Those are correct voltages and they look completly normal. Yes,,the voltages will fluctuate when there is a load placed on the system.

Do you have any Current or History DTCs that are being set?

Bill

 

When you say DTC's do you mean codes? If so I had 15 the other night and some one told me they are historical codes and don't matter. My question to them which I got no response was how did they fire in the first place and then become historical if I didn't change anything. It told me something must be wrong. They are below.

58 sdm
U1000h
U1016h
U1096h
Ao-ldcm
B2236h
B2282h
B2284h
U1064h
U1016h
A1-rdcm
B2283h
B2285h
U1255h
U1064h
U1016h
U1096h

 

Ah,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,The plot thickens. Who ever says that history DTC's (codes) don't mean anything needs to rethink that statement. Something caused the DTCs and that something was temporary/sporadic. H means that it happened but cleared. It was still something. You have a LOT of door control module U series DTCs Loss of comms. That means that you more than likely have door wiring harness or connector issues.

I recommend popping out BOTH door accordion tubes and pulling up the door harness connectors and inspect them Take them apart and look for damaged spread pin, corrosion, damaged wires etc.

Clear ALL of those DTCs and monitor more frequently. If the car dies, safely pull up the DTCs before you restart the car. See what code appear.

BC

 

Will do. Would any of those codes cause my cruise control to shut off by itself? I was going about 75 for a half hour and the cruise disengaged itself twice in about 10 minutes.

 

The cruise control function happens in the TAC Module. That controls the throttle and it directly linked to the PCM. If the PCM serial data was interrupted, YEP, it will trip off the cruise.

BC

 

had the same thing - symptoms like the OP - broken valve spring was the culprit (thankfully had dual springs so valve didn't drop)

 

So here is the question then, how do I check for that? I don't want to rip apart my engine in my garage. Can I take it to the dealer and have them check? Is there a way the DIC can tell me?

When the fuel pump first burned out the check engine light started flashing rapidly and the car shuttered very hard. Could that have broken the valve spring?

 

One more thing. Could a bad O2 sensor be giving me my troubles? I'm going to check the connections right now in the door but if that isn't the issue I am still puzzled. I have a loose heat shield on my front right O2 sensor. It has been loose for about a year. I'm wondering if the sensor has finally gone bad.

Is it possible that the bad sensor would drain power and then with the same throttle position increase the power?

 

Being your car is mostly stock, meaning no cam upgrade, it is pretty safe to assume you did not break a valve spring, well if you did, the car wouldnt run at all. The stock valve springs are not dual springs, so if one broke, the engine would be a total mess....


The O2 sensor would not be giving you alot of those comm codes, it would be throwing codes of its own if it was acting up...

 

Hmm, okay I guess I need to step back and take a look at the whole scenario again.

1: Replaced stock fuel pump with new stock fuel pump due to loud pump noise.

2: 1 month later car shuttered on down shifts from 2nd to 1st. It felt like the engine didn't have enough power to accelerate it forward then it caught up again.

3: Car started to stall, missfired, and eventually quiet.

4: Pulled multiple comms codes while waiting for tow truck

5: Dealer found that the new fuel pump was burned out and replaced it.

6: Received car back from dealer and noticed that in certain throttle positions the car feels about 50 HP lower.

7: While driving at 75 mph cruise control disengaged. Happened again about 15 minutes later.

8: Pulled codes. Found multiple historic codes indicating a comms problem. I'm unsure if those were from when the fuel pump went out and the engine shut down hard.

9: Reset codes. No new codes have fired in the last 4 or 5 days.

10: Tested voltage to fuel pump and voltage was around 14.3. BC indicated this is normal.

11: Need to check connections in door. Went to check them a few minutes ago and I pulled the accordion off the passenger door and can't see the connection. My fat hands can't get into the door properly to pull the accordion off the car itself. I don't want to disassemble my car in the garage for I fear I won't be able to get it back together.

12: Still have the same power problem. I can be accelerating with the same peddle position and the car feels like it hits a power band. This is under non heavy acceleration.

13: I"M STILL LOST!!!

 

There are very good instructions for #11 in the Electrical Troubleshooting sticky. Also instructions for cleaning/repairing the ignition switch (or you can buy a new one from Autozone/Oreilly/GM depending on budget).

I would suggest doing both before going any further.

 

You can just grab the accordion tube and collaps it and yank it out. It pops in and out really easy. The connections are located inside the opening in the door frame (body side) Pull up on the wires and the connectors will come out of the hole. Its really simple.

BC

 

I finally had time to check the connectors and everything appeared to be normal. There was nothing out of the ordinary that I could see. I didn't see any corrosion and everything appeared in line.

I'm wondering if my issues are not related. Is it possible when my fuel pump went out and the car didn't shut down that the codes are from that?

There is still the issue of my cruise control shutting off on its own and the car not feeling right while driving.

Some new theories and updates. I have discovered the car feels much more powerful if I start accelerating around a corner. Then again it always has. I have also noticed my shifts are more sluggish than before. The transmission doesn't feel like it is locking up like it used to under light acceleration. For example: Going 50 MPH and gently accelerating before you could feel the engine connect with the rear end and now it is almost as if the tranny won't hook up and in order for it to accelerate it down shifts. Once it down shifts the power is there, but it takes the downshift and the gear to have the power.

Could the transmission fluid be causing this? The car has 50 thousand miles on it and I drive it through the mountains, city, and suburbs. Should I change the tranny fluid. I'm not sure if the previous owner ever did but when I bought the car with 33,000 miles on it I know I didn't. Could my rear end have problems?

I have an extended GM warranty but I want to direct them in the right direction before I have a bunch of idiots guess what might be wrong.

Thoughts?

 

Best of luck to you. Stealerships lie. Although you have the warranty, they are still out to get money....its just not from your pockets (with the exception of the cost of the warranty.)

IMHO, I would try to problem solve yourself before going to the dealership. People on this forum are VERY EDUCATED with these cars and you could learn a lot. I rather work on them because I take my time. I would hate the fact that I had to go in to a stealership just for them to pull out the same parts out trying to problem solve. More times something is taken out, the higher propabilty of something else breaking....

Ever resolved the issue?

 

I couldn't agree more. With that in mind, does anyone have any suggestions?

 

Have you thrown any codes since the new pump??

Some of the driving issues you cite are somewhat subjective...50 hp less, the tranny doing this...hard to diagnose sometimes without a code or "failure"...

Transmission fluid maintenance surely could not hurt...