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Discussion Starter #1
I'm new to the forum and see lots of guys with diagnostic experience on these engines. I got one that I didn't see in the threads that you may know.

Background: 1995 DCM with 110K miles. Mostly stock. Only had sewer tube intake w/KN Cone filter, home plate removal (hockey puck), Throttle body bypass, Spintech mufflers. Exhaust Manifold Bolt at RT Rear broke w/ no sound of leak but slight carboning in the area indicates possible leak. Runs pretty strong but intermittently lags (I think it's sensor/PCM). That's another story.

Used to averages about 16 mpg. I did get a 21 mpg hwy just before seafoaming it last month but now the mileage dropped. Only getting about 13-14 mpg with mixed driving. Maybe fouled the plugs/O2 sensor. But my question today is.....Symptoms follow:

Check Engine Light comes on intermittently, usually when I'm just tooling through the neighborhood (not at hwy speed or "spirited driving") and the secondary (left side) fan turns on no matter what the ambient air temp is. CEL usually goes away when the engine is turned off and restarted.

I had a scanner put on it and it reads DTC 32 for EGR. I can't find my manual that tells me how to diagnose this. I had a guy try to diagnose it and he put a vacuum gage on the Intake Manifold side of the EGR solenoid and got vacuum, then he checked for vacuum between the solenoid and the EGR valve and there was no vacuum. He said its the solenoid.

I thought to properly check the solenoid you had to apply voltage to the connector so simulate a PCM signal?

The part is not too expensive but don't want to start to throw parts at it. Should I plan to remove the EGR valve and tube to clean it too?

Your advice is welcomed. If I don't respond right away it's because I'm headed out to buy an EGR Solenoid in a bit.
Thanks,
 

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Sounds like the sensor on the waterpump. When it starts to go bad it will make one/both fans come on and throw a check engine light. Also, if you ever unplug it, it will cause a hard start and both fans will come on.


As for the egr, it if is the egr, might as well replace with the F-body egr and solenoid.
 

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Discussion Starter #3 (Edited)
I've read some on that water pump sensor. I have unplugged it to check the secondary fan. I would unplug it and a few seconds later the 2nd fan would go on.

But what you are saying is that it won't tell me if the sensor is bad, right?

Will it also through that 32 code too?

What I have noticed is that my temp gage fluctuates a lot more than before. It used to be rock solid at 1/3 of the scale. I did the throttle body bypass (had to bleed it a few times to get the temp down) and after that I notice the gage tends to rise up more to 1/2 way than before. I know some say that doesn't mean anything because the PCM is set for a high 2nd fan turn on temp but the gage never jumped like that before.

Thanks,
 

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no, wont give you a egr code but it sounded like you had more than one issue and that sensor will cause some of your symptoms.
 

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Discussion Starter #5
Roger that on the Water Pump Sensor.

Hey, I wish I'd get 35 mpg on my Impala too. I bought the impala telling the wife it gets 20+mpg (that's my story and I'm sticking to it) but it came up short in that department.

Even when I drive like grandma 60-65 mph I only get barely over 20 mph hwy.

Maybe solving some of these issues will help.

Mahalo
 

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That sensor is tapered. When you remove it coolant will pour out so be ready. When you replace, dont use too much force as its tapered.
 

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Discussion Starter #7
Water Pump Coolant Sensor replaced.

I got the sensor this morning and put it in this afternoon. Thanks for the note on the torque for the sensor because it was tough coming off and I would have been tempted to crank it back on.

The fans are working fine now and the temp gage is now steady and not jumping around like it was before.

That was a good call to point that out to me because I wasn't even looking for that.

I don't know what will happen as far as the dtc 32 yet but I got word that I need to smog my car this month so I know this won't be a problem for the test.

I'm going to drive it like this for a few days before changing the EGR Vacuum solenoid just to see how the car drives.

Mahalo,
 

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Sounds like you got lucky... :)
I wish I would have read this about a year ago! I was having about the same problems, check eng light, fans constantly running, temp gauge not reading anything. So I thought I'd replace my sensor. I am no mechanic - and I will never touch a thing under the hood again!!!
Put the $15 sensor in, and it would leak around the threads. Removed/cleaned it off, put a little thread sealant on it (per manual) and reinstalled. Just as I reached the torque value it cracked. :eek: Not the sensor... the lower intake manifold. That $15 part cost me $750.

To make matters worse - shop got it all back together and I still get the same problems. Codes now say I have a open thermistat. Arrrrgghhh

BTW: Quick question... One of my fans is going bad - bearings are shot when it's cold. (noisy as heck!) Anyhow, I unplugged that fan until I can get it replaced. Are the fans hooked in series?? I don't think the other fan ever comes on now...???...

L8R
 

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Discussion Starter #9
Wtr Pmp Sensor Installed

I got the sensor in and gage reads in the usual 1/3 range.

Performance is still about the same regarding sluggish off the line.

I also still got a CEL while "cruising" at 25 mph or less.

I read that dtc 27 is for the EGR Solenoid so since I didn't get that code I will probably hold off putting in the new Solenoid valve and instead get an EGR gasket and pull the EGR valve to see if it's clogged.

Anyone want to say weather it's work trying to clean the EGR valve?
Even if the fix is temporary, I'd probably want to see if the EGR is bad before chunking out $140 for a new F-body 6spd Man valve.

Regarding the fans, I don't know for sure about their wiring as I don't have that schematic. I'd guess they aren't. Temp gage probably will go to almost 3/4 range before the 2nd fan goes on.

Aloha
 
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