Chrome user having major issues and out of ideas!

[twinspoolin94]

You said you're running stock injectors. Are you using the flash ECU now?

Yes, tested it with both the stock ecu and the flash and with the stock injectors it runs fine, by fine I mean the fuel cut/ lean condition is gone and idle is stable.

[twinspoolin94]

Are you sure your injectors are what you think they should be?

Thats a good question, I purchased these new from STM and the data they sent w/ injectors shows they are 850's. When I get home tonight I will double check the part numbers to be sure.

[twinspoolin94]

just talked to 3SX, bringing the car back to them tonight.

[twinspoolin94]

Ok, one thing I noticed last night on the way down to bring the car back. I changed the oil quickly before leaving and I also put the montero MAF back on because I am assuming the car will be put back on the dyno to be retuned. Remember with the stock maf, stock injectors, and stock or flash ecu the car ran perfectly fine and the condition was gone. When I got going down the road and the car got fully warm, o2's cycling....Under moderate acceleration the car would go lean, around 16.5 AFR. I dont know how significant this is given the car was on a stock rom and the only changes were to the MAF scaling. I was under the impression that upgrading the maf did not require additional tuning unless you wanted to run more power and that scaling it would keep the tune as before it was installed. If so im wondering why the change. Possibly the montero MAF is bad and that is why they had so many problems dialing in the 850's.

[Greg E]

I was under the impression that upgrading the maf did not require additional tuning unless you wanted to run more power and that scaling it would keep the tune as before it was installed. If so im wondering why the change.

Who gave you that impression?? The first post in my thread states:

http://www.3sgto.org/tuning-engine-e...flash-ecu.html

On the opposite end of the spectrum, there are people who have this strange delusion that the Chromed Clone ECU is some simple plug and play affair which doesn't require any tuning at all. Nothing could be further from the truth! Chrome comes with all 100% stock tables for an American spec 99 VR4. If you car isn't a 100% stock 98/99 with 3 cats, stock MAF, stock exhaust and all emission equipment, then some changes need to be done. While the closed loop feature of the ECU is very good at compensating for many of these changes, it'll really only get your motor to start, run and cruise. That's about it. Don't believe anyone who tells you anything different!

[twinspoolin94]

Who gave you that impression?? The first post in my thread states:

http://www.3sgto.org/tuning-engine-e...flash-ecu.html

Im not saying that chrome does not need to be tuned, that the whole point of what I am trying to do here if it wasnt for the issues ive been having. What I mean is that with a stock rom and the new Montero maf scaled I did not expect it change the AFR, under high throttle conditions, that severly. I thought the scaling was so that it would work basically the same as a stock unit until you upped the airflow. Guess I was wrong on that thought. I am well aware chrome is not a plug and play tuning solution.

[Greg E]

The parts used to manufacture these ECUs and sensors weren't built with as tight of tolerances as we expect. This is the same reason I can't take the tune rom on my car and flash it onto another just like it. There's always variations and it comes from voltage references.

[twinspoolin94]

Ok guys, just got the call from 3SX. Looks like it was the injectors giving the issues. They said they had a lot of trouble getting the car idle correctly with the FIC 850 so they installed a set of precision 750's. Car is idling correctly and driving smooth like it should be. All that is left is to redial in the highs and it should be good to go. I still do not understand why the car must have the jumpers set to federal spec instead of Cali but honestly after all this I don’t care as long as it’s running right. I also told them to leave the stock MAF as both I and 3SX believe it is unnecessary for the level of power I am making (400 AWHP). I want to thank everyone here who took the time to help me work through this and thank Greg and Adam for all their help. Also a huge thanks to 3SX/ Performance factory for the many hours they spent on this car and for really stepping up and taking care of their customers. Ill report back on how she’s driving soon

[Greg E]

Win!!!

Very glad to hear the good news!

[twinspoolin94]

Ok, so I am happy to report the car is running better than it ever has, so whatever issues I was having are resolved. I have put a few hundred miles on it since last Saturday when I picked it up. Idle is steady and low throttle is very smooth. I have a few questions for you guys about my tune. I have noticed that until the car is fully warm my AFR's are around 13.5 and sometimes as low as 12.5. 3SX said this is normal and I should expect it to dip even lower when it is cold. When the car is warm the AFR is stable from around 14.5 to 15.2. I just hooked the logger up to take a look at my trims and I am a little surprised. low is -1 and +6 and mid is +6 and +9. Now keep in mind this is after driving around, through traffic and not letting it idle and then watching the trims cycle 4 times. My question is, is this normal? Should I be concerned about it even though the car is running great and the AFR's look good?