My car did not start yesterday morning. What could be wrong with it?

It's a 1990 Jaguar XJ6 (XJ40). I baught it last month from an auto auction. It ran and everything, but needed a new battery. I put a new battery in it. I also changed the oil/oil filter and put a couple of quarts of automatic transmission fluid in it, because it tended to lose power when I drove it and so that solved that issue. 

The entire two weeks I've been driving it, it always started up fine, except for one time, after realizing the fuel gauge was not working. I just added gas to it via fuel canister and it started right up. 

So have been driving it to work and all as well as other places and yesterday morning when I tried to start it, it wouldn't start up. It was turning over and everything, but it's just not firing. Tried it a little while ago, still nothing.

Update:

Also tried adding more gas to it, the morning when it didn't innitially start.

Update 2:

After work today I got new spark plugs. After putting them in it didn't solve the issue.

3 Answers

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  • Evil C
    Lv 7
    1 month ago
    Favorite Answer

    An engine needs three things to run: Fuel, spark, and compression. 

    The easiest thing to check first would be spark. Remove one of the spark plugs, reattach the wire, touch the plug threads to a metal surface to ground it, and have someone crank the engine. If there is very little or no spark, then you have issues with your ignition system, most probably with the coils, but it could even be as deep of an issue as with the ECU, although that isn't as common as failed coils.

    Engines in modern vehicles have their fuel fed to them by an electric fuel pump, which is usually part of a module assembly located inside the fuel tank. Even your Jaguar has one. When this pump quits working, the fuel will no longer be fed to the engine and thus, the engine will not start and run. However, this can be caused by things such as a blown fuse, bad fuel pump relay, or if equipped, a tripped inertial breaker switch. The easiest way to check for a working fuel pump is to turn the ignition key to the on position and listen for a high pitched hum that lasts for a couple of seconds. That hum is the fuel pump motor priming the fuel system with pressure. If you don't hear that hum or if the hum sounds weak, then you possibly have a bad fuel pump or any of the aforementioned other issues.

    The last thing is the least common, but without compression, the engine cannot run. The engine loses compression when there are internal issues like valves that are not sealing, worn piston rings, severe piston or valve damage, cracks in the cylinder walls, or failed head gaskets. It is probably unlikely in your case, however if any of those problems are evident, you will be looking at a large bill for extensive engine repair if the engine is even repairable.

    • Cap'n. America
      Lv 4
      1 month agoReport

      Also timing/vacuum. Slipped chain, collapsed lifters due to low oil, or a vacc line fell off. Or wire to sensor fell off  or  inadvertently removed. 

  • 1 month ago

    New plugs? Remove one, put back in wire, homld to head while froirnd cranks. Spark?  No? Check fuses.

    A vacc leak can cause sudden problems. Look for loose stuff.

    Also wire to a sensor. If you changed air cleaner, the boot to MAF sensor Must be on. If it senses no airflow past AC, no injectors.

    Slight chance slipped timing chain or collapsed lifters due to  low oil. (I am not sure if Jags use hydraulics or adjustable rocker arms)

    Any  Check Engine light?

  • 1 month ago

    Silly question maybe but does it still have sufficient fuel? We don't know how much you added or how much driving you've been doing.

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