Resetting the ECU makes TSi run much better??

[fourgsixthree33]

I have a 93 TSi AWD auto with 14b turbo and 3.5" turbo back exhaust. Still running on the 390CC injectors.

For the past couple of months, I have been resetting the ECU. The first time I reset it, it was a whole nother car. HUGE difference. I have been resetting it about once a week. Sometimes twice. The reason being it will start to lose power and run lower boost.

I am assuming it is because the octanetrim lowers if you get enough knock thus the ECU wont advance timing as much. I don't have DSMlink or anything so I have no control over any of this nor can I moderate it.

What can I do to keep the octanetrim up? What all could be causing knock?

 

[LiquidX]

Have you been popping any CELs and does your CEL even work? If your lower octane fuel is the issue, the ECU will pull timing to prevent damage.

 

[fourgsixthree33]

No CEL as of the last...month or so. I run 93 octane pump gas. Any way to prevent the ECU from lowering the octanetrim? Without screwing something else up? I really need a good tune. I am trying to save up for DSMlink but it will take some time.

 

[LiquidX]

Something is causing the pull, you need to figure out what it is other than trying to bypass it. 93 octane shouldn't be causing it to pull timing. What boost number are you running with the 14b?

 

[Bud92gsx]

I Know he runs under 12..I've been taking to him for a bit now..

 

[bomper04]

You can unplug the coolant temp sensor and have the car stay in open loop so you have the same fuel enrichment conditions as a cold startup, but your CEL might illuminate from disconnecting that.
Butttt, like stated earlier, there's an underlying cause to all of this.

 

[fourgsixthree33]

When I reset the ECU, I run between 11-13psi. When it gets sluggish after a week or 2, she is down to about 7psi.

What all should I check? Knock sensor? I just don't even know where to begin to look.

 

[brownfinger]

Fuel pump.

It runs like crap since the ecu pulled the timing and all your fuel trims are whack. It's seeing knock because it's running lean. Because the fuel pump is whack. The fuel trims are all whack because it's running lean for no other reason. Because the fuel pump is whack.

Get a new fuel pump, and put it in.

 

[fourgsixthree33]

Could it be from still having the 390cc injectors with the 14b turbo?

 

[90gsxjuice]

^ nope I've been running 18psi on my 14b with no issue but some times I run 94octane when I'm not too poor

 

[fourgsixthree33]

Yea but you probably have the 5 speed 450cc injectors as I still have the auto 390cc injectors.

 

[Bud92gsx]

I could be the fuel pump, but Iv'e never seen one act up before going..I have just seen them go without warning and leave you stranded..

 

[brownfinger]

I could be the fuel pump, but Iv'e never seen one act up before going..I have just seen them go without warning and leave you stranded..

I've dealt only with the opposite: Car keeps running worse and worse, even though I keep replacing everything; coil, plugs wires, plugs, sensors, TBs, etc... On my 93 GS (RIP), after replacing everything else, my fuel trims were all still maxed @ 140%. Even though the fuel pressure gauge read the right pressure, it wasn't delivering the required volume at those pressures. BTW, the car had 215K on it, w/ the original pump. Even the dealership (where it had been purchased, new) said they couldn't find anything wrong with it.

Same story with my 1990 GMC 1500: After a long decline in performance, and lots of dough on replacing stuff that wasn't broke, it stopped running. A new fuel pump had it running better than ever, even though I had replaced the truck by then, with an '01 F-250.

Ditto my '01 F-250: After several weeks of strange vapor-lock-like hot no-starts, it just died completely on me. One fuel pump later; like new.

Trust me. Buy a wally LP 190, and call it a day.

 

[Bud92gsx]

Wow thats very ineresting..I've never seen one act up like that before..That's very interesting.I've seen them just go but never act up..

Thanks for that informative post..That will go into the rolladex..

 

[Gs Dewd]

Have you pulled the ecu and checked the caps? Is it the original ecu to the car? A logger would go a long way here telling what the problem is by looking at the fuel trims. Also do you have a after market boost gauge or are you referring to the factory gauge for your boost readings?

 

[fourgsixthree33]

Brownfinger, I remember seeing several of your posts about the fuel pump issues you have had in the passed. Pretty interesting stuff. I heard I could get a walbro 190 for like $90 so I will look into that.

 

[Bud92gsx]

Yep the 190 is a stock aftermarket replacement, and does not require an afpr..

 

[fourgsixthree33]

Guess I will have to get one after my injectors and fix my tranny issue. $90 is definitely doable.

 

[Bud92gsx]

I would worry about the pump and the tranny issue first..Get it runing right then worry about other crap..And hey if you get the 190 and it doesn't help, at least you have an upgraded pump..

 

[fourgsixthree33]

Haha yea sure thing. Hopefully the new pump fixes it. It gets annoying.