Spark plug fouling

[169mph]

A replaced my spark plugs a few months ago. A few of the plugs looked fouled but overall the plugs looked fine. The engine ran and idled fine initially but over time it started backfiring. Two weeks ago it started to die when stopped a red lights. I pulled the plugs and they were all fouled. This was after being driven less than 50 miles. This week I replaced my plug wires, spark plugs, and the msd ignition coil hoping that would fix what was wrong. This morning I started my car and it seemed to idle better but 2-3 minutes later the engine died. I pulled a couple of plugs and they were both fouled. I plan to call Roush this afternoon to see if I can get the diagnostic tool to help me figure this out. This is very frustrating. Any advice would be appreciated.

Thanks, Mike

[Tommy]

What type of intake / fuel system do you have?

[twobjshelbys]

What model Roush? Are you running one of the fuel-injected versions (-IR)?

[169mph]

Roush 427ir with Borla 8 stack fuel injection.

[jhv48]

Call roush. Their early IR engines were known to have FI gremlins.

[Tommy]

I know little about fuel injections, but your symptoms sounds like a rich condition to me.

[Desert-ValleyMS]

Unfortunately, Roush uses one of the cheapest ECU's on the market - FAST

You can tune it but It's pretty limited. If you're wanting help feel free to reach out to me and I can try and help.

Getting a hold of Roush these days is nearly impossible...

[twobjshelbys]

Originally Posted by jhv48

Call roush. Their early IR engines were known to have FI gremlins.

Indeed. If you have the Accel DFI controller you're in for a ride... It took months, shipping the car to Roush (which accomplished nothing) and finally finding an Accel trained tuner that knew how to adjust all the tables.

If you are at high altitude the early tunes did NOT populate the altitude compensation table. The system uses the MAF sensor on power up to estimate the altitude and make fuel trim compensations. Mine ran incredibly rich all the time as it sounds like yours may be. The system DID work correctly at say below 3000' but failed miserably at our 5800 feet where I was and got really bad in Estes Park at 7000ish... Roush admitted they hadn't completed the tuning process at altitude but never came through with anything to fix it.

If it is the Accel system you will need to acquire their "dongle" and software. You will need the "advanced" system that opens up all of the tables. I found the hardware at Jegs but that was years ago... That particular DFI system is perhaps the most complicated you can get but it is also able to control things rather precisely. It does no self-tuning.

[twobjshelbys]

But before you go diving into the DFI hardware, that 8-stack is incredibly finicky. Acquire one of the vacuum gauges and go through the throttle body adjustments. You have to do an 8-way iterative adjustment that will probably at least once lead to an unsolvable solution in that you can't get one side to converge with the other. You'll have to adjust the throttle cable in the turnbuckle to center it and start over... I think I have the procedure document still around somewhere.

From your description of a few plugs fouled to all I'd start with this adjustment first. If the vacuum device shows the same on all 8 cyls you're ok. Then you go to try to figure out why the afr is wrong. Adjusting the blades to get them all pointed the same angle at the same time will also mess with afr. It's a tedious iterative process.

It's also really finicky since the cam in the 427IR is really lopey and getting a good vacuum registration on the tool at idle is really hard. I raised my idle to 1000rpm...

[eschaider]

+1 on what Dan and Tony said.

Everyone has a favorite EFI system, eventually you will too. Right now (even though yours is fixable) your #1 job is to select the replacement EFI system you want to use going forward.

While there are lots of systems out there I have a personal preference for the DIY Autotune MS3Pro systems in large part because of their performance, feature set, price and widespread understandable Youtube help vids. Here is the link =>MS3Pro Ultimate. There are excellent systems available from any number of providers. The next best bang for the buck systems are the MS3Pro and Holley EFI products.

You can go from the bottom which is somewhere around the FAST system you now have to the top which is a Motec. I believe you will really want to be somewhere in the MS3Pro / Holley EFI play pen. MS3Pro will mean about $2K or less when you're done. Holley will mean about $3.5K when you are done and Motec is, well stunning pricewise. They usually ask you if you own your own home before the sales process begins and when you see the $10K+ price you understand why.

I know this is not what you want to hear but it is real. You can suture up that antique system Roush delivered to you and it will always be problematic or you can replace it with a more modern implementation that works as expected. Bitter medicine, I know but as real as it gets.

BTW FAST has some, more modern (and higher priced) systems available. You should also look at them and firms like Haltech which has some very credible offerings although again at higher prices

I believe in the end you will likely gravitate back to the MS3Pro. If you do be sure to check out the MS3Pro Plug and Play offerings. They will allow you to use an OEM Ford wiring harness out of a salvage yard or ?. The big deal about the OEM harnesses is they are mass produced, factory tested (although yours will be used) very durable and for the most part done. By, 'for the most part done, I mean you might need to lengthen or shorten one or more sensor wires but the PITA job of creating a harness from scratch has already been done for you. The MS3Pro PnP will plug right into the OEM wire harness ECU receptacle — which is also nice.

[twobjshelbys]

Originally Posted by eschaider

+1 on what Dan said.

Everyone has a favorite EFI system, eventually you will too. Right now (even though yours is fixable) your #1 job is to select the replacement EFI system you want to use going forward.

While there are lots of systems out there I have a personal preference for the DIY Autotune MS3Pro systems in large part because of thier performance, feature set, price and widespread understandable Youtube help vids. Here is the link =>MS3Pro Ultimate. There are excellent systems available from any number of providers. The next best bang for the buck systems are the MS3Pro and Holley EFI products.

You can go from the bottom which is somewhere around the FAST system you now have to the top which is a Motec. I believe you will really want to be somewhere in the MS3Pro / Holley EFI play pen. MS3Pro will mean about $2K or less when you're done. Holley will mean about $3.5K when you are done and Motec is, well stunning pricewise. They usually ask you if you own your own home before the sales process begins and when you see the $10K+ price you understand why.

I know this is not what you want to hear but it is real. You can suture up that antique system Roush delivered to you and it will always be problematic or you can replace it with a more modern implementation that works as expected. Bitter medicine, I know but as real as it gets.

BTW FAST has some, more modern (and higher priced) systems available. You should also look at them and firms like Haltech which has some very credible offerings although again at higher prices

I believe in the end you will likely gravitate back to the MS3Pro. If you do be sure to check out the MS3Pro Plug and Play offerings. They will allow you to use an OEM Ford wiring harness out of a salvage yard or ?. The big deal about the OEM harnesses is they are mass produced, factory tested (although yours will be used) very durable and for the most part done. By, 'for the most part done, I mean you might need to lengthen or shorten one or more sensor wires but the PITA job of creating a harness from scratch has already been done for you. The MS3Pro PnP will plug right into the OEM wire harness ECU receptacle — which is also nice.

Frankly, if you're at constant altitude (seems likely if you're in Texas) and you have the Accel system you could consider changing, in which case the above is a starting place, but rather than putting a whole boatload of cash into converting a failing DFI system into another one that will require LOTS of cash for the hardware and even more for a good ground up tuning, just go back to a set of carbs. Go to the ones they put on the 427R since it is known to behave. If I hadn't been driving through altitudes from under 4000' to over 12000 I would have done just that.

Please tell us what DFI system you have. In my car the Accel controller was behind the dash on the passenger side tucked in behind the glove box.

Also, the Accel harness was entirely self-contained and all inclusive and didn't depend on any modern harness bits at all.

[twobjshelbys]

PPS. I am assuming this is an older installation and is not under any current Roush warranty. If so beat them up.

[169mph]

I have a XFI Sportsman with a 5520 street fire ignition. Thanks for the feedback…I’m trying take it all in.

[bobcowan]

Fouling plugs usually points to one of two problems: Rich mixture, Burning oil. Be sure to check for the later before working on the former.

If it was running well, and now is not, you have to look for the common denominator. For example, if it was running fine, but now fouling plugs in 1-2 cylinders, look for a problem unique to those two. Like a stuck injector.

Since all of your plugs are fouled, look for something that controls all injectors. The tune could be corrupted - it happens. Reload the tune from a back up.

Also consider that a sensor may have failed. Ford O2 sensors are pretty famous for failure if not installed correctly. Check the calibration on the TPS. Could be something simple, like the vacuum line to the BPS came loose.

Don't panic. Just start going down the diagnostics list until you find it.

[twobjshelbys]

Originally Posted by bobcowan

Fouling plugs usually points to one of two problems: Rich mixture, Burning oil. Be sure to check for the later before working on the former.

If it was running well, and now is not, you have to look for the common denominator. For example, if it was running fine, but now fouling plugs in 1-2 cylinders, look for a problem unique to those two. Like a stuck injector.

Since all of your plugs are fouled, look for something that controls all injectors. The tune could be corrupted - it happens. Reload the tune from a back up.

Also consider that a sensor may have failed. Ford O2 sensors are pretty famous for failure if not installed correctly. Check the calibration on the TPS. Could be something simple, like the vacuum line to the BPS came loose.

Don't panic. Just start going down the diagnostics list until you find it.

Roush does not provide any tools for reloading the tune.

It could also be the MAF... Unlike most cars the Roush 8-stack MAF is unprotected.

Do you have the K&N filters on the trumpets?

[169mph]

Originally Posted by twobjshelbys

Roush does not provide any tools for reloading the tune.

It could also be the MAF... Unlike most cars the Roush 8-stack MAF is unprotected.

Do you have the K&N filters on the trumpets?

Yes sir.

[eschaider]

Originally Posted by twobjshelbys

Frankly, if you're at constant altitude (seems likely if you're in Texas) and you have the Accel system you could consider changing, in which case the above is a starting place, but rather than putting a whole boatload of cash into converting a failing DFI system into another one that will require LOTS of cash for the hardware and even more for a good ground up tuning, just go back to a set of carbs. Go to the ones they put on the 427R since it is known to behave. If I hadn't been driving through altitudes from under 4000' to over 12000 I would have done just that.

Please tell us what DFI system you have. In my car the Accel controller was behind the dash on the passenger side tucked in behind the glove box.

Also, the Accel harness was entirely self-contained and all inclusive and didn't depend on any modern harness bits at all.

I was stunned looking at the Holley carb pages last week, Tony. It is difficult to get a 750 or larger four barrel for less than about $850 — I couldn't believe my eyes!

[169mph]

I talked to Richard Nedbal with Fast Man EFI and he basically told me the same thing Ed said in his earlier post…I need to cut my losses and buy new ecu. This really sucks!!! Before I start removing the current ecu I’m going to replace the O2 sensor and verify my fuel pressure. Per my conversation with Richard l plan to pull my injectors and send them out be tested, cleaned up, and balanced.

Richard spent 30 minutes explaining why the Fast Sportsman was most likely the cause of my issues. Based on my setup and budget he recommended the Holley EFI.

I appreciate your feedback. Thank you
www.fastmanefi.com

[eschaider]

Before you begin buying anything, it would be to your advantage to school yourself on the alternatives, what each brings to the table, what you need / want and what the ante at the various Poker tables is. If you do not, you may find yourself in a similar position very shortly with the same or a similar conundrum to resolve.

[jhv48]

Makes that $850 Holley carb look better and better.