TPS with proper SAS adjustment

First… THANK YOU TREMENDOUSLY for your help in the videos you produce.

2 Years ago, I had a new JDM import engine put in my 99 3000GT SL. Since the day it was installed, I’ve had stalling issues and cold start issues related to air/ fuel with codes popping up for MAF, TPS and IAC. I’ve since replaced the IAC, MAF, MAP, PTU, ignition coils, BISS screw and o-ring. I am currently battling the TPS adjustment and in the process, I’ve misinterpreted the directions and messed up my SAS screw adjustment.

I love your YouTube videos because they are extremely in depth and helpful. Is there any way you could make a video with the full process of adjusting the TPS complete with the SAS setting and adjusting the idle properly with the BISS screw? Being in several Facebook groups, I’ve seen a TON of posts with others battling this same problem. I feel it would highly benefit the 3000GT community for someone, such as yourself, to explain the process with the help of a basic multimeter (as that’s what most seem to have). The directions people typically refer others to on 3S Wiki refer to the factory service manual and include the use of a datalogger. I’ve never even heard of one till I read the directions, so I was/ am stuck using a multimeter with an audible beep resistance function.

Thank you again!

Michael Maxfield
Aurora, Indiana

Hi Michael
I am sure that I may get round to this at some time but my videos are generally about repair and restoration, not fault finding and modifications.
I have a personal view that you should find the fault and repair it rather than compensate but adjusting or modifying.
These can be quite complex cars to work on but it can be much easier to find a single fault rather than have to correct all of the adjustments that should never have been made in the first place.
I have quite a backlog of videos at the moment but I will look at this in the future for you.

Thank you for responding.

I know it seems as though I made modifications but I am merely trying to fix my 3000GT after a mechanic that decided he no longer wanted any part of working on my car after I paid him a lot of money to put a new engine in it. The old one had spun bearings and wasn’t getting oil to the top part of the engine. I think he said the oil pump went bad. He never could get the air/ fuel mixture right and blamed it on the engine being defective. I refused to believe him until all other possibilities were looked into but he didn’t want to do the testing.

It was weird because the new engine wasn’t leaking oil anywhere, no coolant leaks or mixing. Levels didn’t change except for very little oil burning. It would stall at red lights and idle low since he put the engine in. For a while, it would start fine and ran amazingly well. Once it got cooler out, It started having hard start problems. I eventually got CEL codes for IAC, MAF and TPS, so I bought and replaced each along with the ignition coils and PTU just to make sure they wouldn’t become the next issue. I also replaced the BISS screw and o-ring because of information I had read in multiple sources that said it is often a related issue. It wasn’t until I encountered the TPS that I started to understand about testing with a multimeter.

Unfortunately, I am left with nobody to work on my 3000GT as for some reason mechanic’s shy away from the platform and aren’t even interested in looking at it. This leaves me to do all the work on it myself. Good news is I am learning a lot about my car but bad news is there aren’t many well put together (if at all depending on the topic) videos as the ones I’ve seen on your page.

Btw. So far, your videos have helped me properly remove and replace both door panels, both rear seat panels, dash parts (all for replacement speakers), the PTU, understand more about water ingress from the rear hatch area and how to fix it. All without breaking anything.

I’m trying hard to keep a classic on the road and in great condition. Thank you for being part of the process!

Hi Michael
I am sorry to hear about your story. It is a very common one that you will see on any forum. It seems that you have wasted a lot of money for nothing. Most of the parts that you have replaced could have been easily tested and although a couple of the parts may cause the symptoms that you describe, they are not the most likely cause.
It is VERY important that any suggestions made be people on forums are only suggestions and will not necessarily solve the problem.
Almost every part of the car has a test procedure so you should not go swapping parts just because someone said it may be faulty and NEVER adjust anything without a very good reason.
I will look into the setup procedure by meter and see if I can slip in a video at some time. In the mean time, can I suggest that you have the ECU overhauled if it has not been serviced in the last 5 years as this is probably the most common fault for this type of erratic fault.