Fit diagnostic help

[lucky13]

Car ran this morning. Car will no longer fire. Have gone through checking connections, grounds, etc.. No LED alarm codes but I tried disconnecting different sensors that should cause an alarm with the master on (air temp sensor, water temp sensor, etc.) and I do not get an alarm. The alarm light does blink briefly once when master is first turned on. Opinions?

[Roux]

On a very hot day, I had the original crank position sensor fail (probably as it cooled down.) Stopped on pit lane for tire check and car would not refire. Cranked, but no sign of life

My understanding is the cps is the only mandatory sensor for it to run. In that case I had no error flashing either. I carry a few spares and duct a bit of air to that area to help keep the thing cool and have never had another CPS fail

Fuel pressure completely at zero will also cause this. even with slight pressure it will run at idle

good luck

Steve

[lucky13]

Thanks, Steve. I will give that a shot.

[lucky13]

On a very hot day, I had the original crank position sensor fail (probably as it cooled down.) Stopped on pit lane for tire check and car would not refire. Cranked, but no sign of life

My understanding is the cps is the only mandatory sensor for it to run. In that case I had no error flashing either. I carry a few spares and duct a bit of air to that area to help keep the thing cool and have never had another CPS fail

Fuel pressure completely at zero will also cause this. even with slight pressure it will run at idle

good luck

Steve

Thanks for trying but I changed the crank sensor and it still won’t fire.

[Will Velkoff]

Matt,

I took a quick look through the HPD electrical system manual, and it says when cranking to start the engine, at least 250 RPM needs to be achieved before the crank and cam sensors will synch for the engine to start.

So based on that it sounds like it needs crank and cam sensor feedback plus 250 RPM minimum to start up. Maybe the cam sensor could be the culprit.

Have to checked the basics - fuel and spark? Do you have a data system to monitor the channels that come from the ECU to make sure any other sensors aren't wacky?

[Jon Jeffords]

[QUOTE=Will Velkoff;591675]Have to checked the basics - air and spark?[/QUOTE

Will, you no doubt meant to say fuel and spark. I agree; that's where I would begin the trouble shooting efforts.

[Will Velkoff]

[QUOTE=Jon Jeffords;591676]

Have to checked the basics - air and spark?[/QUOTE

Will, you no doubt meant to say fuel and spark. I agree; that's where I would begin the trouble shooting efforts.

Yes, good catch - I hadn't finished my morning coffee yet!

[lucky13]

Matt,

I took a quick look through the HPD electrical system manual, and it says when cranking to start the engine, at least 250 RPM needs to be achieved before the crank and cam sensors will synch for the engine to start.

So based on that it sounds like it needs crank and cam sensor feedback plus 250 RPM minimum to start up. Maybe the cam sensor could be the culprit.

Have to checked P.M. the basics - fuel and spark? Do you have a data system to monitor the channels that come from the ECU to make sure any other sensors aren't wacky?

Hey Will,
I have 250rpm and I replaced the crank sensor, cam sensor, coil packs, plugs, ECU, harness, etc.. Nothing. I have 50psi fuel pressure when cranking. Plugs are damp and smell of fuel so I have fuel but no spark.

If I disconnect the air temp sensor, water temp sensor, or others listed on the sheet in the manual, I should get an alarm when I turn on the ignition. I don’t. It is as though I am getting no information from the engine sensors to the ECU...the ECU doesn’t even know that I am trying to start the engine, right? I confirmed that the grounds from the harness are good and have disconnected and reconnected the harness a million times...maybe there is an issue with the harness between the engine connection and the ECU?

[Jon Jeffords]

...the ECU doesn’t even know that I am trying to start the engine, right?

If the fuel injectors are truly pulsing, then the ECU is Indeed trying to start the engine. I myself would want more evidence than a sniff test. Pull one of the spark plug wires off a plug (leaving that plug installed), and connect that wire into a spare spark plug. Ground the threads of the spare spark plug against the aluminum cylinder head, and have a partner crank over the engine while you check for a healthy spark with the shop lights off. If you are seeing spark, then the ECU is satisfied with enough of the sensors to meet the starting criteria.

[lucky13]

If the fuel injectors are truly pulsing, then the ECU is Indeed trying to start the engine. I myself would want more evidence than a sniff test. Pull one of the spark plug wires off a plug (leaving that plug installed), and connect that wire into a spare spark plug. Ground the threads of the spare spark plug against the aluminum cylinder head, and have a partner crank over the engine while you check for a healthy spark with the shop lights off. If you are seeing spark, then the ECU is satisfied with enough of the sensors to meet the starting criteria.

Good point. I get 50psi fuel pressure so that’s not the issue.

[problemchild]

Matt, At this point. I would be checking that you have 12volts at the injector connectors, That system brings 12V to each injector all the time, and controls the ground to each connector to fire. Often, you get a value around 3 volts instead of 12, which confirms you do not have the proper voltage but is backfeeding from another source. If you don't have 12 volts there, then check the master switch and the small wires on the master switch. Whenever I have had the "won't start" problem it has either been cooked engine or lack of voltage to the injectors. If it is the voltage supply, 50% of the time it is master switch or small wires on master switch. The rest of the time it is wiring harness/connector issues, usually around the 28-pin connector that connects the chassis harness to engine harness, Hook up your voltmeter then go around connecting, disconnecting, wiggling connectors and wiring to help ID the problem location.

I am no expert, but if this does not help, please email me directly, and I will offer any experience that I can.
greg13rice -at- hotmail.com

[lucky13]

Matt, At this point. I would be checking that you have 12volts at the injector connectors, That system brings 12V to each injector all the time, and controls the ground to each connector to fire. Often, you get a value around 3 volts instead of 12, which confirms you do not have the proper voltage but is backfeeding from another source. If you don't have 12 volts there, then check the master switch and the small wires on the master switch. Whenever I have had the "won't start" problem it has either been cooked engine or lack of voltage to the injectors. If it is the voltage supply, 50% of the time it is master switch or small wires on master switch. The rest of the time it is wiring harness/connector issues, usually around the 28-pin connector that connects the chassis harness to engine harness, Hook up your voltmeter then go around connecting, disconnecting, wiggling connectors and wiring to help ID the problem location.

I am no expert, but if this does not help, please email me directly, and I will offer any experience that I can.
greg13rice -at- hotmail.com

That’s a big help Greg. Not a direction I was headed and based on good experience. I won’t have the car back for a couple of weeks but first thing I will look at is voltage at the injectors. I did check wires at the master but a closer inspection will be second on the list. I will be in touch after doing these things for either way.

[Dave Harmison]

Pardon my jumping in here, I’m a Kent guy, but I also spent years talking to vehicles via CAN. Does the Fit harness and processor support CAN? I was amazed that I could look at all sorts of processor variables and inputs on my Fords with freeware called FORSCAN and a $30 cable.. If there’s something similar for the Fit, it would sure encourage me to swap from Kent to Fit.

[Jon Jeffords]

I believe the Honda ECU for the Formula F engine is a proprietary box; not used on production Honda vehicles. It does broadcast several critical engine parameters via CAN (engine RPM, coolant temp, oil pressure), which can be read by suitable data loggers like AIM. But there is no OBDII diagnostic port to plug into.

[lucky13]

I believe the Honda ECU for the Formula F engine is a proprietary box; not used on production Honda vehicles. It does broadcast several critical engine parameters via CAN (engine RPM, coolant temp, oil pressure), which can be read by suitable data loggers like AIM. But there is no OBDII diagnostic port to plug into.

That’s pretty accurate.

[alangbaker]

Pardon my jumping in here, I’m a Kent guy, but I also spent years talking to vehicles via CAN. Does the Fit harness and processor support CAN? I was amazed that I could look at all sorts of processor variables and inputs on my Fords with freeware called FORSCAN and a $30 cable.. If there’s something similar for the Fit, it would sure encourage me to swap from Kent to Fit.

I believe the Honda ECU for the Formula F engine is a proprietary box; not used on production Honda vehicles. It does broadcast several critical engine parameters via CAN (engine RPM, coolant temp, oil pressure), which can be read by suitable data loggers like AIM. But there is no OBDII diagnostic port to plug into.

That’s pretty accurate.

Specifically:

The HPD Formula F ECU adheres to the Bosch MS 4.3 Grand-Am CAN Spec. This link can be utilized with any compatible dash/steering wheel display. The following parameters are available:


Engine speed
Throttle position
Coolant temperature
Oil temperature (if optional sensor equipped)Intake air temperature
Intake manifold air pressure after throttle plateBattery voltage
Fuel pressure (if optional sensor equipped)Oil pressure (if optional sensor equipped)

[B Reid]

So it seems Greg Rice was on to something. I was able to check the voltage at the injectors and we have 2.55v where it should be what the battery voltage is. I have to work next few days which means travelling so will get on it this weekend. I'm hoping it is the connections at the master and not in the 28 pin connector or the harness.

Many thanks to Greg for his input.

[lucky13]

So it seems Greg Rice was on to something. I was able to check the voltage at the injectors and we have 2.55v where it should be what the battery voltage is. I have to work next few days which means travelling so will get on it this weekend. I'm hoping it is the connections at the master and not in the 28 pin connector or the harness.

Many thanks to Greg for his input.

Big thanks to Greg and everyone who offered help/opinions. Will post summary when solved so that others can learn from our mistakes.

[denny_renfrow]

I would assume this has been resolved. Will you share what you have learned? Many thanks.

[B Reid]

I would assume this has been resolved. Will you share what you have learned? Many thanks.

It basically came down to a faulty engine harness. We had two, an older one which had a wire break and we kept trying with the new harness we had. Turns out the new harness was bad from the beginning right from HPD. Which is still bad and trying to work with HPD on repair or replacement and getting no where.

[Messenger Racing]

Installing the new ECU soon for one of my cars. Would like to visit with anyone else that has gone through the process.

Two things I will be working through -

New ECU docs indicate new requirements to communicate with Aim products - sounds like there may be a download file required as well as setting up all new protocols.

The adapter harness for the new ECU includes a new wire labeled Battery Cutoff - I run a solonoid type of cutoff vs traditional key style - I am researching proper circuit layout.

Anyone?

Jay
806-946-7252

[HPDracing]

Installing the new ECU soon for one of my cars. Would like to visit with anyone else that has gone through the process.

Two things I will be working through -

New ECU docs indicate new requirements to communicate with Aim products - sounds like there may be a download file required as well as setting up all new protocals.

The adapter harness for the new ECU includes a new wire labeled Battery Cutoff - I run a solonoid type of cutoff vs traditional key style - I am researching proper circuit layout - I assume this is a circuit ground break.

Anyone?

Jay
806-946-7252

Hi Jay,

The ECU battery cutoff wire should be connected to a switched power supply (+).

The new AIM file can be obtained directly from HPD at this time. It will be posted on the AIM site soon as well.

[lucky13]

It basically came down to a faulty engine harness. We had two, an older one which had a wire break and we kept trying with the new harness we had. Turns out the new harness was bad from the beginning right from HPD. Which is still bad and trying to work with HPD on repair or replacement and getting no where.

Like Bob said, to make a long story short, the problem ended up being TWO bad engine harnesses. The harnesses resulted in two similar but different sets of clues that made for a long and drawn out process before finally referring back to the Sherlock Holmes quote: "When you have eliminated all which is impossible, then whatever remains, however improbable, must be the truth." Haha.