Somewhat rich LTFT after SRI+TIP install

[MarcoAntonio]

Hello,

Today I installed Sures SRI and TIP and the LTFT started to act up. I got a steady -(8-9)% LTFT on Idle, and the same on regular cruising. After some time driving around the ECU seems to learn the new deal and it's now down to negative 1,6-4%. Idles still at negative 8-9%.

This was unexpected since I thought the new airflow could cause a lean condition instead (more air compared to previously), or is this expected? From an economy point of view if it can normalize I guess that's a gain, just wondering if this might be caused by other issues.

Thanks guys!

[MarcoAntonio]

Update,

The fuel trims while driving seem to have normalized at more stable level at negative ~1-2% (started having LTFT -9 later improved as it learnt)

But the fuel trim on idle is in fact worse, I've reached negative LTFT of ~10-12%. Also having some white smoke coming out on idle (I don't see any issue while cruising, doesn't seem to worsen when I rev or drive normally).

Any tips what kind of issue this might be related to?

Could it be related to the SRI/TIP install? Probably not but maybe, I think of it I've had some white smoke but I thought it was related to the cold weather (~35 degrees F, or 2 degrees C).

Occasionally there will be a small move in the rev when it's idling, changing around 50 RPMs up and down suddenly (not alternating frequently). It's not as rough idle as the ones I see on youtube with vacuum leaks, but boost gague -> vacuums (according to Iphone) seems low at around negative 9-10 PSI (usually that figure would be negative 11-12?)

[Keko]

I don't think intakes generally affect the trims that much, but i suppose it could be the intake change and really cold weather? If your normal driving trims look good there probably isn't any leaks. Maybe someone else can help more, bump

[dale_gribble]

What tuning/map are you running on your car?

[MarcoAntonio]

I have no tuning on it, it's quite stock set up except the inlet and sri,

I did some datalogs just now to test the boost pressure for any leaks, I peaked boost just above 15 PSI (only momentarily before it dropped to 14->13->12)

I fear I might either have a vacuum leak or similar. On engine brake, or red light idle I still get negative LTFT between 9-12. The worst was at negative 12, but just now the STFT was at +3 (net ~9 again). Should I just be patient and hope ECU will learn proper trims or is this indication of something worse? I've read some thread about the turbo white smoke issues and seal failure etc (but man to catch on this 1 year old thread with 9+ pages will take time)

[dale_gribble]

What are you datalogging with? Do you have an accessport?

[Tommy]

Not sure if Cobb has a SURE intake map but I got much better ltft's with the Corksport map than I was getting with the Cobb map. Made sense to me since I have the Corksport intake.

[MarcoAntonio]

Still didn't invest in AP, I'll probably do this during spring when I get some excess cash
For the moment I do some logging (only a small number of available stuff) through OBDII BT connection to Iphone.

I was surprised about the negative LTFT, to be completely frank I just decided to test stuff after the install but maybe this issue existed before (I just hope being a noob fumbler installing I didn't wreck something else, like adjacant hose or similar).

Thanks for support, recon maybe it's just a MAP issue? Sure webpage said ECU can learn it without ecu mod, but didn't expect it'd have to relearn a rich condition why I'm suspecting perhaps another issue now (or I failed the install somewhere and should get the dealer have a look)

[dale_gribble]

The problem with LTFT's is when the computer can no longer compensate for LTFTs, which leads to a usual CEL (check engine light, something like idle lean). Since your car is still able to compensate for the change, you are fine, although the performance might not be as great as it would with a tune.

I would go through and double check all connections. I would then disconnect the battery and let it relearn one more time. Be sure the recirc hose is connected right, the boost controller solenoid vacuum hose is connected right, and the junction to the turbo is connected right.

I find it unlikely that an intake would cause a smoking turbo condition. This usually only happens when you removed backpressure on the turbo's hot side, i.e. test pipe/downpipe.

[mrQQ]

well, I have the same issue with highly negative trims, and so far I can't figure it out.

[MarcoAntonio]

I've been watching the trims today again, I thought perhaps the ECU was getting a succesful long term adjustment seing the LTFT at idle (and engine brake) go down a bit, it improved from negative 11 to negative 6, but when I got home and parked the car, and let it idle a little moment the issue seemed to get worse again , and LTFT would start to go down again (first with STFT later LTFT tagged along). Negative 11.

The white smoke is not as bad as the other day, but still there, lingering like some mystical mist. If it doesn't improve I'll go see the dealer end of this week see if they can diagnose it better than I can.

[Keko]

Did you recheck to make sure everything is tight?

[mrQQ]

the smoke you're seeing might just be cold weather condensation.

but you've got exact same symptoms as me, -10 LTFT, worse after warmup/spirited driving..

i cant wait to hear more from you.

[MarcoAntonio]

Originally Posted by mrQQ the smoke you're seeing might just be cold weather condensation. but you've got exact same symptoms as me, -10 LTFT, worse after warmup/spirited driving.. i cant wait to hear more from you.

Hey man,

I've been looking at my PSIs as well and my vacuum seems to be at ~-9 PSI on idle, I've read the normal value should be at ~11-12 negative, making me think I might have a vacuum leak of some sort.

Can you check the same? Also after getting warm what are your RPM levels at during idle? It seems my RPM gets very low (didn't gauge it yet but looks like 600-750 which seems little low as well).

Another thought from another forum regarding the smoke would be oil getting through (recommends higher density oil), could this cause a rich condition during idle? I'm in doubt, but possible a low vacuum (leak) is leading to worse handling of this oil which then shows as a smoking issue (no significant smoke when driving or I can't see it, possible the valves get better action than when on idle)

I talked to stealership, they wanted ~150 bucks to diagnose and hook up my car to a computer. I told them I won't pay for a diagnostics thing with ECU since I don't have any code errors (according to iphone app at least). I mailed them with symptoms and asked them a price for a vacuum leak test alone. This weekend I'll tear down my inlet + intake and reassemble it again to see if that will help. Cleaned MAF sensor didn't make difference.

[Tommy]

Torque read the same vac for me. AP read higher. Idle is the same for me too. Drive the car and stop worrying about it so much.

[Keko]

Just checked through this thread again. In post #5 you said the boost dropped to 12 psi? at wot? You probably have a leak

[MarcoAntonio]

Is it normal i would get strong stft idle (lean) increase when i pump on the brake while idling? Thoughy this might confirm if its a vacuum leak? Or is it completely normal? Whent for a few sec above 20 stft doing this on idle

[mrQQ]

uhm, what is strong stft idle lean increasse?

[rfinkle2]

Originally Posted by MarcoAntonio Is it normal i would get strong stft idle (lean) increase when i pump on the brake while idling? Thoughy this might confirm if its a vacuum leak? Or is it completely normal? Whent for a few sec above 20 stft doing this on idle

Pumping the brake while idling is unusual and the trims have not learned that behavior, so you'd expect the car to add some fuel because of the increased demand.

Where did your trims finally settle?

Related thread courtesy of ms3blackmica:

Understanding Fuel Trims & Using Them To Detect Leaks

[MarcoAntonio]

Originally Posted by mrQQ uhm, what is strong stft idle lean increasse?

It's equivalent to bad english, sorry I don't know why but I get sloppy writing english on the web (specially since many EU people tend to suck at it, it's kind of becoming it's own internet language, bad wenglish)


Well basically, I was monitoring my LTFT and STFT while idling (engine warmed up), and I got the idea to test the vacuum with the brake pedal. So I start pumping some air into the brake system and it has direct impact on my STFT... I go wtf? My LTFT is now at negative 12 and climbing with air intake temperature. WHen I burst and step on the brake pedal frequently (makeing it use some air to the hydraylics system I guess) will make my STFT show figures up to 20% positive (this effect diminishes When I stop hitting the brake down several times)

After a short moment my STFT is back to normal bur LTFT remains -12%, and if I start hitting that brake again my STFT is jumping to large positive values. Could be perfectly fine but to me it doesn't make sense (being a novice) why it would impact my fuel ratios.

[MarcoAntonio]

Originally Posted by Tommy Torque read the same vac for me. AP read higher. Idle is the same for me too. Drive the car and stop worrying about it so much.

Hey Tommy, I decided I will drop this issue now. LTFT during driving seems reasonable. Also after watching the intake air temp. the most probably cause I'd say is just simple weather conditions. It seems the more idle I'm sitting there, the higher the intake temperature which is just probably impacting the fuel trims. Explaining why the LTFT get worse the longer I sit there idling (temperatures in ingoing air is getting warmer, thus lower density air engine runs more rich?)