Timing Chains done, now car cuts off and back on at 4000rpm

GoneBrokeRacing · Aug 25, 2018

2001 Bullitt Mustang 4.6L 2v

Just did a timing set last night, passenger upper guide in 4 pieces and the lower wore threw on both ends. All new ford parts !
Everything lined up dots and dark links and the cams didn't move so i believe everything is lined up
I checked all the sensors i disconnected and vacuum lines and i never disconnected the battery. The only problem i noticed was my number 1 coil is cracked right at the connector which i'll replace tonight.
It idles completely quiet to the point all I hear is the injectors cycling.
Apon first drive last night it was very smooth, definitely picked up power.
Pulled to a dead stop and stomped it, then everything shut off. almost like i cycled the key off then back on. Radio and all shut off, gauges cycled full sweep then it was back to normal and running fine.
This morning I tried slowly bringing the rpm's up in 1st and 2nd gear and right at 4000Rpm's exactly it did it again both times
I ran a KOEO and KOER test with my scanner and there were no codes.

Any idea ??? I'm lost lol

wmburns · Aug 25, 2018

GoneBrokeRacing said:
gauges cycled full sweep

For the 1999-2004 model year a full gauge sweep is a dead give away the power was removed(or battery voltage dropped too low) from the PCM and/or the cluster. Likely you have a battery/charging system problem. Loose cable, loose ground or the like. Given the intermittent nature of the problem my guess is there's a loose connection.

Double check that the Main alternator B+ terminal is clean and tight. Check for bent/pushed pins in the smaller connector.

Don't forget to cover the basics by checking the battery terminals and cables.

When you re-installed the front timing cover did you re-attach the heavy battery grounding cable? I believe it's on the front left motor mount.

There's a round connector near the battery with a number of black wires and/or black wires with a white stripe. This is the PCM and CCRM ground. Sometimes this is disconnected during a battery swap.

Here's some information that may help. If you are unable to find a weak ground visually the voltage drop test method can determine if there's a problem. And if there is a problem it can help narrow down where the problem is.

Howto perform charging system voltage drop test
https://www.stangnet.com/mustang-fo...perform-charging-system-voltage-drop-test.56/

GoneBrokeRacing · Aug 25, 2018

wmburns said:
For the 1999-2004 model year a full gauge sweep is a dead give away the power was removed(or battery voltage dropped too low) from the PCM and/or the cluster. Likely you have a battery/charging system problem. Loose cable, loose ground or the like.

When you re-installed the front timing cover did you re-attach the heavy battery grounding cable? I believe it's on the front left side of the motor.

I never disconnected the battery or any of the cables. I just unbolted stuff and moved it out of the way.

wmburns · Aug 25, 2018

Is this a manual or automatic? Will the problem only happen under driving load?

Double check that the two alternator mounting bolts to the motor web were reinstalled.

Is there any evidence of belt slip on any pulley?

OK. Let's try this. Measure the voltage at the battery with the motor off. Post.

Now measure the voltage at the battery with the motor idling. Repeat the measurement at the alternator B+ terminal. Post.

Finally repeat the voltage measurement at the alternator B+ while raising to 4,000 RPM's. Make note of ANY change in voltage.

FWIIW, I personally would not leave the main alternator B+ terminal connected and just swing the alternator out of the way. I would be most concerned about putting excessive load on the terminal. Any kind of side loading of the cable could make the stud nut back off. There by creating a loose connection. Or at worst breaking the terminal. But that's just me.

GoneBrokeRacing · Aug 25, 2018

wmburns said:
Is this a manual or automatic? Will the problem only happen under driving load?

Double check that the two alternator mounting bolts to the motor web were reinstalled.
Is there any evidence of belt slip on any pulley?
OK. Let's try this. Measure the voltage at the battery with the motor off. Post.
Now measure the voltage at the battery with the motor idling. Repeat the measurement at the alternator B+ terminal. Post.
Finally repeat the voltage measurement at the alternator B+ while raising to 4,000 RPM's. Make note of ANY change in voltage.
FWIIW, I personally would not leave the main alternator B+ terminal connected and just swing the alternator out of the way. I would be most concerned about putting excessive load on the terminal. Any kind of side loading of the cable could make the stud nut back off. There by creating a loose connection. Or at worst breaking the terminal. But that's just me.

The alternator wasn't removed, or disconnected no belt slip noticed.
Just did a voltage test load off 14.5v all loads on 13.75v and battery voltage with off was 12.8v

wmburns · Aug 25, 2018

What happened when the motor RPM's were increased to 4000 RPM's? Does the motor cut off? Does the voltage change in any way?

My thought is this is electrical. The cluster gauge sweep is a symptom that is hard to ignore. Something power related is happening.

Another option is to get an "add a fuse" or an "add a circuit" and use the pig tail to put a test light on some key fuses. Use a KNOWN good ground. This will give an easy way to monitor the circuit even while driving. If this were my car I would start by CONFIRMING that fuse F2.34, F2.2 and F2.8 have constant key on power.

A alternate spot to test is the red wire to any COP or fuel injector. I would use a test light that will "load" the circuit. This will give an easy visual indication of any change in voltage.

A possible theory is there's a wire that is being pulled upon when the motor moves (such as under high torque). Again using a test light that is visible while driving is useful for trouble shooting a problem that occurs only under certain driving conditions.

1999-2004 MY fuse panel schedule:
https://www.allfordmustangs.com/for...r-swap-wont-fire-please-help.html#post2669271

If spending money on a manufactured test light is not for you, here's some information on a DIY solution.

How To Make Your Own Test Lights

View: https://www.youtube.com/watch?v=-L_fw7xn19k

GoneBrokeRacing · Aug 25, 2018

wmburns said:
What happened when the motor RPM's were increased to 4000 RPM's? Does the motor cut off? Does the voltage change in any way?

No the whole car shuts down ... Almost like i cycled the key off then back on. gauges do a full sweep then everything's normal.
It's a manual trans so everything just jump back on.

wmburns · Aug 26, 2018

I assuming that you have double checked the electrical connection to the CAM and CKP sensors.

Well......

It seems to me that the problem is clearly electrical. My gut tells me that it's fairly high up in the power distribution (the gauge sweep). At this point I'm all out of WAG's as to what is causing your problem and how it could relate to the work done.

I consider myself very good with electronics and electrical trouble shooting. I believe that I have a proven track record of helping people on the forums. The only way I know how to solve your problem is via testing and going where the testing leads. To that end I have given several suggestions on which circuits to test in an effort to locate the problem source (post #6). I'm going to set on the side lines until there's something posted to work with.

Perhaps an ODB2 scanner might help. Here's some information on an affordable Windows based unit.

ForScan ODB2 scanner w ELM327 USB
https://www.stangnet.com/mustang-forums/resources/forscan-odb2-scanner-w-elm327-usb.57/

GoneBrokeRacing · Aug 26, 2018

wmburns said:
I assuming that you have double checked the electrically connection to the CAM and CKP sensors.
Well......
It seems to me that the problem is clearly electrical. My gut tells me that it's fairly high up in the power distribution (the gauge sweep). At this point I'm all out of WAG's as to what is causing your problem and how it could relate to the work done.

I consider myself very good with electronics and electrical trouble shooting. I believe that I have a proven track record of helping people. The only way I know how to solve your problem is via testing and going where the testing leads. To that end I have given several suggestions on which circuits to test in an effort to locate the problem source (post #6). I'm going to set on the side lines until there's something posted to work with.

ok this morning I pulled the battery and tested it. Tester said to replace it, I swapped in a new battery and put new terminals on then took it out for a run. It didn't cure the problem but made it better.
Now at 4000 rpms the engine doesn't cut off, but the Battery light flashes on for a second and the ABS light too.
Radio still goes off and comes right back on.
It acts like belt slip. but I don't hear any belt squeal and I put a new belt while everything was apart.
I think my next step is changing out the belt tensioner. To see if it was belt slip

wmburns · Aug 26, 2018

GoneBrokeRacing said:
Now at 4000 rpms the engine doesn't cut off, but the Battery light flashes on for a second and the ABS light too.
Radio still goes off and comes right back on.
It acts like belt slip. but I don't hear any belt squeal and I put a new belt while everything was apart.

Here's what I think. IF it was belt slip there would be evidence of it (noise or ground up belt material). Previous posts you stated there was not. Further the belt is new. So unless the new belt is too long, IMO it's not belt slip.

Unless the belt accidentally got contaminated with oil. It's certainly possible to clean a belt with brake clean or scrub with soap and water.

Perhaps it's also a good idea to DOUBLE check the belt routing. I know that it's possible that IF the top right smooth idler pulley was missed near the alternator that will lengthen the belt and could make the belt "appear" longer. A missing idler pulley could also offer an explanation as to HOW the new problem could be related to the work performed.

Suggest ruling out alternator brush bounce caused by worn alternator brushes. How? MEASURE the voltage at the battery. Look for any change when the problem occurs.

Or have the alternator bench spin tested.

Or replace the alternator.

Here's some information on how to rebuild your own alternator.

Rebuilding your own alternator:
https://www.stangnet.com/mustang-fo...ternator-how-much-higher.897392/#post-9044147

Note, What I'm thinking was happening is the battery AND the alternator is bad. Perhaps the battery died outright while the work was being done. The battery and alternator work as part of a SYSTEM. IF the battery is weak the alternator can not put out it's max amps and if the battery is weak enough, the alternator will shut down.

At 4000 RPM's the brushes are bouncing enough to cause the alternator to stop putting out. With a weak battery, the problem is worse.

It's better now because with a strong battery the battery is able to carry a greater share of the load when the alternator is not pulling it's fair share.

Back to the information given in the "howto perform a voltage drop test", Today's cars simply will not run right without a strong battery and charging system.

I can't answer WHY the alternator decided to fail right after the timing chain repair. Sometimes the car repair Gods just require a larger blood sacrifice. The bigger the job, the bigger the sacrifice.

GoneBrokeRacing · Aug 26, 2018

wmburns said:
Here's what I think. IF it was belt slip there would be evidence of it (noise or ground up belt material). Previous posts you stated there was not. Further the belt is new. So unless the new belt is too long, IMO it's not belt slip.

Unless the belt accidentally got contaminated with oil. It's certainly possible to clean a belt with brake clean or scrub with soap and water.

Perhaps it's also a good idea to DOUBLE check the belt routing. I know that it's possible that IF one of the idler pulleys was missed near the alternator that will lengthen the belt and could make the belt "appear" longer. A missing idler pulley could also offer an explanation as to HOW the new problem could be related to the work performed.

Suggest ruling out alternator brush bounce caused by worn alternator brushes. How? MEASURE the voltage at the battery. Look for any change when the problem occurs.

Or have the alternator bench tested.
Note, What I'm thinking was happening is the battery AND the alternator is bad. Perhaps the battery died outright while the work was being done. The battery and alternator work as part of a SYSTEM. IF the battery is weak the alternator can not put out it's max amps and if the battery is weak enough, the alternator will shut down.
At 4000 RPM's the brushes are bouncing enough to cause the alternator to stop putting out. With a weak battery, the problem is worse.
It's better now because with a strong battery the battery is able to carry a greater share of the load when the alternator is not pulling it's fair share.
Back to the information given in the "howto perform a voltage drop test", Today's cars simply will not run right without a strong battery and charging system.
I can't answer WHY the alternator decided to fail right after the timing chain repair. Sometimes the car repair Gods just require a larger blood sacrifice. The bigger the job, the bigger the sacrifice.

So, I'm making the problem better lol. The Belt tensioner was bad, the belt size is right and clean .
Now the radio doesn't shut off all the time about 4000 rpms but the battery light and abs still doing the same.
Luckily I have a spare alternator to throw on there to test. I'll do that later after i get off work.

It makes sense what your saying about the brushes are bouncing enough to cause the alternator to stop putting out.
then I can bench test it tomorrow at work.

GoneBrokeRacing · Aug 27, 2018

IT WAS THE ALTERNATOR !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

wmburns · Aug 27, 2018

So were the forums helpful to solve your problem?

Do you have any "lessons learned" from the experience that you can pass on so that others can learn?

wmburns · Sep 6, 2018

Just wondering. Did you remember to re-install the smooth idler pulley that's on the upper right side of the motor in the 2nd picture? I can see how this could cause the belt to be too long and/or under tensioned if forgotten.

https://www.stangnet.com/mustang-forums/threads/what-is-this-piece.905774/

GoneBrokeRacing · Sep 9, 2018

wmburns said:
Just wondering. Did you remember to re-install the smooth idler pulley that's on the upper right side of the motor in the 2nd picture? I can see how this could cause the belt to be too long and/or under tensioned if forgotten.

I did remember to reinstall that bolt lol.
What I learned is not to let the timing clacking noise go that long before i changed it lol

wmburns · Sep 9, 2018

It just seemed to me like you did not believe it could have been a charging system problem and that it took some effort to convince. IE it couldn't possibly be the alternator or battery since they were not touched and worked before the work was started.

Regarding the other parts replaced prior to the alternator such as the tensioner, belt, battery. Was the alternator the primary cause of the complaint?

How did you finally determine it was the alternator? By voltage test? Bench spin testing? Or by process of elimination?

IMO some of these details are important as it may help someone else with a similar problem. Or save someone else the time/effort replacing parts that don't result in a "fix".

IMO it also improves the credibility of the forums to acknowledge the value of the information received.

Timing Chains done, now car cuts off and back on at 4000rpm

GoneBrokeRacing

New Member

wmburns

GoneBrokeRacing

New Member

wmburns

GoneBrokeRacing

New Member

wmburns

GoneBrokeRacing

New Member

wmburns

GoneBrokeRacing

New Member

wmburns

GoneBrokeRacing

New Member

GoneBrokeRacing

New Member

wmburns

wmburns

GoneBrokeRacing

New Member

wmburns

Similar threads

Timing Chains done, now car cuts off and back on at 4000rpm

New Member

New Member

New Member

New Member

New Member

New Member

New Member

New Member

Similar threads

Privacy & Transparency

Privacy & Transparency