1994 E-150 Intermittant "hiccup"

Michael Technician Indiana Posted   Latest  
Resolved
Driveability
1994 Ford E-150 Econoline 5.8L (H) 4-spd (E4OD)
Internittant Hiccup

Hello and thank you for looking at this. 

I have a 94 ford van, in for a running issue. Went to the dealer, and they were told that the dealer didn't have a scan tool for it. 3 other shops and now in my hands.

This is a very infrequent issue, may be twice in a 10 minute drive and it is a spit second occurrence. But enough to make you not feel that this is a reliable ride. At first I thought it was like the main relay for the computer was opening, or the injector power circuit was grounding out on something. If you could take a moment and look at this pico file and tell me what you think. The coil pulles 7 amps and at times it will drop to 4. When it pulls 7 amps the top is cut off as if it is a current limiting type. If you look at frame 16 of 32, you will see the coil go for 10 ms and not be switched off. 15 of 32 shows a 3 ms on time and most others about 6. 

My inclination is to put a coil and an Ignition control module on this thing.

What would you do?

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Mike Instructor
California
Mike
 

There is no scan tool for this it is an EEC IV system. Some scan tools, even NGS, may have some pid data available, but it will be limited and possibly unreliable. I am unable to open your scope captures, but this sounds like the usual 5.8L spark plug wire drop out or cross fire. What repairs have been performed already?

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Michael Technician
Indiana
Michael
 

If you go to picos site you can download the software and it is free. You will then be able to look at the capture and Yes that is why I said what I said about the dealer, I laughed when they told me. Back then they had sbds. It had a pcm breakout, you disconnected the pcm connected the sbds in line and you were able to see all of the values on the screen. It was a huge machine like the old sun…

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Tom Owner/Technician
Idaho
Tom
 

I don't know your exact configuration but Fords of that era had ground wire connectors at the battery area that would corrode and cause trouble. I cut them out and soldered the wires….

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Michael Technician
Indiana
Michael
 

You are absolutly right. That was my first goto check, I voltage dropped grounds to the body and engine first thing, while running .084. Wish it had been that easy. thanks

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Bryan Engineer
Florida
Bryan
 

FIRST: check the system for codes. THIS IS A MUST. Used the image I attached. Google search how to do the key on engine off, and run test. Second: do not over think the diagnosis yet. This is a simple system to diagnose. Get the codes and post them here. I was a Ford EEC engineering assistant. I bet you it is a TPS issue. but get the codes.

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Michael Technician
Indiana
Michael
 

You are right and I had suspected it right off the bat but then couldn't find my old ford book that showed sti and sto and so forth, thanks for looking for me. Didnt even think google would have that. Thanks

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Michael Technician
Indiana
Michael
 

Got a 539 first because I had the A/C on , then after turning that of and waiting 10 secs for the self test to de-energize, I got a 111 system pass. is there a way to initiate a engine running test?

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Bryan Engineer
Florida
Bryan
 

1. Make sure engine is fully warmed. If in doubt, run engine at 2000 rpm for 2 minutes. 2. Turn ignition off and wait 10 seconds for system to shut off. Make sure A/C is off and transmission is in Park (automatic) or Neutral (manual). 3. Hook up light and jumper (or tester if you have one). 4. Make sure vehicle is safe to run and start engine. test will start automatically. 5. Engine I.D…

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Phillip Educator
Ontario
Phillip
 

I agree, scope the TPS signal. It was a common issue and the grounds as mentioned before.

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Roy Owner/Technician
Colorado
Roy
 

Does the idle jump up and then you get a little miss? If so unplug the transmission and see if it goes away, The epc can draw to much power and cause the PCM to have issues causing missfires. Also like stated before check your grounds.

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Michael Owner/Technician
Arizona
Michael
 

The PCMs on these vans develop leaky capacitors, esp. for the transmission pressure control solenoid, that causes a misfire stumble. I would check for hash or noise on a 5v reference circuit, like at the MAP sensor. They eventually get bad enough to cause a misfire at idle in the bay. If the ignition module is black the Motorcraft # is DY-1077 (5U2Z-12A297-D). ALL parts catalogs have the wrong…

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Michael Technician
Indiana
Michael
 

thank you I will scope it, I didn't know that was a thing. Thank you for sharing that with me.

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Michael Technician
Indiana
Michael
 

So, I got back to this and checked the 5 volt ref. It has hash 4 to 6 volts, if you zoom in it looks like garbage communication lines. Is this what you were saying is caused by leaking caps? Also, my signal return is showing a 2 volt variance, -1 to +1 volt. Of course checking with a meter makes all look normal. Should I lean more towards a PCM?

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Michael Owner/Technician
Arizona
Michael
 

Yes, new capacitors should fix it. These are real easy to solder in. Note the polarity. There are three or four caps on the board. 10uf and 47uf. Get (4) each to make sure you have enough. i usually order from Mouser. EEU-EB1J100SH EEU-EB1J470SB should work Make sure the voltage is higher than 16V, like say 63V and the temperature should be 105C rather than 85C. There are some kits on Ebay…

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Michael Technician
Indiana
Michael
   

Hey Mike , Just disconnected the connector at the top of the bell housing while scoping the pip/spout lines. Disconnected, the hash went away and the idle fluctuation stopped. So, are you saying that the caps in the PCM will likely take care of that, or is there a problem with the pressure Control Solenoid. Looking at a diagram, Looks like it shares it's power feed with other solenoids and the…

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Michael Owner/Technician
Arizona
Michael
 

Yes, the problem is inside the PCM. I doubt there's any issue with the solenoid.

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Bryan Engineer
Florida
Bryan
 

I concur, it is in the ECM, likely CAPS are bad.

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Michael Technician
Indiana
Michael
 

thanks you guys are awesome! I'll post once I get it fixed.

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Glenn Owner/Technician
Texas
Glenn
 

Hi Michael, Pull the PCM and open it up. If it visually looks damaged it will be obvious when the CAP's leak. You will get a burnt electrical smell also. They are easy to replace with a little patience and a good solder iron with rosin core fine solder.

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Bryan Engineer
Florida
Bryan
 

And it is a loveley smell too! Like some one vomited in the ECM. It not a question it is a certainty! It has bad caps, they all do at this age. I would change them just for maintenance. Is that causing this issue? Could be; but have to follow the flow chart of steps that ford never made easy to follow. One thing that was never mentioned. Compression Leakdown test. I have built more SBF engine…

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Michael Technician
Indiana
Michael
   

Brian, Just disconnected the connector at the top of the bell housing while scoping the pip/spout lines. Disconnected, the hash went away and the idle fluctuation stopped. So, are you saying that the caps in the PCM will likely take care of that, or is there a problem with the pressure Control Solenoid. Looking at a diagram, Looks like it shares it's power feed with other solenoids and the…

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Cmore Mechanic
Connecticut
Cmore
 

You got me at “no scan tool for this vehicle”. Are you working on a 1994 or 1984 van?

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James Technician
California
James
 

I had one years ago that had an intermittent cut out, that I couldn't catch with a scope. It was a bad ECM. I finally was able to consistently reproduce it by tapping on the ECM when it was hot. Also try the ECM relay.

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Karl Diagnostician
Massachusetts
Karl
   

scope PIP/SPOUT signal. These are charging WAY too long. Does this have the correct ign module in it?

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Michael Technician
Indiana
Michael
 

Yesssss, that was my original question. Why are some of the charge times short and quick(5 ms) and sometimes the coil stays charged 15 ms. This is what was leading me to a coil and a module. Also the fact that the current going from 7 amps down to 4 amps back and forth. The thing is, back in the day, when we were replacing these modules, it was very rare to replace a black one and fix something…

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Glenn Owner/Technician
Texas
Glenn
 

Hi Michael, I had one of these give me fits when I was working in a shop in San Antonio years ago. The early 4.6's had an EGR passage that ran down the center of the block. The center passage had cross drilled passages for each cylinder. Over time the small EGR holes would get plugged with carbon, when that happened it would dump excess EGR gasses into a couple of cylinders and flood the…

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Mark Engineer
Colorado
Mark
   

Michael Agree with others who have already posted this advice, inductive crossfire is real important. Here is a link, you'll have to scroll down a few posts in the thread and you'll see an image of a decal often found under the hood on the core support ford-trucks​.​com/forums/620364…

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Bryan Engineer
Florida
Bryan
 

Is it fixed? Did you ever do a Key on engine run test? Did you get any codes?

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Michael Technician
Indiana
Michael
 

Not at this point, I wanted to get a good coil on it and then scope the PIP/Spout lines while watching the current ramp to see if my charge times line up. Also se if the large variance in amp draw goes away. Thanks again for your help. I will let everyone know how it all turns out. Mike

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Karl Diagnostician
Massachusetts
Karl
   

Michael, here is an image of a 1994 E350 5.8L I was unplugging then plugging back in the SPOUT connector in this file you can see in the lower window. The Fix was a new PCM.

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Michael Technician
Indiana
Michael
 

Karl, absolutely, after your suggestion and others, I scoped both pip/spout and the 5 vref. All of which had the hash in them. I posted images in some other reply's (ill try to find them and post again). Also, disconnecting the EPC (electronic pressure Control) to the Trans, also removed the hash and restored a slight fluctuation in idle that was present. I removed the pcm and disassembled…

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Michael Technician
Indiana
Michael Resolution
 

It's fixed. thank everyone for your help. The clue that did it for everyone was the hash in the different signals (pip/spout), 5 vref, signal return. They all had this hash in them. When you would disconnect the Transmission pressure control solenoid, the hash would disappear, and the engine would smooth out and stop it's slight hunt up/down. I never really said anything about the slight hunting…

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Glenn Owner/Technician
Texas
Glenn
 

Hi Michael, Glad to see you got this one sorted out. I repaired a lot of these PCM's back in the day. Of course that was when Radio Shacks were all over the place and they stocked a large selection of capacitors. I've had many laugh when I suggest opening up the PCM and "sniff test" them. If it smells like burnt electrical, there's damage usually at the capacitors. These early computers were…

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