Motor just quit and wouldn't fire back up

[hotarizona]

I had this happen to me twice now at my last two events and it makes no sense to me. 04/17/21 I ran an all day on Saturday (4 sessions) and car ran fine. 04/18/2021 Sunday morning went out for two sessions and the car ran strong. drove to the grid for the Q-Race and had to shut down for 15 minutes due to track cleanup. Tried to start the car without and with jumper and it just spun over very quickly. Towed back to the paddock got out tried to start it again and it fired right up. shut it down got strapped back into the car and it just spun over again and didn't fire up. Spent twenty minutes checking electrical connections and connected the jumper box back up and the car fired back up. shut it back down and tried again, fired up again. Let the car sit for an hour, drove back out to grid, ran the race from the back and it ran strong without an issue. On Memorial Day weekend we went out to INDE in Wilcox and ran the test day on Friday, we ran four 30 minute sessions without a problem. Went out first session Saturday morning and the car ran great again for the full session. was idling back to my paddock and the car just shut off. Tried to start it and it just spun over fast. No codes on the LED light so didn't know where to start. Tried checking electrical connections, grounds ETC and couldn't find anything wrong. Checked all the Data, fuel pressure, battery voltage, ECU temp, fluid temps etc and could find any anomalies. Tried to start the car all Saturday but it wouldn't light up. Loaded it up and pulled back to the shop Sunday. The car sat in the trailer for three days and I pulled it out today and again checked all the connection, disconnected the Crank Position Sensor, checked the wires, checked the grounds again, checked the Z-Wires on the bottom of the main disconnect and all was fine. I connected the jumper, turned it over and it fired up no problem?????????????? I pulled the plug on the Cam Sensor and it ran for about 5 minutes and shut down. I did that to see if the LED would show a code but it didn't. Fired it back up and pulled the TPS and it changed the way it was running. reconnected that and pulled the MAP sensor and it ran very rough and died. No LED on that one either. I pulled the Crank Position Sensor and it too ran for about 5 minutes and shut down but no LED light code either. Pulled the O2 snsor plug and no light on that either. I don't know if this would trigger the LED code light but I was just throwing mud at the wall to see what would stick. Any Ideas what may be shutting the car down randomly like this and then not allowing it to start back up????

Thank You Ahead Of Time...

[BWC54]

Are you sure your LED light is working? I recently started my car with the O2 sensor unplugged and had code of 7 flashes on my LED. If you disconnected your O2 sensor and had nothing on the LED I would question whether the LED is working.

[David Clubine]

I had a customer car with the same sort of problem, wasted a weekend and a test day. It turned out there was a broken wire at the main connector of the Chassis harness. When the car did start, we started wiggling wires everywhere until it shut off. Not very scientific but it found it.

[BeerBudgetRacing]

I had a customer car with the same sort of problem, wasted a weekend and a test day. It turned out there was a broken wire at the main connector of the Chassis harness. When the car did start, we started wiggling wires everywhere until it shut off. Not very scientific but it found it.

In his description the first thing that came to my mind was that he was IN the car every time it happened.
Sitting/leaning on either a break or a grounding ?

[azjc]

Do you have access or know anyone with an old school automotive oscilloscope? You could watch the pattern all electronic devises one at a time and see what drops out as the engine dies (if you can get it to happen while testing) or gives no signal when cranking test everything until find the failed component. I the 'olden' days we would use a duel trace scope so you could watch fuel pulses and ignition at the same and see which side was failing as a starting point.

If you don't have access I may be able to help - I still have a Snap-On digital scope. It's somewhat packed away as we are renting while our new house is being built - I'm currently in the San Tan Valley area.

My first two guesses would be a component with a thermal failure or a bad connection,

[hotarizona]

Are you sure your LED light is working? I recently started my car with the O2 sensor unplugged and had code of 7 flashes on my LED. If you disconnected your O2 sensor and had nothing on the LED I would question whether the LED is working.

i am going to check out the LED tomorrow to see if it actually works. I think it is a 5 volt power source that illuminates that LED so I will just stack 3 small AA's and see if it will light. If that doesn't work I'll try to switch the polarity and see if that works. Strange that I can disconnect all those connectors and not get a trouble code light reading.

[hotarizona]

In his description the first thing that came to my mind was that he was IN the car every time it happened.
Sitting/leaning on either a break or a grounding ?

I could see if the car quit running when I was on the track but the first time I was on the grid and had to shut it down and then it wouldn't restart. The second time I had just ran a hard session and it ran strong without a miss but the car was idling through the paddock and then just shut down. There is nothing that I lean against or any harnesses that I am applying pressure to while I am sitting in the car. All the wiring is supported and does not run under any areas where I sit. I am going to check the Master Kill Switch and also the Z wires on the master kill switch that supply power to the coils. I will try the wire wiggle technique to see if that may trigger something. Thanks Again To All For The Idea's...

[Garey Guzman]

I had a customer car with the same sort of problem, wasted a weekend and a test day. It turned out there was a broken wire at the main connector of the Chassis harness. When the car did start, we started wiggling wires everywhere until it shut off. Not very scientific but it found it.

The "wiggle test" is the first thing suggested at Dealers to look for intermittent electrical issues.

[E1pix]

No idea what motor we’re talking about, so will assume it’s a Wasserboxer.

If there’s an idle stabilizer gone rogue, it will act like you’re turning the ignition off but any indicator lights will still work.

If the main battery cable on the starter has a cracked eyelet or otherwise-bad connection, it will act the same but no lights will work.

If not a Wasserboxer, Tisk, Tisk, it should be.

[DaveW]

It's in the "Honda Fit Conversions" section, so I'd assume it's a Honda Fit with all the related electronics.

[E1pix]

Ah. That could make a difference.

Edit: OP, not trying to make light of your issue, just throwing out common parts that may be your culprit. Good Luck.

[Pi_guy]

I had a customer car with the same sort of problem, wasted a weekend and a test day. It turned out there was a broken wire at the main connector of the Chassis harness. When the car did start, we started wiggling wires everywhere until it shut off. Not very scientific but it found it.

Paid about 2k for a harness tester. Written in the manual when the harness is all connected perform the shake wire test.....

[mikey]

Fuel filter or pump issue?

[problemchild]

30% chance it is the 2 little wires that connect to the master switch. Redo the connectors on the ends of those wires.

30% chance it is the main connector between the chassis harness and engine harness, which will show conductivity each way when disconnected but not through when connected. I don't recall which pin, but likely the one bringing 12V to the coils.

For either of the above, measure voltage at your coil connectors. You should have 12V at the coil connectors. If you only have about 2 or 3 volts, then it is backfeeding, and one of the two items above is the problem. As a temporary test/solution, run a wire with 12v and splice into one of the coil connectors, ideally supplied from a source that is switched by the Master. I have run multiple events with this patch job, until a more permanent solution was found. One solution is to get it working, then put a splint around it (the big connector) and then secure it to the chassis in such away that it won't move. I have had cars running that way for years.

20% chance it is your fuel pump connector. It was a hack job and then epoxied together, so you cannot really test it. Cut off the original connector and install your own (or wire direct).

20% chance it being something else. Good luck!

Don't shoot the messenger. If you don't like my advice, don't follow it. I have worked on a dozen of theses cars, and found these issues are common. and these patch jobs, no matter how hack they sound, to be effective. Cheers!

[problemchild]

If you have a FF with Honda, and have not yet had these issues, perhaps copy my post above and keep it with your car info you take to the track. Many of our current race cars now have electronics and harnesses that are a decade old or more, and problems like this are common across the board. Fortunately, the HPD issues seem to be several specific issues, unlike the Zetec F2000 harnesses, for example, which appear completely random. Racers with electronics need to learn how to troubleshoot and fix issues, the same way that previous generations had to deal with carburetor floats, coils, and Lucas starter, etc. There is a reason that most Formula Fords now have Japanese starters and pertronix ignition modules. Once you fix a specific issue, you may run for several years before you find your next one. As I stated above, the little wires to the Master switch and fuel pump are difficult to find because the heat shrink masks damaged wires. I would advise racers to just cut off those specific connectors, and redo, BEFORE they let you down.

[Rick Kirchner]

This is a little nerdy from a EE perspective, but connector issues like this are why the US Government designed the Deutsch/Cannon MS38999 series of connectors back during the cold war.

If you were to take the water/dust seal layer out of an MS connector you'd see the pins are a tad loose in the hole - they float. This is because when you have a large number of conductors eventually non-floating or semi-floating pins will have a "bullseye" - essentially a pin where the male goes into the female perfectly and has no contact. If the pins are tin plated instead of gold plated even worse, because the corrosion on the pins will lead to a high-resistance contact and the lack of wiping during mate/unmate will not scrape the corrosion off. MS connectors can have more than a hundred pins.

The mil-spec pins also have a spring mechanism inside the female that will cause the male to make contact.

The dust/weather seal then provides enough support do that all of those pins actually will get started. without that you would have pins "scoop" - that is miss each other enough that when mating it causes the male pin to bend over 90 deg and often times short to adjacent pins.

All of these features cause high mating forces which is why there is a circular cam ring to pull it all together and push them apart.

Unfortunately these connectors are expensive, have long delivery times, and require VERY expensive pin specific crimping tools. You are often forced to use one too big for the job, multiple smaller connectors, or wait 12-18 months for a specific version to be produced, and then you better buy all the spares you are going to need, as there are literally thousands of variants.

The various commercial automotive connectors offered by the same vendors do a decent job at a reasonable price, but I'm sure are better suited for automated manufacture. Physics is physics though, the more pins in the connector the harder it is to get a commercial one to work well over time, especially when hand assembled. Most of the harnesses on weapon systems are hand assembled and the MS stuff was designed for that.

Probably the best thing to do is replace the commercial stuff every 10 years or so, but you have to design the harness with enough service loop to allow for that.

If you could find a big bag of say, 30 pin 14AWG MS connectors with a crimping tool on Fleabay you'd be golden and could build reliable stuff for 30 years off of that.

[E1pix]

Great post, Rick.

Curious... when pins develop “slop,” is dielectric grease a reasonable solution?

[azjc]

Great post, Rick.

Curious... when pins develop “slop,” is dielectric grease a reasonable solution?

Dielectric grease is non conductive, use only external to keep moisture and dirt out. If used on connection you will have an open circuit.