Should I be worried?

[bennypage]

Hi all.

Just two separate issues I was after advice on;

1. Ever since I had my car tuned and an OTR fitted I have noticed that when the car is cold it gives one backfire just as it cranks over and does its first rev on start up before settling at idle (or high idle because its cold). It never backfires at any other time. Sometimes both of the dual exhausts will have a backfire but often its just out of one. Should I be concerned?

2. Last Wednesday night I was coming to rest at a round about and the car was in drive and it just died. No coughing or spluttering. It just quietly stopped. I slipped it into neutral and started it up fine and drove off. It didn't do it on the way home and has never done it before. I have not driven it since as usually she only comes out on weekends.

Details
2010 SS Wagon (auto)
Orssom OTR
Walkinshaw (HM Perry) 2.5' cat back
Walkinshaw (HM Perry Outlaw) high flow cats
Walkinshaw (HM Perry) extractors
Tuned by Sonny at Moranos about 6 months ago.

Thanks
Benny

[dmacey]

who did the tune, cold start might need adjusting.
Deceleration fule cut might have kicked in when you approached the round about and killed all fuel.

[bladerunner]

definately a problem with the tune. backfiring and stalling is a worry. I"d be going back to see sonny pronto.

[bennypage]

definately a problem with the tune. backfiring and stalling is a worry. I"d be going back to see sonny pronto.

Just to clarify Blade, it only backfires at cold start and it stalled once. Can you elaborate on why I should be worried? I am inclined to often over think things with my car and worry about the most smallest of things so I am after a bit more info.

Thanks

[bennypage]

who did the tune, cold start might need adjusting.
Deceleration fule cut might have kicked in when you approached the round about and killed all fuel.

Sonny at Maranos, Croydon mate.

What does the deceleration fuel cut do? Cut fuel in an accident?

[dmacey]

Decel fuel cut is a mechanism that is designed to save fuel when not needed. Im thinking along the lines that your fuel was cut during decel but for one reason or another your engine was not ready for it so it died.

[bladerunner]

What dmacy said. it sounds like something is a miss with the fuel table side of the tune. It could be dumping too much fuel on cold start etc.. a backfiring exhaust can do damage to the cats, 02sensors even blow out a muffler if it's the sort of backfire that goes bang! and not just a bad miss. Hard to interpret what you mean by a backfire on a forum mate lol

[bennypage]

Yeah I get what you guys are saying. The backfire is like a loud pop, but no smoke comes out the back of the exhaust.

I just wondered whether some times the new cars that are controlled by computers do funny things. The other day I took off fast from the lights in drive and the change to second wasn't successful so the car kind of lost power and then it attempted again to go in and away it went. Never did it again and never did it before hand. I was worried about that as well but then nothing has happened since (for the last 5 weeks) so thought nothing of it.

I think I just worry a lot lol

[Luke V8]

Sounds to me like it's the tune...

Mine pops under heavy acceleration sometimes but that's just unburnt fuel caused through running slightly rich after installing a cold air induction without a tune.

The fact you are getting unburnt fuel after a tune makes me think they need to adjust it. Have you changed the fuel type since having the tune?

In regards to the cutting out, no idea- had the exact same thing happen in my BMW back home, only ever happened once and didn't happen again and didn't throw any codes .. Strange.

[bennypage]

Sounds to me like it's the tune...

Mine pops under heavy acceleration sometimes but that's just unburnt fuel caused through running slightly rich after installing a cold air induction without a tune.

The fact you are getting unburnt fuel after a tune makes me think they need to adjust it. Have you changed the fuel type since having the tune?

In regards to the cutting out, no idea- had the exact same thing happen in my BMW back home, only ever happened once and didn't happen again and didn't throw any codes .. Strange.

Thanks for the feedback Luke. I have sent an email to Sonny at Marranos to get his opinion as well. But it sounds like a look at the tune is in order.

[GKW]

Benny,

Two things.

1) I would lean to it being more a mech issue than the tune as I've never heard of anyone having an issue with a tune from Marranos but I could be wrong.

2) Sonny parted ways with Marranos late last year. So if you sent the email to Marranos, you'll probaly hear from Murat.

Best wishes for resolving the issue mate.

[bennypage]

Benny,

Two things.

1) I would lean to it being more a mech issue than the tune as I've never heard of anyone having an issue with a tune from Marranos but I could be wrong.

2) Sonny parted ways with Marranos late last year. So if you sent the email to Marranos, you'll probaly hear from Murat.

Best wishes for resolving the issue mate.

Hey GK. Thanks for the reply. Do you know where Sonny has gone? Do they still do performance work there? If so, is it any good without Sonny?

Typical, find someone I trust and they leave lol

[SilverVH]

Sonny is in the final stages of opening up his new workshop, Autowerks Automotive AutoWerks Automotive - service, repairs, prestige, performance, precision and should be good to go this week.

As for your issues it does sound tune related. Specifically the open loop o2 table and afterstart enrichment multiplier if there is a backfire on startup and in regards to it stalling when coming to a stop this could possibly be throttle body related, MAF related (if applicable) or o2 sensor related. The most common cause of this with the DBW setup is throttle body related. Try giving it a clean and see if it alleviates the issue. It doesn't sound tune related as it would've done it from the beginning after the tune. Also if you have a OBD2 scanner or have access to one, reset the TPS aswell. A sensor failing would most likely throw up a code (particularly one that causes an engine stall).

[bennypage]

Sonny is in the final stages of opening up his new workshop, Autowerks Automotive AutoWerks Automotive - service, repairs, prestige, performance, precision and should be good to go this week.

As for your issues it does sound tune related. Specifically the open loop o2 table and afterstart enrichment multiplier if there is a backfire on startup and in regards to it stalling when coming to a stop this could possibly be throttle body related, MAF related (if applicable) or o2 sensor related. The most common cause of this with the DBW setup is throttle body related. Try giving it a clean and see if it alleviates the issue. It doesn't sound tune related as it would've done it from the beginning after the tune. Also if you have a OBD2 scanner or have access to one, reset the TPS aswell. A sensor failing would most likely throw up a code (particularly one that causes an engine stall).

Thanks for the info SilverVH. I have sent an email to Sonny off his website contact section. Hopefully I hear from him soon. He was awesome when he first tuned my V8. Took me through everything and explained the process and what to expect. It was a really good experience.