Code for map sensor after msd intake install
 

recently installed h/c/i, headers. The car seems to regularly throw a code for the map sensor now. Is it required to recalibrate the map when changing manifolds? Havent been able to come up with anything doing a search. Thanks in advance!

The Map sensor is probably defective or not put on correctly, try putting it on again I know the hole for it is really not that great for the map sensor....

Did you drill the required 1/8" hole for the sensor? I had no issues when i swapped to the MSD before I retuned it.

Yes Drilled with 1/8" as stated in directions. If I clear the code it will usually come on within a minute of starting the car and driving. Car runs great but does seem to have some issues stabilizing at idle. Rpms will fall to about 400 and spike to 12-1300 a few times before it steadies at about 850

Are you still using the stock TB? Did you change the valley cover bolts for something more low profile? Could not be seating on the port side and causing a huge vacuum leak. How many miles are on the manifold? Have you retorqued the clamshell bolts?

I have about 1k miles on it now. All bolts have been retorqued. Vally bolts and throttle body are original. I did notice when installing the throttle body that it hardly fits and the seal kind of worried me. I will have to double check that again.

You might have to take some material off the water pump if the TB is hitting.

Also, I’d take the whole manifold off to make sure it’s not cracked. IIRC, you are supposed to use smaller bolt head bolts because the manifold touches the stock ones.

Did you recalibrate (tune) the engine after the H/C/I/Header install?

That's the FAST manifold you are referring to.

When I installed mine, I used RTV between the shell halves, the mounting bolts (where the o-rings are) and on the MAP sensor gasket. :cheers:

It has been retuned by rpm however I dont think they reclibrated the map for the extra volume of the msd. Is this something I can do using my efi live without messing up the tune they did using a different program? If so, would somone be able to point me in the right direction of doing so. Its been years since I've played with efi live and I'm not all that familiar with it.

Check that your MAP sensor isn't cracked from tightening it down. The MSD manifold leaves a gap between the sensor body and the manifold when it's fully seated. If you tighten too much you will crack the sensor. Happened to a friend's car so I put a washer underneath to take up some of that clearance. It still sits a hair crooked but tightens down without having to worry about cracking the sensor.

https://cimg5.ibsrv.net/gimg/www.cor...a406436541.jpg

I set mine properly in HP Tuners (I can dig up the volume value or you can try to search for it, it's been posted multiple times), but I can say this change isn't going to solve a MAF code issue. 99.5% of MSD installs are still running the default value.

You most likely have a leak, a poor seal or a defective component, in that order.

There is another recent thread where a member discovered his issues were related to the connector. He took the nuclear option and replaced the connector, but an equally effective solution would be to slightly bend the pins so when they are inserted they must make contact with the female side. De-oxit spray is excellent as well. :cheers:

Hello Sir....contact Dynosteve here at our shop he will be able to help 100%.....send him out an email as he is on and off the dyno all day today and he will promply get back to you

dynosteve@rdpmotorsport.com

Another possibility is the wiring loom got rearranged to cause problems. Have discovered in mine when I tried installing MSD coils and the MSD harness that the surge at idle problem came back, I was the one that had the problem with the connector not making contact with the pins, anyway when installing the MSD coils with stock wiring which in mine did not work tried the harness with stock coils and it caused problems but I put the harness in I tried running the wiring parallel with stock ignition and fuel injector harness which was a mistake so now have the harness cross the factory wiring a right angles to the middle top of the intake then straight back to the firewall and then over to the fuse block now the MSD coils work fine. Found reading the factory shop manual that a p0107 code is a possible Voltage above threshold to use GMs terminology and the ignition wiring has a ground, control, low reference voltage which will be 5volts logic circuit, and ignition, so my thinking is the 5 volt reference went above threshold and triggered the surge problem. So routing of wiring is important and in my case the MSD coils work very nicely but when you said you had the intake off its the only thing that I could think of that might be causing the problem other than problems at the MAP itself, or in my case the connector to the MAP and the weird pin problem.