[SRT14PimPin07]

Hey guys, Ive had my Jb4 for over a year now. And my dowpipe for about 6 months roughly. I did the ISO mod maybe 2 moths ago max and after doing the ISO update on the JB4 my car has been having stalling issues.

The engine never shut off on me. But when I come to a stop every once in a while I will see my RPM's drop to about 500, then the engine will make weird reving noises and RPM's will go to like 600-700 and then come back to 600 and chill. It also does it when I start the car, then put it in gear and let off the break. The car will sound like its gonna die due to drop in RPM's then it will pick up and jump up and cause the car to jerk.

Wondering if anyone else is having these problems or if anyone knows anything I can do about it?

I emailed terry, he said it's normal with the catless DP. And he told me to put FUA = 100. But that didn't help it just makes the car's RPM's rev higher at start up....

Now I put the chevron fuel injector cleaner followed by chevron 91 gas. I only fill up chevron, used to be shell.

Any advice?

[F335i]

I also get that on start up when I did ISO, engine seems as if it's going to die but then it revs back to normal sometimes.. it has never done it on cold start, it's kind of embarrassing, that's the only thing I hate about ISO. I e-mail terry about it a while back but they don't seem to figure the problem out. He told me my E-85 content is too high but it has done it when I been running 93 octane.

[xnfsx]

never had that. check ur connections for ur jb4. make sure everything is plugged right. Run logs with the USB and update the most recent iso c hex file.

[Mike@N54Tuning.com]

Idle instability is not uncommon on the N55 w/ downpipe. If setting FUA = 100 didn't help another thing to try is putting the MAF connector #3 back to stock leaving the JB4 MAF plug sitting out of the way. MAF data is read via CAN now and the physical sensor interception is no longer required. Sometimes that can improve the idle.

Mike

[SFGiants]

had this problem too with jb4 and downpipe. went back to stock because i couldn't deal with it anymore. good luck with it.

[SRT14PimPin07]

Originally Posted by xnfsx

never had that. check ur connections for ur jb4. make sure everything is plugged right. Run logs with the USB and update the most recent iso c hex file.

Terry himself installed my JB4 so I know my connections can't be it. I have the ISO_4 hex which is the most recent. I h
Know I should do logs bud haven't because its am inconvenience for me, plus there is nowhere I can do it legally....

[SRT14PimPin07]

Originally Posted by SFGiants

had this problem too with jb4 and downpipe. went back to stock because i couldn't deal with it anymore. good luck with it.

Ugh, sad part is that I've been considering doing this.....hope I don't get frustrated enough to do it.

[SRT14PimPin07]

Originally Posted by F335i

I also get that on start up when I did ISO, engine seems as if it's going to die but then it revs back to normal sometimes.. it has never done it on cold start, it's kind of embarrassing, that's the only thing I hate about ISO. I e-mail terry about it a while back but they don't seem to figure the problem out. He told me my E-85 content is too high but it has done it when I been running 93 octane.

It never did it prior to the ISO update so I know the ISO update is what's causing it.

[SRT14PimPin07]

Originally Posted by Mike@N54Tuning.com

Idle instability is not uncommon on the N55 w/ downpipe. If setting FUA = 100 didn't help another thing to try is putting the MAF connector #3 back to stock leaving the JB4 MAF plug sitting out of the way. MAF data is read via CAN now and the physical sensor interception is no longer required. Sometimes that can improve the idle.

Mike

Well it never did it before when I hadn't don't the ISO update. Ok I will try unplugging that connector.

[jzingerman]

Originally Posted by SRT14PimPin07

Hey guys, Ive had my Jb4 for over a year now. And my dowpipe for about 6 months roughly. I did the ISO mod maybe 2 moths ago max and after doing the ISO update on the JB4 my car has been having stalling issues.

The engine never shut off on me. But when I come to a stop every once in a while I will see my RPM's drop to about 500, then the engine will make weird reving noises and RPM's will go to like 600-700 and then come back to 600 and chill. It also does it when I start the car, then put it in gear and let off the break. The car will sound like its gonna die due to drop in RPM's then it will pick up and jump up and cause the car to jerk.

Wondering if anyone else is having these problems or if anyone knows anything I can do about it?

I emailed terry, he said it's normal with the catless DP. And he told me to put FUA = 100. But that didn't help it just makes the car's RPM's rev higher at start up....

Now I put the chevron fuel injector cleaner followed by chevron 91 gas. I only fill up chevron, used to be shell.

Any advice?

I'm having this same exact problem but it seems to only be happening when I fill up with e85. When I'm using normal 91 the car seems to act fine. Did some logs and he said I was running lean. Still going back and forth with him so ill let you know if I find a solution.

[Slops]

man... kinda reading this makes me happy I didn't do jb4 to be honest... Even though its a great tune and kicks ass in terms of power, just seems like i'm reading about issues almost every day. Even if its a user install error or not, its an issue that probably could be avoided if you can buy a new jb4 with all the required ISO modifications already done and not have it be up to the users to modify boards/wires etc. I would be able to do it, not bitching or anything - just an observation lately.

[Shogun1122]

Originally Posted by Slops

man... kinda reading this makes me happy I didn't do jb4 to be honest... Even though its a great tune and kicks ass in terms of power, just seems like i'm reading about issues almost every day. Even if its a user install error or not, its an issue that probably could be avoided if you can buy a new jb4 with all the required ISO modifications already done and not have it be up to the users to modify boards/wires etc. I would be able to do it, not bitching or anything - just an observation lately.

To the op, it sucks that you are having issues but at least BMS is trying to help/fix the issue.

I think the issue is that people only post when they have a problem. I can tell you that I have had my JB4 for almost a year and a half. In that time I first upgraded to the the flex fuel wires and then a couple of months later did the ISO upgrade. In both cases everything went fine and i have never has one issue. Not one light has come on and no odd behavior from the car and i have run E85 in a number of different %s with nothing but stellar results.

Each time I would send a log to terry and he responded with in 24hrs.

I have never been a brand loyalist and fully intended to move over to Cobb once it was released. However after reexamining my options, considering the customer service and the constant map updates it was a no brainer for me. Others may feel differently.

I guess the point of my post is that although some customers have issues it is likely that most do not and to give some credit where credit is due.


disclaimer: I am in no way affiliated with BMS just a really pleased customer.

[Kalud]

Will all due respect, people often overlook what the JB4 do in reality. The ISO is only ISOlated boost control (boost solenoid). The ISO control directly the boost solenoid and the non-ISO was offsetting the boost solenoid voltage. It doesn't do anything related to idle / rpm fluctuation. Even more without the so called "Flex Fuel wires" with are only high pressure sensor reading / offsetting (to enlean / enrich). But without those, seriously, there is nothing the tune can do. If you had CPS (like the Procede has) then ok, a bad firmware could disturb the engine running idle.

The JB4 basically offset (or directly control with ISO) the boost solenoid and return appropriate offset values to the DME on the MAP / TMAP sensors to make it think its running stock boost. That's it. Nothing else. It doesn't modify the DME maps, doesnt affect the O2 sensors or else that could affect idle. Beside setting a different default wastegate position (affecting the overall exhaust sound).

One thing that could affect idle is the MAF signal, if the DME gets wrong MAF info then yes it could do strange things like RPM fluctuation, but Terry and Mike said its no longer used on the JB4 and you can disconnect that part of the harness.

[bulldog x6]

Originally Posted by SRT14PimPin07

Hey guys, Ive had my Jb4 for over a year now. And my dowpipe for about 6 months roughly. I did the ISO mod maybe 2 moths ago max and after doing the ISO update on the JB4 my car has been having stalling issues.

The engine never shut off on me. But when I come to a stop every once in a while I will see my RPM's drop to about 500, then the engine will make weird reving noises and RPM's will go to like 600-700 and then come back to 600 and chill. It also does it when I start the car, then put it in gear and let off the break. The car will sound like its gonna die due to drop in RPM's then it will pick up and jump up and cause the car to jerk.

Wondering if anyone else is having these problems or if anyone knows anything I can do about it?

I emailed terry, he said it's normal with the catless DP. And he told me to put FUA = 100. But that didn't help it just makes the car's RPM's rev higher at start up....

Now I put the chevron fuel injector cleaner followed by chevron 91 gas. I only fill up chevron, used to be shell.

Any advice?

try resetting ECU adaptations

[fasteddie222]

I don't find it a big deal my car does it too but not in every stop. It does it one in a million. What's the big deal just turn your car back on and keep going lol. Maybe it's easier for me since I'm 6mt

[divisionbell77]

Originally Posted by fasteddie222

I don't find it a big deal my car does it too but not in every stop. It does it one in a million. What's the big deal just turn your car back on and keep going lol. Maybe it's easier for me since I'm 6mt

Your car is stalling?

Catless DP's with ISO update?

Just want to make sure I have it straight.

[fasteddie222]

Originally Posted by divisionbell77

Your car is stalling?

Catless DP's with ISO update?

Just want to make sure I have it straight.

Yeah but it barely ever does it

[SRT14PimPin07]

I think people are taking my thread the wrong way.....I'm not trying to badmouth BMS's products or customer service. I'm trying to seek out help. I'm looking for someone who has the same issue who would know how to resolve it.

I like Terry's fast and excellent customer service. He gets back to my emails ASAP. And I'm not blaming the product, just trying to find a solution.

[ForgedDistributing]

It seems this is just a general issue with JB4 + Catless DP.
Mine has done this maybe 2 or 3 times in the time I have had my JB4 (12k mile).

[SRT14PimPin07]

Originally Posted by ForgedDistributing

It seems this is just a general issue with JB4 + Catless DP.
Mine has done this maybe 2 or 3 times in the time I have had my JB4 (12k mile).

The reason why it bothers me so much, is cuz it does it almost every time I drive my car.....

[mashimarho]

Originally Posted by SRT14PimPin07

The reason why it bothers me so much, is cuz it does it almost every time I drive my car.....

That is definitely unnatural, but this is only since ISO update?

[paradoxical3]

Check your o2 sensors. Trust me....