I recently bought a used hybrid and when accelerating hard the engine will suddenly shut off. After coasting to the side of the road the engine(or system) will not restart until I key off for one minute. It does this at very specific conditions, accelerating hard(100% throttle) from stop to 100km/h. At about 95 to 105km/h it dies without fail. Unit has to be warmed up(doesn't do it when cold), and only when at 100% throttle, if I back out a bit at 90km/h its fine. No DTCs are set. Reading codes using a professional grade(but older), OTC Genisys scanner.

Recently bought the unit with a bad Aux pump module(had codes for it and wouldn't go into autostop). Replaced the module and now it goes into autostop and code is gone. If I can get this stalling thing figured out it will be a nice unit.

Any thoughts or similar experiences?

 

Not sure exactly what you have there (can you supply some details on your vehicle?) but my off the cuff "wild guess" would be you have a partially blocked fuel filter. Lets get a fuel pressure gauge on the fuel rail and check this right away.............

 

Thanks for the reply. The truck is actually a 2009 Chrysler Aspen. It uses the transmission and 2 mode hybrid system as GM. I've come looking for help here to reach more people. There were very few of the Chrysler Hybrids made so the forum for it is dead.

I think fuel pressure is good as it shuts off very suddenly vs sputtering and dieing. And always ar the spot in the acceleration right around 100km/h, just after up shifting to 4th gear.

 

Wow a 2009 Aspen. Looks like they only sold 33 of them in 2009 and sold 46 in 2008 making a grand total of 79 EVER sold, that is one a rare and very endangered species.
Should be able to read fuel pressure from the OBDII? If fuel pressure drops below minimum the ECU will cut the engine off (will feel just like the ignition switch has been shut off) no sputtering...................................Get that scan tool set up and lets run it up to where it cuts off and check it out? Only take a few minutes, get that Hemi in gear man VROOOOOOMMMM LOL.

 

I hooked the scanner back up and did a few more runs. I could not find anywhere in the data to view fuel pressure. Not sure if thats a limitation of the scanner or vehicle.

I did notice that it seems like the RPM spikes a bit before it cuts out. I wonder if the trans is slipping when shifting under heavy load and causing the RPMs to red line and then it shuts down. Still seems strange that it would shut down vs just limiting. I did try running it up in 2nd gear till it red lined, it just hit the limiter but did not shut down.

 

Have you checked on updating your scan tool? On a mechanically sound gas engine one or the other is your culprit either Fuel or Spark, In your case it seems more likely to be a fuel delivery issue under the conditions that you are testing. Go ahead and hook a manual pressure gauge to the fuel rail and check fuel pressure at idle and high rev while parked. Hybrid engine max rev in park should be 3000 rpm. I tried to attach a Hybrid OBDII test procedure but it did not want to cooperate (435 page file)

 

I did check on updating my scanner, $800+. And then I'm still stuck with an old scanner that is slow and has an interface that pisses me off. I've been considering getting a new scanner, something laptop based, possibly AutoEnginuity but not sure. Its $249 for the base kit and then $230 for the Chrysler OEM. I could use it on my truck as well but am still on the fence about it.

I did get the Hybrid OBDII pdf. Thanks! Looks like a lot of good info in there. Now if the **** thing would kick out a code I'd have something to go on.

I sometimes miss the days when cars were as simple as fuel and spark. However there are lots of things that could tell the ECU to shut down the engine resulting in shutting off the fuel or spark. I thought I had it figured out yesterday as I had a look at the APPS 1 and 2 signals and graphed them. I was surprised to APP2 intermittently dropping to 0 and then back. This could definitely cause an engine shut down. I swapped the pedal assembly with another non-hybrid Durango I have, same part number. But still stalls on hard acceleration and the replacement APPS also occasionally would show a drop to 0 and back.

I still am considering the fuel pressure. I wish they still put a test port on the rail like the older models. I'm half tempted to drill and tap a port for my gauge. I did rev it in neutral just to see what it would do and it did stop at about 3000rpm with out any missing or stalling. I've thought about just changing the fuel filter but it looks like its on top of the tank, right on the pump and has the regulator built into it.....

 

Happy New Year.
Strange that there are no codes if the engine is shutting down. I would probably stop by an auto parts store and see if they can pull any codes off that your scan tool might be missing?

 

I actually have a couple of cheaper scanners and none of those came up with anything either. I ended up ordering a new laptop based scanner from Autoenginuity. Wasnt cheap,$500. But it will work on the Dodge Diesel for checking injectors which I need to do soon. Might sell the OTC as well and maybe get a few bucks back out of that.

 

Got the new scanner and it did come up with a new code from the Hybrid module, p0730 gear ratio incorrect. Using the new software I plotted the RPM and it shows that the engine RPMs are flaring as it goes into 4th gear when under heavy load. I'm guessing that 4th gear is just starting to go out and only shows when shifting under heavy load. I'm guessing the hybrid computer sees the spike in RPM and is shutting down the system.

Its frustrating though that the system has to shut down, other wise I'd just back out of it when I feel it slipping, it would also make it much easier to diag.

So has anyone had their trans rebuilt? I've seen a few cases where the trans was replaced by a factory rebuilt unit. I've also looked around and can not find a rebuild kit anywhere online.