Sensor help Hot Startup Stumble

First off I have a 92 2wd. My problem started when I driving on a hot day on the freeway and the jeep just decided to die, so I pulled over and was like wtf tried starting it few time and it started right up. Well I did some research on the forums and decided to replace the “CPS Sensor”. Well I took it out again everything was normal went to put gas in turned off jeep, put gas in then went to turn on and it would turn but no start. It would want to start but it seemed like it was only run on one or 2 cylinders if that makes sense. Disconnected the batteries checked all wiring couldn’t find anything wrong. Well after it sat for a while bout an hour or so went to turn it on and it stumbled a bit, gave it some gas and it fired right up. Well I replace the CPS sensor again just incase. Next trip out everything seemed fine then it did it again, same symptoms driving on a hot day turned it off, went to turn on and would not start. I gave it some time and then it fired right up. I pretty sure now it’s got to be a temperature thing. When its on it runs great no problems or stumbling at all only at start up when hot. Also not getting any codes either

Since then I replaced

• Cps Sensor twice to make sure
• Spark Plugs
• Spark Plug Wires
• Fuel Pump
• Fuel Filter
• Ignition Coil
• Distributor cap and rotor
• Cam shaft position sensor or “stator sensor” in distributor
• 02 sensor

Well went out for a drive and it did it again, thinking it could be the coolant temperature sensor “cts” or possible “Tps”. Any help would be appreciated.


Ok guys im still haveing the problem. I cant figure out this sensor I think its a knock sensor but im not quite sure. Its on the driver side block right above the Oil Pan Lip. I think it might be a sensor for a aftermarket temp gauge that a shop put in a while back as the oem Temp gauge went out. Its Throwing back a 54 code "No fuel sync (camshaft signal) detected during engine cranking" but I replace the Stator Sensor with a new one. And it runs perfectly fine just having trouble when I try to start it when its hot.



Also If you can help me out with these sensors



And this is the temperature Coolant Sensor Correct

CDS, since you're getting a 54 code, and since you've replaced the camshaft sensor already, I'd suspect the wiring going from the sensor to the ECM.
You'll probably need to check the continuity from the sensor plug-in to the ECM pins.
First try unplugging the large ECM connector, and re-plugging it......

Hey I got a question for you just to clarify, since I am not all the familiar with the multipoint that you are running, more on the Renix though. By CPS are you refferring to the Cam Position Sensor (located in the Distributor) or the Crank Position Sensor (located on the back side of the Bell housing). If you replaced the one on the Bellhousing, is your tranny a manual or an auto. I Had a manual that had a leak front seal, the leak caused it to have a no start when hot issue. Turned out to be that I would build up oil on the teeth and cause hall effect to not work correctly thus no start. Not really sure if this helps but maybe it gets you on the right line. Also there are different CPS units for the Renix and the Multipoint that you have...some times the parts stores have them listed as the same, it might be worth looking at; however I believe you would have a no running issue or rough running issue if that were the case.

Stihl029 said:

By CPS are you refferring to the Cam Position Sensor (located in the Distributor) or the Crank Position Sensor (located on the back side of the Bell housing). If you replaced the one on the Bellhousing, is your tranny a manual or an auto. I Had a manual that had a leak front seal, the leak caused it to have a no start when hot issue. Turned out to be that I would build up oil on the teeth and cause hall effect to not work correctly thus no start. Not really sure if this helps but maybe it gets you on the right line. Also there are different CPS units for the Renix and the Multipoint that you have...some times the parts stores have them listed as the same, it might be worth looking at; however I believe you would have a no running issue or rough running issue if that were the case.

Click to expand...

Yes I actually replace the Crank Position Senor Twice thinking it might be bad and I just replaced the Cam Position Sensor in (located in the distributor). My tranny is a auto. I will look into the seal. really crazy I just started it up with no problems right now, and let it run for 15 min i reved it up turning the fan on to cool it down and shut it off. Waited 2 minutes tried to start it and it stumbles, cant figure it out Got my money on the Coolant Temperature Sensor

CDS, do you get the 'stumble with a hot start', every other time it's started?
Also, does the no sync signal (code 54) return after being cleared?

You might try disconnecting the battery for about 10 minutes and see what that does......yeah it sounds crazy but it costs nothing.

The sensor in the first pic is the Coolant Temp Sensor. This is the one that feeds the ECU. The one in the thermostat is the switch for your electric fan. You have a third on the rear of the head for the temp gage.

In your second pic, the one in the middle is the Manifold Air Temp (MAT) sensor. It also feeds the ECU. The other 2 are vacuum ports. I don't know for sure but the one in the rear likely provides vacuum for your cruise control and heater vents. Looks like there's a check valve in it.

Saudade said:

The sensor in the first pic is the Coolant Temp Sensor. This is the one that feeds the ECU. The one in the thermostat is the switch for your electric fan. You have a third on the rear of the head for the temp gage.

In your second pic, the one in the middle is the Manifold Air Temp (MAT) sensor. It also feeds the ECU. The other 2 are vacuum ports. I don't know for sure but the one in the rear likely provides vacuum for your cruise control and heater vents. Looks like there's a check valve in it.

Click to expand...

ok im now totally confused the one in the first pic is the coolant temperature sensor? i thought for a 92 the cts is in the t-stat?

Hallo. That's right picture 3 is the CTS (coolant temp sensor) for the ECU. In the T stat.
and for the E fan.:laugh:

Well today I put in a New

1. TPS Sensor "Throttle Position Sensor"
2. CTS Sensor "Coolant Temperature Sensor"
3. IAC Sensor " Idle Air Control Sensor"
4. MAT Sensor "Manifold Air Temp "

Still having the same problems. Only thing left I think is the MAP Sensor and the ECU, Someone suggested im having vapor lock. Anyone want to add to that ? I know 1998 xj had a problem with vapor lock, fix was to heat wrap the #3 injector well from what I read.

Cold it starts fine I let it get hot enough so fan turns on and then shut it off. I wait 2-3 min start it and it stumbles, If i wait 5 min it will start up fine. Its driving me crazy trying to figure out why it doing that any other help would be great

bump

Did you change the MAP sensor?

If so, any effect?

When you changed the other sensors, did you disconnect the neg from the battery for 30 minutes to reset the ECU?