Need auto mechanic help

[Lunatik3]

here's your solution...

anything more I can't really tell you the problem unless the vehicle looks like this one...

[jporter12]

OK, I looked all over the MAS to throttle body connection.

Couldn't find a vacuum leak. If there is one I don't know how to find it.

Everything looks tight and there aren't any wear spots on anything I could see.

I still can't see that sensor but I can see where it is that I can't see so that is prolly where it is hiding. No way I can get to it with out pulling the balancer. Don't have the tools for that job.

Starting to look like this one is beyond my abilities to fix. Sux!

Hit me with a PM if ya want to bring it out to Johnstown. I'll get ya taken care of, with as little hurt to the wallet as I can.... (I can just see how THAT comment can get torn up on here...)

[serpentracer]

The rear I'm referencing in my earlier post, referring to the 7x crank sensor is near the firewall. It IS possible that one is bad, and not correlating to the 24x sensor properly, causing a code, since there is no code for the 7x! The 7x sensor is also succeptable to interference, as it's an A/C signal that goes to the ignition module. I have seen the harness for that thing cause headaches. It's a twisted pair type setup, and I think it has a ground running through it also.

are you sure you are not confusing the crank sensor for a oxygen sensor?

I've never heard of 2 crank sensors.

Mine has a crank sensor and a cam position sensor. is that what you are thinking of?

I just looked this part up on napa's website and autozone's website and both of them show only one sensor for this engine.

I think the autoparts store the OP went to is out of their minds. LOL

Edited October 2, 2009 by serpentracer

[jporter12]

are you sure you are not confusing the crank sensor for a oxygen sensor?

I've never heard of 2 crank sensors.

Mine has a crank sensor and a cam position sensor. is that what you are thinking of?

I just looked this part up on napa's website and autozone's website and both of them show only one sensor for this engine.

I think the autoparts store the OP went to is out of their minds. LOL

Yup, I'm absolutely sure! Did you miss where I said I've worked on MANY of these engines, and I know most of the history of it, since the early 80's (I think it was 82) when they had a carburetor on it? Alldata (the repair software we use at the shop) clearly shows different labor, replacement procedure, part number, and even description for them both. Try carquest, they list 2 different ones, one with a pigtail, and one without. The one without is in the rear of the engine, and they have used the same design sensor that same location since 1987, when they went to DIS.

[ReconRat]

I hate pulling harmonic balancers...

[jporter12]

I hate pulling harmonic balancers...

Piece of cake with a good puller set. I HAVE to have one since I work on cars for a living! Oh, and air tools help a BUNCH, too!

[Strictly Street]

So I took the car out in the rain last nigh to see what would happen.

On the way to a friends house it acted up only once.

On the way back, well that was another story.

Starts right up, idles fine.

Popped it in gear and down the road.

As long as the RPM's are low it seems to run ok.

But once rolling, as it starts to upshift through the gears is when it gets weird.

The engine seems to stop for a half second.

Again and again. Floor it and the engine roars to life and accelerates away, then it chokes/stops/whatever.

Tried keeping it in a lower gear, no help.

Tried going real easy on the gas, no help.

once it starts doing its thing the only thing to do is either way more gas or way less.

Then going back to the same throttle position gets the same result.

If this was an older car I'd be looking at the timing advance or something like that.

It's almost like it wants to pop/backfire through the carb if it had one.

Maybe a fuel filter, idk.

Hmm... I'll have to look and see if I can find that little item.

Injector system, wonder where the filter is on that? By the tank?

I'm thinking I'm going to have to hit a local shop for this one.

Any idea how much the average shop would charge to change out the 24x sensor?

I don't think it will make it to Johnstown without me shooting it and pushing it over a hill on the way.

Very frustrating to drive. Acts ok, then, well you get the idea.

Edited October 2, 2009 by Strictly Street

[Strictly Street]

Does the engine crank for a while before starting? If so' date=' that's a symptom of a failed(ing) crank sensor. However, this will typically not cause the issues your are experiencing. I've read the thread, again, and am fairly confident you have a failed Throttle Position Sensor.

I don't want to hear anybody say anything about the computer not tossing the code for a TPS. We're talking about a 13 year old Chevy diagnostic system... it is what it is.[/quote']

Nope, it starts right up 2-3 turns of the motor if that.

I had a bad camshaft sensor in another car it acted kinda like this.

Cost a bundle to get that fixed (motor tear down) but after that every time the car acted funny, replace the ECM ($60) and all was well.

Which is why I suspected the ECM (Now known as a PCM) in the first place.

But the code came up as a crankshaft sensor.

What if the code is right and it is the crankshaft sensor?

Would that cause it to misfire, skip a beat while running?

I'm thinking at this point the shifting problem is a symptom of the real fault.

If you loose power then the tranny should shift down.

[jporter12]

The shift points are controlled by the PCM, using throttle position, RPM, vehicle speed, and engine load (airflow). If something is amiss with the engine controls, the trans will likely not shift right.

I went in a re-read the "description and operation" of the 24x sensor.

The 24X signal allows the PCM to determine a more precise crankshaft position at lower RPM.

Kinda vague, but from experience I know that ODB2 vehicles are required to detect misfires, and THAT would be the reasoning for the 24x sensor. I'm not going to tell you to NOT change that sensor, but I have my doubts that it will fix it. Although, if it is bad and sending an odd signal to the PCM, it might get confused and throw the computer controlled timing off.

If I was able to, I would come out and take it for a spin with ya to diag it, but this weekend is pretty busy for us...

[jporter12]

Any news Street?

[serpentracer]

Yup, I'm absolutely sure! Did you miss where I said I've worked on MANY of these engines, and I know most of the history of it, since the early 80's (I think it was 82) when they had a carburetor on it? Alldata (the repair software we use at the shop) clearly shows different labor, replacement procedure, part number, and even description for them both. Try carquest, they list 2 different ones, one with a pigtail, and one without. The one without is in the rear of the engine, and they have used the same design sensor that same location since 1987, when they went to DIS.

I was told it's not 2 sensors but they used two type of sensors. in 1996 and 1995 cars were being converted from obd- I to obd-II. and that's probably why it shows 2 for this car. you just need to buy the one like you have it's behind the harmonic balancer. which you do not have to remove if you have the one that slides into a hole.