ford efi troubleshooting

[bent70]

Figure we can start a thread for this....mabey make it a sticky depending on how well it goes.

To start off.....before posting, if issue is irradic idle and rough running try cleaning maf, cleaning aic sensor, cleaning egr of carbon buildup turning maf sensor 90* of current position and reseting tps. These are common culprits and easy fixes.

Let the tech roll......

[country_boy_72]

Re: ford efi troubleshooting

I had a mustang that had a similar issue it ended up being a bad egr

[CityHick]

Re: ford efi troubleshooting

For reference purposes, from the other thread:

That's my issue with my fuel injection is trusting it. I can't seem to get it to run the same two trips in a row. One day the idle is all over the place the next day is idles fine but will act like it's starving for fuel. I'm about at my wits end with this thing. There are to many vareables to look into. Wireing, vacume , sensers ect. I'm not a electrition. I deliver brown boxes for a living. I would gladly trade my whole set up for a nice clean carb small block. Sorry for the rant. Didn't mean to put a dampener on the efi party.

I feel that we should hold off with in-depth analysis until Rockslut can clarify exactly how his engine is behaving and after he pulls codes (if there are any) and elaborates a bit on which specific parts he's got installed (injector size, which MAF, etc).

I will second the earlier comments about MAF affecting idle. My first MAF was reading voltages way out of spec and I could never get the idle to be smooth. If you do not own a digital voltmeter you should buy one - even the $2.00 variety from Harbor Freight will suit you well. I am not an electrician either but I have learned a lot by comparing observed sensor voltages with published guidelines. The computer operates primarily on feedback with a little feed-forward logic for continuous adjustment purposes. Once you start to observe the correlation between a bad voltage reading and an observed behavior, the computer becomes a lot less scary.

If you do not already own this book you should buy it: http://www.themotorbookstore.com/for...FUeBfgoduYwAmQ

Its well written and not overly complicated. Reading the introductory chapter(s) will get you a long way into better understanding.

[Filgas]

Re: ford efi troubleshooting

Most public libraries have that book as well. If you do not want to buy it, at least check it out to get a good understanding of the fundamentals.

[Lars]

Re: ford efi troubleshooting

For reference purposes, from the other thread:



I feel that we should hold off with in-depth analysis until Rockslut can clarify exactly how his engine is behaving and after he pulls codes (if there are any) and elaborates a bit on which specific parts he's got installed (injector size, which MAF, etc).

I will second the earlier comments about MAF affecting idle. My first MAF was reading voltages way out of spec and I could never get the idle to be smooth. If you do not own a digital voltmeter you should buy one - even the $2.00 variety from Harbor Freight will suit you well. I am not an electrician either but I have learned a lot by comparing observed sensor voltages with published guidelines. The computer operates primarily on feedback with a little feed-forward logic for continuous adjustment purposes. Once you start to observe the correlation between a bad voltage reading and an observed behavior, the computer becomes a lot less scary.

If you do not already own this book you should buy it: http://www.themotorbookstore.com/for...FUeBfgoduYwAmQ

Its well written and not overly complicated. Reading the introductory chapter(s) will get you a long way into better understanding.

You sound like an engineer, Tony. Maybe even a Cal Poly grad That said, I agree completely. If the parts are out of spec, or other details are incorrect, you'll never get it right. An example: Any mass air system requires that the block be sealed. That means no valve cover vents to atmosphere. The one and only valve cover vent should be a hose connected to the port on the throttle body. Otherwise unmetered (air not flowing through the mass air meter) gets into the engine and confuses the computer. I've seen this several times in the last decade. Argued with a few owners. One had the traditional breather on the drivers side cover and insisted it needed to be there. I said take the breather off, cover it with duct tape (passenger side cover had only a hose running from oil filler to throttle body, as any MAF 5.0 Mustang has) and start it. Magic. Suddenly idled perfectly. Just something to be aware of.

[crawlin68]

Re: ford efi troubleshooting

You sound like an engineer, Tony. Maybe even a Cal Poly grad That said, I agree completely. If the parts are out of spec, or other details are incorrect, you'll never get it right. An example: Any mass air system requires that the block be sealed. That means no valve cover vents to atmosphere. The one and only valve cover vent should be a hose connected to the port on the throttle body. Otherwise unmetered (air not flowing through the mass air meter) gets into the engine and confuses the computer. I've seen this several times in the last decade. Argued with a few owners. One had the traditional breather on the drivers side cover and insisted it needed to be there. I said take the breather off, cover it with duct tape (passenger side cover had only a hose running from oil filler to throttle body, as any MAF 5.0 Mustang has) and start it. Magic. Suddenly idled perfectly. Just something to be aware of.

LOL. I too have argued with people about this very same thing. They just don't want to believe it.

[CityHick]

Re: ford efi troubleshooting

You sound like an engineer, Tony. Maybe even a Cal Poly grad

I'm not an engineer, but I play one at work! I'm a technically-oriented business grad (gasp!). While learning about EEC-IV it started sounding a lot like the software they pay me to work on... reading and reacting to measurements in the form of numeric data.
But to be fair, if one can wire a stereo and turn a wrench, one can get Ford MAF-based EFI running.

[bent70]

Re: ford efi troubleshooting

http://www.myo-p.com/Ford-EEC/EEC%20...0part%201.html

[welndmn]

Re: ford efi troubleshooting

The black and white "salt and pepper" connectors are known for poor connections.
They are normally on the passenger side, take them apart and clean them.

Ford's are known for idle issues. They use to sell a spacer with bypass screws that goes under the IAC, you can still find them at the junkyard and help fix SMALL idles issues.

[Lars]

Re: ford efi troubleshooting

The black and white "salt and pepper" connectors are known for poor connections.
They are normally on the passenger side, take them apart and clean them.

Ford's are known for idle issues. They use to sell a spacer with bypass screws that goes under the IAC, you can still find them at the junkyard and help fix SMALL idles issues.

Or better yet, take the damn connectors apart, remove them and hard-wire everything to make the problem go away forever.

I was able to solve a surging idle issue by disconnecting the IAC motor, then backing the idle down till it barely ran. Re-connected the IAC and it's been fine ever since.

[Spaceburger]

Re: ford efi troubleshooting

I'm not an engineer...But to be fair, if one can wire a stereo and turn a wrench, one can get Ford MAF-based EFI running.

I have a feeling this quote will live in infamy.

[welndmn]

Re: ford efi troubleshooting

Or better yet, take the damn connectors apart, remove them and hard-wire everything to make the problem go away forever.

I was able to solve a surging idle issue by disconnecting the IAC motor, then backing the idle down till it barely ran. Re-connected the IAC and it's been fine ever since.

True, mine got wired in too, it's just a cause for so many issues I want people that search to check there.