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Discussion Starter #1
I changed the timing belt on my '88 Escort about a month ago and ever since my engine vacuum has been lower than normal. Before I changed the belt the engine vacuum would run about 20-21 inches of vacuum at idle and 24-25 inches of vacuum during deceleration. Since changing the timing belt the engine vacuum at idle is running 15-19 inces of vacuum while idleing and about the same during deceleration. The vacuum goes up when the temperature goes up??? I pulled the codes and got code 22 - MAP sensor or BP sensor signal voltage out of specification (engine off) or not at normal vacuum levels (engine running). I've rechecked my work on the timing over and over, everything is perfect. I've checked all the vacuum lines several times and replaced one that was in question, but didn't do any good. I've tried a different MAP sensor on it from my other '88 and nothing changed. The vacuum is steady and the car is running good. The worst part is it's caused my fuel mileage to drop anywhere from 2-6 MPG on every tank since I change the belt. Does anyone have any idea what could be the cause of code #22?
 

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"The vacuum goes up when the temperature goes up??? "

Has to be a leak. Re-check, re-re-check all vacuum controlled stuff near the work area.
 

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Discussion Starter #3
It's rainy today, but I'll recheck again. I've been from one end to the other of that engine compartment at least 10 times since I changed the timing belt and still nothing.
 

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Do you remember messing with any gaskets or the like when doing that belt? Maybe bumping the intake or leaning on it? I remember PMing you with the vacuum I get in my car, which is about the same as you (maybe I'm low or something), but I don't have any leaks, and getting really good mileage (40.46 combined highway/back roads/traffic jam). Check the electrical connection to the MAP, or for any broken wires. Also, check the fuel pressure regulator; it may have cracked and is leaking. Maybe run some carb cleaner through the tank, and see if that helps. It's like shooting at ghosts right now until we come up with a solid diagnosis.

Also...a bonehead question, but did you remove the spark plugs from the cylinders when hand-cranking the engine to line it up for the belt change? If you did, check the torque on them, as they may also be leaking.
 

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Discussion Starter #5
Didn't mess with any gaskets other than the water pump gasket. I've checked the vacuum and electrical connections at the MAP sensor and all the vacuum lines about 10-15 times even went over them again yesterday. Turned the engine with a large power bar without removing the plugs. Have already ran injector cleaner. I'll have to check the fuel pressure regulator. Keep the ideas coming.
 

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Well, I just switched over to a conventional PCV system...getting about 17-18" of vacuum, same as before. If I have a vacuum leak, then it's minor, and probably the intake gasket or throttle body to intake spacer....maybe the EGR gasket since I do remember removing it not long ago. I might check and see if that valve itself is leaking, or the EGR controller.

Might be good if you do the same, and check back. When I let the engine decelerate I'm getting a good 24" and it'll drop all the way to 15" when the ICM kicks in to prevent stalling.

Anyone else with a CFI and a vacuum gauge care to chime in?
 

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Discussion Starter #7
Found the problem. The front bolt hole is broke off where the throttle body bolts to the intake. Does anybody have any suggestions on a simple fix!?!?!? I don't really feel up to changing the manifold unless it proves necessary. Right now I have the throttle body loose and have tried reattaching the section that was broke off with a two part epoxy. I've done some pretty miraculous things with epoxy, but I don't know if it's this good or not. I am thinking of also running a thin bead of silicone between the intake and throttle body spacer in hopes it will help seal the vacuum leak without having to put a tremendous amount of stress on the epoxy joint. I'm going to give the epoxy it's full 24 hour maximum strength cure time before attempting to tighten the throttle body back down. Hope I can get it so all I have to do is just snug it down and let the silicone do the rest. If any one else has any ideas please make them known.

Noall, your deceleration vacuum sounds like it's running about where mine was before this incident, but if your vacuum at idle is only 17-18 it's about 3-4 inches lower than what I was at. Mine usually ran about 20-21 inches of vacuum at idle and 24-25 inches during deceleration.
 

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Discussion Starter #10
Well good news and bad news. My repair on the intake worked, but the engine vacuum is still just like it was before. Still open for suggestions.
 

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Mine has always been low at idle too, even though my compression is OK. I assumed it was worn rings from having 130K miles. Maybe it's just the way the engine is timed.
 

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So it's still throwing the 22 code? How much vaccum are you losing between the intake tree and the MAP hose? Also, have you tested for voltage switching at the MAP sensor, while manually applying a direct vacuum to it? That's the only way to absolutely rule out the MAP as the problem.
 

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Exactly how are you checking your vacuum hoses , vacuum connections, and vacuum devices for leaks? If you are not using a MityVac, then you are doing ti wrong.
 
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