xj takes a long time to start?

2001 xj 4.0L 78000 miles
Ok, this all started when my check engine light came on and was missing, I had the coil packs replaced, all new spark plugs. Still was taking forever to start so the mechanics checked the fuel pressure and everything checks out. So, its been a couple months with no check engine lights, but it takes a good 15-20 seconds to start and it does feel like it is missing but runs fine after startup. Smells like gas from the exhaust on start up. Again NO CHECK ENGINE LIGHT? Anyone have a clue?

Try the "poor mans prime".

1. Turn key to ON position. Do not crank engine. Fuel pump will energize and run for a couple of seconds.

2. Turn key to off position.

3. Repeat above 2 more times

4. NOW crank the engine.

If it starts quickly and cleanly this way, the problem is probably the "check valve" in the fuel pump assembly located inside the gas tank. A pretty common problem on your vintage. The valve fails and allows a leakdown of fuel pressure at the rail. Takes extended cranking to build it back up again.

If there is a "stumble" after a long crank, you may have raw fuel leaking into the cylinders due to a leaky fuel injector. Replacement is the only fix there.

Yea the prime didnt work...f

How does the problem present? When hot or cold? If both, are the symptoms more pronounced when hot or cold?

No, it happens the same whether it is hot or cold outside... but that did remind me that when its been running and i shut it off to run in somewhere real quick it starts faster.

I'd be willing to place a rather large wager that your camshaft position sensor isn't correctly synchronized. Did the check engine light point to ignition coil failures?

See http://www.askamechanic.info/askamech2/content/view/36/46/ for further details on the toothpick synchronization method.

Could be a combo.

The check valve in the fuel pump is prone to failure. You can add an external check valve to correct this, no need to spend big bucks on a new pump for that problem.

The other issue sounds like heat soak. The late model XJs suffer from PP engineering. The fuel return was eliminated from the fuel rail, the manifolds were changed and that results in more heat at the fuel rail. Quick and dirty test: drive it until it is really good and hot. Park it, shut off the engine, and open the hood and leave it to cool down for 30 minutes. If this reduces the symptoms you are a getting heat soak. The factory "fix" is to wrap insulation around the #3 injector. If you think that works, I would like to sell you some FL property and a bridge in Brooklyn.

The car runs fine after it starts and drives good so I don't think it can be the cam sync. The fuel pressure at the rail is normal, so I think the check valve is good. And If i start it hot right after shutting it off it starts faster than when its been sitting for an hour. Thanks for all the help though guys!
- I guess Im gonna check the injectors

How long does the fuel pressure last after you shut off the engine? That will tell you if the check valve is good.

mr2guy7 said:

No, it happens the same whether it is hot or cold outside... but that did remind me that when its been running and i shut it off to run in somewhere real quick it starts faster.

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That sounds like the heat soak problem. Try the hood open test I mentioned earlier. If it helps, then add a timer to the efan circuit so the fan will run for 3-5 minutes after shutdown.

Here is a timer:

http://www.naxja.org/forum/showthread.php?t=101118

Numerous other vehicles have a timer built in.

joe_peters said:

How long does the fuel pressure last after you shut off the engine? That will tell you if the check valve is good.

Click to expand...

As well as the injectors. Especially with the misfire, this sounds a lot like an injector hanging and dumping fuel into the engine. Very dangerous to the engine. I bet it starts quicker at WOT (clear flood mode)