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Saturday Mechanic Needs advice please

S

smoraq

New member
Coolant was leaking into unknown area of engine, no white exhaust, no milky oil. Replaced about 2 quarts of water every 4 days or so. Last week I removed and replaced manifolds both Lower and Upper (plenum) gaskets. Installed new thermostat, refilled with new Dex-coolant, bled system. Engine ran fine for several days. No coolant leaks. Then yesterday the Engine light came on and codes P2138 and P1125 appeared on code scanner. Seems to direct to Throttle Position sensor. I am concerned that wires (harness) to TPS might have become frayed while wrestling to remove and replace both manifolds. At any rate, car just died at intersection. Turning key results in no activity from starter. Battery is good, lights, horn etc. But no activity from starter. Any thoughts are appreciated.
 


What kind of car? What year is the car? Throttle cable or drive-by-wire?

If no activity from the starter at all, it's probably unrelated (or very indirectly related) to the work you did...

-BC
 
bobc455 said:
What kind of car? What year is the car? Throttle cable or drive-by-wire?

If no activity from the starter at all, it's probably unrelated (or very indirectly related) to the work you did...

-BC
Click to expand...

Apologies: 2008 Pontiac Grand Prix 135,000 miles, drive-by-wire.
 
Sounds like either the throttle body needs cleaned, or a ground cable needs to be fixed. Or both. Was there a large amount of carbon build up inside the intake?
 
Yes, Plenum had much carbon, cleaned as best as I could. I also cleaned the throttle body very well.
Additional info: I rechecked codes after stall, no crank no start condition. Found the following:
P0068, P0113, P0102, P1125, P2125, P2138, P0068 and P0106.
Yesterday I re-tightened ground wire from battery.
 
Did you use any form of solvent or liquid to clean the TB? if so it needs to dry out completely, there's a few circuits in there that could be shorting out. A t20 torx security bit will get the plastic cover off the side, pull it apart and set it on a table in a warm dry room for at least a full 24 hours.

Don't try adjusting anything inside, your PCM will freak out and you won't have any throttle control.

Which ground wire? The one on the fender or the one on the engine block, next to the starter? Take both off, wire brush all of the corrosion off, then smear some electrical grease on them and put them back.
 


The cable I tightened was from Battery Negative to engine block.
By plastic cover, are you referring to the rather large connector with about 10 pins (tps)? I can remove that connector but I believe you suggest removing the unit entirely from the throttle body? Thanks so very much for your help.
 
This is only if you used some form of liquid to clean the carbon out of the throttle body, there isn't a perfect seal between the butterfly valve rod and the body of the throttle body, so liquid can seep into the servo housing or onto the circuit board itself, and liquid plus electronics equals bad.

You will have to drain some coolant from the engine for this, if you haven't sealed the coolant ports...

Pull the throttle body off of the intake manifold
Unclip the throttle body harness
Stuff a rag into the intake, keep random crap out of it.



The black cover with the 4 torx security screws, that is the cover I am talking about. Inside will be the connector pins, circuit board and servo with the gear drive for the throttle valve.
Don't touch any of the screws inside, I made that mistake already.
Leave it apart, either in a warm dry room or a box with dessicant(basically heavy duty damp rid) or some other way of drying
Let it sit for at least one full day, you want it to be completely and totally dried out.
Reassemble and put it back.
 
Cant thank you enough. Do you still believe the issues with the TPS etc and the No crank No start are separate issues?
Will start tomorrow.........
 


Canned air might be ok, but if there is condensation inside it might push it farther down in. If worst comes to worst, you could bake it in the oven at a really low temp, like 200° for a few hours. Just be careful when you pull it out, so you don't mess up the gasket.

Or burn yourself.

Photo bucket works well on this forum, for future reference.
 
WarStryker13 said:
Canned air might be ok, but if there is condensation inside it might push it farther down in. If worst comes to worst, you could bake it in the oven at a really low temp, like 200° for a few hours. Just be careful when you pull it out, so you don't mess up the gasket.

Or burn yourself.

Photo bucket works well on this forum, for future reference.
Click to expand...

WarStryker13: Thank you so much. Was unable to work on car for a few days. Yesterday put Throttle body in oven for a few hours, let cool, reinstalled. Placed small amount of dielectric grease on connector, and other connectors. Attempted to Start, got continuous clicking. Hmmmmmmmm. You mentioned earlier about removing and sanding battery ground cable. I just tightened it. This time I listened, removed cable, sanded, replaced cable. Battery very low, trickle charged overnight. Just now, key in, turned..........................BINGO. Starts, run smooth. Now I will drive for a bit and see if codes return. Again, I thank you very much for your expertise and time to help.
 
Good, glad I could help.

I had to figure out this same issue the hard way, trial and error... took me three days. Also why I know that it's a bad idea to touch the adjustment screws inside. lol

You mentioned in your first post you're still using Dex-cool, have you had any build-up of orange/brown sludge? I know I had a crap ton when I did my intake gaskets, so I switched to green. Still have some floating around in there, lol.
 


I did not want to use Dexcool however I searched and searched for some definitive answer and surprisingly found that the controversy continues after all these years. At any rate I reluctantly used it but I think it's too early to tell. I can say that I still see small amounts of rust color sludge in the system. Green stuff has worked for generations. It wasn't broke to my knowledge.
 
I have heard that the newer formulation of Dexcool doesn't have the same acids that cause the sludge, but I would still rather go with green. It's just simpler. lol

If the new dex doesn't start to change, leave it until the next time you need to do a coolant change. Follow one of the how-to threads on here for a full coolant flush, I know Scottydoggs has a good one. Get all of that gunk out that you can, nobody needs that kind of negativity in their life. lol
 
I would really like to flush all orange crud and changeover to Green Coolant. Could you please direct me to Scottydoggs link that you mentioned. I am unable to locate the search etc link. Thanks
 
[FONT=&quot] how to flush coolant.[/FONT]
[FONT=&quot] [/FONT]
[FONT=&quot]remove the t stat, put the t stat housing back on, take the upper hose off the radiator, then push it down to the ground to a bucket or let it fly.[/FONT]
[FONT=&quot] [/FONT]
[FONT=&quot]get your garden hose out, put it in the rad turn it on, then fire up the car, let it run till clear water pumps out the top hose. [/FONT]
[FONT=&quot] [/FONT]
[FONT=&quot]then turn the hose off, run the car till no more water comes out the upper hose. then turn it off.[/FONT]
[FONT=&quot] [/FONT]
[FONT=&quot]put your t stat back in, with new gasket, the upper hose back on. [/FONT]
[FONT=&quot] [/FONT]
[FONT=&quot] [/FONT]
[FONT=&quot] [/FONT]
[FONT=&quot]now take 1 gallon of full strength green antifreeze, not the 50/50 crap. ( parts store cheap green is fine to use) dump the whole gallon in the radiator, fire up the car, fill the rad with hose water till its full. top as needed till its ready to be bled of air. it will burp and take coolant as the water in the block warms up the t stat opens up for a few seconds till cold coolant hits it and it shuts again.[/FONT]
[FONT=&quot] [/FONT]
[FONT=&quot]now to bleed the air out, let it idle rad cap off till the fans turn on, (when the fans are on the temp is over 195 deg, the t stat is wide open) then open the bleeder screw on top the t stat housing a few turns till a steady stream of coolant comes out the hole, shut the screw, top off the rad. cap it.[/FONT]
[FONT=&quot] [/FONT]
[FONT=&quot]done.[/FONT]
[FONT=&quot] [/FONT]
 
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