I need a part identified - and Astro P.I.'s out there?

[djdawg]

My story starts with a mechanic I got off of Craigslist...don't they all?

I'll save you most of it and cut to the chase...he did some diagnostic work on my Astro ('99, fwd, 4.3) and determined the part that I needed. We talked briefly about it and he was going to pick it up a few Sat's ago and come over and install it. The problem is I haven't heard from the guy for almost two weeks. (no, I didn't prepay him....ha ha) I've emailed him, called, etc...I don't know if he's in jail or what but I'm tired of waiting and I just want to buy it and install it myself.

We talked briefly a few a few times about the part and he told me what it was, but I kind of half listened because I thought he was going to handle it. I'm hoping that with the clues I have someone might be able to come up with the name of the part. There is a line that runs from the top of the engine down and ends up in the area accessible by removing the doghouse (see pics) and I believe this line connects or is a part of the part that needs to be replaced. I also want to say he said it was a "master" something or other but I could be wrong. He said that he would charge me $35 to purchase the part used and install it. This part apparantly has been responsible for my problems in acceleration/tranny. What I mean is that for months I thought my tranny was failing me but he diagnosed the van and said it wasn't the tranny but it was this part that was affecting the acceleration at certain speeds...the van tends to slow down when on the fwy and when I pull back on the gas pedal, it seems to start speeding up again. I'm hoping that this might help...I appreciate everyone's help!

[MountainManJoe]

I think what you're holding in the photo is the cruise control cable.

Another possibility, which is in the same engine area, is the vacuum source (could be called master too). You can read about it here...
viewtopic.php?p=6689#p6689
That will have an effect on your acceleration.

[djdawg]

I think what you're holding in the photo is the cruise control cable.

Another possibility, which is in the same engine area, is the vacuum source (could be called master too). You can read about it here...
viewtopic.php?p=6689#p6689
That will have an effect on your acceleration.

Thank you timeless...I read that whole thread...so it's an inexpensive vacuum hose? Could this affect my acceleration in a big way though? I'm talking I'm on the fwy and I drop down to 35-40mph....and yes! That is the cruise control line and when you said that it reminded me that this guy said the same thing. Does that line run to anything specific? Thanks again....

[LiftedAWDAstro]

We need a little more info...

Does it only do it when you have the cruise control set? If it does, when you press the gas pedal with your foot does it take off normally? If you drive without the cruise control on, does it hold speed like it should and downshift on hills all by itself to keep the speed?

If you answered yes to all of these then I would say you need a cruise control module. You can try a junk yard one or buy a new one at Rock Auto. They are expensive so a used one might be a wise choice.

[djdawg]

We need a little more info...

Does it only do it when you have the cruise control set? If it does, when you press the gas pedal with your foot does it take off normally? If you drive without the cruise control on, does it hold speed like it should and downshift on hills all by itself to keep the speed?

If you answered yes to all of these then I would say you need a cruise control module. You can try a junk yard one or buy a new one at Rock Auto. They are expensive so a used one might be a wise choice.

Thanks for your help lifted....this problem has been happening for several months now and I have never had the cruise control on since it started. When it first started I'd be cruising along at 60 and when I hit a slight incline the van would start slowing down even though I'd have my foot on the gas pedal. I would back off on the gas pedal just a bit and it felt like it would "catch" for lack of a better term....engage and start speeding up. It has gotten increasingly worse since then. There have been times where I had to drive longer distances and I've noticed that if I stop for a bit after driving awhile (turning off the engine) - even just stopped for 10 mins - it would get better for a bit. Also one of the things that this guy did was while I was in park I floored the van to rev the engine up and the engine would cut back almost like it wanted to die - but wouldn't - then I pulled back on the gas pedal and the engine would rev up normally again. I think this was one of things that led this mechanic to believe that it wasn't tranny related. We also did a pretty extensive test drive and I shifted through gears (and he drove too) and he also seemed to think that also pointed to not a tranny problem. My tranny fluid has always been great and to the right level....I hope that helps.

[MountainManJoe]

so it's an inexpensive vacuum hose?

ABout 10 bucks.

Yes, a vacuum leak can definitely impact performance. The control system actually measures the amount of air coming into the engine (via MAF sensor), and uses that to decide how much fuel to add. Air that enters the engine through a leak, such a broken vacuum line, will not be measured, hence throwing off your air-to-fuel mixture. A quick look under the doghouse should tell you right away if that's your problem or not.

To me it sounds like either an ignition, or fuel delivery problem. Any trouble codes?

[djdawg]

Thanks again Timeless...I plan on going to the Chevy dealer and picking up this part tomorrow...I'm looking at the pic in the other thread - is it the larger diameter hose that looks like it has black tape around it in spots? And is there more than one vacuum line? What specifically should I ask for when I go in there? I can tell him the $10 one...ha ha.

[v8famvan]

Looks like these guys have correctly identified the cruise control cable for you in the pic you posted. I has also been correctly stated that this part is not contributing to your issue as you are not using your cruise control when the fault occurs.
Additionally, yes there is a common vacuum line that breaks in there, however, it will not be causing the kind of driveability concern that you describe.

I could list a number of things that could cause the concern that you describe, but some testing needs to be utilized to make a determination of the fault. The place that I always start is an evaluation test drive, however, I am a trained GM tech with 20 + years of experience in driveablity & electrical concerns. If you are going to stop in at the Chevy dealership tomorrow, ask if you can get the shop foreman to go for a drive with you to get his opinion on the concern. Pepper him with questions & see what you can glean from that conversation - worth a shot?

For example: A failing cat converter (loose pieces). Driving down the road hitting bumps & the cat converter material turn sideways & restricts the exhaust. You let off the throttle - flow changes - piece shifts position & volia! your power is back. This kind of theory can be verified a plausible by an experienced professional. Of course there is further testing that needs to be done to confirm the theory, but it is a start.

[djdawg]

Looks like these guys have correctly identified the cruise control cable for you in the pic you posted. I has also been correctly stated that this part is not contributing to your issue as you are not using your cruise control when the fault occurs.
Additionally, yes there is a common vacuum line that breaks in there, however, it will not be causing the kind of driveability concern that you describe.

I could list a number of things that could cause the concern that you describe, but some testing needs to be utilized to make a determination of the fault. The place that I always start is an evaluation test drive, however, I am a trained GM tech with 20 + years of experience in driveablity & electrical concerns. If you are going to stop in at the Chevy dealership tomorrow, ask if you can get the shop foreman to go for a drive with you to get his opinion on the concern. Pepper him with questions & see what you can glean from that conversation - worth a shot?

For example: A failing cat converter (loose pieces). Driving down the road hitting bumps & the cat converter material turn sideways & restricts the exhaust. You let off the throttle - flow changes - piece shifts position & volia! your power is back. This kind of theory can be verified a plausible by an experienced professional. Of course there is further testing that needs to be done to confirm the theory, but it is a start.

Ok, James, thanks for that...I don't know if that makes me feel better or not. Ha...I wish this guy would call me back so he could just tell me the name of the part....ugh!

[djdawg]

Hey everyone...I picked up that vacuum line since it was only $10...after talking to the dealer parts guy, he was thinking it might be a clogged catalytic converter. (didn't someone mention that?)

He suggested an exhaust shop that could install an aftermarket one...I asked him if there was anyway for me to pull it off and "unclog" it but he said there really wasn't. However after googling for info I'm seeing that there might be a few options...

Catalytic converter cleaner - I'm reading how you can use an engine additive version or you CAN take it apart and clean it. Does the additive work? I think my situation is pretty extreme so I'm wondering if it would do anything at all...is it hard to pull down the cc and clean it? I'm going to do some searching on the board here in a min to see if I find anything about that option.

I'm also seeing a "universal" CC by magnaflow that's only around $50...would this be an option to just replace the one I have? I'm assuming welding is needed? Thanks!

[djdawg]

I'm reading stuff on the boards about gutting the Cat C....if I have a clogged on then that would probably solve it but if it's gutted I'm assuming I won't be able to pass emissions? We do it every other year here in WA.....

[MountainManJoe]

I'm no exhaust expert, so if I'm talking jive, hopefully someone will chime in and correct me, but here's what I know.

If the inside of the catalytic converter is clogged, then it could be the source of your problems as v8famvan said. If freeway driving didn't clear it, then there's no cleaner that will help you. The inside which is supposed to look like this

probably looks like this

Just bang it with something and see if you hear bits rattling around. It's strange that it's speed related, but maybe when you slow down, the pieces inside kind of relax and fall to the bottom, and when you go fast they all stick to the back. Who knows.

You could theoretically cut the CC out, remove all the bits, weld it back in place, stink like hell, and possibly get a ticket.
As for the universal, you'll have to check with your state laws, but it's unlikely it does the same job as the OEM CC.

Good luck!

[1Gary]

I just went through this on Rufus and Cat's.Pull a pre cat O2 sensor closest to the cat.Run it like that and if the power is back consistently by relieving the blockage,it is likely a blocked cat.The truth about the cheapo aftermarket cat's is they don't hold as much air as the O.E.M. replacement ones do.So it is entirely possible to replace it with a $50.00 cat and still have a check engine light.There is a indirect rebate in replacing with a more expensive O.E.M. style cat.Either if you replace it or have someone do it for you,you want the cat that was taken off to take to the scrap yard.A O.E.M. cat I turned in,I got I think was $125.00.

So you see my point??.The better Walker cat was $263-$125.Not too shabby when you consider the Walker is all that much better of a part.

I almost forgot.The cheaper cat's don't have the hole for the post O2 sensor,so you have to mess around with drilling a hole and welding a bug on a exhaust pipe.Kind of a PITA.

[djdawg]

Thanks guys...I'll be doing some work on the van tomorrow so I will do the tapping Timeless. Gary, I've done some work on Astro's in the past but the cat is new to me...I understand that sometimes there is more than one sensor? Sometimes one on both ends? Is it a clip type of connection where you pry the tab and then pull it off? If there are two sensors would it hurt anything if I pull both off? When you say "before" the cat, are you talking towards the front of the vehicle of towards the rear? Thanks again....seems like if it is the cat then welding will probably be required so that looks like I'll end up taking it to a shop anyway.....

[djdawg]

Here's a thought....if I pull the sensor and it goes back to working awesome would there be any long term harm to anything if I just left the sensor disconnected? We have emissions testing here every other year and I already know that I won't have to go through that this upcoming January 2013...so I wouldn't even have to worry about emissions until Jan 2014. Chances are I won't have this vehicle anymore by then...that would be a great, free fix if it wouldn't do any damage to anything else....?????