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Discussion Starter · #1 ·
I just replaced the timing cover, timing gears, water pump, thermostat, hoses and belt. I reset the cam sensor using Casper's cam sensor tool, added fluids and primed her prior to start up.

1. She started up and (of course) the idle was erratic. Tlink displayed Malfunction Code 15 and I visually checked (what I believe to be) all of the harness connections. The twin pin connector on the front driver's side of the manifold was disconnected. I reconnected it, but it had no effect. Meanwhile, the coolant temps soared to 210*F in a span of 15 to 20 minutes and I shut her down in fear of overheating.

2. Additionally, my #s are all screwy. After attempting to reset and adjust the IAC several times, I've got no joy. I know the CTS malfunction has effect on fuel, timing, idle, etc., but man.
What's the likelyhood of my CTS going bad during a timing chain replacement?

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87 GN (50K miles)
-TE-44, Dutt. necked IC, MSD 50's, THDP, ATR 2.5" exhaust, Boost/knock gauges, Tlink, Hotwired RA XPFP, BGC AFPR, Lubrant 93 chip, Translator Plus, LT1 MAF, ATR Bad Boy cold air kit, Vac brakes, Tie down strap
 

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If you have a decent ohmmeter check the following.

Ground should be on the black wire in the harness make sure the pin is good and out all the way.

Measure accross the sensor itself with the harness unplugged.
Air temps. of 70 or so and the car not run in a while you should read about 3K ohms accross the sensor pins, do you?

Check on the voltage scale at the harness connector the yellow wire, it should read 5 volts to ground.

This is a start.


[This message has been edited by salvageV6 (edited April 27, 2002).]
 

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Surely you jest
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Discussion Starter · #3 ·
Okay, Salvage...I let the car sit for 45 minutes after it's last spike of 207*F. It's matching the VDO gauge. The outside temp is about 70* (and rainy
). The engine was quite warm to the touch (I'd say borderline "hot") and this is what I got

1. Harness connection gives me 5.06V with the key on. 0.0V with key off.

2. The sensor read .64 Ohms on the 20K scale.

One more thing: During the last test drive, the coolant temp hovered around 165*F (on the road). When I brought back into the garage and idled, she shot up to 207*F before the fan kicked on. This brought it back down to 200*F and the fan shut off. My fan never runs after I shut the car down. I believe this is a different problem, but could be a contributing factor. Watcha got for me, Daddy-O?

[This message has been edited by *JOKER* (edited April 27, 2002).]
 

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Try to read the sensor on a lower scale such as the 2K one or even lower. Read it until the meter pegs or goes OL on the display.

You using an analog or digital meter?

Not sure what .64 on a 20K scale means exactly...


If it's an analog meter scale put the reading in the middle of it. Remember to 0 the meter when changing scales.

Lower ohms is higher temperature, it actually may be working ok now.
 

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Discussion Starter · #5 ·
Thanks for the quick reply, Salvatore. The engine hasn't run since the last time I wrote, so it's pretty cool now. I went back and took another reading a few minutes ago and got 1.46 on the 2K scale of my digital multimeter. What's the story?
 

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That means it was about 105-110 degree water reading.

Probably nothing wrong with the sensor.
 

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Discussion Starter · #7 ·
DAMMIT!

110*F after 4 hours of sitting? Isn't that a bit much?

What else should I do?
 

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I would let it sit overnight and cool.

In the morning take another reading and it should be about 3.4K or so for 70 degrees.

If it is in the ballpark I wouldn't worry about the sensor.

I have no clue as to what if anything is driving your temps. up.

The chip should command low speed fan at 160 and hopefully you have a 160 stat.

 

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Sorry to hear about the trouble Ray. It can get frustrating at times. Can you tell if the water is circulating at all? Damn near sounds as though it's not...getting hot that quick. Are the radiator hoses hot?? Maybe the thermostat is stuck & not letting any/enough water get in.
You haven't noticed the hose collapsing at all??

The CTS code does sound suspicious though...seeing how it wasn't there before the work. I sound more confused than you huh?
You want answers not more questions?!!
I don't mind using the cts sensor off of my car if you decide you want to try it. Just let me know. I also have a spare ecm.
 

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Since you have a "new" thermostat that would be suspect unless you boiled it in a pan of water on the stove and checked to see what temp. it opened at.

If the fan doesn't come on low speed near 160-180 the temps. will shoot up to 200 or so when the high speed fan kicks on.
 

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Discussion Starter · #11 ·
Alright. So I have:

1. A possible incorrectly placed thermostat
. What is the proper orientation of the thermostat?

2. A fan that doesn't operate in low speed mode
. How do I trouble shoot this?

and

3. A persistent code 15 registering on the Tlink
. Could this be caused by problems 1 & 2?
 

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If I read his post right, sounds like the thermostat is OK, since the engine runs down around 160 at highway speeds. However he did say that while sitting and letting it idle or slow driving the temps go up to around 200-207, this is an important clue, especially since he said the fan wouldn't come on until the temps got up over 200! Could be a couple of things.

1. The chip isn't commanding the fan on untill it hits stock fan settings (195).

2. The chip isn't commanding the fan on at all which could mean a fan relay problem, and what is turning it on is the high temp coolant switch, which kicks the fan on at around 205-210. This can be easilly confirmed by turning the A/C on with the engine idling. The fan should kick on when the A/C clutch engages.

Probably fan relay problems.



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TurboDave & Kathy Huinker, mailto:[email protected][email protected]</A>
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Thermostat goes in front or the pointy part aiming out at you.

A persistant code 15 is a problem. I am sure you reset the ECM power but I would do it again and make sure your connections are good to the coolant sensor.

Next I would do Daves test and put the A/C on and see if the fan turns on at idle in the driveway in Park.


If it doesn't come on low speed I would swap the two small relays on the drivers side.

If it comes on after that the relay is bad.
 

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Discussion Starter · #14 ·
Thanks, Dave. Thanks, Salvage.

This is weird.

1. This morning, I tested the CTS again. ZERO ohms! Tlink, however, reads virtually the exact same as my VDO gauge. Wouldn't the ECM get a false reading from the CTS?!

2. I turned A/C on and the fan did not come on.

3. I swapped out relays, but the fan operated exactly the same.

Next?
 

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You didn't break the coolant fan speed resistor when you were in there did you? It's the long white thing on the fan shroud just past the connector. A crack in it is ok as long as it's not broken.
Obviously theres no mechanical problems with the engine as it seems to run ok when driving but warms up at idle correct?
since the low speed fan is ECM controlled it should come on at a certian temp which will probably vary with chips. The high speed fan only comes on when coolant temp reaches 224'F or the A/C is on. Does your A/C work the fan only comes on after the compressor engauges through a pressure switch on the high press side.
My GN has a 160 t-stat in it and it will still run at 200'F until the fan comes on.
Did you run it with the can tool before and verify that it's not running the same?
207'F is no big deal unless your racing, remember water doesn't boil until 212 so your not going to hurt anything.
Didn't disturb any grounds on the front of the block


And this concludes my thinking and typing at the same time
 

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Discussion Starter · #17 ·
Thanks raregn. Thanks Steve.

The fan speed resistor is intact, but the wire connection on the passenger side has seen better days. Would that cause a code 15? I'll replace it tomorrow.

The fan does not come on when I turn on the A/C. It DOES come on around 207*F, though.

It always ran a little hot and the fan never operated (during my ownership) in low-speed mode.

My priority is in fixing the code 15 first, unless the fan issue is connected. I appreciate any suggestions on both.


Steve, the Tlink is accurately reflecting the same temperature that the VDO displays. Does the Tlink not read from the same source as the ECM?
 

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To check the low speed operation take a 10-14 gauge wire and go from the Battery + to the bottom of the white resistor block.

The fan should run low speed.

Do it car off and stay away from the fan.


If it works we will next troubleshoot the low speed fan relay circuitry.
 

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Discussion Starter · #20 ·
YOU GUYS ROCK!

Steve, I disconnected for the orange wire for a second and voila...code 15 gone. To state the obvious, I never reset the ECM after reconnecting the sensor
.

Salvage, It's too dark to work (and NVGs remove depth perception), so I'll try the 14 gauge wire trick tomorrow and repost.

Thanks!
 
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