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Discussion Starter #1
Hey guys,

Me again. Okay so in my former post:
https://www.fordforumsonline.com/th...1991-ford-e150-302-5-0l-with-efi.30674/page-2

I tried everything I could think of. Including what you fine folks suggested & bringing in a few experts but we never did find the electrical gremlin plaguing my motor. Finding an OTC 104pin diagnostic box is nearly impossible in my city (I called 46 garages) so I think at this point after spending 1700$ I'm SOL unless I replace this antiquated computer.

I called FAST and they told me everything I need in order to make their kit work:
https://www.summitracing.com/parts/fst-302000-06
https://www.summitracing.com/parts/fst-306007
https://www.summitracing.com/parts/fst-307004
https://www.summitracing.com/parts/fst-307005
https://www.summitracing.com/parts/fst-307007
https://www.summitracing.com/parts/fst-308030

That is EXCEPT the transmission. I'm going out to the shop this evening to confirm exactly which one my van came with but I'm curious if anyone has had any experience with these kits and installing on their 1990-1992 ford 302's and if the 2 connectors coming off the trans is something I can just ignore?

As always thanks everyone here for you're stellar advice.
Chris
 

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Hey guys,

Me again. Okay so in my former post:
https://www.fordforumsonline.com/th...1991-ford-e150-302-5-0l-with-efi.30674/page-2

I tried everything I could think of. Including what you fine folks suggested & bringing in a few experts but we never did find the electrical gremlin plaguing my motor.

That is EXCEPT the transmission. I'm going out to the shop this evening to confirm exactly which one my van came with but I'm curious if anyone has had any experience with these kits and installing on their 1990-1992 ford 302's and if the 2 connectors coming off the trans is something I can just ignore?

As always thanks everyone here for you're stellar advice.
Chris
In your last post in that old thread you said -
"I have a feeling the lifters I was sold are weak and not dong their job. "

Didn't know that you had an electrical gremlin.

As to the transmission, (Assuming it is an automatic) I believe you have a E4OD. If correct, the E4OD has four forward speeds and electronic shift controls replacing the hydraulic governor control mechanism of the C6. The electronic part of the transmission is controlled by the EEC IV processor.
I am not sure how the transmission would work without the electronics connected. My guess is ... not good

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Discussion Starter #4
Yeah we solved the lifter clatter with alot of trial an error but the electrical issue remained. Tried a new ECM and replaced all the wire to the sensors sharing the same circuit right back to the ECM (laid the entire harness on the ground).

We're stumped and fed up I'm afraid.

In your last post in that old thread you said -
"I have a feeling the lifters I was sold are weak and not dong their job. "

Didn't know that you had an electrical gremlin.

As to the transmission, (Assuming it is an automatic) I believe you have a E4OD. If correct, the E4OD has four forward speeds and electronic shift controls replacing the hydraulic governor control mechanism of the C6. The electronic part of the transmission is controlled by the EEC IV processor.
I am not sure how the transmission would work without the electronics connected. My guess is ... not good

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Discussion Starter #5
Nice find! Way lower then the cost of the first one I found for sure, the only thing is I'm stuck looking at all available options. So do I drop 500$ Canadian on this, potentially not find the issue and still be stuck with an antiquated ECM no one will work on OR do I upgrade to a modern ECM that will have an OBDII port and if something happens to me my partner could theoretically find a garage to work on the van? Also the FAST EZ-EFI should increase resale as well.

Very tuff call.

You do not need a break out box to work on EEC IV.
If you want one it will set you back $375
https://www.ebay.com/itm/otc-3235-e...524357?hash=item2ac9475f85:g:lKQAAOSwY3tbPNfy

And the shop manual electronic manual is a great reference. ($40)
https://www.ebay.com/itm/1991-Ford-...267934?hash=item46a4c7cb9e:g:QNgAAOSwUvhd~p2m

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Replacing the PCM almost never works. And I have heard from rebuilders when they get a core, the core is almost always passes the tests. People replace this because they are frustrated and do not know what to do.

Is the check engine light on?
If yes pull codes and post.
If no post that as well.

EEC IV is not as easy to work on as OBDII at least in my opinion. But there is a logic to it and if you follow a diagnostic steps you will find the issue with out the need for a break out box. I have met techs in the day swear by the break out box. I allows them to get to the issue faster. And others that had the box and never used it.

A star tester would be easier to pull codes. But you can get codes with a voltmeter.

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Installing an aftermarket system, I would not want to do that at all.
I seriously doubt it would increase resale value. Likely it would have the opposite impact. Especially if it disables the transmission electronics.

EEC IV can have up to 25 sensors and actuators. It is a vary accurate system for engine controls. Which is why it was used for a couple of decades. (Not so for EEC III) EECIV is not antiquated at all. You just don't understand that and that is why you have the opinion you do, which is OK.

Most professional techs that have been working for the past 20 years do not know the system. The federal government mandated the change over to OBDII in model year 1996.

Your choice

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Discussion Starter #8
If I lived in a larger urban center I could see your point for sure, the thing is I don't we're a smaller city and after calling nearly all the shops in my area no one would take on the job of diagnosing it. they all saw it for what it was an older vehicle and a huge time suck. Like I said I called over 40 hops only 2 guys had the 104 pin OTC tool and one of them said his was broken so resources here at least are very minimal. Would it increase the resale here? I think so. It has a modern OBDII port, a more modern O2 so slightly better miles per gal and the ability to set Target air fuel ratio with different presets for different driving conditions.

That said what you told me about the trans is a very good point. I will likely have to replace the trans to make this work and that's not the end of the world to me as I have access to a pile at the shop.

I may lay the wiring harness on the ground one more time and triple check my cousins work & might try a wrecker ECM (verifying the edition on it is the same as mine) but outside that not sure there is more to check here. Obviously something I'm missing but after 6 months and this much headache.. give me an OBDII already?

Chris

Installing an aftermarket system, I would not want to do that at all.
I seriously doubt it would increase resale value. Likely it would have the opposite impact. Especially if it disables the transmission electronics.

EEC IV can have up to 25 sensors and actuators. It is a vary accurate system for engine controls. Which is why it was used for a couple of decades. (Not so for EEC III) EECIV is not antiquated at all. You just don't understand that and that is why you have the opinion you do, which is OK.

Most professional techs that have been working for the past 20 years do not know the system. The federal government mandated the change over to OBDII in model year 1996.

Your choice

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Is the check engine light on?
If yes pull codes and post.
If no post that as well.

And the Emission book I linked above is $40 US.
I know it isn't sexy to read a book.
But it walks you through the diag steps

Stop looking at ECM replacement!

So is the check engine light on????


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Discussion Starter #10
The light is on and off intermittently the code is 63.

Recap:
- New ECM
- Replaced all wires on the pins that connect the TPS and anything on the same lines as the TPS
- New TPS (well technically 4 new TPS (Original, 1 from wrecker and 2 bran new in case of defect)
- New EGR Pressure sensor
- New terminals for all replaced sensors
- Tried contact spray
- New Knock sensor
- New Coolant temp sensor
- New IAC
- Replaced throttle assembly
- Opened one of the TPS's and looked at the contacts to confirm the diagram I found for the TPS was correct (Orange is 5v, black is ground and Green is the variable voltage lead)
 

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tps-connector.jpg

I have to believe you have seen this pic.
I assume you have a digital VOM not analog

The code is for the TPS. (Throttle Position Sensor (TPS) signal too low)

None of the other items or the ECU is the problem. ( I would like to have the parts you took off)
https://axleaddict.com/auto-repair/How-Do-You-Know-if-a-Throttle-Position-Sensor-is-Bad#:~:text= 1 Now backprobe the signal,the throttle plate is fully closed. More

The 5 volts is what the system (actually all of Ford's EEC systems) run off of.
Are you getting 5 volts at the plug with key on, engine off at one of the pins?
Do you have a ground at the plug with key on, engine off at one of the pins?
This is what a break out box does is allow you to test voltages without disassembling the system.

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Discussion Starter #12
So I appreciate all the help for sure but I tested all the parts I took off and they were weak so please let's not jump to conclusions :) Also those parts share some wires so that's why I mention them (at-least according to the haynes).

Next yes, well aware the code was for the TPS. (Throttle Position Sensor (TPS) signal too low). Good to confirm, thanks.

I saw the same article from Axleaddict and as I mentioned on the previous forum this is the result of the test (also yes engine off):
  • Ground pin: I see 12V from the ground pin to the batt
  • 5V ref voltage pin: I see full 5v
  • Variable voltage pin: On all 4 of those TPS's I see .21 volts with the throttle closed and up to .71 with the throttle wide open.

I've also tested moving the position of the TPS by hand or with a screw driver and like I said the throttle body has been replaced as well.

This is what lead me to think okay could be wiring or ECM replaced all the wires the haynes showed shared any of the same leads as the TPS & replaced the ECM. Still no dice.

Also forgot to mention I replaced the MAP sensor too and the wires on that part of the harness as well they share some of the same wires.

The problem makes zero sense. 5v goes in something close to 1-5v should come out & there is like zero chance this is not the TPS but yet.. I've tried 4 now?


View attachment 45838
I have to believe you have seen this pic.
I assume you have a digital VOM not analog

The code is for the TPS. (Throttle Position Sensor (TPS) signal too low)

None of the other items or the ECU is the problem. ( I would like to have the parts you took off)
https://axleaddict.com/auto-repair/How-Do-You-Know-if-a-Throttle-Position-Sensor-is-Bad#:~:text= 1 Now backprobe the signal,the throttle plate is fully closed. More

The 5 volts is what the system (actually all of Ford's EEC systems) run off of.
Are you getting 5 volts at the plug with key on, engine off at one of the pins?
Do you have a ground at the plug with key on, engine off at one of the pins?
This is what a break out box does is allow you to test voltages without disassembling the system.

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  • Ground pin: I see 12V from the ground pin to the batt
  • 5V ref voltage pin: I see full 5v
  • Variable voltage pin: On all 4 of those TPS's I see .21 volts with the throttle closed and up to .71 with the throttle wide open.
I do not know this for a fact, and my guess is the spread on the variable pin is not great enough. Roughly a 1/2 volt spread from open to close is not enough. With the code stating the voltage is too low, that makes sense to me. With the throttle wide open the voltage is less than 1 with 5 going in. Ding ding ding there is a problem.

If you are going to replace the engine control system don't worry about it. Take that direction. Scrap the factory system. I have never seen that, so if you go there create a thread, take pictures and post. There may be many that would be interested in seeing the result.

If you are going to repair this problem, you have to figure out why the voltage is so low. Your Haynes manual isn't going to give you that support. Aftermarket shop manuals just do not go into the detail needed to diagnosis a concern like this. That factory manual (I have two for different vehicles. One is for 1990) will walk you through If this result, then do this. Over and over.

That Ford Engine and Emission manual I posted a link for does that step by step process. It is no joke about 4 to 6 inches thick. And will take some time to drill through it with a DIGITAL volt ohm meter.

Good luck my friend

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So I appreciate all the help for sure but I tested all the parts I took off and they were weak so please let's not jump to conclusions :) Also those parts share some wires so that's why I mention them (at-least according to the haynes).

Next yes, well aware the code was for the TPS. (Throttle Position Sensor (TPS) signal too low). Good to confirm, thanks.

I saw the same article from Axleaddict and as I mentioned on the previous forum this is the result of the test (also yes engine off):
  • Ground pin: I see 12V from the ground pin to the batt
  • 5V ref voltage pin: I see full 5v
  • Variable voltage pin: On all 4 of those TPS's I see .21 volts with the throttle closed and up to .71 with the throttle wide open.

I've also tested moving the position of the TPS by hand or with a screw driver and like I said the throttle body has been replaced as well.

This is what lead me to think okay could be wiring or ECM replaced all the wires the haynes showed shared any of the same leads as the TPS & replaced the ECM. Still no dice.

Also forgot to mention I replaced the MAP sensor too and the wires on that part of the harness as well they share some of the same wires.

The problem makes zero sense. 5v goes in something close to 1-5v should come out & there is like zero chance this is not the TPS but yet.. I've tried 4 now?
Hello Chris Morley,

I hope you don't mind my 2 cents here about a couple of things. First lets touch on the current system and the TPS problem. You say you have 5.0 volts on the power lead going to the TPS, but on the wiper terminal you only get 0.21 volts throttle closed and 0.71 volts with WOT.

Lets narrow this down, when testing the voltage on the wiper do you have another meter you can use to measure the 5.0 volts going in? What we need to do is check to see if the 5.0 voltage is getting dragged down first.

If it is a solid 5.0 volts through idle to WOT and the wiper voltage is still low, find the that TPS wiper wire going into the ECU and pull the pin out of the connector and run the test again. If the wiper voltage now goes to near 5 volts at WOT the problem is in the ECU. Chances are the component that protect the ECU from static discharge from handling may be shorted. And in actuality it's just a resistor in series and a capacitor bypass to ground to protect the A-D converter in the ECU. Although sometimes a resistor isn't used. ( I used to be a testing engineer, then design engineer for the Big Three, Toyota, and eventually class 8 truck manufacturers)

Repairing discrete surface mount components on an ECU is definitely best left to someone who knows what they are doing.

About the transmission, unless the van was ordered with some kind of heavy duty package I can't see a 1/2 ton van with a small 302 having an E4OD (4R100). It's probably an AOD transmission. Easy way to tell is look at the throttle body, if there is a cable leading down to the transmission it's an AOD as they are controlled via this cable and not electrically. The connectors on the transmission may be a VSS and or neutral safety/gear select switch.

If your speedometer has no mechanical cable then it's electric and needs the VSS off the transmission to operate.

A word on the Fast EZ - EFI, I am not sure what you mean about OBDII port. It almost sounded as if you were trying to convey that this system has an OBDII port. If that is the case, it does not, nor is it OBDII compliant. People who end up working on this would need the tablet as regular automotive scanners will not talk to this, which again puts this in a unique situation to what you have now.

Now if you were talking about putting in a later Ford ECU that was OBDII, that's another sticky wicket. That's not going to be a direct swap. Let me explain. When GM went from OBDI to OBDII in the 1995 to 1996 year they added a crankshaft sensor to their small V8 in order to comply to OBDII guidelines. I don't know what Ford was doing to their Windsors in this time line. As a result many countless hours of research will need to be done to see what's in order.

Plus you will need a full programmer for the OBDII Ford ECU as you will have to reconfigure it so that it works properly. For example if you have the smaller AOD transmission, it is not electrically controlled. But by 1996 the AOD turned into the AODE which is, so the ECU will be looking for signals and trying to control something that isn't there and trigger the check engine lamp. You'll need to go in and disable all those DTC's so that only valid problems trigger the Check Engine Lamp.

Also OBDII checks the status of the catalytic converter(s) via a rear set of o2(s) behind the cat(s). Again that needs to be disabled otherwise the Check Engine Lamp will saying there is problems with the cat(s) and O2(s).

This is the rabbit hole you'll want to avoid.

Good Luck.

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Discussion Starter #15 (Edited)
Update - So thanks all for your help and feedback. I managed to get to a no code state. In the end I decided to lay out the wiring harness from the motor back to the body and painstakingly replace every single wire compared to a friends E150 that was identical to mine (well a 1990 but same in every regard) I came to the conclusion the ECM was fine by putting mine in his van and observed a no code state.

Now I see .90 - 4.90V on that variable voltage pin on the TPS.

Looks like I can stick with the factory ECM. I still have to wrap my new rebuilt engine harness with Split Wire Loom but she drove for 45 min without issue this AM!

Chris
 

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Was there a bad wire?

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Discussion Starter #17
There must have been or several but as I said I replaced them all. Alot of the wires had discoloration from heat and like I had previously stated I had already replaced all the ones on the same pins as the TPS so this time I took the timeto replace it all. I didn't bother testing voltage or resistance across though I know that would have been an option as well.

I wish a new harness wasn't worth a grand but since that was so pricey I just made my own.





Was there a bad wire?

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Good job. Thanks for posting

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