Help with IAT Please!

For discussing how to choose sensors and create a wiring harness for all Bowling and Grippo versions of the MegaSquirt® EFI controller.
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
PaulO
MegaSquirt Newbie
Posts: 21
Joined: Sat Feb 28, 2009 5:45 pm

Help with IAT Please!

Post by PaulO »

MSII Ver. 357. Using relay board and GM IAT sensor. Noticed my reading is always stuck at 70 deg. no matter what. Connected the stim and the readings vary with the pot adjustment so it is not the ECU. Disconnected the two wires from the sensor where they connect at the relay board and I get the steady 70 deg. I would guess that the problem is either in the relay board or the cable between the relay and the ECU? What I found a little strange is that with the stim connected, if you dial the pot to the highest setting, it gives the same result - constant 70. The temp will climb with the pot to what I suppose is the max. and then goes to 70 and stays there. Does this mean anything or is this normal and I just have a bad relay or cable?
Thanks,
Paul
66fb

Re: Help with IAT Please!

Post by 66fb »

On the stimulator with the pot at the higher settings you'll hit the "failsafe" This is the value MS recognizes as sensor/input failure and a value (mine is 180*F) is substituted to keep the engine running. If your CLT reading is ok you might try removing its connector and jumping it to the IAT sensor. If you get a reading close to your CLT reading (cold engine) than you'll know your IAT sensor is ok and you have a wiring problem.
Does this mean anything or is this normal and I just have a bad relay or cable?
The relay board just feeds the IAT wiring straight from the 20 pin terminal strip to the DB37, no relays involved.
Post Reply