LT1 Communication Timeout - Any Ideas???
12-05-2009, 09:29 PM
#1
LT1 Communication Timeout - Any Ideas??? ALL Tuners:
My LT1 has been mail-order tuned several times, but given its current modification level (STS, Meth Injection, MSD, 39 lb Injectors, etc...) I wanted an honest to goodness "Dyno" tune.
The individual tuning the car stated that he tried data-logging my car using 4 different scan tools and their associated software, but every time the S/W would crash / timeout when communicating with MY car, however all S/W packages worked with another 97 LT1 car at his shop.
When I talked to the tuner, he was quite perplexed; he had no answers as to why this happened, only a thought that maybe there was "noise" on the ALDL data line.
Given that, my question to the Tuning community is: Has anyone else ever had this type of problem, and what was done to correct the problem?
If this is a problem with my car, I'd like to fix it so it can indeed be dyno tuned, but this tuner can't help me fix this issue; can anyone else?
Thanks in Advance!
MIKE
My LT1 has been mail-order tuned several times, but given its current modification level (STS, Meth Injection, MSD, 39 lb Injectors, etc...) I wanted an honest to goodness "Dyno" tune.
The individual tuning the car stated that he tried data-logging my car using 4 different scan tools and their associated software, but every time the S/W would crash / timeout when communicating with MY car, however all S/W packages worked with another 97 LT1 car at his shop.
When I talked to the tuner, he was quite perplexed; he had no answers as to why this happened, only a thought that maybe there was "noise" on the ALDL data line.
Given that, my question to the Tuning community is: Has anyone else ever had this type of problem, and what was done to correct the problem?
If this is a problem with my car, I'd like to fix it so it can indeed be dyno tuned, but this tuner can't help me fix this issue; can anyone else?
Thanks in Advance!
MIKE
12-06-2009, 07:27 PM
#4
Thanks for the suggestions All -
I appreciate the feedback; I'll answer each comment below.
Nope. It is indeed an OBD II vehicle, with an OBDII-based PCM.
Why? What makes you think the PCM is bad?
Let me rephrase that:
If the PCM does communicate with the scan tool, but only for a short amount of time (i.e. - as the tuner stated, around two minutes), then how does a loss of communication after this period of time lead you to believe that the PCM is faulty?
Please understand, I'm not dismissing your suggestion, I'd just like to know how you came to this conclusion?
Anyone else care to chime in on this?
MIKE
I appreciate the feedback; I'll answer each comment below.
Why? What makes you think the PCM is bad?
Let me rephrase that:
If the PCM does communicate with the scan tool, but only for a short amount of time (i.e. - as the tuner stated, around two minutes), then how does a loss of communication after this period of time lead you to believe that the PCM is faulty?
Please understand, I'm not dismissing your suggestion, I'd just like to know how you came to this conclusion?
Anyone else care to chime in on this?
MIKE
12-07-2009, 01:15 PM
#6
I would verify that you have good clean grounds all throughout the vehicle. Anywhere a ground is loose or corroded or broken, can result in electrical noise that can make scan tools intermittent, and give you a hassle with tuning software too. Clean/tighten/repair every ground in the vehicle before going any further.
After that, I would verify that none of the wiring harnesses under the dash and in the engine bay are chafed or damaged (by animals or a hack previous owner installing any wiring)...if you do all of that, I think you'll probably be all set.
There's a lot an LS1 owner can get away with regarding tuning, as it only takes our cars a little less than 25 seconds to accept a new flash (when writing calibration only) through the ALDL, but an LT1 car takes longer, and thus it's more important that things not be intermittent. LS1 cars will see the same problems datalogging, but LT1 owners can damage their PCM's trying to write to them with a bad connection much easier than an LS1 owner can.
After that, I would verify that none of the wiring harnesses under the dash and in the engine bay are chafed or damaged (by animals or a hack previous owner installing any wiring)...if you do all of that, I think you'll probably be all set.
There's a lot an LS1 owner can get away with regarding tuning, as it only takes our cars a little less than 25 seconds to accept a new flash (when writing calibration only) through the ALDL, but an LT1 car takes longer, and thus it's more important that things not be intermittent. LS1 cars will see the same problems datalogging, but LT1 owners can damage their PCM's trying to write to them with a bad connection much easier than an LS1 owner can.
