Pulling codes with SCT chip in place..interestin results

[DMAN302]

I decided to pull the coded on my 88 and can only conclude the SCT chip is screwing with the readings..or I have HUGE problems. The car starts fine at 1400 or so,but the cold idle will fall off a touch quickly and drop the RPM's to 500-600 for a few seconds (5-10) before increasing RPM again to the 1200-1300 rpm range and holding constant for near a minute or so at which time the idle will work it's way to the 900-950 range where it's been set. Once this issue is run it's course the car starts and finds idle perfectly every time. So with this I decided to see if it was just a characteristic of the new chip program or another issue...so I pulled the codes. KOEO codes are 15...which I attribute to the SCT overriding the computers original program..so I disregard as the car runs flawlessly both in drivability and all around. NOW comes the interesting part....KOER test. Once started the test begins..idle up and down testing exactly as it should..HOWEVER the reader indicated a 6 cylinder is being tested...it runs the test and reveals to me an 11 upon complettion...this indicates no codes issued and test passed!! How unusual is that! Again did the test..same result, perfect performance from the vehicle..good milage...recent dyno indicated no issues and good power..but the reader is a little confused I think!!

 

[jrichker]

There is no simple way of knowing what the add on chip did when it overlaid the stock tables in your computer. For sake of getting an accurate reading, I would try running diagnostics without the chip in place.

 

[DMAN302]

agreed, thanks...still kind of amusing though.

 

[vristang]

That is weird.

Assuming the SCT chip works the same as a tweecer module (I am pretty sure they would), then your SCT chip should not affect the codes in any way.

How the SCT tune was done though... that is another issue.

Was this chip burned on a dyno?

Sorry I don't really have any answers for you

But I am very interested in what happens with the chip pulled.

Let us know,
jason

 

[DMAN302]

yeah chip wass burned during a dyno tune..it's a multi program chip, my tuner said to simply revert to the number 3 setting which retains the stock settings, we'll see. As is with the whole ordeal of trying to work the computer into position with the limited room in the kick panel and the extended lenght of the computer, chip, and jumper plate via FMS mass air conversion kit I'm not sure I want to risk damaging the chip which is pluged into the back of the computer and is completely exposed with really nothing to protect it from damaged. If the program change does not correct the code issue I likely will leave good enough alone and just accept the fact that's she's a grumpy little bear when cold.

 

[vristang]

yeah chip wass burned during a dyno tune..it's a multi program chip, my tuner said to simply revert to the number 3 setting which retains the stock settings, we'll see. As is with the whole ordeal of trying to work the computer into position with the limited room in the kick panel and the extended lenght of the computer, chip, and jumper plate via FMS mass air conversion kit I'm not sure I want to risk damaging the chip which is pluged into the back of the computer and is completely exposed with really nothing to protect it from damaged. If the program change does not correct the code issue I likely will leave good enough alone and just accept the fact that's she's a grumpy little bear when cold.

I wouldn't leave it as is if I had paid for a dyno tune.
With the money you spent, you should not have ANY issues.

Switching back to the stock setting may help, but you will want to clear the KAM of course.

If you get the same result on the stock setting, then I would say to pull the chip.
There shouldn't be much risk of damaging the chip by removing it.

jason

 

[DMAN302]

After talking to the tuner he said without question that I could stop by at any time and he would make any changes I wanted with regards to his programing. I did remove the chip and found the error codes are now only smog related as they always have, he also suggested the problem might simpy be a result of the car needing more wheel time and the computer adapting to the cold start scenerio. Honestly the car has seen less than an hour or two total drive time since the switch so I'm inclined to give the car a chance to adapt.

 

[vristang]

I don't think the computer does any adapting in cold start conditions.
The KAMRF's become active after the car is warmed.

I would love to hear how things work out though.

Please keep us posted.

jason

 

[DMAN302]

Is the cold start a feature that can be modified? I did not actually ask this question when speaking to the tuner...we discussed possible causes but I failed to inquire about the cold start proceedure being a feature that could be adjusted.

 

[sweet88gt]

I have had problems with a chip and tune. All though I do not have a SCT the same ideas should apply. I have a Diablosport chip and have been trying to figure out a driveabilty issue. Pulled codes and the normal along with code 15. Remove the chip and cleared exsitng codes. No more code 15. I called Diablosport fot tech assistance and they say code 15 is normal. The intresting part is code 15 is for failed computer test-if I remember correctly. Diablosport is telling me that in the tune via their chip removes some of the computers adaptive control. This to me is a concern ?? Why would I want the computer to have less adaptive control ?? I removed the chip and didnt change anything else and with the exception of a couple of hiccups the car does run. Soemthing it wouldnt do the first time I installed the blower. Point to my story is code 15 is a little more than just a failed test and maybe should be looked at in a different light.

 

[HISSIN50]

I don't know much about tuning but I'm not so sure I'd want to remove adaptive control (you really kind of want it around in case sensors start to fail). I'd rather just shift the scale so you're running a little fat (so even if it adapts a little lean, you're still good).

Just something I guess I'd ask the tuner (whether or not this is true, it's probably good to ask just to make sure the tune is being done as one desires. Not unlike the WOT tunes that suck at part throttle).

 

[vristang]

Is the cold start a feature that can be modified? I did not actually ask this question when speaking to the tuner...we discussed possible causes but I failed to inquire about the cold start proceedure being a feature that could be adjusted.

Very much so.

I have not had to mess with them much myself, but there are a few tables for cold start fuel and timing.

Odds are one of these are a little out of whack.

I doubt it would take the tuner long to figure out which and make the needed changes.

However, he may have to see the car when it exhibits the problem.
Otherwise he won't really know what the problem is, and would just be guessing.
I would want to know the AFR at cold start, but the O2's need time to heat up first.

This could be part of the issue?
Are you running LT headers?

These are just my thoughts. Remember that I have no experience with your type of chip.

jason

 

[DMAN302]

Tuner indicated the car was still going to be adaptive in terms of drivability..and infact he was right..the car has responded exceptionally well with more time driven. Fact is the car has never been more user freindly...no warm surge (a major issue prior to tune) no idle hang, no surge coming to stop, much better gas milage not to mention excellent power gains across the board. The cold start instability is something I can certainly tolerate if need be if the result is the drivability I have gained.
I will continue to drive the car and see if the problem persists and if it becomes an issue the car can be brought in at any time next yr, we have an excellent relationship and he's very persistant about me coming back if anything is not of my liking. I attribute the cold start issue to the car coming out of fast idle to abruptly and resulting in the system not being able to recover quick enough for some reason to find the set idle rpm, it will very soon after, but not quick enough...that is of course just opinion at this time

 

[sweet88gt]

I don't know much about tuning but I'm not so sure I'd want to remove adaptive control (you really kind of want it around in case sensors start to fail). I'd rather just shift the scale so you're running a little fat (so even if it adapts a little lean, you're still good).

Just something I guess I'd ask the tuner (whether or not this is true, it's probably good to ask just to make sure the tune is being done as one desires. Not unlike the WOT tunes that suck at part throttle).

Thats my point, adaptive control so as to let the computer adapt for aging sensors or adverse conditions.
As far as the tune my car idles good and WOT is good everything else in between just plain sucks.