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No spark 4.9 troubles

  #1  
Old 06-21-2018, 08:01 AM
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No spark 4.9 troubles

Alright guys, i bought and have been daily driving the 89 listed in my sig a few months ago. Gave it a tune up, oil change fixed a few leaks etc..basic housekeeping stuff.
PO replaced Ac, both fuel pumps, fuel press reg, water pump rad. etc etc
Drove great for a month or two. Recently my ignition switch started giving me fits sticking so in the mean time i drove it a few times by jumping the solenoid to start it. I pulled to the end of my driveway with some tools and concrete to install a mailbox, shut the truck off and next time i went to start it nothing, may have sputtered a bit but i cannot remember.. Pulled back to shop and confirmed fuel but no spark.
Pulled the spout, still no spark. Confirmed dizzy was spinning first.
So then I tested all the pins on ICM as well as coil and confirmed the ICM was bad. Bought a new one at parts store and after much frustration and them telling me they were not able to test them I figured out that one was bad as well because a buddy of mine loaned me a known good distributor to rob parts off of. I tried the ICM on it which was an older looking wells and drove to work one day. About a 45 minute rade where the truck really heats up by about the halfway mark. Around that time when i would get into the throttle it would hesitate and ping depending on throttle position. As i went further i could use less and less throttle to keep from the ping/hesitation/missing to the point when i got off the exit to work i had not been able to maintain 55 anymore.
Another few miles in a 35 mph zone to work it gradually got worse to where i literally coasted into the parking lot. it would restart, run fine for few seconds and then shut off etc, i eventually got it parked and came back with trailer that night to tow home and the truck cranked up and ran fine. I let it run the whole time i was loading and powerbraked it a few times to put a good load on it and it ran fine.
Fast forward... I took it home put new ICM on it thinking it was heat soak related to the used one i had put on. Took truck for a short ride about 6 miles each way to gas station and back in 90* heat, on the way back same thing started but progressed faster.

Tested everything again following this Part 1 -How to Test the Ford Ignition Control Module (Distributor Mounted)
Everything checked out, so i thought heat related, maybe coil despite it testing good. Finally got time last weekend to install the new motorcraft coil. Cranked and ran the truck a few times on a saturday. Went out sunday to install coil, no start, no spark. Fuel pump comes on with Key on like it should. Pulled spout, no spark still. Changed to old known good coil...no start. Ready to drive it in a pond.

In the midst of all this I have done a KOEO and KOER test with no codes. EGR valve is hooked up and does not make a difference at idle with vaccum un plugged.

Can you guys give me some fresh ideas or tell me im and idiot or something? I feel like i screwed something up electronically jumping the starter solenoid because the issues happened all of the sudden. Should i pull the ECM and check capacitors? Is there somewhere to order some ahead of time in case that is the culprit? Maybe test the PIP sensor again? Time to work on truck is precious right now so i would like to make the best use of it.
I had a replica of this truck a few years back, drove it nearly 100k miles in 6 years beat the **** out of it and never had any issues other than normal maint. items.
 
  #2  
Old 06-21-2018, 10:12 AM
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Did you make the LED tester as noted in the link you gave?
If so test the PIP signal again while making sure you have power from the Ignition Switch to the coil and TFI.

It sounds to me like you might have a fuel pressure issue also,
Caps in the ECM might be an issue also but if you disconnect the ECU plug you will remove it as to why no spark.
 
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Old 06-21-2018, 11:54 AM
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First of all, thank you

I did not use an LED, i thought i read in the article a regular test light was ok. I printed all of the pages out at work and plan to read everything carefully ( i get no service in shop so it was interesting using my tablet) as i go thru the tests again. sounds like i need an LED tester for the pip signal specifically.

Where are you guys getting your fuel pressure test gauges? all i have is the old school low fuel psi test gauge

Does anyone know if the PIP can be affected by heat soak?
 
  #4  
Old 06-21-2018, 12:35 PM
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Per the instructions in the link you previously posted concerning testing the PIP signal: Do not use a test light for this test!

I have used a cheapo fuel pressure gauge from Harbor Freight for the last 15+ years. You can also rent one from many auto part stores.

Yes, the PIP is very susceptible to heat related failures. That is the typical failure mode. When hot the spark gets erratic then drops completely. Once cooled down the ignition circuit works fine.
 
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Old 06-21-2018, 12:41 PM
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Old 06-21-2018, 01:03 PM
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I knew i had to be missing something obvious, I looked right over it reading on the tablet but i see it now plain as day.
thank you all!

I will check fuel pressure and cobble something together for led test light.

I have a buddy with similar 89 truck and similar issues, Do you all see many of the crappy new distributors come with bad or defective pip and or ignition modules?

ordered this
Amazon Amazon

and
Amazon Amazon
 
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Old 06-21-2018, 02:07 PM
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I plan to test everything this weekend and report back.

fuel pressure should be +/- 45 psi at idle? How about key on engine off pressure.
i will also run another koeo test.
 
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Old 06-21-2018, 02:18 PM
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Originally Posted by KubotaOrange76 View Post
Do you all see many of the crappy new distributors come with bad or defective pip and or ignition modules?
Yes to both. The only Ignition Module you should use is a Ford/Motorcraft. The aftermarket versions tends to be crap. Be sure to use thermal compounds on the back of them when installing. Dielectric grease will not work properly.

Rebuilt distributors are notorious for bad PIPs.
 
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Old 06-21-2018, 03:24 PM
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I would think more around 50psi at idle and around 60psi KOEO with pin #6 of the test-pug grounded.
 
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Old 06-21-2018, 05:24 PM
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isnt the 87-91? 4.9 fuel pressure lower than the latter versions?

Thank you for the tips on the aftermarket garbage
 
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Old 06-21-2018, 07:27 PM
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Originally Posted by KubotaOrange76 View Post
isnt the 87-91? 4.9 fuel pressure lower than the latter versions?
Now that you say that I do recall something about it being lower around 85 & 86. They also raise it later to avoid vapor locking. They also put a Fan on the fuel rail in the those years.

I do not have much information on a 1987 but my 1989 Ford shop manual says that a 4.9L fuel pressure is 45-60psi engine running and 50-60psi KOEO.
All the 4.9L Ford trucks from 1987-1995 use the same fuel pressure regulator.
So I stick with what I said about the fuel pressure in post #9 above.
 
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Old 06-21-2018, 08:21 PM
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McLeod has a good reputation on FTE.McLeod has a good reputation on FTE.
I have the same fuel pressure tester but mine is Bosch brand.
Good unit and individual parts are available on the Actron website.
Anyone with this unit should be aware that the pin inside of the connector will go MIA in short order. Also, the INNOVA adapter for FORDs works with this gauge.

Sorry about going off topic.
 
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Old 06-22-2018, 07:22 AM
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thankyou, keep yall posted on how the truck does rolling into pond
 
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Old 06-24-2018, 07:14 PM
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Seems that i have it fixed. I had two problems. Connector at icm was causing the no-start, pin #5 was loose. Pulled it apart and fixed that.
Next I changed the distributor and ran it long and hard. Ran great never could get it to miss or ping. Ran it twice as long as last time that is acted up. Used the old icm so i believe it was in fact the PIP sensor getting heat soaked.

Thabks to all for your input.
 
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Old 06-25-2018, 08:39 AM
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Thanks for reporting back! Looks like you got the problem fixed for good this time.
 

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