2005 swapped 3rd gen modules into 2nd gen and now misfire...

I have a 2005 Prius with about 260K miles on the car. I had planned to get a Highlander Hybrid soon, yet decided to swap in the 3rd Gen battery pack I got on the cheap. It was balanced with a Prolong Hybrid Charger and cycled through with the intelligent discharger. I checked each module after the balancing, they were all within .01 of each other and at least 7.93V.

I swapped all the modules (boy is that job fun on the 2nd Gen battery chassis, that thing sucks compared to the 3rd Gen!) over, put everything in, made sure that everything was unplugged yet decided to clear the ECU using a bluetooth OBDII device (recommended by Dr. Prius app). Went on a short drive around town, everything seemed to be working great. Stop and go, battery power levels were sustained and working superb. I did this drive for just about over a half hour.

When I got back home, I stopped the car and turned it off. I then turned it back on and then the engine started shaking really bad. In hybrid mode, no shaking. Figured its a misfire.

Ran Torque Pro, first got a P0302, Cylinder 2 Misfire. I'm like ok, let's do the coil pack dance. I cleared the faults and I swapped 2 to 1 and vice versa.

Then I got the first image:

I'm like wth, ok maybe that coil pack is bad since its starting off with #1. Swapped 1 now to 3 and vice versa.


I get a pending P0301 flash, not even a sustained error code until I drove it around for about 10 minutes. Hesitation is always there when trying to hit the gas. P0301 now shows as a sustained code but only after driving around. Didn't look at plugs yet, it was too dark out and I wanted time to dig out all 4.

I just thought it was weird in proximity to the hybrid battery swap, but alas, I drove it around for about half an hour without hitch.

I felt like driving her into a wall, I was so tired after having the lovely 30-40 mph winds we were having today.

 

Thanks for the reply.

Been reading around, and it did rain a bit last night. I was wondering if coincidentally while I was driving around I managed to slosh some rain into the ignition system.

I did check the oil level, and its fine (right on the line actually).

I read about this online, and mine is a 2005, so gonna check this out tomorrow.

https://lusciousgarage.com/blog/2004_2005_prius_misfire_condition/

 

That sounds like it too. I did throw in some Seafoam into the gas tank.

Did you get the flashing cylinder misfire code?

 

Well folks, I was lucky enough to have my cousin swing by who drives a 2005 Scion xB. As some of you may know, a lot of the engine parts are the same on those 1NZ-FE engines. We were able to identify the temperamental/bad coil pack by cycling all four from my engine on his #1 cylinder.

The code it through was weird, it said something about the circuit not being completed. Vice versa, took his #1 coil with the tested good three, and Prius runs like a champ again. If digging for donors, look for junked xB, xA, Echo, Yaris, in addition to Prius 2nd Gens. The coil packs are the same for those cars.

Oh, and just FYI, took out the spark plugs and the ceramic sleeve surrounding the electrode chipped off a bit on Cylinder #1. For Cylinders 2-4, its showing signs of burning through, so thinking this is where Cylinder #1 went (I hope). I knew this spark plug ran hot, but didn't know it ran THAT hot. It was on the recommended plugs list for the Prius too. Read on the forum and elsewhere and this seems to be a pretty common occurrence, not sure why spending bank on iridium if they don't last for jacksquat.

Swapped in some NGK coppers. They wont last as long, but I really didn't like what was happening with the Densos. Terrified me that the ceramic pieces scored up my engine cylinder. I'd like the POS to last just a little bit longer...

 

Thanks. The plugs are supposedly Denso IK16TTs.

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I read a bit about them on the forum here, said they ran a bit hotter than the standard long-life plug, but improved gas mileage (which was my end goal). Coincidentally, it didn't make a dent on my mpg numbers, yet I figured it was because the hybrid battery was getting tired during summer (which it was, found two modules out of balance and lower voltage than the rest). Turns out the pack was another rebuild from unknown rebuilder (has a mix of modules from two different packs).

I agree with you that the plugs might be counterfeits. I emailed Denso and the eBay seller I bought them from, kinda ticked off because I just bought the set late July 2020. Since it was during the shutdown due to COVID, I've driven like maybe 1K miles total. For them to fall apart like this means its complete shite. Gonna torch Denso or the eBay seller either way.

 

Agreed, I looked over the Denso guide for counterfeit and these things are 100% bogus. Seller hasn't replied so far.

 

Threw in a used coil harvested from a junkyard xB and the car is in perfect operating order again. Guess at nearly 275K miles those ignition packs are really, really tired and that a newly juiced hybrid battery pack really gave it a wake-up zap.

Still at war with the eBay seller, had the audacity to try and offer 1/2 off purchase price. I escalated to PayPal.