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Strange start and then die problem

Hi everyone,

This is a 2010 Honda Odyssey 65K.

It has been running well until now. After not using it for many days because of the covid-19, I tried to start it. It cranked, started, and died after a few seconds, and the battery icon lighted up at the dashboard. When starting, the RPM did go up. Here is the video link: 2010 Honda Odyssey start and die

I have tried the followings:

  1. Put in a new battery. No change.
  2. Replaced the ignition switch. No change.
  3. Cleaned the Mass Air Flow sensor which looks OK to me but I had no experience. No change.
  4. Replaced the fuel pump relay. No change.
  5. Cleaned the throttle body valve. Still start and die. However, before cleaning, when I started the car, the RPM will go up and then down. But after cleaning, when I tried to start, I did observe that the RPM sometimes go up and down and go up again and then die, and sometimes RPM won’t have the second “up”. Not 100% sure though if it does the second up ever before I cleaned the throttle body.

The battery measured 12.4 v when off and 14.5 v when starting.

I also tried to press the gas when starting, the RPM will shoot up but it will still die after a few seconds. Here is the video where I tried twice to start the car. The first time at 0 to 0:14, you can see the RPM has the second “up”, and the second time (0:16-0:24), I simultaneously pressed down the gas paddle and the RPM shoot up and then come down.
Tried to start the car after cleaning the throttle body and pressing down the gas paddle

I don’t know what to do next. Please advise. Thank you all!

You posted a lot of things you’ve changed but not how you determined they needed changing. If you just guessed that was the problem, you’ve likely spent a lot of money to replace perfectly good parts. That money could have been used to buy diagnostic tools or pay a mechanic to diagnose the actual problem.

Here’s where I would have started in the first place and where I’d start now as well.

Scan the OBD2 port for error codes, yes, I see no check engine light on but start there anyway. The OBD device should read real-time data so I’d look at oil pressure - either a real reading or an OK, not OK switch and fuel pressure. to start. The engine may have a fail-safe that if no oil pressure is seen, the engine won’t stay running. The fuel pressure should also drop if that is the case. I’d also look at the commanded throttle coming from the ECU.

Do that and report back. Or find a good independent auto repair shop that can fix the van.

It seems to me there is a problem with the fuel when the engine is trying to idle. Did you try holding the throttle down about one third of the way to see if the engine would keep running? If the engine will keep running when you keep the throttle pressed down then see if there is a cold start valve. You may need to inspect it and clean it.

Thank you Mustangman,

I did scan for error code. But got nothing. Speficially, I added “Fuel Pressure” display but it said “no data” (I don’t understand why.) I have recorded the app screen here: ODB Torque(Lite) screen recording when try to start

There was a pending code P050a.

Thank you Cougar. I have just tried holding the throttle down about 1/3 per your suggestion. Nothing changed. Still started and then died.

The pending code P050A indicates a cold start idle air control system performance issue.

Since the engine doesn’t have an IAC valve, and you’ve cleaned the electronic throttle body, the problem might be with engine coolant temp sensor for the computer.

Tester

You don’t get a fuel pressure reading because there isn’t one. Some engines have them many do not… so No Data.

I’d check to make sure the throttle body actually moves when you press the pedal and make sure there are no cracks or tears in the intake tube between the MAF and throttle body. If nothing shows, then I’d agree with Tester that the coolant temp sensor may be bad. That you should have access to in Torque. See if its reading makes any sense.

The fuel pump might be turning off. Check a circuit diagram: on some cars if the oil pressure sensor does not detect oil pressure, the circuit to the fuel pump is interrupted.

Something seems to be shutting down either the fuel system or the ignition system for whatever reason. Perhaps the security system is getting activated somehow. If there is an oil pressure shutdown circuit that should be checked also, like @Mustangman suggested .

Thank you Tester. I have just read the coolant temperature with the scanner. It reads 6C which was about right as the current ambient temperature is 38F. The reading did not change as I tried to start.

I cleaned the throttle body with the throttle body cleaner spray and paper tower by hand. I didn’t take out the throttle body to clean though.

Any further advice is greatly appreciated. Thank you very much.

Hi Mustangman,

Thank you for your advice. How would I check if the throttle body actually moves? There is no visible crack or tears in the intake tube. I just used Torque to read the coolant temp and it showed 6C (about right with the current outdoor temp).

Any further advice is greatly appreciated. Thank you guys so much.

Hi shanonia,

Thank you for your advice. Could you be a little specific on how I should check if the fuel pump is turned off? I am new to diagnose by myself. Your help is greatly appreciated!

Hi Cougar,

Thank you for your advice. Could you be a little specific on how I should check if the security system is activated? I am new to diagnose by myself. Your help is greatly appreciated!

Thank you to all your guys!

I’m no pro, but I would analyze the circuit diagram and see where I could run a wire from the battery to the fuel pump, so the pump runs whenever that connection is made.

Pull off the intake hose and watch while a buddy start turns the key on and works te gas pedal. Or video it with your phone while you do it alone.

I think the key symbol in the dash indicates the condition of the security system. Check your owners manual. Check to see if there is an oil pressure shut down circuit also. What ever is causing the issue it seems to me it is shutting down the engine operation.

As Mustangman suggested, I disconnect the MAF sensor and pulled off the intake hose and start and press on the gas pedal. The engine keeps running even after I were not pressing down the gas.

As soon as I reconnected MAF and the intake hose, the “start and then die” happened again.

Even if I opened the engine air filter box (just in case something there blocking the air; and I had replaced the engine air filter), the “start and then die” problem is there.

So it looks like something wrong with the MAF sensor?

I can get reading on the scanner for MAF. MAF would start with about 0.3g/s to max ~12-14g/s and then dropped quickly back towards 0.

AFR(measured) would become 10.14 when starting and then become 29.40 when it dies.

I did use a MAF cleaner to spray the sensor before starting to post here (although I don’t know if my cleaning is good).

Thanks you all. Any suggestion for what I should do next is greatly appreciated.

Yes, it looks like some air side issue is shutting down the engine operation, because as I pulled off the throttle body intake hose, the engine can keep running (see my replies above).