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5.0 EFI runs like dookie. Need help, please!

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tonytheplumber

tonytheplumber

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Messages
114
Loc.
Lowell, IN
So the check engine light gets 12v power from the ignition switch in run and start. As stated the ECU provides the ground.
So one of those wires in the painless harness for the check engine light should have power to it during the described times.

You running a VSS in the C4? Is there wiring for that?
Usually the EFI harness has a few wires that can be changed depending on whether you have a manual or Auto tranny. Are they in the correct position for your auto?

The Pro M folks are a good group, as are their products. So if it is calibrated for 24lbs injectors, you should be good there.
Any chance the MAF got dirty from sitting or from an over oiled air cleaner?

Again, as others have stated, not a Fan of the Alphabet cams in a Bronco. You may have to pull the timing cover to get the part numbers off the end of the cam to be sure what you have.

Most definitely need a tune, which will be a piggyback chip. Too many changes for the ECU to compensate for.

EFI Guy is the person you need to chat with... Garry will hook you up.

I suppose I can test each circuit for the CEL independently. I'll see what I can find out there.

There are VSS leads on the painless harness, but they are vacant since my C4 does not accommodate a VSS.

Very slim chance the MAF got dirty, but I'll check that out as well.

A custom piggyback chip or tune seems to be the consensus. I'll hit up EFIGuy after I gather some more mechanical info.
 
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tonytheplumber

tonytheplumber

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Messages
114
Loc.
Lowell, IN
Last thing I feel I can add— are you using an LED for CEL? Led lights only burn with current going one way. Maybe you’ve got the led backwards??


Sent from my iPhone using Tapatalk

I had the same thought a few weeks ago so I reversed the connection. Still no light.
 

Timmy390

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Yep, I will NOT be programming it myself. There are some things I am eager to learn. That would not be one of them. I'll message EFIGuy in regard to a chip. I will have a hiccup trying to tell him what the compression ratio is and I would have to guess at the cam model. I'm really close to yanking the engine this weekend so I can disassemble and confirm what I have. If I do that I will likely swap the cam for a more modern grind.

I would love to learn Ford EFI tuning as there is a HUGE gap in Ford tuning. No one and I mean no one around here does it. That said, I don't have the time. I know a guy that has a dyno and he tunes stuff all the time only it's all Chevy. He can't even spell Ford.

I would pull the engine and figure out exactly what you have. If you're really running the F or X cam, I would ditch it. Both are racing cams and designed for boost. Not really a street cams. There are better options out there for sure.

Garry can burn you a killer tune but only if he knows what you have. Guessing at it will only cause you frustration.

Tim
 

904Bronco

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San Martin, CA
I suppose I can test each circuit for the CEL independently. I'll see what I can find out there.

There are VSS leads on the painless harness, but they are vacant since my C4 does not accommodate a VSS.

Very slim chance the MAF got dirty, but I'll check that out as well.

A custom piggyback chip or tune seems to be the consensus. I'll hit up EFIGuy after I gather some more mechanical info.

Sorry, should have noted that a VSS would have been in the Transfer case, at the end of the speedo cable.

How about putting a test light on each wire and see if either one is hot with the ign switch in the run position?
If not, maybe you can down load the wiring harness directions for your kit from the Painless website? Then you can track the wires down...
 

Timmy390

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Manual for the harness you have is here...... https://www.painlessperformance.com/Manuals/60510.pdf

Page 6 mentions the CEL and says to "plug it into the harness"

IF I recall correctly, the ECU pin 17 is the trigger for the CEL i.e. the ground. Keep in mind it will only "ground" when codes are there....

That harness appears to have the OBD1 test port. It's odd shaped and red with a small separate gray connector. Should have gray wires and white/pink and or pink wires running to it.

Tim
 

Timmy390

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There are VSS leads on the painless harness, but they are vacant since my C4 does not accommodate a VSS.

The VSS sensor plugs "inline" with the speed cable. On the Bronco the speedo plugs into the D20 (well mine does) Remove Speedo cable from D40, install VSS then plug speed cable into VSS. It's held in with a clip.

I recall buying new speedo cable but I don't recall it being due to the VSS.....Think i just needed a new one......

I run a VSS on my EFI. 93 Mustang sensor as I recall.........

Tim
 

904Bronco

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The VSS sensor plugs "inline" with the speed cable. On the Bronco the speedo plugs into the D20 (well mine does) Remove Speedo cable from D40, install VSS then plug speed cable into VSS. It's held in with a clip.

I recall buying new speedo cable but I don't recall it being due to the VSS.....Think i just needed a new one......

I run a VSS on my EFI. 93 Mustang sensor as I recall.........

Tim

VSS takes a special end on speedo-cable, not the factory one.
 

904Bronco

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You can modify the VSS to accept the factory cable.

You mean like cut off the factory end and crimp on the correct end? Or use another VSS?
 

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tonytheplumber

tonytheplumber

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Joined
Sep 1, 2012
Messages
114
Loc.
Lowell, IN
Sorry, should have noted that a VSS would have been in the Transfer case, at the end of the speedo cable.

How about putting a test light on each wire and see if either one is hot with the ign switch in the run position?
If not, maybe you can down load the wiring harness directions for your kit from the Painless website? Then you can track the wires down...

So I've got a yellow lead and a pink with light green tracer for my CEL. After looking at the Painless manual again, the fuse box has a dedicated circuit for "Check Engine Light". The yellow is hot with ignition on, so the pink must be the CEL signal to ground, but I'm not getting that ground (the power circuit is operating as it should). If I'm reading the pinout I have correctly, and if painless followed the Ford colors, the pink with lt.green should be pin 17 on the ECU. Is this correct? if so, I will poke at that pin.

From what I've found code 29 will be set if the VSS is not hooked up. It was also said that it can be programmed out with the addition of a chip. I am funning a GPS speedometer from Speedhut so I bought a nice plug for the speedo hole in the D20 from T's Cases (he sells them for 205s but it turned out to be the same diameter and bolt tab location on the D20). The VSS signal appears to be a non-critical data which is said to mainly be used in manual trans mustangs to keep RPMs up a little when the vehicle is in motion and the clutch is disengaged.
 

Boss Hugg

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I’m thinking you need to open the computer up and check for burnt goods.... there are ground circuits that burn easily in those.


Sent from my iPhone using Tapatalk
 
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tonytheplumber

tonytheplumber

Jr. Member
Joined
Sep 1, 2012
Messages
114
Loc.
Lowell, IN
Sorry, should have noted that a VSS would have been in the Transfer case, at the end of the speedo cable.

How about putting a test light on each wire and see if either one is hot with the ign switch in the run position?
If not, maybe you can down load the wiring harness directions for your kit from the Painless website? Then you can track the wires down...

Manual for the harness you have is here...... https://www.painlessperformance.com/Manuals/60510.pdf

Page 6 mentions the CEL and says to "plug it into the harness"

IF I recall correctly, the ECU pin 17 is the trigger for the CEL i.e. the ground. Keep in mind it will only "ground" when codes are there....

That harness appears to have the OBD1 test port. It's odd shaped and red with a small separate gray connector. Should have gray wires and white/pink and or pink wires running to it.

Tim

I back probed pin 17 and do not get a ground signal. Disconnected the ECU to check for corrosion, bent pins, whatever. No issue found. reconnected and still get no signal. Therefore I cannot read codes either. Bad ECU??
 
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tonytheplumber

tonytheplumber

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Messages
114
Loc.
Lowell, IN
I’m thinking you need to open the computer up and check for burnt goods.... there are ground circuits that burn easily in those.


Sent from my iPhone using Tapatalk

I opened it up, but honestly if just looks like any circuit board to me. Nothing looks or smells burned ?:?
 

Timmy390

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I back probed pin 17 and do not get a ground signal. Disconnected the ECU to check for corrosion, bent pins, whatever. No issue found. reconnected and still get no signal. Therefore I cannot read codes either. Bad ECU??

Are you sure you have a CEL code to display? I mean it's running like crap I get it but OBD1 is very basic

You need to try a code reader.......It will provide you with stored codes and CEL codes and run a test on the components (KOEO and KOER) As I recall, the VSS code does not light up the CEL. I had mine hooked up wrong (long story don't ask) and it didn't light up the CEL. I found it when I hooked up the scanner.

https://www.amazon.com/INNOVA-3145-...ocphy=9025754&hvtargid=pla-434264198620&psc=1

Tim
 

BanditBronco

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Messages
690
The VSS will help the tuner get you a better tune on the dyno for a smoother running engine but its not going to currently make it run any better. I have never been able to get my CEL circuit or the code reader port to work on my harness, but it is really a non issue if you know the basics of what your engine needs to run and how the EFI works which is seems that you do. To me it sounds like your engine is running well enough to get it tuned and it should solve your issues. Doesn't seem like you have any underlying timing issues or anything that would cause the engine to not be able to tune. I would suggest getting it on a dyno rather than just an over the phone tune from EFI Guy if you can get a hold of him. Especially if you do get VSS hooked up as you can only see those inputs on a moving vehicle.
 
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tonytheplumber

tonytheplumber

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Joined
Sep 1, 2012
Messages
114
Loc.
Lowell, IN
Are you sure you have a CEL code to display? I mean it's running like crap I get it but OBD1 is very basic

You need to try a code reader.......It will provide you with stored codes and CEL codes and run a test on the components (KOEO and KOER) As I recall, the VSS code does not light up the CEL. I had mine hooked up wrong (long story don't ask) and it didn't light up the CEL. I found it when I hooked up the scanner.

https://www.amazon.com/INNOVA-3145-...ocphy=9025754&hvtargid=pla-434264198620&psc=1

Tim

I jumped out the DLC to retrieve codes. That should at least give me a code 11 but I got nothing. Also, the Painless manual states that a bulb check should occur when the ignition is powered on.
 
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tonytheplumber

tonytheplumber

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Messages
114
Loc.
Lowell, IN
The VSS will help the tuner get you a better tune on the dyno for a smoother running engine but its not going to currently make it run any better. I have never been able to get my CEL circuit or the code reader port to work on my harness, but it is really a non issue if you know the basics of what your engine needs to run and how the EFI works which is seems that you do. To me it sounds like your engine is running well enough to get it tuned and it should solve your issues. Doesn't seem like you have any underlying timing issues or anything that would cause the engine to not be able to tune. I would suggest getting it on a dyno rather than just an over the phone tune from EFI Guy if you can get a hold of him. Especially if you do get VSS hooked up as you can only see those inputs on a moving vehicle.

I agree 110% that a dyne tune will outperform a mail order tune. My hangup with the VSS is that I wrapped the entire vehicle harness with Powerbraid and it's going to be a pain in the pecker to unwrap it to add the VSS wiring ;D

But, if a tuner tells me it's a necessity, then I'll do what I have to.

Garry did respond to my PM to him. I am supposed to give him a call. He said he can send a tune to me via web. Also said the CEL issue is likely inside the ECU and he "likely still has the parts on hand to repair it". Not positive shat that means, but he doesn't appear concerned.
 

Timmy390

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Also, the Painless manual states that a bulb check should occur when the ignition is powered on.

Well you got me there....I just checked my CEL and it DOES light up with key on.

Garry has fix many a ECU that's for sure. He burned a chip for mine and popped it open and gave it a good looking over.

Yes Garry can send you a tune. He can also so some live stuff. He has offered to do that for me several times. I never took him up on the offer because I was never convinced my issue was of his doing. Turns out I was right. It had nothing to do with his tune. It was perfect......I had a vacuum leak inside my brake booster that was causing me issues. Not an easy one to track down. I fixed that a few months back and my rig runs perfect just as it did when I first got the tune.

Tim
 

EFI Guy

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Glad to hear you got your problem solved Tim!

The burnt CEL circuit in the PCM is a problem that I never used to see but is becoming more common. Sometimes the trace is burnt on the board and sometimes the transistor for it is bad. Either way, it's a cheap fix.

VSS has almost no effect on tuning. The only thing that it is good for is to prevent stalling when coming to a stop with a manual trans. I can tune the stalling out if there is no VSS, but I definitely recommend keeping VSS with a manual.

In a situation like this with an unknown cam and injectors that lack tuning data, I would not opt for a mail-order tune. Instead, I would remote tune it.

With remote tuning, I am only dialing in the idle in real-time. After that, I show you how to datalog. You basically hit record and go out and drive it using real-world scenarios. The file that it spits out gets emailed to me. I review the file and modify the tune which I email back. That process repeats a couple of times until the numbers look good on my end and you are happy with it on your end. Then I buy the tuning hardware back and send the final tune to you on a permanent chip.

The biggest advantage a dyno has is that it is a safe environment to go wide-open throttle. It's also nice to have RWHP and TQ numbers, the tuning software is only able to calculate flywheel numbers but both are still good for bragging rights. The dyno provides better repeatability for WOT pulls, but street driving provides for more accurate loading that the vehicle will actually see, especially with how much 1 bronco can vary from another. So any good dyno tuner should actually spend more time driving it on the street and just using the dyno for WOT pulls.
 
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tonytheplumber

tonytheplumber

Jr. Member
Joined
Sep 1, 2012
Messages
114
Loc.
Lowell, IN
Glad to hear you got your problem solved Tim!

The burnt CEL circuit in the PCM is a problem that I never used to see but is becoming more common. Sometimes the trace is burnt on the board and sometimes the transistor for it is bad. Either way, it's a cheap fix.

VSS has almost no effect on tuning. The only thing that it is good for is to prevent stalling when coming to a stop with a manual trans. I can tune the stalling out if there is no VSS, but I definitely recommend keeping VSS with a manual.

In a situation like this with an unknown cam and injectors that lack tuning data, I would not opt for a mail-order tune. Instead, I would remote tune it.

With remote tuning, I am only dialing in the idle in real-time. After that, I show you how to datalog. You basically hit record and go out and drive it using real-world scenarios. The file that it spits out gets emailed to me. I review the file and modify the tune which I email back. That process repeats a couple of times until the numbers look good on my end and you are happy with it on your end. Then I buy the tuning hardware back and send the final tune to you on a permanent chip.

The biggest advantage a dyno has is that it is a safe environment to go wide-open throttle. It's also nice to have RWHP and TQ numbers, the tuning software is only able to calculate flywheel numbers but both are still good for bragging rights. The dyno provides better repeatability for WOT pulls, but street driving provides for more accurate loading that the vehicle will actually see, especially with how much 1 bronco can vary from another. So any good dyno tuner should actually spend more time driving it on the street and just using the dyno for WOT pulls.

Nice! I didn't realize you data logged and used that info to burn a chip. Real world driving as opposed to WOT dyno pulls also makes sense. I don't really care about HP and TQ numbers until it's time to sell as that would just be more info for a potential buyer to have security of.
 
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