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No injector pulse, Help please!

K_Hairston

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Joined
Sep 8, 2007
Messages
22
Ok, I have spark, 41# fuel pressure and no injector pulse. I am running a RJM 95 351 with bc adaptor and mustang 5.0 upper. The first attemp to fire the engine. It will run on supplied fuel throught the intake. I thought the same signal from the distributor that went to the computer to fire the coil also sent the signal to the ecm to fire ground to the individual injector. I have batt voltage at one side of the injector and m not getting the ground pulse from the ECM. Where do I start?
 

bax

Contributor
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Aug 22, 2005
Messages
14,491
Sounds like you ecm is not getting the engine RPM signal. No signal no injector fire. Check your dist wiring harness again.
 
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K_Hairston

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Sep 8, 2007
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I have a breakout box, but don't know what I am supposed to see comong on PIP 56? Also, I have batt voltage on one side of all injectors with key on, should this be 5V???
 

Viperwolf1

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Aug 23, 2007
Messages
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I have a breakout box, but don't know what I am supposed to see comong on PIP 56? Also, I have batt voltage on one side of all injectors with key on, should this be 5V???

This page shows what the PIP signal looks like. http://fordfuelinjection.com/?p=25 You could attach a tachometer to this wire to test the PIP signal coming from the distributor. You probably wouldn't see a good steady rpm during cranking but should see the pulses. An analog voltmeter would work great too.

The injectors operate on 12v.
 
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K_Hairston

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I have some small movement on the tach. Almost none. Is there a better way to know whether or not the PIP is doing its job?
 

Viperwolf1

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I have some small movement on the tach. Almost none. Is there a better way to know whether or not the PIP is doing its job?

An oscilloscope would work. You could also measure the PIP coil resistance but you'd need to pull the TFI module off first. 600-1300 ohms is good.

Edit: Nevermind the coil resistance test. This is for older non-Hall effect TFI distributors.
 
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K_Hairston

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Sep 8, 2007
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I pulled the distributor back out and removed theTFI. I am driving across town to another AZ to get a new distributor as soon as AZ opens.
1) Is there a wat to test the distributor off the engine at the parts store?

2) If not I can ohm it out but what two points do I connect my multimeter to?

3) Third pin on the right of the stator is the PIP out signal, and where else?
 

Viperwolf1

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Aug 23, 2007
Messages
24,316
I pulled the distributor back out and removed theTFI. I am driving across town to another AZ to get a new distributor as soon as AZ opens.
1) Is there a wat to test the distributor off the engine at the parts store?

2) If not I can ohm it out but what two points do I connect my multimeter to?

3) Third pin on the right of the stator is the PIP out signal, and where else?

Here are some module tests.
 

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K_Hairston

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Sep 8, 2007
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In the last 12 hours:
(1) NEW ECM
(2) new TFI Modules, (1) wells, (1) BWD
(3) Reman distributors

Still No injector pulse. All the powers and grounds listed on FordFuelInjection.com are evident, only the codes that are to be expected were revealed with the KOEO test, Fuel Pressure is 40#, 12V on one side of each injector no ground pulse to any injector. I do not have a good grasp of what voltages should be at the TFI during KO or when starting although I have seen some info on this.

Could anyone clarify what you are supposed to have at the TFI, while connected to the harness during KO and start. Thanks.
Keith
 

Viperwolf1

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There is one instance when the ECM would kill injector pulses. That is when the engine is flooded and you have your foot all the way down on the accelerator. I imagine you don't have your foot down but it's the TPS's job to measure this. Check the TPS output voltage.
 
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K_Hairston

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Sep 8, 2007
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What should the TPS output voltage be? It uses 5V ref, right? Also, should I disconnect the TPS to try it?
 

bax

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Aug 22, 2005
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It should still run with the TPS disconnected. Give it a try.
 

Viperwolf1

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What should the TPS output voltage be? It uses 5V ref, right? Also, should I disconnect the TPS to try it?

Yes 5v ref. At idle it should be just under 1v output. You would have to leave it connected to check voltage but Bax is correct, it should run with it disconnected.
 
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K_Hairston

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Sep 8, 2007
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I checked the three wires at TPS:
Blk: grd
Grn: .961V
Org: 5V

Unplugged and tested for injector pulse---Nothing.
 

Viperwolf1

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I hate to say it but it sounds like either a harness wiring problem or a bad ECM. If you have spark the PIP is working. Sorry I didn't catch that earlier.
 
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K_Hairston

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Sep 8, 2007
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I thought so too so I got a BRAND new Motorcraft ECM out of a New motorcraft box and tried it, no change. I checked continuity between the PIP harness at the distributor and at the ecm- good- 3.9ohms

It runs with starting fluid, but doesn't even begin to rty and start without it. I pulled the No.1 spark plug and it is dry, but smells of Ether from my starting fluid.

I am out of ideas.....
 

Viperwolf1

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Aug 23, 2007
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look at the ECM connector #47. This is where the TPS return voltage goes. It may have been mis-pinned with a Vref wire.
 
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K_Hairston

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Sep 8, 2007
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I thought ECM as well, so I tried a brand new ECM out of a Motorcraft box- no change. My original thoughts were that if the ECM is reading the PIP and not sending out the injector pulses. But that would be an ECM issue, not a hraness. If it were the harness I would expect to get some cylinders firing, but maybe not all. So I checked continuity between the PIP coming out of the TFI and the connector at the ECM-2.9ohms.

If there is a problem with the harness, how can I check it? I am out of ideas.
 
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