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takes a while to start ?

dan89XJ

NAXJA Forum User
Location
Oregon
Hi, I have had my XJ(89 with 4.0L) for a few weeks now.. I bought it with 203,000 miles.. and driven it about a thousdand miles by now.

The jeep starts up every time.. but I have to crank it over for a while each time - crank crank crank crank crank start. I'm not sure if this is normal, but I'm wondering if there is a problem here somewhere.

Also, I'm not sure - but the jeep seems to idle a little bit high. Sounds to me like a 1000 rpm's. However I just swapped the cluster gauge for one with a Tach and it registers about 800 or 900 at idle. I dont know how accurate the factory tach is.

Any help or ideas would be great !

Thanks,
Dan
 
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dan89XJ said:
Hi, I have had my XJ for a few weeks now.. I bought it with 203,000 miles.. and driven it about a thousdand miles by now.

The jeep starts up every time.. but I have to crank it over for a while each time - crank crank crank crank crank start. I'm not sure if this is normal, but I'm wondering if there is a problem here somewhere.

Also, I'm not sure - but the jeep seems to idle a little bit high. Sounds to me like a 1000 rpm's. However I just swapped the cluster gauge for one with a Tach and it registers about 800 or 900 at idle. I dont know how accurate the factory tach is.

Any help or ideas would be great !

Thanks,
Dan

factory tach is fairly accurate. If its an Auto i believe idle should be around 800-850, my 5spd sits right at 750 all day long.

If its a slow start and you havent done ANY work to it yet, then the MANDITORY tune up, oil and lube change is in order.

My jeep takes about 3 seconds to fire. Turn your key on and count to 2 . This gives your fuel pump time to pressurize, and then turn it over. Should only take a couple of cranks to get'er up.

If you have the tools also do a compression check. Never hurts to know where you sit.
 
Some good info might be YEAR and ENGINE...... (edit: i see your screen name has 89 so i assume its an 89 xj)

If it is an 87 to 90..( aka RENIX system) long crank times are pretty normal...turns over 6 or 7 seconds before firing. this is due to the way the computer determines position of #1 cyl. before it will start.

if it is 10 to 15 seconds or you have to crank it twice, fuel pressure comes to the forefront.
Fuel is draining back to the tank and takes a bit to fill the lines and injectors. The most common problem is the fuel pump itself... there is a check-ball built into the pump that wears out its seat after many many miles
 
Digger87xj said:
Some good info might be YEAR and ENGINE...... (edit: i see your screen name has 89 so i assume its an 89 xj)


Oops, forgot to add that info.. 89 with the 4.0L

Thanks for the ideas, I'll try and give the fuel pump time to prime.

I ALWAYS do an oil change whenever I buy a vehicle.. however I dont always do an ignition tune up. Perhaps that'll help the slow start ?

Thanks !

Dan
 
also i know that the clamps that hold the hose onto the fuel pump work themselves loose sometimes. this has happened on all three of the xj's ive had. all you have to do is take the fuel pump out and tighten those two clamps and it will hold fuel pressure better. this might not be the problem but its worth a try.
 
IUPxj94 said:
also i know that the clamps that hold the hose onto the fuel pump work themselves loose sometimes. this has happened on all three of the xj's ive had. all you have to do is take the fuel pump out and tighten those two clamps and it will hold fuel pressure better. this might not be the problem but its worth a try.


:D

Yep, thats what the problem was when I bought my XJ. Got it cheap and fixed it w/o spending any $ I thought I was gonna have to replace the pump.
 
dan89XJ said:
Oops, forgot to add that info.. 89 with the 4.0L

Thanks for the ideas, I'll try and give the fuel pump time to prime.

I ALWAYS do an oil change whenever I buy a vehicle.. however I dont always do an ignition tune up. Perhaps that'll help the slow start ?

Thanks !

Dan

b-4 you by the parts to do the tune up, just pull the cap, and look at te condition of the rotor and cap. Also check the condiiton of the plugs, make sure they look alright.

If you think they are queestionable then get the replacements.

BTW if/when you do the cap replace one wire at a time. I found this is what I should have done at 5:45 am before I went to work one morning.
 
Digger87xj said:
Some good info might be YEAR and ENGINE...... (edit: i see your screen name has 89 so i assume its an 89 xj)

If it is an 87 to 90..( aka RENIX system) long crank times are pretty normal...turns over 6 or 7 seconds before firing. this is due to the way the computer determines position of #1 cyl. before it will start.

if it is 10 to 15 seconds or you have to crank it twice, fuel pressure comes to the forefront.
Fuel is draining back to the tank and takes a bit to fill the lines and injectors. The most common problem is the fuel pump itself... there is a check-ball built into the pump that wears out its seat after many many miles

Agreed, Renix (87-90) is especially slow (around 7 seconds is normal) to "synchronize" when cold starting. After it's been run/warm, it tends to fire in about 1/2 (3-4 sec.) cranking time. '91 - newer is different EFI and only takes a moment of cranking to start. Personally, I like the extended crank time of the Renix since it allows a little oil pressure before firing pressure is applied to the rod bearings.

While it's a good idea to keep starter, battery, cables, etc. in good condition the low compression 4.0 doesn't need much improvement in those areas.
 
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I did all of the above......still have to crank for awhile to start......just the "nature of the beast"....something you have to get used too. At least you build up some oil press. this way, of course when mine does start it idles at about a gizilliion RPM's, time to check TPS again...just replaced it a few months ago.
 
I have same issue with my 89 4.0. I have replaced the fuel filter, fuel rail disconnects, plugs, wires, cap and rotor, TPS and installed an Optima Red Top. I have been told the issue probably is the Crank Position Sensor.

It happens when it is cold or warm. It happens when I let the system have time to pressurize as well. A good check would be to make sure the CPS is clean and well grounded.

Ed
 
My old '90 would never take more than 3 or 4 seconds to fire up in freezing temps.

7 seconds of cranking? That's crazy.
 
90Pioneer said:
My old '90 would never take more than 3 or 4 seconds to fire up in freezing temps.

7 seconds of cranking? That's crazy.

Did you have a late '90 with Chysler MPI? You probably enjoy calling people crazy but that's what my '89 Renix system does. And remember I said "AROUND" 7 seconds? I've never used a stopwatch and it's probably not as long as it seems at the time, might be 5, 6 or 7??? All I know is what I actually experience and will again this morning when I go out to start.

90Pioneer - this "crazy" user would like to know if you still have your '90? Are you 100% certain it was Renix MPI? Would you know Renix system if you saw one? Do you wish to back-off from your "crazy" insult?
 
I agree I haven't timed it on cranking but it doesn't just crank and start. It takes several seconds. If you haven't driven a Renix equiped XJ or MJ in a while you might not understand. In 91 Mopar went to there own FI system on the 4.0 and that doesn't have the issues apparently.
 
blaisetd said:
How easy is it to get to the clamps by the fuel pump?

Easy !
What I did was put the rear wheels on some cylinder blocks, slid myself under there and with a punch/hammer took off the retaining ring that holds the fuel pick up assembly on the side of the tank. Pull the pump out, tighten clamps standard slotted or 1/4" drive/socket. slip it back in and put the ring back on.. and Volia your done! However, I dont know if this is a problem for you.. when it happend to me, my jeep wouldnt move, it'd just die if I gave it too much throttle.

Everyone else, thanks for your inputs.. makes sense that it takes a while for these Renix jeeps to start up.. because of that crank sensor. I'm gonna look at it as a good thing now.. since it'll pump the oil though more before it starts :)

Dan
 
red91inWA said:
Turn your key on and count to 2 . This gives your fuel pump time to pressurize, and then turn it over.

Yep, this helps a lot. It used to take mine a while to start, but I installed a remote starter, and it started just fine with that. Then I realized that the remote starter was smart enough to run the fuel pump for 2 seconds before cranking, and I learned a lesson from it. :D
 
A friend had an 86 XJ with the 2.5L (TBI). It took him about three seconds of cranking, and that was a lot of time! My 95 (4.0) starts in about 1.5-2sec.
 
XJXJ said:
Did you have a late '90 with Chysler MPI? You probably enjoy calling people crazy but that's what my '89 Renix system does. And remember I said "AROUND" 7 seconds? I've never used a stopwatch and it's probably not as long as it seems at the time, might be 5, 6 or 7??? All I know is what I actually experience and will again this morning when I go out to start.

90Pioneer - this "crazy" user would like to know if you still have your '90? Are you 100% certain it was Renix MPI? Would you know Renix system if you saw one? Do you wish to back-off from your "crazy" insult?

It seems to me you're the only one who's made any insults.

No I sold my '90 two months ago. Yes, it was Renix. Yes I know the difference. I have also been around several other Renix era XJs and none of them took 7 seconds to fire up. So I would say you’re either exaggerating, or your XJ has some type of problem.

By crazy I was referring to the amount of time, not to you or your character. May I suggest untwisting your panties?
 
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