Hey guys... I have an 88 Power ram, 318 auto with TBI. Recently, I have been having some engine idle issues, and the engine light as been giving me some codes, lots of stuff about the MAP sensor vacuum leak. I don't need to pass emissions anymore, so I just pulled the belt of the air pump, and then blanked off all of the vacuum lines going to the throttle body. Since there is no vacuum now though, the MAP sensor is throwing a code all the time. If I am not mistaken, the MAO sensor is on the firewall, kinda opposite the glove box. Is there a way that I can electrically bypass it so that it always thinks it is perfect, because it no longer has a purpose, and I want my engine light off. Thanks.

BTW, pulling that pump belt off must have tripled my HP... its like a whole new truck!

Jake

 

You will still need the map,it sends a variable signal to the computer.
A single vacuum line from the back of the throttlebody like stock is easy.

 

If you gutted all the emissions why not 'gut' the check engine light bulb?

 

That will get rid of it every time.

 

I could gut the whole thing, but currently Im just going for a functional engine. I may later on go to a carb. instead of TBI, but I dont have the money or the time right now. But doesn;t the computer govern the fuel to the TBI? So if that was to be taken out, then I would be getting rich or imbalance fuel mixtures.

 

You are anyways if the sensor is not giving the right data.

and you missed the point...
if you want the light to stay off... remove the bulb.

 

Either you reconnect the MAP sensor or do away with the TBI and computer and change the distributer. The engine with a TBI cannot run correctly without the MAP.

 

Ok, so I put in a new MAP sensor, and I then replaced the rubber line. It corrected my engine a lot. The idle got nice and smooth, and it stopped galloping. However, today, I was driving alone, and came to a stop light, and it started to gallop again. Its almost like the idle is too low all of a sudden. When the engine is running well, its about 800, but when its shudders, it runs at 500,then drops to 3 or 4, and then keeps reving up and down like that. The MAP sensor fixed the light, and stopped the computer from throwing mixture and vacuum codes, but I still have this intermittent issue. Any ideas?

 

Try disconnecting the battery for half hour or so? I'm told that will reset the computer, so when you give it power, it will re-initialize. If the computer was "used" to working with the broken sensor, then it's compensating for the broken one even though you have a new one. Sounds weird, but might help.

 

Could you have knocked the wires loose on your idle speed control actuator. This is what the computer uses to set your idle speed to compensate for varying loads on the engine.