: False Overheating?



Rustbucket350
07-20-12, 06:37 PM
I have a 96 Eldorado that goes into limp mode around 190 degrees. I pulled the codes and along with the overheat code it also has a #8 cylinder misfire and a bad O2 sensor. Would a misfire cause the early overheat condition? Obviously the engine isn't actually overheating since there is no spillage from the surge tank and the temperature is too low. Could it be the temp sensor or possibly a bad pcm?

vincentm
07-20-12, 06:52 PM
Check the purge line and do a block test

Rustbucket350
07-20-12, 09:47 PM
What do you mean by block test? I tested the coolant for exhaust gases and I didn't see any. I'll check the purge line though

Ranger
07-20-12, 10:19 PM
I wonder if you might not have a faulty ECT sensor.

Rustbucket350
07-20-12, 11:02 PM
I'm wondering that too. I do have a new one that I can put in so I'll try that too. I realized its not quite going into limp mode but it gives me the idle engine message at 190 which I still think is a little early.

Ranger
07-20-12, 11:24 PM
It's not a "little" early. It's VERY early. You shouldn't get that message til about 265 degrees (maybe a tad earlier).

jimsbox
07-22-12, 07:34 PM
I'm confused, if you know it is 190 from the dash read out, would that not have been reading the ECT? Maybe the computer has a glitch in it posting the message at 190 which isn't even up to normal temperature yet.

Submariner409
07-22-12, 08:23 PM
Ummm............ "Limp mode" is very, very different from "Camel mode".

Limp mode occurs when some part of the emissions or ignition system fails and defaults the timing to about (fixed) 10 degrees BTDC.

Camel mode drops successive pairs of cylinders during extended intervals of engine temps above 265 degrees.

Rustbucket350
07-25-12, 12:45 PM
Well it appears the purge line is fine. I should probably mention that the car also runs fairly hot most of the time. It doesn't overheat but it runs around 240 degrees or so and I haven't been able to figure it out. The water pump is new and the fans work fine. Maybe its the radiator or thermostat?

Ranger
07-25-12, 03:49 PM
GM DID use the sealant tabs in '96. I suppose it could not hurt to flush the radiator and blow out the cooling fins with compressed air and then flush them with a garden hose. Remember, the A/C condenser is in front of it. Also check the WP belt tensioner. Thermostat is possible, not probable.

djmumm
07-31-12, 04:33 PM
Hi
I had a similar problem with my 93 eldo. n* engine. It would go into camel mode, and then back out of camel mode 5 to 20 seconds later. It would declare that the engine was hot, it would kick the fans on high, and go to half power. The temp reading was always fine on the dash readout, before going to camel mode. It would never blow any anti-freeze out of it. Unfortunately, the readout cannot display the temp, and complain about overheating at the same time. I worked through a number of things to try to see if the engine really was hot. I was worried that it had sucumbed to the dreaded head gasket problem. I replaced temp sensors, checked thermostat, etc. Anyhow, to make a long story short, I narrowed it down to suspecting the ECM. I then went to my nearest junk yard, picked up a cheap ECM, ($20), and the problem was fixed. I have since put 20K miles on it and all is well. It turns out that the ECM in the 93 is prone to cold solder joints. The ECM that I got from the junk yard happened to have been rebuilt, so even the better. My 93 ECM is a common one with a removable PROM. Unfortunately, I believe the the ECM in a 96 may be one that needs to be programed? Others can probably help with this question.

I just read that your car is running at 240 degrees, so my experience is much different. My car was always between 190- 210 when the problem occured.

Good Luck. Dave