No Spark or Fuel During Engine Crank

[Posi]

Also, when your replaced the pickup coil did you mark the trigger wheel for install orientation. Pin tapped into locating hole?

 

[thundley57]

Re-check for any engine codes

Distributor set on the "compression" stroke?
How many vacuum lines do you have going to the TB and intake, are there any T's?

Inspect all vacuum lines for leaks
When the engine tried to start last did you apply throttle to keep it going?
What is your base TPS set at?

Do only test 3, part 1, post your findings.

No codes registered in the ECM. Flashes code 12 three times then starts repeating.

Checked TDC on #1 piston by removing the spark plug and fishing a piece of bailing wire into the cylinder until it hit the top of the piston. Had a friend slowly roll the engine over with a wrench until the piston quit rising and then starting falling again. Reversed the direction of the roll until the piston quit rising again and looked at the timing mark which was exactly on 0 deg.

Checked and double checked all of the vacuum lines and found no issues.

When the engine starts opening the throttle only makes it run worse and eventually dies.

The only problem I came across when testing the TPS was that my connector differs from the one in the instruction sheet, mine having 4 wires (see picture) while the one in the instructions has three. One of my 4 wires was dark blue like the one recommended to test in the instructions so that's the one I tested. The results were -1.31 volts (yes, I did have the red lead connected to the wire and the black lead to battery neg). I did open the throttle to see if the values moved any but they did not so I guess I either have a bad TPS or I was testing the wrong wire. Unless somebody knows exactly which wire to test I'm going to call Troy and see if he knows. I could find nothing on Google in regards to testing the GM 4.3L TPS with 4 wire connector.

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[thundley57]

Also, when your replaced the pickup coil did you mark the trigger wheel for install orientation. Pin tapped into locating hole?

Yes sir, the trigger wheel actually has two grooves exactly 180 degs apart while the distributor shaft only has one. From what I can tell, installing the trigger wheel with either groove lined up with the shaft groove makes no difference with the orientation of the triggers to the pickup coil but I'm going to double check this tomorrow and will take a picture.

 

[Torxhead]

On my Howell wiring harness, It is only 3 wires for the tps. Originally the 3 wires adapted into a 4 wire plug to a non-adjustable tps. When I replaced the tps years ago, the new one came with a 3 wire plug so I just removed the 4 plug adapter and plugged the 3 wire connectors together. So, what I am saying is that you might have an adapter there to run both the 3 wire and 4 wire tps units. I do have another t.b.i. with an adjustable tps and it only has a 3 wire plug for it. With the Howell efi kit a is a service manual that you should have. The tps diagnostic is on page 28-29. You should have a code 21 or 22 for a bad tps.

 

[thundley57]

On my Howell wiring harness, It is only 3 wires for the tps. Originally the 3 wires adapted into a 4 wire plug to a non-adjustable tps. When I replaced the tps years ago, the new one came with a 3 wire plug so I just removed the 4 plug adapter and plugged the 3 wire connectors together. So, what I am saying is that you might have an adapter there to run both the 3 wire and 4 wire tps units. I do have another t.b.i. with an adjustable tps and it only has a 3 wire plug for it. With the Howell efi kit a is a service manual that you should have. The tps diagnostic is on page 28-29. You should have a code 21 or 22 for a bad tps.

Thanks Torxhead, I will check out the manual.


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[Posi]

The pic you posted looks like the IAC plug not the TPS.
The colors match the wires going to the IAC as well.
The IAC and TPS is on the same side of the TB, can you post a pic of that side with the plug still removed?

I only had you preform one test on the TPS for a reason. If the numbers are not correct for the test I gave you doesn't mean the TPS is bad.

 

[Torxhead]

Good catch there Posi. Those wire colors do match my iac also, which is located on the high rt. side corner where the tps is on the lower center rt. side. I did have an iac go bad on the trail once, the symptoms were an inconsistent idle. My tps wire colors are gray, blue, and black.

 

[thundley57]

Good catch there Posi. Those wire colors do match my iac also, which is located on the high rt. side corner where the tps is on the lower center rt. side. I did have an iac go bad on the trail once, the symptoms were an inconsistent idle. My tps wire colors are gray, blue, and black.

My bad....I will look again tonight and perform the test on the RIGHT component this time

 

[Lumpy Grits]

Again-I really think this thread must become a sticky. It has far more details in troubleshooting and such, than any other I have seen on this FI system.
I thank you all for the gained knowledge I have now.
Respectfully,
LG

 

[thundley57]

The pic you posted looks like the IAC plug not the TPS.
The colors match the wires going to the IAC as well.
The IAC and TPS is on the same side of the TB, can you post a pic of that side with the plug still removed?

I only had you preform one test on the TPS for a reason. If the numbers are not correct for the test I gave you doesn't mean the TPS is bad.

Peso, you were correct in that I was testing the IAC instead of the TPS last night. That's what I get for being in a hurry and not inspecting things closely. With red lead of volt meter hooked onto the blue wire of the TPS, the black lead clipped to battery neg and key on I got .713 volts constant which according to the instructions are within limits. For the benefit of other dumb asses like me that may be following this thread here's a picture of the two components which are on the passenger side of the throttle body.

As I mentioned in my post yesterday, here are a couple of pictures of the installed trigger wheel inside the distributor. The pics show the grooves on each side of the wheel where the key inserts into a matching groove (1) on the dist shaft. As you can see the grooves are 180 deg apart and are both in the middle of a spoke so in my mind it shouldn't matter which groove you end up using to connect to the shaft. I'm not sure what the blue paint on the one spoke is for unless the PO marked it. Hopefully somebody will tell me if I'm wrong here. By the way, for those that may be wondering, the wheel was not installed upside down.

One other thing I checked this evening was the EGR valve to make sure it wasn't stuck open which it wasn't.


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[thundley57]

The IAC and TPS is on the same side of the TB, can you post a pic of that side with the plug still removed?

Posi, I just realized that you wanted a pic with the IAC connector disconnected. Let me know if you still want this and I will get one tomorrow.



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[Posi]

No need for that pic.
Your TPS is not adjusted properly.
I'll post later when I have time.

 

[Posi]

I got .713 volts constant which according to the instructions are within limits.

You should have your TPS set at or as close to .54 as you can get without going under. Anything higher will show a percentage of throttle to the ecm. .54 = .2 % .713 = about 1.9 Your TPS should be set within 1 %.

What was your engine idle before your problem started?

What is your throttle blades set at?

The throttle blades should just be slightly opened. You can use a 1/4" strip of paper as a feeler gauge to get an idea of how far their opened.

If the throttle blades are out of adjustment they must be adjusted “before” adjusting the TPS. Adjusting the throttle blades with change the TPS setting.

Adjusting the throttle blades on a non-running engine. On the front drivers side of the throttle body is the adjustment screw. It may be behind a silver plug. If so just use a nail or punch to poke it and remove it. Then use a #20 torx bit to adjust the blades to 1/4” open.

There is another procedure of setting your idle when the engine is running.

By adjusting the throttle blades your adjusting the idle.

Once the blades are correct you then adjust the TPS. The factory TPS will not have much room in the holes for adjustments, or may have none at all so I use a file to elongate the holes as needed. To adjust, just loosen the screws and twist the TPS. You can monitor the voltage on the blue wire of the connector with the key on or at pin C13 of the ecm.

 

[thundley57]

What was your engine idle before your problem?

The engine idled perfectly at 800 rpm's

Once the blades are correct you then adjust the TPS. The factory TPS will not have much room in the holes for adjustments, or may have none at all so I use a file to elongate the holes as needed. To adjust, just loosen the screws and twist the TPS. You can monitor the voltage on the blue wire of the connector with the key on or at pin C13 of the ecm.

I'm a little confused on this one. So loosen the screws and twist the TPS until I get the desired reading but if I can't get the desired reading I need to pull it out and elongate the holes, is this correct?

Are you fairly confident that this is my problem? I mean, do you think my TPS changed it's setting between before my engine just died and now? The test procedure you shared with me indicates it is in spec? I have the new tach filter now which either way I'm not sending back (will keep for spare). Should I just install it and see if that fixes the problem?


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[Torxhead]

There are specific instructions on setting the idle speed by disconnecting the idle air connector in the Howell instruction manual. I believe this has to be done to coordinate the adjustment with the computer. As a guess, I am thinking that the issue is with the ignition timing as it has not been set correctly since the reinstallation. I did think also that the tach filter was for the multi spark systems like the MSD ignition.

 

[thundley57]

There are specific instructions on setting the idle speed by disconnecting the idle air connector in the Howell instruction manual. I believe this has to be done to coordinate the adjustment with the computer. As a guess, I am thinking that the issue is with the ignition timing as it has not been set correctly since the reinstallation.

Yes, this is how I made the initial adjustment.


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[Posi]

What I'm saying is the TPS should be adjusted, not saying this is your no start problem.

If you have a manual Transmission then I would say your throttle blade are in the correct position. But check them to be sure.

If your plan is to keep the tach filter regardless of the out come I would swap the new one in and see what happens, doesn't hurt anything if your not sending it back.

That's correct, if you can't adjust the TPS remove it and elongate the holes, install it and make the needed adjustments.

No need to touch the IAC at this time.

 

[Posi]

As for the no start.
Once you posted the TPS readings I thought there was a chance your throttle blades were not in the correct position.
This would cause a not start.
My questions were inline with this.

 

[JR74CJ5]

I will sticky when im back at actual computer. Good stuff all

-Jr

 

[thundley57]

Well unfortunately the saga continues. I finally found enough time this evening to break away from the kitchen remodel and install the new tach filter. Having the same issue, the motor starts but barely runs and then dies shortly thereafter. Good fuel pressure, bright spark...WTF! The only thing I know to do now is replace the ECM but for $AMC 150 with no certainty that that's the problem, very frustrating! I included a video of what it's doing while trying to get a good shot of the injector spray volume in the hopes that any of you can steer me in the right direction.

https://youtu.be/zNIA8rRt9cM


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