HARD START WHEN WARM

1999 Jeep Cherokee

Tiny

MarkyZ

July, 21, 2010 AT 2:46 PM

Engine Performance problem
1999 Jeep Cherokee 6 cyl All Wheel Drive Automatic 275000 miles

So my Jeep started having some issues, i'm wondeirng if they are all related. Symptoms are below:

- Hard start when WARM not cold, not hot. If I start the car in the morning, starts no problem. Start the car after having it off for 5 min, no problem. Start the car after 2 hours of sitting, hard start.

- Poor acceleration and rough idle.

- On two occasions the engine temp gauge showed high (over 220F) and the engine idled rough. I shut the engine off, restarted it after a few seconds and it registered fine.

- Normal operating temperature seems to be below 200F while cruising on the hwy with the AC on. Goes up to about 210 at at idle in traffic.

- Good fuel economy, not sure if this is a symptom, but the gas mileage meter in the evic says i'm doing 13.5L/100km which the truck has never done.

- No check engine or warning signals.

The only thing out of the above that really concerns me is the hard start. I'm worried that i'll drive somewhere and it will go from a hard start to a no start condition.

FOUND 3593 RELATED QUESTIONS

1991 Hard To Start

41 ANSWERS
4 IMAGES

Engine Does Not Stay Running

33 ANSWERS
8 IMAGES

5 Answers

Tiny

rasmataz

July, 21, 2010 AT 6:00 PM

Hi MarkyZ, Welcome to 2carpros and TY for the donation

Lets do this test the coolant temperature sensor its like a carbuerator choke that gives fuel during initial start ups. If okay check the static fuel pressure and residual fuel pressure with a fuel pressure tester this pressure should not drop to quick when you turn the engine off.

The fuel pressure should be 44.2-54.2 psi

Tiny

MarkyZ

July, 23, 2010 AT 6:41 PM

Thanks Rasmataz,

So for the million dollar question, how do I test the CTS? The CTS appears to be on top of the thermostat housing, do I have to remove it to test it? If it tests bad and I have to replace it, do I need to do something to the coolings system to make sure that there is no air in it? Thanks in advance.

Tiny

rasmataz

July, 23, 2010 AT 9:44 PM

Take the reading before you start the vehicle and when the engine is fully warmed up.

Use a high impedance volt-ohmmeter. Resistance should be less than 1000 ohms with a WARM engine (examples = 212* would be about 185 ohms, 160* would be about 450 ohms, 100* (not warm enough) would be 1,600 ohms).


http://www.2carpros.com/forum/automotive_pictures/12900_cts_48.jpg

Tiny

MarkyZ

July, 28, 2010 AT 9:50 AM

Alright so a friend tested it using your chart and the numbers are bit off, looks like it's not putting out enough resistance.

What is the procedure for replacing it? Do I just crank it out and replace it with another? Do I need to do something to make sure I don't get air in the system?

Tiny

rasmataz

July, 28, 2010 AT 3:16 PM

Just remove it and make sure it doesn't leak

Please login or register to post a reply.

Fuel Pump Replacement Done Right
Fuel Pump Pressure Test
Fuel Pump Replacement Ford Mustang
Fuel Pump Test Chevy Tahoe
Fuel Pump Replacement