'89 BII 2.9 problems

[Spitfire1975]

That's pretty low vacuum from I understand. Should hold steady between ~19-22 in. Not saying it is the cause of your problems, but also not necessarily good.

[97fordrunner]

there is a minor exhaust leak in the drivers side manifold. Low Vacuum=Low Compression?

[kimcrwbr1]

You probably have done so but go through and check all your wires and connectors pull the connectors apart to inspect and put them back together with dielectric grease and make sure all the pins are all the way in. check all the vacuum lines for cracks TB and EGR gaskets and intake manifold bolts are tite. The vacuum is way low hence the map code once the wires and vacuum issue is addressed and you fix the codes as they come up lower numbers first then erase the memory first the disconnect the batt for 1/2 hour. Then you need to run the engine at medium speeds until the engine reaches operating temp and run the codes hot. There is probably nothing wrong with the computer first lose the map code then address the next in line one at a time one sensor can throw multiple codes and always reset the computer whenever you change or clean a sensor to set the new values.

[adsm08]

Spitfire is right, that is kind low for vacuum, and since you have a vacuum driven pressure regulator low vacuum will simulate a higher than actual throttle position, thus causing it to dump fuel.

Low vacuum doesn't always mean low compression, but that is one possible cause. I would suspect intake gaskets, bad vac lines, or even a bad brake booster before I tear into the engine. A compression test isn't out of order at this point however.

I'm also interested in your two temperature sensors that are out of range. I don't have diagram handy, but I think those two sensor share a ground somewhere. But then again on an 89 it could just be two bad sensors.

[kimcrwbr1]

Put your hand over the TB when it is running and see if the vacuum reading goes up will tell you if you have a vacuum leak somewhere the best way I have found to find a leak is tape a soft piece of wire to the end of a vacuum hose about three feet long leaving the end of the hose open. Stick the hose up to your ear and search around all the gaskets and hoses listening for leaks you will hear a hissing noise when you get close and can bend the wire to reach tite places but I am guessing either throttle body or egr gasket loose or needs replaced and yea the brake booster can have a internal leak push on the brake and see if the engine reacts or pull and plug the vac to it. If the compression is even focus on the intake in the tech library it tells you how to read the vacuum guage scroll down close to the bottom. It says 17-21 at an idle but the 2.9 should be at least 19 if the valves and rings are good.

[kimcrwbr1]

Sorry abut the egr you dont have one but put a new PCV valve in it if you havent and is the door on the air cleaner housing working properly could be the IAT code and if the engine is not up to temp for the ECT code.

[97fordrunner]

Thanks for all the great info. I am gonna put it to use tomorrow night hopefully!! Thanks again