2008 tc
51,200 miles
Dezod S1, AEM FIC, 8psi, 850cc, catted dp, since 42,500 miles
Mobile1 synthetic 10-30

This just happened to me on the way to work this morning:

I was driving fine on the highway going ~70-75, downshifted to fourth for a quick lane change when my car bogged and started pegging 10.0 AFRs. Oil pressure and boost/vac numbers seemed ok, but it was hard to tell when she was driving like this. I put it in neutral as I was cruising down the highway to see the idle AFRs, and then it died (still going about 50-60). Started her back up, and no matter what RPM or which gear I was in, I simply could not stop running rich 10s. I did not get any CELs while this was happening. Luckily, I was near my office and able to get it there and park it pretty quick. It seems I dumped a ton of fuel as I lost nearly a quarter of a tank in less than a couple of miles. Looking under the hood, nothing seems out of place; no gas leakages, vac lines connected, IC piping connected, etc.

I disconnected the battery for a few minutes to clear the ECU, reconnected and started her back up, and at first it ran the normal warmup AFRs (starting lean then dialing back down to settle in the low 14s, high 13s), but it went straight back down to running way too rich and and pegging 10s. WTF?

My first thought is fouled spark plugs, but that's just a hunch. Thoughts or suggestions? Thanks!

P.S. Yes I've searched, but we all know the SL search function is broken. I had better luck finding relevant info by googling "scionlife" and my search terms, but I still didn't find anything that seemed applicable.

 

make sure the vacume line didnt pop off the FIC. also check in the FIC that it is reading vacume and boost correctly.

 

what do your fuel trims look like?

 

@scioncrew - I checked all the vac lines, including the FIC port and all are tight. I haven't logged into the FIC yet because I'm at work, but I'm not sure if I can keep it idling long enough to get a read.

@batman - fuel trims are good. zeroed them out with the battery disconnect, but even after normal driving my map hangs around +-3 for STFTs and +- 7 for LTFTs.

 

That's what your fuel trims are and your stuck at 10.0 afr??

There might be something up with your primary O2

Call Dezod and tell them this info

 

No, sorry, I mean my fuel trims under normal driving conditions. I haven't logged anything from today since it happened on the way to work.

 

I'm also getting opinions that it may be a boost leak somewhere after the MAF. Like I said earlier, it all looks good at first glance but I will need to get under it to get a better look. But if it were a boost leak, shouldn't I be able to idle somewhat normally?

 

its ok. you can check with the car off. im thinking maybe the FIC map sensor may have gone bad on you. when you have time log in tho the FIC. bring up the dash gauges. look at your map sensor gauge it should be reading around 14-15 psia with the car off.

 

Charge pipe blew off or something like that. Check all connections and report back.

 

Just got back from taking another quick look, and Paul hit it on the head. The first charge pipe from the turbo to hotside of the IC blew off. It's hard to see unless you give it a good shake.

I want to thank the SL community for being so responsive at random times. Y'all helped me go boost, and now y'all help me fix it. Great stuff!

 

Glad I could help.

 

good to hear it was an easy fix!

I would have thought that if a charge pipe blew off it would go super lean under vacuum because air would be entering the throttle body completely unmetered...

 

Was gonna say this, it happened to me twice and scared the sh*t out of me lol

 

On pull through MAF setups, this is what occurs. This is due to the fact that leak occurs AFTER the MAF and that air was already metered. So now that air is expected to make passage into the plenum, however it has escaped, but the fuel and spark delivery had already occurred and delivered to that combustion cycle. Too much fuel and a loss of metered air = a dead rich scenario.

 

but wouldnt a leak actually pull air in when the car is in vacuum?

 

it wont have enough suction to pull it through the IC and the rest of the piping before the throttle body...

i had the same thing happen to me after doing some work on the turbo (same pipe blew out of the coupler)

 

Correct. Even if it did, it's after the MAF. The MAF is still reading air metering because the turbo is still pulling air in, however that meter air is never reaching the plenum.

 

ahh now I understand, thanks!