Do i have to remove the engine in my 1990 cadillac sedan devillle in order to fix the starter? yes or no.

No spark....You need to check to see if you have spark at the spark plug. There is a spark testing tool made just for this...I'm sure you'll find that you don't have spark...

if it's a northstar engine, you have to remove the intake manifold.

First, I would determine it is bad. I have a 1990 Cadillac Sedan Deville, and sometimes it doesn't turn over. But, if I toggle the switch a few times or up to 5 times, it starts to turn over and the car starts.

I have the same problem with a 1997 Cadillac Deville.

If you are set on changing it, here is a picture and instructions on how to test:
Starter TESTING Voltage Drop Test Fig. 1: Schematic of a voltage drop test
NOTE: The battery must be in good condition and fully charged prior to performing this test.

1. Disable the ignition system by unplugging the coil pack. Verify that the vehicle will not start.
2. Connect a voltmeter between the positive terminal of the battery and the starter B+ circuit.
3. Turn the ignition key to the START position and note the voltage on the meter.
4. If voltage reads 0.5 volts or more, there is high resistance in the starter cables or the cable ground, repair as necessary. If the voltage reading is ok proceed to the next step.
5. Connect a voltmeter between the positive terminal of the battery and the starter M circuit.
6. Turn the ignition key to the START position and note the voltage on the meter.
7. If voltage reads 0.5 volts or more, there is high resistance in the starter. Repair or replace the starter as necessary. NOTE: Many automotive parts stores have starter bench testers available for use by customers. A starter bench test is the most definitive way to determine the condition of your starter.
   

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Remember to disconnect the battery and remove the wires from the starter at the hex nut.

Then, remove the 3 or so bolts that hold the starter on using an extension and ratchet if necessary.

Hope this helps.

lower left side on driver's side near the hood release.

firing order is 1-8-4-3-6-5-7-2.
hope this helps

Sounds like the engine is idling to high. There is a procedure that you must go through to set it. Reply and I will let you know how to set it.

To avoid confusion, remove and tag the spark plug wires one at a time, for replacement.
If a distributor is not keyed for installation with only one orientation, it could have been removed previously and rewired. The resultant wiring would hold the correct firing order, but could change the relative placement of the plug towers in relation to the engine. For this reason it is imperative that you label all wires before disconnecting any of them. Also, before removal, compare the current wiring with the accompanying illustrations. If the current wiring does not match, make notes in your book to reflect how your engine is wired.



4.5L and 4.9L EnginesEngine Firing Order: 1-8-4-3-6-5-7-2 Distributor Rotation: Counterclockwise

Hope helped with this (remember rated this help) Good luck.

Has the motor siezed from lack of oil or water

as mutch as you probally dont want to hear this yes the radiator,fan assembly and starter need to be removed to prevent any damage to them and to make things easier

Battery terminals like bad or corroded. Replace, and you should be fine.