Bad map sensor
Hello everyone Im new to the form and just installed my first unit on a customers car. Its a mild 383 in a Austin Healey. I have not drove it yet but adjusted the IAC and runs pretty good at idle and hitting the throttle. My issue is the MAP. I have noticed it does not change. Its stuck. MAP:58.8, Vacuum:-12.1. Does not change, engine running or not.
PS Im running the 30003
When those values are locked up, it usually means there is some electrical interference. Any codes or out of range RPM values? Are you running timing control?
Thanks for the reply Austin. I did forget to mention p0335. Rpm is stable and no timing control. I have a Vantage Pro (graphing multi meter) and will check the tach signal tomorrow. This the second unit to do this I figured it was just a bad MAP and got a new unit. I did more testing on the first one before sending it back and as the temp came down the MAP would get closer to normal.
Fixed it. It was the gasket between the ECM and the MAP port. It was pinched and acted like a check valve holding vacuum on the MAP sensor. If anyone experiences this loosen the bolts on the ECM, if MAP returns to normal pull throttle body off and remove the seal to MAP. cut the small round part off seal and reinstall.
Quote from Scrogs on February 6, 2020, 3:59 pmFixed it. It was the gasket between the ECM and the MAP port. It was pinched and acted like a check valve holding vacuum on the MAP sensor. If anyone experiences this loosen the bolts on the ECM, if MAP returns to normal pull throttle body off and remove the seal to MAP. cut the small round part off seal and reinstall.
This is the 2nd time I have seen this recently. Never seen this problem before. Not aware of a design change, but for some reason this is coming up.
Hi there,
Thank you so much for this post. This was exactly my issue and cutting off the end of the little orange seal fixed my MAP problem It was trapping vacuum as described.
Very recently bought a 30004 power adder and being new to Fitech and fuel injection I was wondering why the system was running so rich (max trim and max learn negative most of the time). I thought the MAP value was a bit weird but it did change somewhat. The numbers were not adding up however.
Had to reload the default and start over but it fired right up and idled nicely right away. The upside to the problem was I did lots of searching on how to tune and settings and am much more knowledgeable about the system now.
I suspect this may be a common issue...perhaps with the newer units. I searched everywhere online and finally come across this post which was bang on.
Haven't got to drive the car and let it learn yet. I just set it up on a test stand to get the bugs worked out first. So far I like it !!
Cheers
Awesome!!!!
I am having an issue and sent FiTech my data log. They gave me the exact same advice and a picture of where to cut, so this does appear to be a common issue. They also suggested a ground wire from the front passenger mounting tab direct to the batter, and I figured it couldn't hurt...
By the way, I emailed FiTech last night and technical support has emailed twice this morning...on a weekend. It seems emailing tech support is better than a phone call.
I just posted about this,mine was stuck vacuum at 10.4. Loosened screw to ecm all ok,vacuum worked. Tightened the and back to stuck vacuum at 10.4. There is a red/orange gasket that was deformed between ecm and vacuum sensor,trimmed it at the small end and all ok now. Never ran so good yet. My gasket fell out, be careful. Till this was solved life was miserable with the fitech.
Quote from Scrogs on February 6, 2020, 3:59 pmFixed it. It was the gasket between the ECM and the MAP port. It was pinched and acted like a check valve holding vacuum on the MAP sensor. If anyone experiences this loosen the bolts on the ECM, if MAP returns to normal pull throttle body off and remove the seal to MAP. cut the small round part off seal and reinstall.
Anybody have a pic for us newbies?