TPSdot noise and 4ms signal

The forum to discuss:
- V2.2, V3 assembly,
- V2.2, V3 troubleshooting, and
- Connection troubleshooting
Forum rules
Read the manual to see if your question is answered there before posting. Many users will not reply if the answer is already available in the manual.

If your question is about troubleshooting, configuration, or tuning, you MUST include your processor type (MS-I or MS-II) and code version in your post. If your question is about PCB assembly or modifications, you must also include the main board version number (1.01, 2.2 or 3.0).

If you have questions about MS1/Extra or MS2/Extra code configuration or tuning, please post them at www.msextra.com Such questions posted here will be moved to: a temporary MSextra sub-forum, where they will be removed after 7 days

The full forum rules are here: Forum Rules, be sure to read them all regularly.
Post Reply
thr3shold
MegaSquirt Newbie
Posts: 33
Joined: Mon Jun 13, 2011 12:27 pm

TPSdot noise and 4ms signal

Post by thr3shold »

Got a V3.0 MSII with 2.905, relay board, MSD6a, mopar. I've been trying to track down some issues with the set up since I got it running back in August. Looking over some logs I noticed there seemed to be a lot of noise coming through the tps signal, when I know my foot was steady. Looked at the TPSdot and there are semi periodic jumps up to ~10% throttle. This happens though to a somewhat lesser degree even with the engine not running and the key only in the run position. Disconnect the tps wire bundle, it stops. Disconnected msd ignition box, no change. Disconnected the tps signal wire from my relay board and it stops. Hooked up tmy pocket scope to the disconnected signal wire and the reference terminal (still connected) and I see a 4ms noise signal. Checked the tps return against the ground terminal and it is pretty steady except for a 0.02V square wave variation with a many second long period(i never checked, but it was over 10 seconds)

Any ideas?
Thanks.
Matt Cramer
Super Squirter
Posts: 2951
Joined: Sat Jul 03, 2004 11:35 am

Re: TPSdot noise and 4ms signal

Post by Matt Cramer »

Is the TPS grounded to the MS?

Where is the MS grounded?
thr3shold
MegaSquirt Newbie
Posts: 33
Joined: Mon Jun 13, 2011 12:27 pm

Re: TPSdot noise and 4ms signal

Post by thr3shold »

The TPS has 3 wires, reference, signal and return, they all go back to the relay board positions 12,13,14. The MS is grounded to the common ground for the whole system on the engine block.
Post Reply