about the Cam sensor
failure in there dealing with the 87 recall. The wires from the
distributor were breaking and the diagnostic they give was no injector
pulse. There is also a separate ground for the injectors and one Jeep
mechanic at the local dealer was showing me where he had problems in
that big hulking connector on the firewall with that, so that's also a
good start, too. The cam sensor is easy enough to check - one pulse
per revolution of the engine. It's a Hall Effect switch just like the
Crank sensor.

I've dealt with the crapped out crank sensor and the limp home mode.
Boy! Is that ever an appropriate decription. It would start and idle
but anything much above idle it work buck and load down immediately.
I came home basically at idle playing with the gears all the way. I
think I got 1000 rpm max - sure did irritate the folks who got stuck
behind me. Even 5th gear at 1000 RPM makes the tortise look fast. I
guess if they know the crank angle from the CPS they could fire both
ignition and injectors for each pair of cylinders together but they
would still have to know where #1 was and I don't remember any unique
notch pattern on the flywheel ring that would tell them that.


On Thu, 12 May 2005 13:12:54 UTC Mike Romain <romainm (AT) sympatico (DOT) ca>
wrote:

I 'think' in another group some Jeep 'mechanic' insists that our renix
will start and run without the cam sensor even plugged in?

I had injector failure and it was a bad ground strap from the body to
the engine. Some things can steal a ground, but not all. Once the
starter is cranking, it can not leave enough juice to get around to
everything and fire up the computer if it has bad connections.

Mike

Will Honea wrote:

He says the fuel rail is pressurized and has no injector pulse - can
you think of anything besides the cam sensor that would inhibit the
injectors but not the spark? I assumed that the fuel pressure stayed
up during cranking. That long crank to start the Renix MPI 4.0 like
ours appears to be due to waiting for the #1 tdc pulse before putting
fuel to the cylinders. This also sounds a lot like the recall for the
'87 XJ/MJ where the Cam sensor leads were breaking off at the
distributor.

On Wed, 11 May 2005 18:03:11 UTC Mike Romain <romainm (AT) sympatico (DOT) ca
wrote:

There is a ballast resistor out on the drivers side fender near the rad
that controls the power to the fuel pump.

Do you hear the pump hum when the key is first turned on?

When was the last time the fuel filter was changed? It is on the frame
rail just in front of the tank, drivers side.

The pump also needs a ground which is supplied via the mesh strap from
the rear of the head to the firewall. I test that by putting a booster
cable from the battery negative tot he firewall to see if they start
then.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

sevensixtwo_fmj (AT) hotmail (DOT) com wrote:

Hey,
actually Help!

Here's my symptoms:

1. Cranks fine
2. Lots of good spark
3. Timing was set TDC on compression stroke.. verified twice.
4. Fuel Rail is pressurized
5. Crank Pos Sensor functional (as far as we can tell)
6. Map Sensor Functional (voltage too the sensor)
7. Throttle Position Sensor is functional

Big clue is the following and explains why its not firing:

We stuck a Noid light on two or three injector plugs and
there's no pulsing to the injectors. This explains the lack
of starting. But WHY??? What could cause the fuel injectors not
to be pulsed.

We haven't done a compression test but we've got a professionally
built long block so I'm not sure it needs to be done...

Any thoughts or insight would be appreciated..
HELP HELP HELP

Thanks

James

--
Will Honea

--
Will Honea

"sevensixtwo_fmj" wrote:

Hey,
actually Help!

Here's my symptoms:

1. Cranks fine
2. Lots of good spark
3. Timing was set TDC on compression stroke.. verified twice.
4. Fuel Rail is pressurized
5. Crank Pos Sensor functional (as far as we can tell)
6. Map Sensor Functional (voltage too the sensor)
7. Throttle Position Sensor is functional

Big clue is the following and explains why its not firing:

We stuck a Noid light on two or three injector plugs and
there's no pulsing to the injectors. This explains the lack
of starting. But WHY??? What could cause the fuel injectors
not
to be pulsed.

We haven't done a compression test but we've got a
professionally
built long block so I'm not sure it needs to be done...

Any thoughts or insight would be appreciated..
HELP HELP HELP

Thanks

James

Having pretty much the same problem.
It seemed to start with the sensor on the flywheel so that was
replaced.
The next time it stopped I had some test equiepment with me and I had
no fuel pressure, replacing the relay seemed to fix it but not for
long.
Next came the fuel pump and filter, seemed to fix it but not for long.
I have checked all the ground wires, I have no power to pump, fuel
pump relay pulls in for three seconds, pump does not run, there is no
ballist resistor anywhere to be found.
On the drivers side fender there is a EGR selonoid and a relay that
should be the fan control.
This is a 87 AMC 4.0.

--
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The ballast resistor for the fuel pump is out on the drivers side fender
by the radiator.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

langer1 wrote:

"sevensixtwo_fmj" wrote:
Hey,
actually Help!

Here's my symptoms:

1. Cranks fine
2. Lots of good spark
3. Timing was set TDC on compression stroke.. verified twice.
4. Fuel Rail is pressurized
5. Crank Pos Sensor functional (as far as we can tell)
6. Map Sensor Functional (voltage too the sensor)
7. Throttle Position Sensor is functional

Big clue is the following and explains why its not firing:

We stuck a Noid light on two or three injector plugs and
there's no pulsing to the injectors. This explains the lack
of starting. But WHY??? What could cause the fuel injectors
not
to be pulsed.

We haven't done a compression test but we've got a
professionally
built long block so I'm not sure it needs to be done...

Any thoughts or insight would be appreciated..
HELP HELP HELP

Thanks

James

Having pretty much the same problem.
It seemed to start with the sensor on the flywheel so that was
replaced.
The next time it stopped I had some test equiepment with me and I had
no fuel pressure, replacing the relay seemed to fix it but not for
long.
Next came the fuel pump and filter, seemed to fix it but not for long.
I have checked all the ground wires, I have no power to pump, fuel
pump relay pulls in for three seconds, pump does not run, there is no
ballist resistor anywhere to be found.
On the drivers side fender there is a EGR selonoid and a relay that
should be the fan control.
This is a 87 AMC 4.0.

--
Posted using the http://www.autoforumz.com interface, at author's request
Articles individually checked for conformance to usenet standards
Topic URL: http://www.autoforumz.com/4X4-89-Jee...ict119514.html
Visit Topic URL to contact author (reg. req'd). Report abuse: http://www.autoforumz.com/eform.php?p=601383

On 8 Jun 2005 20:37:46 -0400, langer1 <DoNotEmail (AT) AutoForumz (DOT) com>
wrote:

"Mike Romain" wrote:
The ballast resistor for the fuel pump is out on the drivers
side fender
by the radiator.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

langer1 wrote:

"sevensixtwo_fmj" wrote:
&nbsp;> > Hey,
&nbsp;> > actually Help!
&nbsp;
&nbsp;> > Here's my symptoms:
&nbsp;
&nbsp;> > 1. Cranks fine
&nbsp;> > 2. Lots of good spark
&nbsp;> > 3. Timing was set TDC on compression stroke..
verified twice.
&nbsp;> > 4. Fuel Rail is pressurized
&nbsp;> > 5. Crank Pos Sensor functional (as far as we can
tell)
&nbsp;> > 6. Map Sensor Functional (voltage too the sensor)
&nbsp;> > 7. Throttle Position Sensor is functional
&nbsp;
&nbsp;> > Big clue is the following and explains why its not
firing:
&nbsp;
&nbsp;> > We stuck a Noid light on two or three injector
plugs and
&nbsp;> > there's no pulsing to the injectors. This explains
the lack
&nbsp;> > of starting. But WHY??? What could cause the fuel
injectors
&nbsp;> > not
&nbsp;> > to be pulsed.
&nbsp;
&nbsp;> > We haven't done a compression test but we've got a
&nbsp;> > professionally
&nbsp;> > built long block so I'm not sure it needs to be
done...
&nbsp;
&nbsp;> > Any thoughts or insight would be appreciated..
&nbsp;> > HELP HELP HELP
&nbsp;
&nbsp;> > Thanks
&nbsp;
&nbsp;> > James

Having pretty much the same problem.
It seemed to start with the sensor on the flywheel so that
was
replaced.
The next time it stopped I had some test equiepment with me
and I had
no fuel pressure, replacing the relay seemed to fix it but
not for
long.
Next came the fuel pump and filter, seemed to fix it but not
for long.
I have checked all the ground wires, I have no power to
pump, fuel
pump relay pulls in for three seconds, pump does not run,
there is no
ballist resistor anywhere to be found.
On the drivers side fender there is a EGR selonoid and a
relay that
should be the fan control.
This is a 87 AMC 4.0.

--
Posted using the http://www.autoforumz.com interface, at author's request
Articles individually checked for conformance to usenet
standards
Topic URL: http://www.autoforumz.com/4X4-89-Jee...ict119514.html
Visit Topic URL to contact author (reg. req'd). Report abuse: http://www.autoforumz.com/eform.php?p=601383




Sure wish it was, I even removed the washer tank and looked under
there.

I've never worked on a jeep but doesen't the ECM control the pulse on
the fuel injections system? Do you have any ECM codes present and is
there any reason to suspect a faulty ECM?



---
Elbert Clarke
elbert.clarke@**adelphia.net
remove ** to email

Fuel pump won't stop the injectors from firing. I'm surprised at you,
Mike. This is a perfect place to point to the ground strap <g>. Jump
the battery negative to a clean bolt on the firewall and see what
happens ( try jumpering to the ground lug on the firewall up by the
MAP sensor - the one with the braided cable on it - as that's the
cable that rots out).

On Wed, 8 Jun 2005 18:40:18 UTC Mike Romain <romainm (AT) sympatico (DOT) ca>
wrote:

The ballast resistor for the fuel pump is out on the drivers side fender
by the radiator.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

langer1 wrote:

"sevensixtwo_fmj" wrote:
Hey,
actually Help!

Here's my symptoms:

1. Cranks fine
2. Lots of good spark
3. Timing was set TDC on compression stroke.. verified twice.
4. Fuel Rail is pressurized
5. Crank Pos Sensor functional (as far as we can tell)
6. Map Sensor Functional (voltage too the sensor)
7. Throttle Position Sensor is functional

Big clue is the following and explains why its not firing:

We stuck a Noid light on two or three injector plugs and
there's no pulsing to the injectors. This explains the lack
of starting. But WHY??? What could cause the fuel injectors
not
to be pulsed.

We haven't done a compression test but we've got a
professionally
built long block so I'm not sure it needs to be done...

Any thoughts or insight would be appreciated..
HELP HELP HELP

Thanks

James

Having pretty much the same problem.
It seemed to start with the sensor on the flywheel so that was
replaced.
The next time it stopped I had some test equiepment with me and I had
no fuel pressure, replacing the relay seemed to fix it but not for
long.
Next came the fuel pump and filter, seemed to fix it but not for long.
I have checked all the ground wires, I have no power to pump, fuel
pump relay pulls in for three seconds, pump does not run, there is no
ballist resistor anywhere to be found.
On the drivers side fender there is a EGR selonoid and a relay that
should be the fan control.
This is a 87 AMC 4.0.

--
Posted using the http://www.autoforumz.com interface, at author's request
Articles individually checked for conformance to usenet standards
Topic URL: http://www.autoforumz.com/4X4-89-Jee...ict119514.html
Visit Topic URL to contact author (reg. req'd). Report abuse: http://www.autoforumz.com/eform.php?p=601383

--
Will Honea