My Prius will start run for 30 seconds then stall

Sounds like P3191. The car probably isn't running, it is just the HV system that spins the gas engine, giving up after 10-20 seconds of failure to detect ignition.

Things to check are the throttle body, esp. the plate which tends to get stuck shut, as well as the MAF sensor. It is the typical troubleshooting of no-start: spark, fuel, air. It really helps to know what the codes are as well.

 

Absolutely accurate. The car is not running, its trying to start. You need to be able to read the codes that are causing those lights to come on.

P3190/P3191 are very common on the gen 1.

Eric

 

IF: Any of this work has not been done? I would automatically change the air filter, clean the MAF sensor and air throat, change oil and filter and last but not least the AC filter. plus recharge the 12, Ascertain that it is GOOD. The last owner sounds incredibly LAX, hope you got a good deal.

 

Treat it like you've had it for sometime and are now taking it for full service.I suggest you change oil,change spark plugs,clean throttle plate,change ATF,check coolant levels (both engine and inverter),check if the inverter coolant pump is working,change oil and air filter.That's what I did after I bought my Prius...didn't want to take any chances.

 

Very Smart!

 

I hope you don't run down the HV battery by trying to start it too many times. That thing is not a simple matter to recharge.

 

I don't have a Prius yet (look and waiting for a seller to return my call) but I do have experience with ICEs in non-hybrids.

You should also run a couple of tanks of gas with a Techron based fuel system cleaner - Chevron's Techron (get the concentrated stuff) or Gumout Regane Complete (yellow bottle) - to clean stuff out (injector and the like).

Also, look at replacing the fuel filter as well. I know it's not talked about much any more but the Gen Is seem to have a normal filter filter at least according to RockAuto's picture.

 

Another reason why you would be wasting time trying to buy Prius parts from a place like that.

The Prius fuel filter is located within the fuel tank, so if you wish to replace the filter you will have to replace the fuel tank.

Regarding the OP's no-start problem, I hope he understands that the engine did not actually start; he is just seeing MG1 spin the engine for a while until the hybrid vehicle ECU gives up.

I suggest that the throttle body interior and throttle plate be cleaned using throttle body cleaner sprayed onto a cloth. The cloth is then used to scrub the interior and both sides of the throttle plate, after the air cleaner housing is removed for access. Do not drown the intake manifold in throttle body cleaner.

If that doesn't help, then remove and clean the MAF sensor using the correct MAF sensor cleaner. Replace the iridium spark plugs using the correct NGK or Denso plugs. Check fuel rail pressure which should be at least 43 psi. Replace the engine air filter if dirty and inspect the ducting to make sure there is no blockage.

If still no joy, then I suggest you have the car towed to your local Toyota dealer so the DTC can be read and a diagnosis provided.

 

There is one more possibility, although probably remote. I bought a Gen-1 with a bad HV battery one time. It would actually spin the engine, but it would never start. I spent days troubleshooting it. The spark plugs were firing, but the fuel injectors simply weren't delivering any fuel. eventually when I replaced the whole HV battery with a new one, it started up first time. I came to the conclusion that the voltage was so low on the HV battery that it would not spin the ICE up to the required RPM for the computer's satisfaction to actually start feeding it fuel. I don't have any specific numbers, but say for example the computer requires 1,200 RPM before it starts feeding it fuel, but the HV battery could only spin it at 1,000 RPM due to the low voltage.

 

It does not quite work like that, the HV Battery does not come into play until the 12V battery initiates the ECU which spins the MG and the ready light comes on. ( Just speaking off the top of my head ) So the critical Battery IS the 12V; as is the case in any other car.

 

If MG1 is trying to start ICE, system is already in [READY] mode and that means 12V battery must have enough power to supply to the ECUs and SMRs to get HV battery on line. Please don't blame everything on the Aux Battery.

I agree with adric22 that the HV battery may risk running down if many start attempts fail. Besides, the SOC should already be low since it has been sitting for a year. The OP should not continue trying to start the car, instead should try to get the DTC for the engine no start problem.

Vincent

 

Yes, but the original poster mentioned that the engine "runs" for 30 seconds and stops. But in reality the engine is probably just spinning as a result of MG1, which draws power from the HV battery. If this continues it will drain the HV battery, then the engine will no longer spin at all.

 

I think we lost the original poster.

Just to be clear, the 12V powers up the ECM, HV ECU, and Battery ECU. This process energizes the system main relay, connecting the inverter to the HV battery. Now the HV ECU can command MG1, powered by the inverter via the HV battery, to spin the engine, while the ECM runs injectors, timing, etc. The 12V is critical to make the car Ready, while the HV battery is critical to start the engine.

Adric, yours is an interesting story, thanks for sharing. Do you happen to remember what the voltage and or SOC was on the weak HV battery? It is something that I have always been curious about, the minimum SOC requirement.

 

Unfortunately, I had very little equipment back then. I had pulled out the main battery and it had 3 bad modules that were reading about 1 volt, so I know it was bringing the main voltage down quite a bit. I had tried to charge up each module one at a time with an R/C car charger. It would take nearly a whole day to do this. Once it was done, I could get about 10 start attempts out of the battery. With each attempt, I could tell the RPM was slower each time, until eventually it would no longer spin. Then I would pull the battery and spend another day charging it up. I knew the battery pack was bad when I bought it, but was trying to get the engine to start to rule out any other problems before spending the money on a new pack. After pulling out my hair, I finally bought a new battery pack and it started up first try and I drove that car as a daily driver for about a year before selling it.

I know I'm not the only one who has experienced this. TexomaEV also had the same issue on a Gen-1 he bought with a dead battery.

 

I always respect your opinion Vincent, but I always look at the 12V first. For remote troubleshooting it's not a bad place to start. Obviously the OP is considerably more knowledgable than most.reggers:

 

BTW, it may seem like 30 seconds, but more likely it is "running" for only 8-9 seconds...time it with a stopwatch, then smell the tailpipe...probably no smell of combustion...MG1 is turning the engine for 8-9 seconds trying to start it, then the process bails.

 

I just joined this site 4/11/18 for the same problem, a gen1 prius runs around 7 seconds. Let me clarify RUNS for 7 seconds. Then dies. & my girl gladys bought this car new in 2002. We dumped a lot of money in this prius. The money we spent fixing this 2003 prius in the last 5 years way way exceeds the fuel savings. The car is in plantation florida usa.

Thats it, im junking it. Fed up w this bs of finding info online & now here!

I guess prius owners don't have to work a job. Finding info on these cars is a full time job

Yeah im fed up w this allright

 

Your car is not starting, so you need to pull codes.

If you have P3101 and p3191, if so, a thorough cleaning of the throttle body and sop up any oil in the intake manifold should solve the problem (clear the codes after cleaning intake) and car should ready up. If you have other codes, post them here.