PLEEEEAAASE HELP! '01 SSEi "skipping"

[Oldman]

This is driving me crazy!

I have an '01 SSEi, a few months ago, it started skipping under acceleration and the tachometer would drop to zero. The SES light came on and the codes were for Crankshaft Position Sensor and Catalytic convertor. The converter has been removed for over a year. It needed to be replaced and I didn't have the money, so I tood it off.
I replaced the CPS, but that accomplished nothing. I then got a Ignition control Module from Harofreak and replaced that. The problem with the speedometer was solved.

The skipping came back. The code for the CPS came back.
I figured I the I had solved one of two separate problems, so I replaced Plugs and wires, sprayed the MAF with MAF cleaner, poured a can of seafoam in the gas tank, and cleaned the throttle body. The code for a bad CPS went away, but not the skipping.

No improvement. It continues to get worse in spite of everything I try.

I live on the coast. I actually live on a coastal island. So, each day I have several bridges to cross to get where I need to go. The skipping takes place when getting up to speed. Once I get going, the car drives great at a steady speed. When I go over a bridge or up any incline the "chugging" starts.

It's my understanding that if it is an ignition problem, there would be a code for a misfire. I have no such codes showing up. So, I'm starting to wonder if it's an injector, a vacuum issue, or something fuel/air related.

It idles perfectly, so pulling off one plug wire at a time to look for a bad cylinder isn't possible.

This thing is really getting bad! It doesn't backfire. There's just a skip or hesitation overy couple of seconds when I am accelerating.

Any help would be greatly appreciated. I just can't figure out what would cause this problem that would not give me a code.

I had all codes erased yesterday (the only one was for the catalytic converter) and the SES light has not come back on, but the problem is certianly there.
Oh, I poured some Lucas injector cleaner in a half tank of gas today and have driven about 40 miles with no improvement.

The car has close to 200,000, but the engine was replaced at 135,000.

Thanks for whatever suggestions you might have.

[SSEiMan01]

Could be a bad CPS again, where did you get it from? I've had bad ones off the shelf at AutoZone. I went through 4 CPS's in a span of a few weeks on my LeSabre.

[Oldman]

If it was a bad CPS, wouldn't I be getting an error code again? And how would a bad CPS work halfway? I don't mean to give you a hard time, but I after I replaced the CPS, I started thinking that it was a waste of time and money. It just seems like if the CPS was bad, you would get no fire and it wouldn't start.
I'm not an electronic ignition expert, but it just seems that the CPS is something that works and the car fires, or it doesn't work and the car will not run.
Am I wrong? Can a CPS "sort of work"?

[SSEiMan01]

My 01 had a CPS that would do something similar to what youre describing, so in a way, it can "sort of" work. Im no expert on electronics either, but I do know a CPS doesnt always throw a code nor does it just flat out fail every single time. :btruestory;

[harofreak00]

An ignition problem also doesn't always show a code. You might have a bad coil, plug/wire, etc...

[Oldman]

Again, I can run at 60 MPH all day long without a skip or any problems. Until I reach an incline, or attempt to accelerate up to 70MPH to pass someone.
What causes timing advance on these cars?
In my days of working on small block chevy motors in the 70's, I would suspect timing problem. How do you check/adjust timing on these cars? If it had a carb, I would replace the accelerator pump or adjust the mixture screws. What would be the equivalent thing to do on my car?
I do not have a consistant skip. I have a skip on acceleration. I can't remove a plug wire and see if it makes a difference at idle, because there are no problems at idle. I had the problem before I canged plugs and wires and I still have the problem. So, I don't think it's a plug or a wire.

[Archon]

Have you checked for vacuum leaks? How about fuel pressure? Tried running with the MAF unplugged? Has the O2 sensor been replaced? Does it do it just when it goes into boost, or will it do it at other times, too? The timing is controlled by the PCM.

[Cujo]

I had this same problem. I did all the ignition stuff and nothing ever improved so i gave up and took it to a trans shop and they found 2 problems. 1-my converter was failing, 2-(this is the one i think really caused the issue) now i don't know what it is exactly called so someone else here might be able to correct me but a part of the valve body (solenoid,spring?)had basically worn the sleeve it was in out and it had just enough room to let fluid pass and couldn't keep the pressure. Now this apparently was a well known issue because when the shop contacted GM about this they sent them a pre-built kit that came with a new "larger" solenoid and sleeves to correct the problem.

[Archon]

Your problem was likely this.
http://www.tripleedgeperformance.com/TC ... ation.html

[Oldman]

Thanks so much for your responses guys.
Harofreak, I'm not sure how to test coils and or plugs and wires. I know if I had a dead skip at idle, I would remove the wires at the coil one at a time and be able to determine a bad coil that way.
The only way I know to test coils for a skip that only occurs during acceleration would be to purchase a coil and try replacing each coil with the replacement one to see if the problem goes away. That might be what I need to do. As far as wires and plugs go, they have just been replaced with no change in the problem, so I have to think that I have eliminated that possibility unless I had a bad plug and or wire and now have replaced thes parts with another that is bad and acting up in the same way. That seems unlikely.
Archon, I have sprayed down the entire motor while idling and didn't experience an increas in RPM's like you would if you sprayed it near a bad vacuum line. I have not tried running it with the MAF unplugged, but will try that today. I was thinking that the car would not crank with the MAF unplugged. I know on other cars when the breather is off, the car wouldn't crank and I thought that was because of the MAF. Maybe I'm confused. Also, the O2 sensor has not been replaced, because I assumed that the bad O2 sensor reading was the result of the CAT being removed. What are the symptoms of a bad O2 sensor other than the code?

Again, I appreciate your help and I will continue to struggle through this until I get it running like it should. I have some suspension poblems as well, and am anxious to take care of them as weel, but I refuse to spend money to repair any other problems until it is running right.
I will be traveling in the next few weeks to attend my Son's college graduation and some other trips for another sons wedding. I really don't want to have to take my wife's minivan on these trips, so I sure hope I figure this all out pretty quick!! Having to drive the minivan is always emasculating and is usually the result of me not being able to diagnose and repair a problem with my car.

Not a good feeling.

If you think of something, please don't hesitate to send me a PM or add it to this post.

[Archon]

You didn't answer if it only did it in boost. A procedure for testing the coils is in techinfo.

Physically inspect all of the rubber connectors on the vacuum hoses. bend them slightly to see if any cracks show up. Problem areas are the blocked off port on top of the supercharger, the lines to the BCA, and the "T" connected to the LIM under the supercharger.

The car will crank fine with the MAF disconnected. May run better...may run worse.

A bad O2 sensor can cause various problems, including what you are experiencing.

[Oldman]

I unplugged the MAF. With the MAF unplugged, when I give it a little gas, it shuts off. With the MAF plugged in, it takes the gas but with a little hesitation. It may be that this only happens with boost. What would that indicate?
I will check all of the vacuum lines again.

Thanks,

Is there any way to check an O2 sensor without replacing it? I simply don't have the money to keep replacing parts unnecessarily.

[Archon]

It could indicate a problem with the BCA. If the O2 sensor has never been replaced, at 200K miles, it is more than due. If you have a scanner, you can check its activity.

[Ken_W]

This sounds like my SSEi's "chugging" problem (there is another thread about it). So far I've replaced both O-2 sensors, my vacuum harness, spark plugs, wires, and ignition coils. Nothing yet has made any difference. Several other members have reported the same thing (everybody describes it in their own words; there is no commonly-accepted name for this yet).

Ken_W

[Oldman]

This morning, it developed a new trick. My car will not start without pressing lightly on the gas pedal. It'll spin, fire and sound like it's cranked, but when I release the key, it shuts off. When it's cold, I have to hold the gas pedal town just a little to make it stay running.

[Oldman]

Archon, I don't understand your questions.
What do you consider "in boost"? Are you asking if it only happens when the boost gauge is 0 or higher? I don't know what your asking. Also, what is the BSA, or whatever you are talking about?

Thanks,

[Oldman]

COils checked out fine. Is there anyway to check the O2 sensor?