S5 Turbo, JSpec motor, USDM ECU

So a couple weeks ago my car started bucking...if I hold the throttle just enough to maintain a constant speed and not accelerate or decelerate, the car go into an epilepsy fit, until I either give it throttle or let off. Seems it has to be driven for a few minutes before it starts doing it, so warm condition.

So, I pull codes and I get #12 which is the TPS. So I order one, install, set 1 volt at idle engine warm. Reset memory and take for a drive and still bucking.

Pull codes again, and now I get #51, Fuel Pump Resistor Relay. So I have swapped out like 5 of these, and no change, still bucks, still same code. The only ones I have are non-turbo, but I don't think it matters, haven't checked into it though.

Anyone have any thoughts?

 

Code 51 is Fuel pump resistor relay.

 

yeah, couldn't remember what it was called, thanks

 

You could try bypassing that particular relay by disconnecting the plug and jumpering two Blue/Red wires to the two Blue/Green wires and take the car for a drive and observe for any improvement.

EDIT: Non turbos do not have these relays.

 

Ok, bypassed those two wires and have same results.

Are we talking about the same thing? All S5's have them, I am actually using the one that was in the vert when I did the Turbo swap. The part I am talking about is under the airbox just behind the headlight.

 

Sorry about the non turbo comment. Didn't realize all S5's were equipped with them. Try disconnecting the vacuum hose to the Boost sensor and plug the hose and take the car for a brief drive. Also check to see if the hose to the Boost sensor has the restrictor pill/orifice located within the hose.

 

Whoa, this is new to me. I replaced that hose with some vacuum tubing and I also have it tee'd off to my blow off valve.

I'll try it and see what happens.