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Hose question & error code 30 and 34

1406 Views 3 Replies 3 Participants Last post by  91TexasSeville
First, I know I should be dragged out and shot (or injured) for not paying attention, but in my defence the dissmantling took place in february and assembly in october.

There's a hose that I don't know where it connects too and I'm getting the following error codes: 30 (idle speed control circut), 34 (vacuum sensor/map hose), and 52 (ecm memory reset indicator).

I had to replace the timing gears since the old nylon ones gave out. Now that it is replaced, the engine runs fine (rather high idle actually) and I get a Service Now light. There's a hose that I don't know where it goes (can't find a place for it to connect) which I think is part of my problem. The hose comes from the very left hand side (when looking at the engine from the front) and out from the firewall. It's very long (probably 2.5-3 feet) and solid plastic with a small rubber hose connected to the end of it which I assume goes on whatever its supposed to connect to.

Can anyone tell me where abouts on the engine this hose should connect? The air filter has a hose coming out of it which I believe goes to the back of the throttle body, but is this the right place? Could anyone that has the same engine tell me where the hose coming off the air filter goes?

There's a little black plastic box near the front left of the engine (behind the alternator/AC pump area) that has a bunch of hoses comeing out of it. On the front of it are two places where hoses attach stacked vertically. There is a hose on the bottom, but nothing on the top. Should there be a hose here?

Sorry for all the questions, just trying to get this problem solved.

Thanks in advance!
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Sorry guys, to clarify this is an 84 Deville with the HT4100, new timing chain & gears, + battery.

I do not know much about 4.100, but from your description the hose is a vacuum one, and the plastic box may be the EGR solenoid and it should have plastic hoses attached. Can you post a picture?
Okay...This applies to the 4.9L but may also apply to the 4.1L

I'm thinking the long vacuum line attaches to a strong vacuum source at or near the throttle body to operate the climate control doors inside the cabin. There may also be a thermally controlled vacuum device attached to the intake near a water jacket to supply vacuum to the MAP. (34)

Since the engine tear down, the computer lost all history (52) so it must relearn the idle speed. The ISC and TPS (30) must be calibrated according to the FSM (Factory Service Manual). It is a simple process of making sure the throttle plate is COMPLETELY closed and the ISC foot is "X" distance from the plate. The TPS data variable is outlined in the FSM. You need only to adjust the TPS to the correct value, then retest.
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