No Spark or Fuel During Engine Crank

[thundley57]

I know this thread keeps coming back around like a bad dream but I'm still fighting this issue and have been for about 3 months. Quick recap: original post was for "no spark or fuel during engine crank" but without going into all of what has been done to resolve the issue thanks mostly to Posi and a couple others, I now have spark and fuel and the engine starts but will not come up to full idle and dies after a few seconds. Completed a Howell TBI upgrade at the end of 2016 and she ran fantastic until one day it suddenly died and would not restart. Found a bad distributor pick up coil, replaced it which brought my spark and fuel (tach signal) back but she just doesn't want to run.

You have something going on with your crank signal.
You should only have 12v while cranking and 0v in the run position, you have .6v in the run position.
The C9 wire should be connected to starter solenoid S post that is hot only when the key is in the crank position.
I'd inspect the wire and the starter solenoid to find the source of the .6v.

Posi, I rechecked this and discovered that I previously confused 6.4 MV with 6.4 V. I have 12V during crank and then my meter shows approximately 6.4 MV's while the key is in run which I'm considering to be 0 volts (please tell me if I'm wrong). Sorry to have taken you down that path.

Additionally, check your grounds when you get your ecm back.
Battery connected and key off, probe A11, A12, D1, D2.
You should have 0 ohms or 0v

I checked all of these grounds, battery connected and key off and got 0 ohms and 0 volts on all.

I got to thinking that maybe my manifold heater wasn't working and that maybe while cold the gas wasn't getting vaporized enough so I jumpered the oil pressure switch, disconnected the wire to the heater and checked with my volt meter with key on and got 12V. Just to ensure the heater wasn't burned out I hooked the wire back up and turned the key on again and felt the bottom of the manifold which heated up nicely.

I also removed the flexible plastic wire cover from the main harness looking for any opens, burnt wires, shorts, etc. and found nothing.

Posi (or anybody), do you have any other tricks up your sleeve before I pull my final hair out? I can't help but think that it is an electrical issue but I'm at a loss on where to look next. I'm tempted to replace the Howell wiring harness but since all of the ECM pin tests that Posi had me do seemed to be with-in spec except for the fact that I couldn't perform the tests while the engine was running.

 

[Lumpy Grits]

Who's dizzy pick-up coil did you buy? IF, it's a china made one, go to NAPA and get an American made one.
When the engine dies-How hot is the coil? Can you keep your hand on it?
LG

 

[Torxhead]

Glad you have not given up yet. From a video that you sent in a while back, I did notice quite a bit of raw gas being squirted from the injectors. Although it did look like a good spray pattern it was just too much and I have the opinion that your engine is being flooded out. I know you have done a tremendous amount of testing and remember Troy mentioning a bad computer. I really hate to suggest for you to put out the coin for another one of those or even a new harness. Hopefully, if you just keep at it you will find the issue and become an authority on that system.

 

[Lumpy Grits]

I had forgotten about that vid. Yes-WAY to much fuel IMHO.
LG

 

[thundley57]

Who's dizzy pick-up coil did you buy? IF, it's a china made one, go to NAPA and get an American made one.
When the engine dies-How hot is the coil? Can you keep your hand on it?
LG

It's totally understandable since this thread has turned into a novel but information is starting to be repeated. Several posts back I stated that I replaced the PU coil with a NAPA Echlin brand PU and the first one I purchased was actually bad (had zero ohms out of the box) and had to be exchanged.

Glad you have not given up yet. From a video that you sent in a while back, I did notice quite a bit of raw gas being squirted from the injectors. Although it did look like a good spray pattern it was just too much and I have the opinion that your engine is being flooded out. I know you have done a tremendous amount of testing and remember Troy mentioning a bad computer. I really hate to suggest for you to put out the coin for another one of those or even a new harness. Hopefully, if you just keep at it you will find the issue and become an authority on that system.

A few posts ago I mentioned that I sent my ECM back to Howell for them to run on their test Jeep. According to Troy they plugged it in and the Jeep ran with no issues.

I had forgotten about that vid. Yes-WAY to much fuel IMHO.
LG

Any speculation on what may be causing this? What's confusing is that I've tried unplugging one injector which cuts the fuel flow in half and saw no improvement. I also tried pinching the fuel hose down with needle nose pliers slowly reducing the fuel flow still with no improvement. Fuel pressure to the throttle body is the specified 12 psi by Howell. This is so discouraging especially now that I have no idea on where to look now. Was really hoping that all of the testing I've done would have revealed something.

 

[Lumpy Grits]

I did forget that it was NAPA-CRS is a
Still-I would have it tested.
Is there any way to adjust the fuel pump psi down just a bit? You want just enough psi to 'trigger' the injectors.
POSI-you out there??
LG

 

[Torxhead]

The map sensor signal controls the signal to the injectors:https://www.youtube.com/watch?v=B8EVhFc5Yqw
I think this issue is beyond that.

 

[Posi]

He has the correct reading for the map sensor with key on.

The IAC typically is trouble free but it's something we haven't checked.

Attach a jumper between pins A and B of the aldl connector. This puts the ECM into aldl mode. Turn the key on (not start) and the IAC should drive completely closed. You will normally hear a buzzing from the IAC. Now look in the throttle body to make sure the pintle is driven closed. If it's closed remove the IAC plug and turn off the key. Remove the jumper and try to start the engine.

A test I would like you to do before checking the IAC.
Use a voltage meter, + side of coil and good ground.
Key on, start, run, and when it dies out.
Start the engine and note the readings.
Does the voltage cut out, or present when engine dies.
Testing to see if the engine dies from an electrical cutoff or fuel/air.
If your still showing voltage do the same test and swap out the voltage meter for a timing light. Attach the clamp to the number # ignition wire and read the strobe.

 

[thundley57]

He has the correct reading for the map sensor with key on.

The IAC typically is trouble free but it's something we haven't checked.

Attach a jumper between pins A and B of the aldl connector. This puts the ECM into aldl mode. Turn the key on (not start) and the IAC should drive completely closed. You will normally hear a buzzing from the IAC. Now look in the throttle body to make sure the pintle is driven closed. If it's closed remove the IAC plug and turn off the key. Remove the jumper and try to start the engine.

A test I would like you to do before checking the IAC.
Use a voltage meter, + side of coil and good ground.
Key on, start, run, and when it dies out.
Start the engine and note the readings.
Does the voltage cut out, or present when engine dies.
Testing to see if the engine dies from an electrical cutoff or fuel/air.
If your still showing voltage do the same test and swap out the voltage meter for a timing light. Attach the clamp to the number # ignition wire and read the strobe.

Thanks for giving me more hope Posi. As long as I have specific actions to take I have hope that I will eventually find the problem. I will test and report back.

 

[Posi]

I would suggest making a remote start so you don't have to depend on anyone else to start the engine while you take readings. Some jumpers and a toggle switch will do, makes things a lot easier when working on your engine.
Just attach the jumpers to the starter solenoid.

Made this one.
https://youtu.be/tT-UAhvpy8Y

 

[thundley57]

I would suggest making a remote start so you don't have to depend on anyone else to start the engine while you take readings. Some jumpers and a toggle switch will do, makes things a lot easier when working on your engine.
Just attach the jumpers to the starter solenoid.

Made this one.
https://youtu.be/tT-UAhvpy8Y

Thanks, I have one.


Sent from my iPhone using Tapatalk

 

[thundley57]

My apologies for not updating this post after all of the in depth troubleshooting by key members of this forum. I had to take the time to finish the kitchen remodel (mentioned in previous posts) or face divorce so now my wife is happy but my mother-in-law is pissed off (where my Jeep is stored) with all of the tools spread over here garage floor and a piece of junk Jeep (in her eyes, not mine). Unfortunately my beloved Jeep is still broke and it is now in the upper 90's and low 100's here in Bakersfield which diminishes my motivation to work on it.

I did have a friend come over a few weeks ago to have a second set of eyes take a look at my problem and we resolved nothing but when cranking the engine to show him how it starts but barely runs then dies, we noticed that the fuel pressure was only 9 psi when the spec is 12 psi. This is a fairly new problem as I have checked it many times while working this problem and have observed 12 psi. At any rate, we disconnected the hose going to the TBI, cranked the engine and observed plenty of flow while directing it into a bottle so our conclusion was that it isn't a plugged filter. We did notice that the pressure does come up to 12 psi and above if the fuel return hose to the tank is pinched with vice grips.

I'm wondering now if there is a problem with the bypass regulator which I'm assuming is in the TB?

Another thing that happened during this whole process is that we completely lost spark (my original problem) and the engine would no longer start at all. Beings how my original loss of spark was traced down to a bad distributor pickup coil, I checked the resistance across the leads and got 0 ohms. This is while the coil was installed and testing it again after I removed the distributor also resulted in 0 ohms. So off to the parts store to buy yet another pick up coil which tested good at the store (.64). Took it home and installed it in the distributor a few days later and for sh*ts & grins tested the supposedly bad coil again and low and behold, it now had .62 Ohms! Am I going crazy here!!! I have not had a chance to re-install the distributor and try starting again.

I hate sounding like a broken record but once again I apologize for this long thread which with the awesome help from a few of you that just when I think is leading to the problem, another problem pops up!

 

[Posi]

This is a quick reply that I'll revisit when I have more time.
Your engine won't run on less then 10 PSI.
If your showing 9PSI you need to increase pressure by compressing the spring in the TB pressure regulator located at the rear of the TB.
I"ll go into detail when time allows.
I would recheck your engine ground and your distributor wiring as well.

 

[Torxhead]

Nice to hear from you again Thundley, I am sure your life is similar to many of us. I am sure that you will have your rig up and running after spending a fortune on it, again like the rest of us and be much wiser afterwards. I wish that I was as close to the Sierra Nevadas as you are and have been there many times. Sounds like you need to do some research on that fuel pressure regulator and distributor pick up coil. On my CJ I keep a stack of throttle body gaskets just for changing the fuel pressure if there are any issues and it is set up for easy removal. When my pick up coil went bad I just got a reman distributor. I have had my CJ drivable with as low as 6 psi when my icm was failing. If the fuel pressure is low enough to make the engine run lean, the check engine light will come on.

 

[Posi]

The engine light won't go on if the engine isn't running.
It's the internet! I'm sure there's dozens guys running 3PSI fuel pressure on a chevy TBI where the engine runs outstanding!

You don't need TB gaskets to adjust the FPR
Just need to remove the injector pod
Start with the fuel lines
Fuel line fittings
8 (IIRC) Torx screws and it's out.
The gold can is the FPR
Some FPR are adjustable and some you need to make adjustable.
I made mine adjustable.
If yours is adjustable turn the round ring at the bottom of the FPR counter clock wise to increase fuel pressure.
This will compress the spring and move the tab to the top.

If you have a pair of thin ignition pliers you don't have to remove anything just make your adjustments to the round ring under the FPR (located at the rear of the TB).

 

[thundley57]

Thanks Torxhead/Posi. It will be a few more weeks before I have the opportunity to get back over to the mother-in-laws and do some more work but will post when I do.


Sent from my iPhone using Tapatalk

 

[Posi]

I believe your problem is in your primary circuit.
I would start with the pickup coil wiring, plug, and engine ground
Inspect the trigger wheel and work out from there.
It may be a intermittent problem, wiggle wires then test again, test without the engine turning over, test while the engine is turning over.
Typically pickup coils are usually good or bad.
Your pickup coil texted bad while in the distributor, yet good before you installed it, and after you removed it.
Focus on the items I mentioned above first before moving on to other components if their needed.
Failure related to the pickup coil has been present from the beginning.
You have to keep digging into the primary circuit until you uncover what is keeping the pickup coil from working as it should.

 

[thundley57]

Again, apologies for not providing a timely update to this long thread. Went on an extended vacation and it's been a long hot summer here in Bakersfield robbing me of my motivation to continue my troubleshooting efforts on my beloved CJ7 . Here's a brief summary of the original issue followed by an update:

• Installed the Howell TBI kit with no major issues and she ran like a dream for a couple of months after the upgrade
• Engine instantly died one day while driving and had no spark or fuel (loss of fuel was caused by lack of a tach signal)
• On advice from this forum, tested the resistance of the distributor pickup coil and had 0 ohms (normal = approximately 650 ohms)
• Replaced the distributor pickup coil fully convinced that my problem would be solved
• Now had spark and fuel and the engine would start but would barely idle and die after a few seconds
• Swapped ignition module and coil to no avail
• Replaced the battery as it seemed to be a bit week and I wasn't sure of the age to no avail
• Replaced the tach filter supplied by Howell per Troy's recommendation to no avail
• Sent the ECM back to Howell who plugged it into their test Jeep which ran fine with my ECM installed
• Came close to selling her as is!
• Performed a host of many other troubleshooting procedures outlined in this thread
• Recruited a friend who previously owned a CJ7 to come lay another set of eyes on the problem and entirely lost spark again after starting the engine several times
• Tested the distributor pick up coil which apparently had failed once again as evidenced by 0 ohms across the leads.This was double checked with the distributor installed and removed but after removing it from the distributor to install a new one I tested it again for sh*ts and grins and suddenly it had the normal 650 ohms. At a loss on this one!

Update:
So after a couple more months passing without getting a good opportunity to work on her I recruited a co-worker who is a master mechanic to come take a look at her a few weeks ago.We re-installed the distributor with the new pick up coil installed and went for a start but still had no spark. After poking around a bit longer we noticed that the previously un-used (prior to the TBI upgrade) purple wire from the Duraspark ignition module to the TBI wiring harness had pulled out of the wire nut that I had connected them with. We reconnected the wire and low and behold the engine fired and idled perfectly. This wire obviously popped out during my last troubleshooting attempt when we went from having spark to suddenly no spark again.

So my Jeep is now running after 5 months of downtime but I'm still unsure of what the real problem was which doesn't give me a whole lot of confidence to take it out on the trail. I figure it was either a bad distributor pickup coil the entire time or the issue is an intermittent electrical problem (I'm guessing the latter).

Anyway, I'm back in business for now and will report back if the issue happens again.Many thanks to those of you on this forum who stuck with me during this process and provided great troubleshooting tips which at the very least caused me to learn a lot more about the workings of my Jeep. Thanks in particular to Posi and Torxhead who offered many good tips and troubleshooting techniques. This forum is invaluable with the combined knowledge of all of the members especially the ones that are willing to share their knowledge. There isn’t much that can’t be solved with a little patience, persistence and clear communication. I will definitely be giving back when I can.

 

[Torxhead]

Thanks for the update, solder works a lot better than a wire nut.

 

[Lumpy Grits]

Thanks for the update, solder works a lot better than a wire nut.

Fix one time, and attach it correctly. Same for any other wire nuts. Wire nuts are designed for solid wire use. They will cut stranded wire, and shake loose from vibration.
TNX for the update.
LG