UCON EMS problems

First time ive really had a questions that i couldnt find an answer to, i bought and installed urd's ucon ems about a year ago. When i installed it i put a new timing set in and cam position sensors. I have no check engine lights but almost everytime i accelerate aggressively the truck bucks until i let of the gas. The crank sensors and everything else seems to working as they should just can figure out if this is a tuning issue or something else? Any advice is great.

 

Welcome to TacomaWorld

 

Welcome to TW!

 

That would likely be the Guardian kicking in. Mine would do the same when it would lose control of air fuel ratio on one bank. Basically in my case, it could not maintain commanded AFR on bank 2 and so it would kick in when it saw that it was running leaner than commanded.

I would start by making sure there are no intake, vacuum, or exhaust leaks. Also, do you have an AFR gauge, and are you supercharged, or what are the details on your setup? You may need to reach out to URD and have them get you a session with Scott, their remote tuner. Unfortunately, i have been down this road in the past. My advice to you is to start with the simple stuff. A good starting point would be to disconnect the battery for at least three minutes and see if it runs any better afterwards. Is your truck throwing any codes? I would get intermittent misfire codes and codes for the coil packs when mine would act up

If you're N/A i highly recommend removing the UCON and seeing if it does the same stuff on the stock tune. If you're Supercharged or boosted, I would highly recommend buying a spare ECU and trying a tune with HPTuners. My problem ended up being the circuit boards on the UCON were bad, and i spent months chasing it and throwing parts at it only to find it was the UCON that was bad from day one. If you have any questions, feel free to reach out

 

Check out this thread, lots of good info in here https://www.tacomaworld.com/threads/hp-tuners-for-2005-2015.600793/#post-20190631

 

Wow thanks for the replies everyone.
Im N/A but ive got intake and throttle body spacers on the truck but ive put new gaskets and torqued everything to spec. Ive only ever gotten one code for the coil packs and that seemed to just need to be plugged in a little better and the code when away. While on the joyful journey of installing the whole system and relatively unlearned in what i was doing, gadget told me if my timing marks didnt line up id have to retime the truck, so i did and later had my cam sensors went out, so the truck sat for several months before i tracked down the issue there. The air fuel ratio problem definitely sounds like its something that could cause this with the spacers being on there.

 

Since you're n/a the first thing i'd do is pull the UCON and see how it runs with the stock ECU. i bet it's a night and day difference. Whatever you do, try to knock out one variable at a time so you can isolate the problem

 

I doubt the spacers are causing an AFR issue. The UCON should be able to adapt to your mods. If the guardian is kicking in as you described, something is amiss

 

With the cam gears being installed, is it fine to run it without a tune and the ucon?

 

Yes, it's perfectly safe. You will make a little less power as the tune is not optimized, but it is 100% safe for troubleshooting purposes.

 

Basically you can run the stock ecu with or without cam gears, but you cannot run the UCON without cam gears because it has a more aggressive tune for them

 

Thats really helpful I'll give it shot and see what results i get.
If the bucking were to stop does this mean the ucon is bad or what route would take? Sorry for the noob questions ecus and stuff in that field are not my strong suit.

 

If it runs good on the stock ecu, all things would point to the UCON being the culprit. If this is the case, I would reach out to URD, let them know you isolated the problem to the UCON by swapping back to the stock ECU and that you'd like to have them replace the circuit boards in it.

 

Thanks for help, and the quick replies, i appreciate it.
Ill do that this week and see if i get this gremlin chased and eliminated.

 

Sure thing, keep us posted, im curious how it turns out

 

For sure.

 

I am currently dealing with a similar issue. I am having some very hard starts. All crank and no fire. Also it falls on its face driving as well. Originally I thought the fuel pump was going out being 240k miles on the truck, so changed it out for the URD kit. Nope. So I suspected the tune, but still been chasing other things. Now seeing this, I affirms that I am having a UCON issue. So I hope to unplug it ASAP and find a positive result.

 

Definitely the first place to start is to try and run it on the stock ecu and see what happens. I suspect it will run perfect. Likely faulty circuit boards in the UCon. That was the issue with mine

 

damn shame. When it works, it works real good. I’ll try and swap the plugs tonight without pulling everything.

 

That's how mine was ran good most of the time, but then it'd run dangerously lean on one bank only from time to time going WOT. Luckily, once i was able to isolate the problem and i made that clear to URD, they were very helpful and replaced the boards on mine free of charge. The replacement UCon works great. Did you buy yours new or used?