CSX3170 first time out with new engine

[Cobra #3170]

One word best describes the experience Disaster! The new FAST XFI is susceptible to electrical noise and low voltage to a point that the car will not run with the supplied harness used by Kinetics for dyno runs and tuning.
I drove the car last Friday near my house and it quit two miles out. It was 97 degrees and really nasty. I was out there about 2 1/2 hours till I got a ride back to my house to get the trailer and pick up the car. I tried jumper batteries and charging it from another vehicle, still no start. At this point I was very tired , hot and unhappy. I called Scott and told him I wanted to pull the plug on Goodguys Pleasanton. He asked me to try and fix the issue so we could qualify for Scottsdale. I decided to put my battery charger on and let it charge about two hours. I went out about seven PM and tried it and it started immediately, jumping to an erroneous conclusions I assumed the battery was low and all was good. I loaded the car up along with all our other junk and got about 4 hours sleep before leaving for Pleasanton at 4:15 am. We unloaded there and all seemed normal until it was time to run, it leaked water because I overfilled the expansion tank and we had a pretty good oil leak from the dry sump pump outlets too. This pissed the officials off so they booted us out of line to deal with our issues. We drained the overflow bottle and tighten the oil lines and got back in line. The car made a mediocre run and quit at the finish line for no apparent reason. We made one more try and Scott went off course. At that point we decided to go after the oil leak, unfortunately you have to pull the right hand headers to get at the hose ends a bad job in the garage and miserable in the field. When we finished everything we got back in line and it quit before he could even start. Are you seeing a pattern? I tested battery voltage during cranking and it was low 9's high 8's so we ran out and bought a crappy Optima red top for $270 at NAPA. They saw us coming! Got back in the line up and it started until he got near the course and quit again. It was now 5:00 pm so we brought the trailer over and loaded the car, generator and tools and moved it to trailer parking.
I am thinking that it must be an electrical issue probably voltage or crank sensor related. Went to bed about 10:00 pm and got up at 5:00 am to do electrical work. We ran a 10 gauge wire from the XFI to the battery and then soldered the crank trigger directly to the harness to eliminate a suspect
weatherpack connector. Sounds like not much but it took two hours so Scott missed the drivers meeting. Guess what, it still would not start so I pushed in on the rear XFI connector and it started right up. Simple, put a tie wrap on the connector and pull it and harness to the box. We took it to the course and unloaded it. Scott drove it around the lot and all was fine. He went up to the start and you know what is next right? It quit AGAIN!!!! I am ready at this point to pour gas on it and light it on fire. Well I didn't but I had Scott drive me around so I could watch the indicator lights. Seems that whenever it quit the injectors did not fire nor did the "points wire", light come on, more on this later.
Scott was offered a ride in Mike Maiers fine 65 Mustang with a Yates engine so we put the Cobra away after a very frustrating 3 days. They put me on suicide watch for the rest of Sunday. So I just helped with a little tuning advice until leaving for home.

Good things:
- FAST people think that is was slipping into Flash Mode because of noise spikes or low voltage caused by high ground currents so maybe it can be fixed.

- The engine feels stronger that the old one (we had to disconnect the secondaries) until I finish hooking up traction control

_ The engine is even louder than the old one good because loud usually = HP
bad because loud means new mufflers

- The engine revs like a banshee Scott touched 9000 on his first run with ease it accelerates really hard too

- The new needle bearing rear A arms have produced slightly better grip because of friction reduction

Bad things: I am going to have to provide separate ground circuits for 5 separate pins on the ECU back to the battery 3 are 10 gauge to try and prevent noise contamination.

I will also run a separate power lead as it is installed all ready and re-pin several of the main harness connectors because they may not be making full contact.

If this does not work I will be buying a Holley system to run the car.

It really is a shame the car will blow the tires off in second gear at 30 mph
which means that we will now have explosive power off those GoodGuys U turns at 15 mph in low. It actually feels faster than the old engine and it was no slouch, looks like higher revs and a deeper gear were the answer but won't know for awhile. It is has fuel cut off at 9300! If only the electronics were on a par with the mechanicals. I will post here when I get it fixed with what ever fixed it.

[hinoonaz]

Looking forward to seeing you run again at the Good Guys, Scottsdale. Good luck with the gremlins. Just don't say beetle juice three times!

[1795]

Sorry to hear about the problems, was really looking forward to hearing good things. As you know, racing can be frustrating. You think that you have everything figured out, and then all of a sudden something goes south.

Good luck with the fixes and hope that it works out better for the next run.

[Gaz64]

Hope you can sort it.

I bet it is a weapon, revving to 9000+.

Gary

[rodneym]

Sorry to hear about your frustrations but I must admit, it was quite a read.
You and Morris are just about the only things worth checking out around here lately
Good luck!

[Dominik]

Following with great interest and holding thumbs that you solve the frustrating issue!
I know how that feels...

[Tommy]

Bruce,
I empathize with your frustration. But it is somehow comforting to know that even the most knowledgable racers occasionally have weekends like us ordinary folks. .... I find that the more frustrating the problem, the more satisfying it feels when the solution is in hand. I hope that works for you too.

[patrickt]

Originally Posted by rodneym

You and Morris are just about the only things worth checking out around here lately

Yep. I did buy one of the M/E Wagner Adjustable Dual Flow PCV Valves last week. I was going to post an extensive write-up, but my fingers got tired.

[Cobra #3170]

Originally Posted by Tommy

Bruce,
I empathize with your frustration. But it is somehow comforting to know that even the most knowledgable racers occasionally have weekends like us ordinary folks. .... I find that the more frustrating the problem, the more satisfying it feels when the solution is in hand. I hope that works for you too.

Thanks Tommy,

We threw the kitchen sink at it but unfortunately it was not enough. We also had a minor clutch release problem that I did not mention but that can be solved by up sizing the master cylinder. I will get the car up on jack stands tomorrow or Friday and get back on it. If the engine did not run so well I would have a lot less enthusiasm! The new engine is down about 90 lb/ft in torque but the gear ratio multiplication puts it effectively right back in the low 600 lb/ft range. We have exactly what we wanted, higher rpm at very low speeds for port velocity and a high enough range so it can reach 68 mph in low. If the damn injection and TC just worked I would be a happy camper.
It looks like we can use 2nd gear only in a normal autox and not shift at all because 2nd is good for 88 mph and can run down in the 25 mph range easily.

In summary the plan was good, execution not so much.

[Grey 65]

If all else fails you can call Ron Sutton...

[Morris]

Bruce

Desire, Determination, Dedication to coin a Vince Lombardi phrase is what got you here and will get you where you want to be.....Have at it, and let us know how you make out.....

It took us a while to work out our Dominator.....but when we did.....look out and I'm sure the same applies to you and you Passion.

[Morris]

Bruce

This works very good.....Electronics Cleaner Improves the Performance and Reliability of All Electronic Equipment.

Deoxit contact cleaner.....just used it the other day where contacts arc'd and burnt a plug.....cleaned as best as we could and used this stuff and it worked great....just saying....

[Buzz]

Thanks for sharing your adventures in CSX3170, Bruce! Its always a fantastic read with your great insights into the nuances of tuning, sorting and racing an original 427 Cobra. A first hand account of thrashing the car that inspired many of our automotive dreams is a rare and special thing 50 years after the Cobras ruled the earth.

[Ron61]

Bad things: I am going to have to provide separate ground circuits for 5 separate pins on the ECU back to the battery 3 are 10 gauge to try and prevent noise contamination.

I am not much of a mechanic but could you wrap your wire with a filter type wrap to prevent it picking up noise and other electrician interference? We used that type of wrap on out main frame computers and also in some of the missile guidance systems. I hope that you get it sorted out and am looking forward to your next posts as I try to keep up with what you and Morris do.

Ron

[Cobra #3170]

Originally Posted by Ron61

Bad things: I am going to have to provide separate ground circuits for 5 separate pins on the ECU back to the battery 3 are 10 gauge to try and prevent noise contamination.

I am not much of a mechanic but could you wrap your wire with a filter type wrap to prevent it picking up noise and other electrician interference? We used that type of wrap on out main frame computers and also in some of the missile guidance systems. I hope that you get it sorted out and am looking forward to your next posts as I try to keep up with what you and Morris do.

Ron

Thanks Ron,

Yes shielded wire is very effective at blocking inductive or capacitive coupled signals. I have it on all the low signal level input lines. This problem is related to voltage drop over ground circuits which effectively lowers input voltage because the computer just sees the difference between ground and input lines. The theory is that the ECU is going into Flash mode which automatically cuts off the fuel injectors and the pulse that fires the MSD.

They think a low voltage condition could cause the jump to flash mode. Since I have 1/0 welding cable for a positive feed to the starter solenoid I am going to upgrade my ground to the same thing and go from the battery to the block. I will also put the ground wires they recommend on the ECU as well just to eliminate that as an issue. The alternator current going up and down as I come off idle might cause a big drop across ground loops so hopefully that solves the issue. I just now moved the car into the garage and it ran perfectly of course, I am not at an event where it would surely quit again.

[ScratchBuilder]

Bad things: I am going to have to provide separate ground circuits for 5 separate pins on the ECU back to the battery 3 are 10 gauge to try and prevent noise contamination.

Hello,

I'm an Electrical Engineer and I would suspect that the larger gauge wire will help with voltage drop, but not during cranking or noise issues.

Can you get some EE support from FAST? I would think the noise source would be from the ignition system and maybe different routing of it's power connection may help or adding some capacitance to the input power pins to the FAST ECU which can help with noise and brownouts.

I find it curious that the system jumps into flash mode.
I can see a low voltage causing a brownout and the controller to reset but not go into upgrade mode. Can you try another FAST controller, maybe this one has an issue with it?

Best,

SB

[Cobra #3170]

Originally Posted by ScratchBuilder

Bad things: I am going to have to provide separate ground circuits for 5 separate pins on the ECU back to the battery 3 are 10 gauge to try and prevent noise contamination.

Hello,

I'm an Electrical Engineer and I would suspect that the larger gauge wire will help with voltage drop, but not during cranking or noise issues.

Can you get some EE support from FAST? I would think the noise source would be from the ignition system and maybe different routing of it's power connection may help or adding some capacitance to the input power pins to the FAST ECU which can help with noise and brownouts.

I find it curious that the system jumps into flash mode.
I can see a low voltage causing a brownout and the controller to reset but not go into upgrade mode. Can you try another FAST controller, maybe this one has an issue with it?

Best,

SB

I too am an electrical engineer although trained many years ago I still build many micro processor based projects and write my own code in low level language. I am familiar with filtering and isolating inputs with my own projects
so it seems odd to me that they would put a product on the market that is susceptible to low voltage spikes or electrical noise within a vehicle environment. They did not bother answering my email at all regarding these questions. I am getting help from a gentleman that is familiar with all these after market systems and helped with the tuning effort on the dyno. He is not sure why it goes in to flash mode but says it can happen with a low voltage condition. You would think they would make it more difficult for that to occur say require multiple pin inputs of 12v or more but who knows what the designer was thinking. If you look at comments on the product there are lots of complaints about low voltage stability so the basic design has issues. Changing ECU's is not an option right now because FAST does not care what I think. I suppose if this isn't resolved I will switch to Holley and try to use some of my FAST tables as a starting point. The car runs in alpha n mode so it just uses look up tables based on MAP, TPS temp, and RPM. I saw some fluctuation in alternator output so there may be an issue with the Nippondenzo alternator regulator. The MSD ignition is grounded to the block and it's source voltage is significantly isolated from the FAST input voltage.
The problem with most aftermarket electronics is poor engineering, that is why I run a Bosch fuel pump for the injection. I am trying to make this work so I don't have to drop another $2200 on a new ecu and then reprogram it.
I think the ECU pins have lots of room for improvement like gold plating them for corrosion resistance, my battery terminals are gold plated why not dry circuit ecu connectors? It doesn't cost that much, again poor engineering.
Now that I am home I can run the engine with a computer connected to the system to monitor error codes and put a scope on to look for noise and voltage spikes. Since I have that ability now, it will probably run fine while being watched and then fail at the next event July 1 when I can't do anything about it. (joke) I will get off my soap box now and get back to work on it.

[Barry_R]

I have wrestled with a few of these installations as well. A friend who is pretty darn good with electrical and electronic stuff (has hands on some projects in orbit...) says that the FAST guys always blame the ground no matter what's wrong. It's their favorite "whipping boy" and probably often accurate given the installations they see in the garage builder & street market.

As an old street racer and sales guy with a car habit I do not have the true knowledge to diagnose these things - I just repeat what I am told, and keep trying stuff until it works - or breaks. Take my comments as such.

I suspect that some of the aftermarket sales volumes on these kits are as low - or lower than the prototype volumes on an OE project. Means that there are limited development opportunities or resources, and consumer products are fairly immature from an OE perspective. Every customer gets to be a development engineer.

My buddy demands that I install a couple of those big "firecracker" capacitors in line with the power supply. He also concurs with the idea of keeping all the sensor side leads isolated from any high voltage stuff, and wants the ignition box wires completely isolated from the EFI system wires. Almost seems like the two companies never speak with each other (with Holley acquiring MSD those two may have an eventual advantage). I really dislike the wiring terminals and attachment to the box - seems like some sort of mounted pigtail and strain relief to a robust connector would be more effective in a race car oriented product.

And when nothing seems to work you send back the box and they send you another one that fixes the problem. You never learn what that fix entailed, nor whether your wiring was "cause or effect" but you do learn that the mysterious problem really existed in the box and not in your installation.

[hinoonaz]

Enjoying this post. It seems a lot of people from different sites and car shows claim FAST is really good. Is it because most of us are in the norm as far as sophistication on engines or what. MSD and Holley 650 work well for me and I can work on it. I can change the oil on my wife's Pilot and don't want to go any further. You on the other hand are in a knowledge zone way beyond me for sure. Curious though on what do NASCAR and even Pro Stock drag cars use. One constant RPM and the other for 6 second bursts. They are all EFI now. Thanks for sharing with us shade tree mechanics. Gary

[Dominik]

In the 90s I had the most troublesome ECU controlled cars in our shop. 90% of failures are gound related.

The crank sensor is very sensitive when it comes to gapping and a pick up behind the balancer might help (axial instead of radial, if my english doesn't fail me).

ECUs typically have a compensation for voltage drop when starting with a weak battery or in winter to "convince" the management system to start irrespective. Dending on the range you could just be too low.

A welding cable for negative from the battery direct to starter cannot be a mistake (35 or 50 mm2).

Good luck!