04 Cobra miss at idle/low rpm bucking

[matth121]

You need to fix that connector before trying to figure anything out- as stated above- jblood37 told you his car was doing the same thing- while he had his broken connector taped, like you do. Once he replaced the bad connector it fixed his problem. Don't half ass repairs that could affect your engines health, or any if you love your cobra like i love mine. And I agree that your 1st compression test was not done properly so you might wanna redo that just to be sure there's no major difference between heads. You need to do these things 1st before looking into any further tuning or fuel changes- once you know thats good- you can look into other possibilities. Best of Luck man

I'm going to be taking it to a knowledgeable shop around my area.

please show them your broken COP connector

 

[Jsantana91]

You need to fix that connector before trying to figure anything out- as stated above- jblood37 told you his car was doing the same thing- while he had his broken connector taped, like you do. Once he replaced the bad connector it fixed his problem. Don't half ass repairs that could affect your engines health, or any if you love your cobra like i love mine. And I agree that your 1st compression test was not done properly so you might wanna redo that just to be sure there's no major difference between heads. You need to do these things 1st before looking into any further tuning or fuel changes- once you know thats good- you can look into other possibilities. Best of Luck man


please show them your broken COP connector

Yeah I do need to fix it but that's not my problem. I'll be taking it to a shop in a week or 2 when I get a chance. I'll update this thread than. 04sleeper is also reviewing a datalog for me.

 

[matth121]

Yeah I do need to fix it but that's not my problem.

ok, but keep in mind that it was jblood37's problem and the exact symptoms you're experiencing which he fixed by replacing a bad taped up connector- I'm sure 04sleeper will get you sorted though

 

[Jsantana91]

ok, but keep in mind that it was jblood37's problem and the exact symptoms you're experiencing which he fixed by replacing a bad taped up connector- I'm sure 04sleeper will get you sorted though

Yeah that's true man I'm try to get a connector this week. I hope 04sleeper sees something no one else has.

 

[matth121]

i'm gonna leave it alone after this- if you have 04sleeper looking at logs with a possible bad connection to a coil- you're making him work harder than he has to and it might be the kinda thing that isn't visible in DL other than seeing AF off or misfires(the cause might not be apparent). You owe it to both him and yourself to correct any possible problems before getting him to spend time trying to help you. He's the best in the game as far as i know and is for sure doing you a favor. fix it..lol. best of luck- you'll get it

 

[Jsantana91]

i'm gonna leave it alone after this- if you have 04sleeper looking at logs with a possible bad connection to a coil- you're making him work harder than he has to and it might be the kinda thing that isn't visible in DL other than seeing AF off or misfires(the cause might not be apparent). You owe it to both him and yourself to correct any possible problems before getting him to spend time trying to help you. He's the best in the game as far as i know and is for sure doing you a favor. fix it..lol. best of luck- you'll get it

Installed new coil connector. Problem is still present. Installed new tr6 plugs gapped at .030 with no difference. The cobra just developed a new symptom "long cranking on cold start" only on cold starts starting to think the pumps are going out. Going to install new injectors with a tune this week hopefully. After this I'm done I'm selling the damn thing.

Will post again when I hear from 04sleeper

 

[big dad]

Try and duplicate the condition and monitor the 02 sensor voltages with the tuner. You could have an 02 sensor that isn't responding (switching) or (cross counting) in that particular rpm range, basically being lazy. It should be switching rapidly between .10-.80v.

 

[Jsantana91]

Try and duplicate the condition and monitor the 02 sensor voltages with the tuner. You could have an 02 sensor that isn't responding (switching) or (cross counting) in that particular rpm range, basically being lazy. It should be switching rapidly between .10-.80v.

Thanks for the reply man I'll check those out this afternoon.

 

[Jsantana91]

bringing this back from dead installed new injectors and continued with BAMA tunes. needless to say after 4 different tunes they still cant get my car to run correctly. I'm currently left with a cobra that runs full rich on idle and full lean when i want to accelerate. if anyone can recommend a tuner so i can get a tune file thru an email to at least drive the damn car to a tuner near me to do a dynotune i would appreciate it thanks.

 

[Woody6799]

pm 04sleeper

 

[Jsantana91]

pm 04sleeper

I pm'd him I will update this thread if he can get me a quick tune file. At this point I think it's BAMAs tunes not my car. Thank you man for your help

 

[MG0h3]

How are you identifying a difference between the bucking and missing? Seems odd that the bucking has cleared up but you still have a misfire. Did you buy the car like this or did it develop after you had it?

I really doubt your fuel pumps are the issue since you say it pulls hard at WOT.

I would look at closed vs open loop systems like TPS and O2 sensors. like someone else said, you could have a lazy or stuck O2 (rich) and its forcing the car lean until you go open loop (wot).

 

[Jsantana91]

How are you identifying a difference between the bucking and missing? Seems odd that the bucking has cleared up but you still have a misfire. Did you buy the car like this or did it develop after you had it?

I really doubt your fuel pumps are the issue since you say it pulls hard at WOT.

I would look at closed vs open loop systems like TPS and O2 sensors. like someone else said, you could have a lazy or stuck O2 (rich) and its forcing the car lean until you go open loop (wot).

Hey thanks for the reply man. So the bucking got cleared up when I had the EGR system shit off in the tune. Now the misfire I'm having is present at idle and low rpms. The misfire was sort of present when I bought it but it cleared up slowly. Since I've been with BAMA tunes the miss got a bit better but on the last tunes with new mods the miss had been greater. The issue the car has is it goes rich on idle only but everything else is normal. I checked the tps voltage thru the sct X4 and it seems correct. My 02 sensors seem normal also. I'm trying out a new tune today with the 02 sensors shut off according to the tuner. He said this should get my car running better.

 

[MG0h3]

Well I hate seeing someone shut the O2s off. Doesn't do much for fuel mileage but I'm sure a good tuner can get part throttle drive ability there.

Coolant temp can play a part in this too. Or at least what the CTS is sending the pcm.

 

[Jsantana91]

Well I hate seeing someone shut the O2s off. Doesn't do much for fuel mileage but I'm sure a good tuner can get part throttle drive ability there.

Coolant temp can play a part in this too. Or at least what the CTS is sending the pcm.

Well that didn't go well now the car won't even run for more than 30seconds... I don't even know what to say anymore. Definitely wanna get a tune to just drive it to a tuner to dynotune. I don't wanna tow it 3 hours away from me lol

 

[MG0h3]

MalcolmV8 had an issue with his handheld where when he was loading tunes they got corrupted. Or maybe it was the port on his laptop. It's in his black goo thread in the distillery.

I'd just load a stock tune and diagnose from there. May be that the O2s were the only thing keeping the car running before.

 

[Jsantana91]

MalcolmV8 had an issue with his handheld where when he was loading tunes they got corrupted. Or maybe it was the port on his laptop. It's in his black goo thread in the distillery.

I'd just load a stock tune and diagnose from there. May be that the O2s were the only thing keeping the car running before.

I'm actually going to try this out today when I get off work I think it may be the sct x4 fault. I'm return the car to stock reset the x4 and see if there are any updates. I'm go check out that thread. Thanks for your help man!

 

[Jsantana91]

Well reviving this from dead the car has been dyno tuned. The noise I hear is spark drop according to the tuner. The car was tuned by AED. My mods are 2.76 pulley, bbk cai, 60lb injectors, sct 2600 maf, 170 stat, magnaflow catback, and AFCO heat exchanger. The car made 435hp and 478tq. What do you guys think? We believe the blower may need a rebuild.

 

[Rich'sTRsvt]

Horsepower is a little low but the torque number is good. If it was on a mustang dyno those numbers are very good. How does it feel to you is more the question.

 

[Jsantana91]

Horsepower is a little low but the torque number is good. If it was on a mustang dyno those numbers are very good. How does it feel to you is more the question.

Yeah the tuner and I felt hp was way too low, that's why we think the blower needs a rebuild. And unfortunately I don't know what kind of Dyno it was, But this thing definitely pulls hard now. A C63 Benz pulled aside me in the freeway and we raced from 3rd gear 3k RPM to the end of 4th and some of 5th. I definitely beet him by a football field if not more. I'm happy definitely looking into a bigger blower and fuel pumps.