Did something wrong!
Thread Starter
Heel & Toe
Joined: Apr 2010
Posts: 15
Likes: 0
From: Auburn GA
Did something wrong!
Hey guys, last week I removed the intake on my 93 to repair the common LT1 oil leak. That went well not a bad job at all. The after effects have me stumped. Now it's to start when cold, idles high and wants to stall when starting off. Quickly warms up and then runs OK. Also the cooling fans run anytime the motor runs. The check engine light is on the the code I get is a 15. I think that's a low coolant temp. None of these problems existed before. I've checked all my connections and looked for possible vacuum leaks. Not saying they're not there but I don't see them. Any help would be appreciated.
Le Mans Master
Joined: Jan 2006
Posts: 5,620
Likes: 206
From: Orlando FL
I would start checking 2 items. Look at the IAC motor and make sure it is working OK. Check the connections and the plugs and any pulled or broken wires.
Code 15 low coolant temp would be caused by something wrong with the temp sensor in the water pump. Also look at the digital temperature read out in the spedo. See if it displays correctly. Temperature should come up from ambient to operating temperature (190-210). If it does not do that, check the wiring to the sensor. Check the wires going to the ECM also.
The code 15 might be causing the fans to run since the ECM might think there is a cooling problem.
Code 15 low coolant temp would be caused by something wrong with the temp sensor in the water pump. Also look at the digital temperature read out in the spedo. See if it displays correctly. Temperature should come up from ambient to operating temperature (190-210). If it does not do that, check the wiring to the sensor. Check the wires going to the ECM also.
The code 15 might be causing the fans to run since the ECM might think there is a cooling problem.
Thread Starter
Heel & Toe
Joined: Apr 2010
Posts: 15
Likes: 0
From: Auburn GA
Did something wrong
Thanks for the replies. The IAC valve sounds like a good place to start. the throttle body was very dirty and I cleaned it. Looks like that would be a good place for debris to collect. I did bleed the coolant system but It may worth a redo. I'll post my results.
Melting Slicks
Joined: Jan 2009
Posts: 3,482
Likes: 195
From: folsom california
last time I worked on the cooling system (replaced thermostat) on my LT engine, even though I used the bleed screw, it still took four or five cycles of start, run, allow to cool, add more water before all the air was actually expelled and the cooling system functioned properly.
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Thread Starter
Heel & Toe
Joined: Apr 2010
Posts: 15
Likes: 0
From: Auburn GA
I would start checking 2 items. Look at the IAC motor and make sure it is working OK. Check the connections and the plugs and any pulled or broken wires.
Code 15 low coolant temp would be caused by something wrong with the temp sensor in the water pump. Also look at the digital temperature read out in the spedo. See if it displays correctly. Temperature should come up from ambient to operating temperature (190-210). If it does not do that, check the wiring to the sensor. Check the wires going to the ECM also.
The code 15 might be causing the fans to run since the ECM might think there is a cooling problem.
Code 15 low coolant temp would be caused by something wrong with the temp sensor in the water pump. Also look at the digital temperature read out in the spedo. See if it displays correctly. Temperature should come up from ambient to operating temperature (190-210). If it does not do that, check the wiring to the sensor. Check the wires going to the ECM also.
The code 15 might be causing the fans to run since the ECM might think there is a cooling problem.
Thanks for the great advise, you hit the nail on the head as they say. I removed the IAC and it was toast. Replaced it and after a couple of starts and shut downs to allow the computer to learn the valve I'm running like normal. I'll tackle the cooling fans next. I'll follow Sara Lou's advice on that and see what happens.
Melting Slicks
Joined: Feb 2008
Posts: 3,286
Likes: 6
From: Palm Beach
What has all that to do with the code 15? Some DTCs cause the fans to run continuously. Code 15 is one of those.
Check that the coolant temp reads ambient at start and rises normally as the engine warms up. Compare digital to analog.
Eddie
Check that the coolant temp reads ambient at start and rises normally as the engine warms up. Compare digital to analog.
Eddie
Last edited by MK 82; Sep 17, 2011 at 04:17 PM.
Thread Starter
Heel & Toe
Joined: Apr 2010
Posts: 15
Likes: 0
From: Auburn GA
I can't catch a break. The IAC solved the running problem and clearing the codes solved my fan problem. Left the house last night with engine running better than it has in a while. After a few miles it stuttered a couple of times and died at the next traffic light. I have spark and pressure to the fuel rails. Will do some searching later today. Guess something is keeping the injectors from firing. AAA is becoming my buddy.