FordMan59

I changed the timing belt on my '88 Escort Pony a couple months ago. Prior to changing the belt the engine vacuum ran at 20-21 inches of vacuum at idle and 24-25 inches of vacuum durring deceleration. Ever since I changed the belt the vacuum reading at idle runs anywhere from 14-20 inches of vacuum at idle and 15-21 inches of vacuum during deceleration. The engine vacuum goes up when the temperature is warmer. I rechecked the timing several times to make sure the timing belt wasn't off by a tooth and it checks out perfect. I've also checked all the vacuum hoses several times for leaks and can't find any. I've checked the EGR valve to make sure it isn't leaking vacuum and it holds vacuum. Does anyone have any suggestions on what the problem could be or other things to check? It has caused a drop of 2-5 MPG in my gas mileage and that hurts when you drive as much as I do.

car questions

The timing belt replacement would only affect engine vacuum if the belt was off a tooth and upset valve timing (it would also through off the ignition timing), or you caused a vacuum link during the installation.

If the engine runs fine, fuel economy has not changed, and the check engine light has not come on, I wouldn't worry about it.

Kind of curious why you checked vacuum before and after.

FordMan59

I've checked the timing since istalling the belt and it is dead on, not off a tooth that was the first thing I checked. I've also traced and checked all vacuum lines to make sure none of them had got knocked off while I was working on it and have also checked them for leaks. The way I knew about the vacuum variation is because I have a vacuum gauge hooked up all time and in the car so I can monitor engine vacuum to assist in better fuel efficiency. Higher engine vacuum equals better fuel efficiency.

jwko

OK, the timing at the crank & cam is dead on. Have a timing light put on it and check the timing at the distributor. I'll almost bet it needs advancing.




The timing marks on the 1.3L, 1.6L and 1.9L engines consists of a notch on the crankshaft pulley and a graduated scale molded into the camshaft drive belt cover. The number of degrees before or after Top Dead Center (TDC) represented by each mark can be interpreted according to the decal affixed to the top of the belt cover (emissions decal).

1.6L and 1.9L Carbureted Engines

See Figure 1

1. Place the transaxle in the P or N position. Firmly apply the parking brake and block the wheels.

2. Turn OFF all accessories (A/C, heater, radio, etc.).

3. Once the timing marks are located, clean with a stiff brush or solvent, if necessary.

4. Remove the vacuum hoses from the distributor vacuum advance connection at the distributor and plug the hoses.

5. Connect a suitable inductive-type timing light to the No. 1 spark plug wire. Do not puncture an ignition wire with any type of probing device.

6. Connect a suitable tachometer to the engine.

7. If the vehicle is equipped with a barometric pressure switch, unplug it from the ignition module and place a jumper wire across the pins at the ignition module connector (yellow and black wires).

8. Start the engine and let it run until it reaches normal operating temperature.

9. Check the engine idle rpm if it is not within specifications, adjust as necessary. After the rpm has been adjusted or checked, aim the timing light at the timing marks. If they are not aligned, loosen the distributor clamp bolts slightly and rotate the distributor body until the marks are aligned under timing light illumination.

10. Tighten the distributor clamp bolts and recheck the ignition timing. Turn the engine OFF , remove all test equipment.

11. Unplug and reconnect the vacuum hoses.

12. Remove the jumper wire from the ignition module connector.

13. Attach the barometric pressure switch connector.



1.6L MFI Engine and 1986-90 1.9L CFI/MFI Engines

See Figure 2

1. Place the transaxle in the P or N position. Firmly apply the parking brake and block the wheels.

2. Turn OFF all accessories (A/C, heater, etc.).

3. Locate the timing marks and if necessary, clean the marks with a stiff brush or solvent.

4. Connect a suitable inductive type timing light to the No. 1 spark plug wire. Do not puncture an ignition wire with any type of probing device.

5. Connect a suitable tachometer to the engine.

6. Unplug the single wire white connector near the distributor.

7. Start the engine and let it run until it reaches normal operating temperature.

8. Check the engine idle rpm if it is not within specifications, adjust as necessary. After the rpm has been adjusted or checked, aim the timing light at the timing marks. If they are not aligned, loosen the distributor clamp bolts slightly and rotate the distributor body until the marks are aligned under timing light illumination.

9. Tighten the distributor clamp bolts and recheck the ignition timing.

10. Attach the single wire white connector near the distributor and check the timing advance to verify the distributor is advancing beyond the initial setting.

11. Shut the engine OFF , remove all test equipment.