andy-gts

I have had some intermittant trouble with the gts stroker for about 4 months. ie dying at stop signs with ac on, having to pump the gas to not die at stop signs when trying to take off. then intermittant choking and spitting while cruising.

car sits for 3 weeks before I drive it much, 7000 miles on since the stroker came home and tuned to 4500 rpm (tps wasnt working quite right ) since sept 2011.

I had the tuner put in a remote fuel pressure gauge that reads on the link g4 extreme brain with peripheral read out. SEems to improve with a can of seafoam.

Fuel pressure , idle , idle increase with ac on ....all ok !!! finally plugged in the lap top to the link brain and.....


but the DAM O2 sensor is out....how could it run and only with those problems above with no o2 sensor....got me but dyno tuning to 7200 rpm now going on and numbers will be alittle better than 498 rwhp I think this time...we will see.

I am at work and will find out monday how the tune went

andy

rexpontius

Did you get 500rwhp by "just" stroking the engine? What's the size now? 6.5 ltrs?

Cheers

andy-gts

sorry I left out bunch of info,,,,,used to be in sig but got tired of it there. stroker with itb and cams and greg browns head workd and new brain etc. It just blows me away it didnt cough and spit and die much more than it did wiht the o2 sensor out. but I have read alot of posts and this is sonewhat in line wiht what others have found...thanks for sharktuner like products that can help diagnose easily.

I really thought the new "Link" brain was on the fritz or wierd ground issue etc.... anyway it was easily fixable...

thanks for viewing.

andy

Mrmerlin

Andy what did you do to fix this i have not a clue????
A few guesses though

andy-gts

the whole culprit was the dead o2 sensor!!! just seemed odd that I wouldnt have more trouble..

andy-gts

o2 sensor was dead. I was just awe struck that the problems werent any worse....

SeanR

Mine did this two weeks ago, same issues and symptoms. When I pulled my O2 it was caked with carbon, new one in and it was great.

Maleficio

I wonder if something besides age killed it?

andy-gts

yea, hmmmm, it was new 1 yr ago,....any way hope I can pick it up tomorrow

dr bob

Sean--

I'd be looking fast and hard for a cause for the oxy sensor caked with carbon. Especially a kompressor car, since any extra oil will hasten detonation issues, like sudden engine death. Checked spark plugs lately?

Mike Simard

I feel that the O2 sensor should only go along for logging and not be trusted with making real time adjustments on an engine like this.
Logs can be poured over after drives and fine adjustments made to the fuel table to cover the conditions it will see in real life. Then it will be well tuned and can be left alone.
An O2 sensor controlling mixture is fine for mass produced cars without individual tuning but a shame for a serious effort that's getting tuning time anyway.
That's my opinion anyway, I also really enjoy going over logs and fine tuning, it's the most enjoyable part of the project!

BTW, once I had an O2 sensor go bad during dyno pulls. After that I added a copper sheet in place of the washer to act as a heat sink. The idea is to not let it get too hot.

GregBBRD

The idea is to get the actual map as close as possible and then just let the O2 sensor do minor corrections.

I do like to leave the O2 sensor "active" and in control (closed loop.) This allows it to make minor changes in mixture, to compensate for changes in weather, engine temperature, altitude, etc. Of course, past a certain throttle position, the O2 sensor gets ignored and the tune is totally about what the map tells the injection to do.

Porsche runs all of their "Cup Car" and RSR's in closed loop, up to about 3/4 throttle. If it is good enough for them it is good enough for me.

Andy. I think your injection will be much happier when the TPS signal is better.

SeanR

I did, once I put in the new fuel pump my fueling was ultra rich. Used the ST and made it right.

andy-gts

Got the car back today....makes me almost weep I love this car so much . runs great ! never had such a nice build!!!! I wish everybody could have one....I could call it "Obamacar"" hehehehehe!!

andy

Herman K

Now you can do 3rd coast in 1/2 the time