Bartman Posted February 25, 2008 Share Posted February 25, 2008 So I've been having some issues with my LT1 and it looked like just about everything was resolved...until now. It was running good and I was enjoying a nice drive when all of a sudden it started running a little hot. I thought it would come back down, but it didn't so I turned around and went home. It turned out a bolt on the electric water pump came loose and let the coolant out, so that was an easy fix. The problem is now it doesn't run very good at all, it feels like it's missing or the timing is off. I hooked it up to my laptop and made a recording and everything looks fine - except it's staying in open loop. Any idea of what could be the problem? Thanks, Bart Quote Link to comment Share on other sites More sharing options...
jbc3 Posted February 25, 2008 Share Posted February 25, 2008 Bart, Make sure the coolant temp sensor is still reading correctly. The LT1 has 2 sensors, one on the water pump and the other in the driver side head. The head sensor works the dash gauge, the sensor on the WP goes to the computer. If it is not reading... the computer can stay in open loop. Also did your coolant dribble all over the Optispark??? Hopefully not, because that could be causing the poor running condition. Jody So I've been having some issues with my LT1 and it looked like just about everything was resolved...until now. It was running good and I was enjoying a nice drive when all of a sudden it started running a little hot. I thought it would come back down, but it didn't so I turned around and went home. It turned out a bolt on the electric water pump came loose and let the coolant out, so that was an easy fix. The problem is now it doesn't run very good at all, it feels like it's missing or the timing is off. I hooked it up to my laptop and made a recording and everything looks fine - except it's staying in open loop. Any idea of what could be the problem? Thanks, Bart Quote Link to comment Share on other sites More sharing options...
Bartman Posted February 25, 2008 Author Share Posted February 25, 2008 Bart,Make sure the coolant temp sensor is still reading correctly. The LT1 has 2 sensors, one on the water pump and the other in the driver side head. The head sensor works the dash gauge, the sensor on the WP goes to the computer. If it is not reading... the computer can stay in open loop. Also did your coolant dribble all over the Optispark??? Hopefully not, because that could be causing the poor running condition. Jody Jody,Thanks for the quick reply, I really appreciate it. The coolant temperature sensor in the head did go bad and I replaced it so that my gauge is reading correctly. So the one in the WP may also be bad, but would that make it run poorly as well? I'll look at my recording again, but I think it contains fairly normal coolant temperatures. I'm hoping that the Opti isn't having problems, but it feels like that could be the issue...again. The Opti is vented, but the coolant could have been dribbling on it. Quote Link to comment Share on other sites More sharing options...
Bartman Posted February 25, 2008 Author Share Posted February 25, 2008 Well I checked my file and the coolant temperature sensor looks like its still working. The temperature started at 120 degrees and it was at 177 when I stopped the recording. From previous recordings, it looks like it was going into closed loop at 160 degrees. What else could prevent the system from going into closed loop? Quote Link to comment Share on other sites More sharing options...
deja Posted February 26, 2008 Share Posted February 26, 2008 I found this site a while back, maybe there is some info in it for your case. http://www.lt1howto.com/articles/pcmtuning.htm Looks like your O2 sensors are the first place to start assuming your PCM knows you're at operating temp. Quote Link to comment Share on other sites More sharing options...
Bartman Posted April 5, 2008 Author Share Posted April 5, 2008 I finally completed installing a new genuine GM vented Opti - and it runs great. I drove it around for a while and it's probably running better now than it ever has before. I jumped on it a little on a back road and man that put a smile on my face. It's almost too fast - but I think I can get used to it. I should be ready for the West Coast Nationals performance driving event in a few weeks and I'll find out how well the new wheels and sway bars work. Quote Link to comment Share on other sites More sharing options...
deja Posted April 5, 2008 Share Posted April 5, 2008 I hope this finally fixes all your issues, Seems like you've been fighting this for quite a while. Good luck in the West Coast Nationals. Quote Link to comment Share on other sites More sharing options...
love-my-V8-280Z Posted April 11, 2008 Share Posted April 11, 2008 Bart, Tell me, you are getting pretty close to a LT1 expert... Has the opti been a huge amount of your problems? Would you say stay away from after market optis? I will have my LT1 on the road this summer and do not look forward to the problems you have been dealing with.... Quote Link to comment Share on other sites More sharing options...
Bartman Posted April 11, 2008 Author Share Posted April 11, 2008 Bart,Tell me, you are getting pretty close to a LT1 expert... Has the opti been a huge amount of your problems? Would you say stay away from after market optis? I will have my LT1 on the road this summer and do not look forward to the problems you have been dealing with.... I've had a few problems with my Opti, and based on my experiences and research I would stay away from the aftermaket units. The price of genuine GM units has come down quite a bit and it seems people have beter luck with them. Hopefully I won't be dealing with mine again for a long time. I've had a couple of problems that turned out to be due to my Opti and one lingering problem that wound up being due to fuel pressure. My aftermarket Walbro pump wasn't getting enough voltage through the stock fuel pump wiring. Quote Link to comment Share on other sites More sharing options...
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