No pulse on injectors and ignition coils. Help!!

[SlipperySnake]

Haven't been on here in a while so hopefully posting in the right section. I have a twin turbo 04 cobra and the other day got to the big moment of starting the car yet to find out that all it does is turn over. After diagnosing I came to conclusions that the injectors and ignition coil plugs are getting no pulse. I did extend the wires on the injectors and ignition coils for a wire tuck, all connections were soldered and heat shrunk and they were wired correctly two wires at a time, I know I didn't miswire anything. The coils and injectors have 12v on the hot wire with key on, no pulse with motor cranking over on both. I tested the camshaft posisitioning sensor and ground on the plug to it. I haven't tested the crank sensor yet and am going to this evening, but the pcm is displaying RPM during cranking on my aeroforce gauge. Block is grounded, I've gone over and made sure all plugs are good to go and I can't find anything that isn't grounded. I don't have the alternator installed but I've heard and am almost positive that wouldn't affect this. Anything I'm missing that y'all may need let me know. I've come to think it may be the CCRM, bad PCM, bad crank sensor(that picks up rpm) or something I am missing somewhere. Car has been down 3 years and ran fine before but a lot has changed. Any help is greatly appreciated, thank you in advanced guys! I want get this damn thing running!!!!

 

[MG0h3]

The PATS is activated is it? dashes instead of ODO

 

[SlipperySnake]

Mileage is displayed, I'm not having an issue with pats. I have gone over everything and am so lost. Either the motor is timed incorrectly which I highly doubt or the pcm is bad. I have ODB scan tool and am getting readings on the oscilloscope. Tested all grounds on the PCM harness and grounds to the injectors and coils all good.


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[MalcolmV8]

Oscilloscope shows crank and cam sensors working? They are variable reluctance sensors so you'll read a small low voltage sine wave at low cranking speeds. If that's there and the ECU has power and PATS is not blocking you it should be firing the coils and injectors. It does so by grounding a coil or injector accordingly. Sounds like you already verified positive power there. Perhaps check any coils or injectors are getting grounded as you crank. Perhaps timing is off and it's just firing the wrong coil/injectors.

 

[SlipperySnake]

I've tested pulse ground with noid light on injectors and coils with negative results. I'm having tuner send me a tune that will bypass pats tomorrow to be sure on that. Timing is good I'm very positive on it. I was there when my builder timed the engine, we followed Ford manual and check the degrees afterwards. I appreciate the help. Any ideas continue to post!


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[MG0h3]

Following what Malcolm is saying, you may want to confirm that the ground circuit is sound on the injectors and coils. Just check continuity from the plug to ground. I cant remember so Malcolm may need to chime in; you may need key on engine off or key off.

 

[hotcobra03]

I would check crank sensor..

Maybe just a loose connection..

This is a no start sensor. .

Cam sensor doesnt stop starting

 

[MalcolmV8]

Following what Malcolm is saying, you may want to confirm that the ground circuit is sound on the injectors and coils. Just check continuity from the plug to ground. I cant remember so Malcolm may need to chime in; you may need key on engine off or key off.

Well that's a little more tricky because the injectors and coils don't go straight to ground. They go directly to the ECU which in turn grounds them when it wants to fire them. So you'd have to verify continuity all the way to the ECU pin and then splice into the wire right at the ECU and check for grounding when cranking the engine over. It will pulse really quick.

This is way more work than I'm sure you'd want to do but here's something I did recently and it works fantastic.

It's a little jig I made with a stock crank trigger wheel that I just spin with a drill.

You can then scope the crank sensor's output but even better you can feed the signal to the ECU and now its receiving a high RPM crank input, about 3k RPM on my drill. This allowed all the coils and injectors to be firing continuously giving me time to check them.

Here you can see a reading of the crank sensor itself. The spikes are the missing tooth.

You can then also scope the injector and coil grounds and see if they're grounding out. Because if they're not grounding obviously nothing is going to fire even if you have power to them.

Turning off PATS in the tune was going to be my next suggestion just in case something is failing there but sounds like you're already on top of that one.

If they don't check out I'd go back to looking at your crank sensor. Are you absolutely sure it's working properly? Those pulses are critical. Without them the car will never fire.
I'd tap into the crank sensor wires right by the ECU, to ensure no breaks in the wiring, and scope it while cranking and verify pulses are getting there.

The cam sensor won't stop the car from firing. It just tells the ECU which is TDC so without it the car would just crank longer till the ECU figures out which is compression stroke and fire off the engine.

 

[SlipperySnake]

I have tested the grounds on the ignition coils and injectors to the harness at pcm and have continuity. I have done the same at the crank and cam sensors. I check all pcm grounds on the harness and all are good. I installed a new crank sensor with no change. The crank reads rpm so I know it works. I also checked the trigger wheel which is installed correctly, patruding teeth forward. Last thing to do is wait for my tuner and the bypass tune. I've plugged everything in just because I'm so paranoid it could be that one plug at this point. No change like I assumed. If I have a friend with a Mach 1 can we swap pcm's and I use his key to try his pcm if pats is disabled? I'd rather be sure it's the pcm before I buy one and trailer the car to ford to have it programmed for 1,000... fml. Lol.

 

[MG0h3]

I googled a few things and saw some guys post your situation and they found a harness connector not seated after reinstalling an engine. Somewhere on the pass side. Not sure if the its the main one by the hood hinge or not.

 

[big dad]

With the key on engine off you should have 12 volts at each injector. You can check this with a test light. The other wire on each injector plug is the ground circuit from the PCM. I would also check each fuse in the power dist. box under the hood and also under the dash. When I was a tech. I always did that first. If you don't know where the problem is, find out where it isn't.

 

[SlipperySnake]

Where are these situations posted? I have checked that connector at the firewall there and it seems fine to me. I even tried hooking my Lexus to the battery so it has constant voltage. Electrical components don't like low voltage. If you find out which connector exactly let me know. I appreciate your help MH0h3.

 

[SlipperySnake]

With the key on engine off you should have 12 volts at each injector. You can check this with a test light. The other wire on each injector plug is the ground circuit from the PCM. I would also check each fuse in the power dist. box under the hood and also under the dash. When I was a tech. I always did that first. If you don't know where the problem is, find out where it isn't.

I have 12v at coils and injectors. All fuses have power, only fuse I noticed that didnt have power on both sides was fuse f2.35 or 34, whichever one is 15amp because it was blue. I read somewhere that fuse only has power when the brake is applied, abs shit or something.

 

[NastyNate420]

Id wait for a a tune with PATS disabled and then go from there.

 

[SlipperySnake]

Id wait for a a tune with PATS disabled and then go from there.

That's the plan as of now. I'm curious, but doubtful.


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[MalcolmV8]

Any codes from ECU? If not maybe try and unplug a coil and one injector and crank over a few times and try read for codes again. See if it picks it up.

 

[SlipperySnake]

Any codes from ECU? If not maybe try and unplug a coil and one injector and crank over a few times and try read for codes again. See if it picks it up.

No codes and I'll try to see if it's picking up an incomplete circuit as you mentioned.



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[MG0h3]

Good idea Malcolm...Id try and unplug the crank sensor as well and see what happens.

 

[SlipperySnake]

Good idea Malcolm...Id try and unplug the crank sensor as well and see what happens.

I've got my friend coming over today, he is a ASE L1 technician. We are gonna go over everything and confirm the problem. If I can't find it, he will, very sharp guy. I really wanna rule out pats, there's no signs that it would be an issue, theft lift blinking, etc. It won't even let the starter engage if it's that, correct?

 

[SlipperySnake]

Well that's a little more tricky because the injectors and coils don't go straight to ground. They go directly to the ECU which in turn grounds them when it wants to fire them. So you'd have to verify continuity all the way to the ECU pin and then splice into the wire right at the ECU and check for grounding when cranking the engine over. It will pulse really quick.

This is way more work than I'm sure you'd want to do but here's something I did recently and it works fantastic.

It's a little jig I made with a stock crank trigger wheel that I just spin with a drill.

You can then scope the crank sensor's output but even better you can feed the signal to the ECU and now its receiving a high RPM crank input, about 3k RPM on my drill. This allowed all the coils and injectors to be firing continuously giving me time to check them.

Here you can see a reading of the crank sensor itself. The spikes are the missing tooth.

You can then also scope the injector and coil grounds and see if they're grounding out. Because if they're not grounding obviously nothing is going to fire even if you have power to them.

Turning off PATS in the tune was going to be my next suggestion just in case something is failing there but sounds like you're already on top of that one.

If they don't check out I'd go back to looking at your crank sensor. Are you absolutely sure it's working properly? Those pulses are critical. Without them the car will never fire.
I'd tap into the crank sensor wires right by the ECU, to ensure no breaks in the wiring, and scope it while cranking and verify pulses are getting there.

The cam sensor won't stop the car from firing. It just tells the ECU which is TDC so without it the car would just crank longer till the ECU figures out which is compression stroke and fire off the engine.

Can a crank sensor read rpm and still be bad? That's probably a dumb question since the waves are what creates the rpm calculations in the pcm. I put a new one on and same results, I believe I mentioned this already.

Also does anyone know which ground coming off the pcm is for the injectors and coils? Maybe its grounding, but the ground isn't there. I've check all the grounds at the harness where they would correlate with a pcm pin named "ground" in the pinout diagram, all have continuity.