Spark plug fouling

[twobjshelbys]

I think you're going too fast...

Answer this. Did the car run OK at some point? Did this suddenly start?

If so, something is broken. Fix it.

Complete EFI systems don't just fail. You could be looking at any number of external issues that replacing the EFI system will leave you 4K or 5K poorer and still broken.

[FredG]

My 2014 Roush 427R came with an 850cfm Holley. I called Roush to confirm it was the Carb they put on it. I replaced it with the same Carb with a Blue/Chrome option. I have the original sitting in my garage.

Originally Posted by jhv48

Makes that $850 Holley carb look better and better.

[169mph]

Originally Posted by twobjshelbys

I think you're going too fast...

Answer this. Did the car run OK at some point? Did this suddenly start?

If so, something is broken. Fix it.

Complete EFI systems don't just fail. You could be looking at any number of external issues that replacing the EFI system will leave you 4K or 5K poorer and still broken.

I’m not replacing the EFI until I’ve ruled out all potential causes. When these issues originally started. I thought I could plug my laptop into the ECU and I would be able to run diagnostics to see if a sensor was faulty or a fuel injector was stuck open. Is this not possible. I’ve downloaded what I believe to be the latest FAST software for my ECU. I’m trying to find the correct USB to CAN connector so can I connect my computer to the ECU. Is this a waste of time? Again, I appreciate y’alls help. Thanks, Mike

[spdbrake]

Curious if your plug fouling has been Wet or Dry fouled?

This may be of help on the plug readings.
https://www.youtube.com/watch?v=lVCs5gWLUyI&t=169s

If its a Wet fouled issue a compression check will help you see if its a Motor issue Top end vs Bottom end.

If you have a Dyno shop nearby? a quick tailpipe AFR check my reveal any possible mixture issues.

Lastly Roush has somewhat of an reputation for oil consumption. Not saying they suck, but they advise higher oil consumption is normal in their motors. Info--> Roush Engine Warranty Exclusions.

[twobjshelbys]

Originally Posted by 169mph

I’m not replacing the EFI until I’ve ruled out all potential causes. When these issues originally started. I thought I could plug my laptop into the ECU and I would be able to run diagnostics to see if a sensor was faulty or a fuel injector was stuck open. Is this not possible. I’ve downloaded what I believe to be the latest FAST software for my ECU. I’m trying to find the correct USB to CAN connector so can I connect my computer to the ECU. Is this a waste of time? Again, I appreciate y’alls help. Thanks, Mike

So you've confirmed it's the FAST and not the Accel EFI system? If so that is good.

I would suspect you can get whatever tools you need to confirm the tune from them (FAST). If they have a standard tune that has evolved I'd say it probably won't hurt - treat it like any other software update. But if the tune was modified by Roush I wouldn't put a different tune in it. The reason is that the faux 8-stack injection is not linear with throttle position and air flow. I've gone into the details in other posts (don't ask me where) but the air flow over the throttle body vane varies by the position relative to the injector, with the net effect being that in the case of at least the Accel, at idle it was running extremely rich because the air/fuel didn't get a chance to mix until the throttle blade was open to about 1/2. I don't know how FAST deals with this characteristic. I never figured out who made the Roush 8-stack so if it is Borla you could perhaps turn to them for some advice on how the off the shelf FAST tunes work.

[169mph]

Originally Posted by spdbrake

Curious if your plug fouling has been Wet or Dry fouled?

This may be of help on the plug readings.
https://www.youtube.com/watch?v=lVCs5gWLUyI&t=169s

If its a Wet fouled issue a compression check will help you see if its a Motor issue Top end vs Bottom end.

If you have a Dyno shop nearby? a quick tailpipe AFR check my reveal any possible mixture issues.

Lastly Roush has somewhat of an reputation for oil consumption. Not saying they suck, but they advise higher oil consumption is normal in their motors. Info--> Roush Engine Warranty Exclusions.

I haven't notice excessive oil use. I may have added 1/2 quart once between oil changes. The plugs smell like gas when I pulled them. Definitely not wet. I checked each cylinder with borescope and there was a little carbon build up on the pistons. Very thin coat on less than a square inch. I was unable to start the engine this weekend. it turns over and sounds like its about start but I was concerned about flooding the engine. I plan to do compression check just for peace of mind. I think the 02 sensor needs to be relocated. Its only measuring on cylinder. I think it should be located downstream of the collector. This isn't causing my issues but its seems like a bad setup.


Thanks, Mike

[169mph]

Originally Posted by twobjshelbys

So you've confirmed it's the FAST and not the Accel EFI system? If so that is good.

I would suspect you can get whatever tools you need to confirm the tune from them (FAST). If they have a standard tune that has evolved I'd say it probably won't hurt - treat it like any other software update. But if the tune was modified by Roush I wouldn't put a different tune in it. The reason is that the faux 8-stack injection is not linear with throttle position and air flow. I've gone into the details in other posts (don't ask me where) but the air flow over the throttle body vane varies by the position relative to the injector, with the net effect being that in the case of at least the Accel, at idle it was running extremely rich because the air/fuel didn't get a chance to mix until the throttle blade was open to about 1/2. I don't know how FAST deals with this characteristic. I never figured out who made the Roush 8-stack so if it is Borla you could perhaps turn to them for some advice on how the off the shelf FAST tunes work.

It's a Borla 8 stack with a FAST XFI Sportsman ECU. I was told that FAST no longer sells my ECU and there's very few people who can tune them or at least not willing to tune them. I believe Roush tune the engine. If so, they should have a copy of the tune or I'm I being too optimistic??

Thanks, Mike

[jhv48]

Those plugs appear to be covered with fluffy carbon deposits and if so, that’s a rich condition. I wouldn’t run the car too much until you figure out why the injection system is dumping too much fuel into the cylinders.
It’s a good thing the car won’t start now. You don’t want to drive it much running rich, as the excess fuel can wash down the cylinders and cause real problems.

[twobjshelbys]

Let's try this again. I've asked but I don't think I've seen the answer, so let me ask you one single question so we don't get Qs and As mixed:

Did this car ever run properly?

[twobjshelbys]

Now I'll ask another:

How old is it? Is the engine still under Roush warranty?

[twobjshelbys]

Originally Posted by 169mph

It's a Borla 8 stack with a FAST XFI Sportsman ECU. I was told that FAST no longer sells my ECU and there's very few people who can tune them or at least not willing to tune them. I believe Roush tune the engine. If so, they should have a copy of the tune or I'm I being too optimistic??

Thanks, Mike

I don't know how Roush does this any more but when I was having the problem with mine Roush was fairly cooperative. But often that is more related to the individuals involved than corporate policy and my contact was with a direct engineer.

That said, your tune is most likely intact. You can try to get it from Roush but I doubt it will be different than what you have currently since you have no evidence that it was subsequently tuned by someone else (do you?)

However, I don't know how much self-learning this system does. It's possible its learned itself into a corner that it can't get itself out from. If you can get the FAST software maybe you can simply reset the adaptives and let it start over again.

I still assert there is something besides the ECU that is causing this problem. Something is leading the fuel system to over-fuel since I sincerely doubt Roush would ship an engine that behaves so badly by design. You need to find that first.

[twobjshelbys]

Regarding O2 sensor location:

The entire system is based on averaging. If the engine, 8-stack adjustments and fuel injectors are properly balanced then sampling one cylinder is the same as sampling 8 (for a two O2 system) or one side for a one O2 sensor config...

My car had bungs in two locations: On one cylinder header and downstream past the point where the 4 individuals join but before the muffler itself. It is difficult to get the ideal position for this location. Ideally the O2 sensor is vertical but you can't do that. Mine was mounted on the passenger side at about 10-oclock.

I moved the sensor from one location to the other and there was a difference... My tuner expert said the difference was that at low idle speeds air does in fact find its way back into the muffler to the O2 sensor and "fool" it. My solution was to raise the idle speed to about 0200/1000 (depending on which direction you're looking), ie, just off horizontal, and pointed inward towards the chassis. For this reason it is important that if you use a tailpipe sensor at a shop that you get the sensor inserted far enough but not so far as to get it in one of the feeders. Regretfully, I don't have any photos of the O2 sensor installation.

This exercise taught me a lot more about DFI systems than I really wanted to know!

This is a tedious process that took me nearly a year to sort out. I'm an engineer so tried much of it myself using test drives where I could get the RPMs up. I would data log, do a run, adjust a table and try again. The Accel system is not self-learning so all tables had to be complete. Eventually I concluded the only way to really do it was on a dyno.

[twobjshelbys]

Originally Posted by jhv48

Those plugs appear to be covered with fluffy carbon deposits and if so, that’s a rich condition. I wouldn’t run the car too much until you figure out why the injection system is dumping too much fuel into the cylinders.
It’s a good thing the car won’t start now. You don’t want to drive it much running rich, as the excess fuel can wash down the cylinders and cause real problems.

I concur. Mine looked like this.

However, I also had another symptom: My rich portion of the DFI tables were beyond 1/2 to 3/4 throttle. Running steady at that speed/rpm/position and then letting off the throttle would result in backfires... I could also get it to backfire by "foot on the pedal" acceleration/shifting like you'd get when merging into highway traffic and then letting off the throttle...

Do you have a backfiring problem?

[169mph]

Originally Posted by twobjshelbys

Let's try this again. I've asked but I don't think I've seen the answer, so let me ask you one single question so we don't get Qs and As mixed:

Did this car ever run properly?

I'm the second owner. I've put around 2000 miles on it in two years and the only engine related issue has been the engine the rpms would periodically drop while the car was idling. The rpms would drop then right before it stalled the rpms would jump back to normal (1050 rpms). It would idle up and down until the engine eventually stalled. This usually happened when the engine was cold. After driving for a few minutes it would idle fine … not always. I've chased this issue for about year but it would start idling fine before I found the cause. Hope that helps.


Mike

[169mph]

Originally Posted by twobjshelbys

I concur. Mine looked like this.

However, I also had another symptom: My rich portion of the DFI tables were beyond 1/2 to 3/4 throttle. Running steady at that speed/rpm/position and then letting off the throttle would result in backfires... I could also get it to backfire by "foot on the pedal" acceleration/shifting like you'd get when merging into highway traffic and then letting off the throttle...

Do you have a backfiring problem?

When I first bought the car it had nasty backfire when decelerating. The flanges connecting the header to the side pipes were leaking. The backfiring went away after I replaced gaskets and bolts. The last few times I drove the car it would backfire when accelerating and decelerating That's what led me to check plugs.

Thanks, Mike

[jhv48]

I’m no FI expert but could the problem be a failing/rusted/plugged 02 sensor?
Might be a simple cheap thing to try first.

[twobjshelbys]

Originally Posted by jhv48

I’m no FI expert but could the problem be a failing/rusted/plugged 02 sensor?
Might be a simple cheap thing to try first.

Yes, it could be, but only because it had a primary reason to fail.. O2 sensors rarely fail on their own, especially at this age...

Which does make me wonder. I'd get in touch with FAST support and see if there is an equivalent of a "check engine light" code that can be read. You mentioned it had an OBDII connector - how about getting a bluetooth OBDII reader and seeing if it's throwing codes???

Have you tried to download the documentation for that system??? They usually have some kind of troubleshooting tree.

You mentioned that it did backfire, so it's been running rich probably since the beginning. Instead of post-installation troubleshooting I'd start with verifying that the installation was done correctly.

One more... My very initial problem turned out to be that while the engine ran, the throttle position sensor cable was wired backwards (yes, it was a Roush part, and they told me it was likely mine was and it was.) That causes lots of problems because the DFI system at true idle thinks it's running WOT and at WOT is closed... That's really confusing to the software. Their software should give you real-time readouts of TPS and other sensors...

[169mph]

Here's a short clip of the engine idling up and down


https://youtu.be/2eeasd1m2bA

[FlyingGumby]

Originally Posted by twobjshelbys

Yes, it could be, but only because it had a primary reason to fail.. O2 sensors rarely fail on their own, especially at this age...

Which does make me wonder. I'd get in touch with FAST support and see if there is an equivalent of a "check engine light" code that can be read. You mentioned it had an OBDII connector - how about getting a bluetooth OBDII reader and seeing if it's throwing codes???

Have you tried to download the documentation for that system??? They usually have some kind of troubleshooting tree.

You mentioned that it did backfire, so it's been running rich probably since the beginning. Instead of post-installation troubleshooting I'd start with verifying that the installation was done correctly.

One more... My very initial problem turned out to be that while the engine ran, the throttle position sensor cable was wired backwards (yes, it was a Roush part, and they told me it was likely mine was and it was.) That causes lots of problems because the DFI system at true idle thinks it's running WOT and at WOT is closed... That's really confusing to the software. Their software should give you real-time readouts of TPS and other sensors...

+1 on trying an OBD2 reader (if you have a port). Used on my Roushcharged 4.6 3v to diagnose a few things.

First to troubleshoot CHT code. Lucky it was a loose harness at back of engine and not CHT sensor under the intake and supercharger.

Next... went from running great to running rough (and smelling a little rich) overnight. Saw ST and LT fuel trims off with the reader. Turned out the intake snorkel came loose after the MAF at the throttle body. Think the ECU went rich as engine was getting more air than MAF was measuring. Cleaned the air filter and MAF, and reconnected everything. Back to normal.

Another time car ran rough almost like being in limp mode. Popped on the OBD2 reader and got code for TPS mismatch. Removed and cleaned TPS connections and it ran good as new. Never would have guessed that. Will replace TPS at some point.

I leave the reader connected to have data after each run - RPM, intake air temp, coolant temp, relative and absolute TPS, fuel trims, etc.

Worth a try. Good luck.

[eschaider]

Let's say you do have, and can find, a faulty component for replacement. When you are done you will still have an early generation, antiquated EFI system, which will ambush you yet again at some point in the future that is still unknown other than it will be carefully selected, by your EFI system, to optimize the pain you will experience.

Out with the old and in with the new and, if carefully selected, better EFI system. The current horse is dead. Continued beating on him will not get him up again. Time for a new horse — as the old knight said to Indy, "choose wisely, he did not."