Long Cranking???

My Jeep has been running fine and starting quickly, but just recently it's started requiring long cranking times or it won't start the first time you crank it if it's cold. I'll have to crank it for a few seconds, stop, and then crank it again for it to start.
Once it's warm, it'll fire right up.

I don't know if this could be part of it all or not, but I recently replaced the distributer cap and plug wires. I know the wires are on correct and the cap as well.

Any ideas???

Whats your ride? I'm guessing RENIX? (87-90 XJ) Right?

I have a 98 XJ Classic automatic with the 4.0.

Had this same problem bro. It went on for about 2 months and then it just quit cranking over for good. Took it to the shop and they told me that it was the crankshaft position sensor (cps) and that i needed a new one. 45 minutes and 130 dollars later my XJ was back on the street. Hope this helps.

It sounds like loss of fuel pressure, not uncommon. Try this: instead of cranking the first time, just turn the ignition on without cranking, wait a few seconds, turn it off, and then restart. If it always starts up, that's what it is. Your choice whether to live with it (cheap and easy) or fix it (expensive, probably involving a new fuel pump, and on a 98 definitely dropping tank).

Check valve on the fuel pump assembly is probably faulty as Matthew Currie points out. It is a VERY common failure on your vintage XJ. Mine started acting up at around 90k on my 99. Yes, you would need to drop the tank and replace the assembly to fix it. Not fixing it doesn't mean your fuel pump is going to go out and leave you stranded, it's just that you'll have to manually prime it by cycling the fuel pump a couple of times before trying to start (key-on, key off, repeat, then CRANK)....

Another thing (longshot but it happens) is that low available battery voltage can result in a long crank. It does happen but the fuel pump check valve is the most common root cause.

Good Luck!

Good info. I'm going to have to try the key on first before cranking. See if that works.
So, it sounds like it's either the CPS or the fuel pump.

And on the CPS you can sometimes get away for awhile with just unplugging it blowing it out then plugging it back in. Dust gets in the connector and degrades the connection. HTH also.

Where is the CPS located?

Crank sensor is on the bellhousing, drivers side.

Long crank times but eventually starting are not "typical" symptoms for a crank position sensor failure. If a cps is going, it generally either misses intermittently, doesn't start at all or starts and runs for a while, then fails when hot (thermal failure). Sometimes there is a NOBUS indicated.

Try the manual prime test on a cold engine (sitting overnight) which only takes a minute and could very well confirm the problem. Turn key to ON position; do not crank the engine. Fuel pump will energize and run for 2 seconds. Turn key to OFF. Repeat above twice more. NOW try to start the engine. If it starts cleanly with this experiment, you have confirmed that your problem is fuel drainback (check valve) and not the CPS.

If it still takes a long time to crank, have your battery tested as low available battery voltage has in some rare instances, presented symptoms of a long crank time. Sounds weird but it happens.

Good luck.....

So, how does one go about fixing the back flow valve if you find out your fuel pump is the problem? Do you buy a complete new assembly or just a pump rebuild kit? Cause my guage acts funny every once and a while, so Im hopping I can just do a rebuild kit and clean everything up. What say thee XJ folk? Also, anyone know of any good sites to get the parts for whatever I need? Thanks.

Bunookana said:

So, how does one go about fixing the back flow valve if you find out your fuel pump is the problem? Do you buy a complete new assembly or just a pump rebuild kit? Cause my guage acts funny every once and a while, so Im hopping I can just do a rebuild kit and clean everything up. What say thee XJ folk? Also, anyone know of any good sites to get the parts for whatever I need? Thanks.

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i'd like to know this one as well. I have the crank for a bit then starts fine also.

I just moved my air intake to the cowl and put on a K&N cone filter in there and now the Jeep starts right up without the long cranking issue anymore. Don't know how that would affect it, but it seems to be working. Maybe cleaning out the air filter and getting some fresh air in there will do the trick!