I would feel much better about dropping $3000 to $5000 on a new EFI if knew without doubt what was causing my issues. Hopefully it's an easy fix. Regardless, I still plan on replacing the EFI down the road. This would be a short-term solution. Thanks, Mike

FYI..

I have a quote $2700 for a Holley HP EFI system. Price includes a new distributor but not injectors

I talked to Borla and they recommended the Holley Terminator X EFI. I got a rough estimate from Borla for $1500 to $2000. They will send me an actual quote this evening.

The price of poker at The New EFI Table is not that high unless you want to make it that high. You can easily buy in for well under $2K. Click here > Well Under $2K Buy In. Then go to a salvage yard and get a 1999 - 2004 harness — maybe $100 / $200. Take the sensors with the harness. The MS3Pro PnP uses all OEM Ford sensors.


p.s. They are the only EFI supplier with a lifetime warranty <= clickable

I’ve never installed or replaced an existing ECU harness. Is there a reason you can’t replace the existing harness connectors with the connectors from the ‘99-‘o4 harness? Thanks got h he

Your EFI system will likely come with the necessary wiring.

But let me ask you.

Assuming your problem is external when you fix it, what will a new EFI system do that the old one won't, except make the seller of the EFI hardware richer? The old one probably ain't broke. You're at sea level more or less. At constant altitude an EFI system doesn't do more than a carb...

If you buy the MS3Pro Ultimate it will come with a harness that you need to cut to length for your install and crimp on the appropriate connectors, just as Tony has suggested.

If you buy the MS3Pro Plug and Play, the ECU box has a connector on it that exactly matches the OEM Ford connector on the OEM ECU pin for pin. It expects to see an OEM Ford harness — hence the salvage yard or dealership (long shot) alternatives I suggested.

If you go the PnP route, some harness wires will be long and some will be short. You job at that point is to lengthen the short ones and shorten the long ones.

My path forward depends on what's causing the issue I have now. I'm trying to collect as much info as I can to help make that decision.

Yes, I understand that ford harness from 99-04 mustang would plug into the MS3. I preface this by saying I've never worked on any car electrical systems and prefer not to rerun a new wiring harness. Is it possible to cut the existing connectors and replace them with the new or used harness connectors? Thanks for the help.

If you guys want a quote for a new EFI system feel free to PM me, email, call or text me...

I've done tons of the Holley EFI systems on these intakes.

dan@desertvalleyms.com
954-464-5637

You are struggling with an antiquated system that even if it were operating correctly ought to be replaced for no other reason than serviceability. The idea of discovering what is wrong with the EFI and then fixing and/or replacing the system might satisfy curiosity but little else.

Out with the old and antiquated and in with the new. Time spent on analyzing the old malfunctioning system that needs replacement serves no good purpose. Get on with the replacement and start driving the car again.

In your replacement search determine what features are important to you. Review the purchase options available to you that support the features you are looking for. Determine what the budget you have available for the project is. Select the system that fits into your budget with the most features you want.

If you can not select features because you are not informed then either spend the time to get informed (learn) or select a name brand system that fits into your budget. There are no commercially available name brand systems available today that can even come close to how unsuitable the system you now have is.

In the end you can easily cover the feature set you need by selecting any of the name brand systems. That means your selection will come down to price. The provider that has the lowest purchase price ECU will be your best choice, selection limitations notwithstanding.

BTW the alternative is to continue to wring your hands over lack of operation, spend lots of money and in the end discover you could have achieved the same thing for many, possibly thousands, of dollars less.

As daunting as this fix sounds it is pretty simple and straight forward. Time to just do it.

Ed, I respectfully disagree. It seems that every time this comes up you're trying to sell a new system. This engine ran when it left Roush. Fix the external issue and the ECU will do a fine job given his location and usage.

I don't necessarily disagree with the find the issue and fix it approach, Tony. In this situation one of the components is old and its function (which may be the source of the whoops) could easily be compromised. The diagnostic tools other than a remove and replace approach are pretty thin for that generation of EFI system

I normally only encourage replacing an EFI system for a more current system if it was antiquated or severely damaged. 169mph appears to be wrestling with either an early (antiquated) Accel DFI system or an early FAST system. The replacement rationale looks like this ...

Irrespective of the manufacturer, the diagnostic and tuning tools available are more limited because it is an early-generation EFI system that is misbehaving. The probability of a compromised 'successful ending' that would result in a replacement purchase after the fact is high. The monies spent following that solution path would be more, and the result would be the same as abandoning the antiquated system at the front end and using a current technology replacement..

I am attempting to encourage 169mph to pursue a solution that will provide a similar (likely better) result with less frustration, less time and less money spent.

If it were the Accel system I'd be 100% behind ditching that POS. In many ways that system was an early predecessor to the MoTeC. Highly advanced, knobs for every possible thing, "don't try this at home" complexity.

But the simple FAST system he has is ADEQUATE if the external problems can be solved. And for the way he most likely uses it, spending 3K-5K for a new one will not add to the enjoyment of the car.

There are plenty of cars out there with 80's and earlier factory fuel injection systems and you'd probably not advise them to replace their fuel injection controller for fouled plugs...

Maybe I'm just too chincy, but I got over the "throw parts at a problem until it goes away" method coupled with "don't fix it if it ain't broke".

And I'll go back to part of my original advice: For old-style 60's/70's Windsors in cars like this fuel injection rarely gains anything over carbs. I liked it for my altitude. Other examples , for example there was the guy with the original Cobra that did autocross with his and in that application it made a difference. But for the street and even occasional track use by an amateur in most cases a properly adjusted carb will fill the bill nicely. And if I were ditching the EFI system in this case I'd go back to carbs for under a grand vs all the expense of a new EFI system that will ultimately run 4K+. I just don't think it adds enough value.

There is only one reason for staying with EFI in this case. He'd have to ditch the 8-stack. Which I had to admit looked cool and was a factor when I bought it but wasn't so important that had I not been able to whip it into submission. Going to a carb'd 8-stack is perhaps as evil as a malfunctioning EFI 8-stack. Although there were lots of them in the day, all the people with the technical expertise - talent - to keep it adjust properly are old enough to be your great grandfather. And I'll still assert that once the root cause is found the existing system will be ADEQUATE.

Just my opinion.

I would agree as long as the root cause is a replaceable component or a tune related adjustment. Beyond that IMO the ECU replacement path is the short way home — or a carb replacement but not a Weber Carb replacement (price and complexity)

I found and downloaded the latest (I think) FAST software for my ECU. I was to communicate with the ECU. My battery is too low start engine but with the key in the run position I was able to see if I had any faults, which I do not. Will the ECU detect faults without the engine running? At this point, I think I’m going to put in a new set of plugs, charge the battery, and try to find some one willing to remotely tune my engine or at minimum check the tune I have to see if something isn’t configured correctly. I was told there were only few people that would consider tuning my engine due to the FAST ecu. Is this correct? If not, do y’all recommend someone? Again, appreciate y’all’s feedback.

Thanks, Mike

Hey Mike - I tried reaching out to you a few times. I can definitely help you out with the FAST software as well.

I know others have said the engine left ROUSH running correctly but I'm not sure they've had to replace as many FAST ECU's that have failed as I have.

There was a point where Jim at ROUSH wouldn't even question what was wrong and just send me a new ECU and harness. I've had multiple ECU's with failed injector drivers, some when the car gets up to operating temperature it'll just stall and not restart, some just refuse to communicate with a computer... Honestly I don't know why ROUSH went with FAST it's pretty bottom of the barrel EFI.

If you do plan on having either me or someone else remote in I highly suggest purchasing an seperate wideband gauge and putting it into the side-pipe. This is done to make sure the FAST O2 sensor isn't giving the ECU bad readings.

I wouldn't suggest megasquirt or any other diy type ecu for this application unless you truly like tinkering with it all the time. IMHO, Holley is the way to go. Ease of use, plug and play, pretty advanced self tuning, everyone and their mother can tune it, price it right, and I've not had a single issue with the 100's of Holley installs I've done in my years doing installs at Backdraft other than an O2 sensor fouling going bad.

Either way - if you're interested in having a conversation about anything on your car (even if it isn't EFI related) feel free to call me at (954) 464-5637

I've got over 16 years experience building kit cars and worked at backdraft for the last 8.

If anyone is west of Texas and looking for a good shop let me know I'm now living in Las Vegas and my shop will be open Jan 1st!

Mike,

If the original FAST ECU is as failure-prone as Dan suggests, I would be reluctant to replace a failed unit with another identical unit that would likely fail the same way at a later date.

I am still back at believing the tune was good because the car ran at one point and the reason for non-operation right now is a failed component either inside or outside the ECU.

If you believe the ECU has failed and is additionally old technology, you would be doing yourself a favor by going to a modern aftermarket ECU. Which one to choose is your call.

When attempting to select an ECU, you should shoot for a feature set that allows you to tune for and manage good daily driving manners. In the FWIW bucket most units today will do this. Then how do you choose? It ultimately comes down to pricing and engine fail-safe features. It is worthwhile remembering that almost all the providers today will match each other nearly feature for feature.

You will find some units, typically race oriented units, offer feature sets that can help you "map" a race course for example. This is a really nice feature for a race application. It is not meaningful for a car like ours. When you finish your probably exhausting if not exhaustive evaluation you are going to discover everyone provides similar tuning tools/features usually with slightly different naming conventions.

The upshot of all this provides you with a single differentiator — price. I will add one more dimension capture ratio. What I mean by capture ratio is the need for the services of a professional tuner. Some systems are relatively easy to tune while others can be more challenging. If you purchase one of the more challenging you have painted yourself into a corner that requires the services of a fee based tuner.

If you purchase a more user-friendly system you will find you can do much if not all of the tuning yourself. Look for a system that has good 'how to' videos available and a complete tuning feature set with an easy user interface. The Holley system fits that model and provides a pretty good self learning capability that will both get you started and also get you well down the path to the tune you finally want.

Along with Holley you will find similar self learning capabilities and how to videos for the MS3Pro products along with an easy-to-navigate, relatively intuitive user interface. Start to finish the MS3Pro will typically come in $1K to $2K less expensive than the Holley system and give up nothing feature-wise.

Ultimately you need to make the call. If you fall back into the 'buy a tune from a shop that sells EFI systems' mode, you will find your initial solution will be more expensive and your follow on visits will be more frequent than you believed or were led to believe. Should you did not learn how to use the tool, you will be bound at the wallet to the tuning shop you have chosen or possibly replaced the original shop with.

EFI is not a dark science known only by high priests descended from who knows where. It is simply a digital calibration system used to balance the air and fuel your engine needs to run. This stuff is eminently learnable by everyone of us — unless you do not want to. If that is the case you will be better served by a shop that offers the service.

Don't sell yourself short.


p.s. The Megasquirt units are the only units available today that have a lifetime warranty. Wouldn't it have been nice if your current unit had that warranty?

OK, so Ed really, and I mean REALLY thinks you should just go spend 4K on a new EFI system. You're gonna hate yourself when the problem still is there and the root cause was a $50 O2 sensor or a distributor. Exhaust all those areas first...

I do agree with you, he should exhaust all options. It could be anything from a a bad tps to a bad o2. That's why I'm offing him the option to reach out to me, someone who's knowledgeable in these roush Itb engines. Not going to charge anyone anything just to chit chat with me...

Also, I see you're in Las Vegas. Do you head out to the cars and coffee ever?

I used to go to the gathering at the shopping mall on Eastern (by Twin Peaks) which was called Cars & Coffee, trademark owned by the guy that ran it - he had the famous one in CA before he moved here. I still see him (he's in the local Porsche group) but he "sold" C&C to the guys that have the exotic car place. But I sold the GT and haven't been since. Peter Brock was a regular when I was going. This event still happens.

The named C&C went to the track place on southern end of LV Blvd and I think now might be at Shelby American but I don't think they get a very big turnout any more.

You guys are overreacting.

I do believe he should check all his sensors for a failed unit. However I also suspect, and even more so after Dan's observation about Roush's FAST ECU failures, that Mike is likely dealing with a failed ECU.

I actually think the Accel DFI units that Roush used before the FAST units were even worse. That said, the FAST units have demonstrated, at least in Dan's experience an abnormally high incidence of failure. Replacing a bad design component with another bad design component is a real world example of doing the same thing over and over expecting a different outcome. There will not be one, at least not consistently — which is what Dan's first hand experience verifies and confirms.

In so far as the cost of the new system, it really comes down to just the box in the case of the MS3Pro. You can use all the existing sensors because the MS3Pro either already supports them or allows you to provide the calibration data for them so they play happily with the ECU. That means the cost of poker at the table is the ECU ($1,499) plus a wiring harness out of a salvage yard. The MS3Pro supports all three common fueling strategies Alpha-N, Speed Density and MAF based, which means it covers what ever the FAST system used — which is most likely Speed Density.

I am not attempting to flatten Mike's wallet. If anything I am attempting to provide him the low cost, highly reliable short way home, purchasing the minimum of new 'stuff'. This is the short way home effort-wise and cost-wise.