My Surging Car Has Finally Been Fixed...by Me!

[ravenhard]

Well since Ive had my custom tune done with the bulk of the mods done at he same time my car would surge. What I mean by surging is while cruising at 60-80 and I give it some WOT the car would jerk back and forwards and not be smooth at all.

Happened the first drive home from the tuners, went back to same tuner 3 more times to try and solve the issue. It didnt help he was 1 hr drive away. Each time he said it was fixed but the drive home said different. He did manage to increase power and give what looked like a smooth power curve on the dyno printout but never with AFR's or boost even though I asked

Next plan of action as suggested here was to replace:

-fuel filter

-tight all silicon hoses

-fuel pump

-valve springs

-spark plugs

-coils (all 6)

Took it to another tuner and got another dyno and finally got a dyno print out with boost showing its going up and down from 13-14-13psi continually. That tuner wanted me to get a custom tune with hom but I resisted. I decided to take of the boost solenoid and just run spring pressure for a while. Actuator is a 12lb but still got the surging ARRGHHH at this stage I want to roll the damn car into the river and claim insurance its that fustrating and time consuming.

that's the background and I'll try and keep it short as people have short attention spans and I congradulate anyone that has read it this far.

Anyways the fix for me was basically from what I can tell boost leak and it didnt come from any of the main silicon hoses that join the intercooler piping or intake from as far as I can tell. What I did was I scored a set of hi-flow series cold side piping(that gets rid of the X-Over) and the underbattery CAI from RAP1D last week and installed them myself. I took off my old performer series pipes and checked all the joiner and all seemed OK, but while I had complete access to my engine bay I redid all the other vacum hoses that attach things like the actuator to the boost solenoid and back and also all of the BOV hoses. I either got new hoses clamps or got new/bigger cable ties. There was actually 2 or 3 hoses that didnt even have clamps or ties on them. I suspect from when the actuator was change and also when someone previously had installed a boost activated intercoole spray.

I suspect it was boost leak as it wasnt able to hold the higher boost on WOT but correct me if Im worng as it defintely wasnt the tune. SO next time some says their car is surging suggest boost leak and make sure ALL hoses are redone not just the big intercooler joiners!

I got it on the dyno the other night and the power curve and the AFR's look horrible. You would have thought getting rid of the cross-over you would lean out a bit not get overfuel on the top end.

No increase in power according to the run from the other night but I can tell you there is a huge difference in seat of my pants feel. Going by other cars that have been on this dyno and other T's I have been in my car would definitely be over 300 if I went back to original dyno and if I really cared about numbers. I suspect the first dyno was reading a touch high plus it wasnt done in shootf6 more which would have made a difference. I wont go back to the first tuner to do a comparison as I wasnt happy with his original efforts

Original dyno run from months back

New dyno run...looks shocking hey? Not smooth power and AFR's that are crap top end.

[Henz]

My car's been doing a similar thing, and I havent had time to take it back to the tuner yet.

I'll be sure to check everything over this weekend.

Thanks for the info!