TOPIC: 2000 Mazda B2500 - First Groove

Karl - first I want to apologize - I spoke like I knew how your Mazda was configured, and it sound like it is somewhat different from my Honda.

Did your idle return to normal after removing the plate?

The little pipe you mention is worth looking into. It may only sensor for perhap the MAP, in which case it does not leak air into the engine. Can you disconnect the hose and suck on it (I suppose gentlemen use a vaccuum pump)? If it holds a vaccuum, warm and cold it is probably ok to leave be.
If not, you could try leaving the hose off and capping the pipe.

It is not likely that this little pipe leaks as much air as the idle air port you tried blocking before - it might be worth trying that one again. When I blocked mine, I only put a tiny poke in it with the tip of my knife to improve cold idle. May not work on yours, I don't know.

Just to be thorough - have you reprogrammed your ECU? And disconnected and plugged any other active vaccuum compromises on your intake manifold?

Karl - first I want to apologize - I spoke like I knew how your Mazda was configured, and it sound like it is somewhat different from my Honda.

No problem Mark. I would rather have someone shoot suggestions at me even though some may not apply because maybe one will and would solve my problem. Your efforts are appreciated.

As far as that mystery hose. Its in the pictures of my TB where a metal angeled 4" hose juts off the TB and that connects or slips into some rubber hose sticking out from under the intake manifold. Where that hose leads to is a mystery because it is hidden from view. I was wondering why this hose was never mentioned in all the posts.

Since I cant plug this hose or the TB will not be able to be re-attached, I can always tape/plug the hole shut inside the TB and see if this affects anything. I just bought a Mighty-Vac and can test the hose and see if it holds vacuum. That hole in the TB that leads to this hose is on the dynamic side/after the groove but on top side of the TB not like the IA hole that comes from the IAC valve which is on the side wall above the groove as in the pics.

Will do the test in a few hours and see if there are any results.

Did a re-cut of the groove after filling in with JB Weld and changed the 02 sensor before the CAT to see if anything would change. Nothing changed in HP and it doesnt look like MPG changed yet by the readings from my ScanGauge II but will know in about a week.

The suggestion was made to do some vacuum tests since it sounds like there is a vacuum leak somewhere to not have an immediate increase in HP.

Ok, Here is what I found.

Did a test on the EGR and it seems to be holding a vacuum.
The metal 4" pipe coming off the TB that gets slipped into a rubber hose when back on manifold, has the blue pen top inserted in it in pic #1




That rubber hose connects to a metal pipe which is wrapped in a blue covering in pic #2




That metal pipe travels down under the frame/chasis and goes toward the rear of the vehicle.
Have no clue what that long thin pipe is for that travels alongside the frame.
Did a vacuum test on the hose which leads to the pipe and it seems to be holding a vacuum.
Also taped closed the hole in the TB that leads to the pipe as suggested and drove it with no difference in performance. Since the pipe seems to be holding a vacuum anyway, should I remove the tape since that hole is there for a reason?


Did a vacuum test on the red plastic tube coming off the manifold in pic #3 and that seems to be holding a vacuum.



Did a vacuum test on the brake booster in pic #4 after pulling off the hose that comes from the manifold and that was not holding a vacuum. My question is that since the hose comes from the manifold into the brake booster, shouldn't it hold a vacuum and if it isnt, is that the reason why no HP or MPG increase with the groove? Is the pressure from the groove/manifold being lost in the brake booster? [/color][/b]

Karl, most boosters like that will hold vacuum that blak valve is a check valve.The only way it should have no vacuum inside is stepping on brake pedal or if its leaking.Are you losing any brake fluid that will eat seals up in a hurry.


Dan Merrick

Hi Karl

Sounds to me you have found your problem, the leaky brake booster.
Remove the tape from pic 2 and fix your booster.

If you really want to, you could plug of your booster and go for a ride on a quiet flat bit of road to see if you can feel a difference in the acceleration. Just be very aware you will not have power brake assistance!! It will take a lot more foot pressure to stop!
Probably safer to just fix it

I reckon you'll be a happy chappy

Karl, most boosters like that will hold vacuum that blak valve is a check valve.The only way it should have no vacuum inside is stepping on brake pedal or if its leaking.Are you losing any brake fluid that will eat seals up in a hurry.

Dan,
So the vacuum test with he Mityvac would not be valid because of the check valve?
I am not leaking fluid that I know of. Should my test for vacuum shown a vacuum anyway?
Thanks for the info but confused on the validity of the vacuum test.

Rino,

Its night here(after 12am) but got a bolt to plug the hose to the booster and clamped it on.
Left the booster hole open for the moment.
Did a spin but didnt notice any HP increase. Did find that the brakes were greatly compromised
so lucky I didnt have to stop suddenly or I would have been in trouble.
Seems like this is turning into a nightmare. Thought that finding no vacuum on the booster was the answer or maybe its me not applying suggestions properly. Maybe there was a HP increase with every little change I make looking for the answer and have not noticed it since its been gradual.
Will know soon after changing the 02 sensor if there is a MPG change since the Scangauge II doesnt register one.

Thanks again for your help.

Karl, one detail in checking booster vacuum--I discovered on one of my vehicles that it took many pumps of my Mityvac to pull a vacuum on the booster, like a couple dozen pumps. Mityvac only has small displacement per stroke, I thought I had a leaky booster, then kept pumping till it pulled a vac, which it did hold.

Tracy G

If it were in my shop, I would be sure I did a thorough test on the line to the booster. You MUST have a tight seal on the hose. This can be very problematic.

One way to ensure a good connection is to apply a coating of Vaseline or KY Jelly or axle grease to help the connection. Once this is applied, your pump down will be an accurate gauge. But you MUST make sure the connection is good.

If, when you test, you get a Sero Vac condition, remove the hose and test it alone. If that holds, then plug into the booster. Again, you MUST make sure you have a good connection with your pumper.

You're going to do well, all you need is to take a little more care with yoru testing. If you shortcut in any way, you will continue to have problems in your diagnostics, so take your time!

The results are worth it!

Ron

Did another vacuum test on the booster as suggested with multiple pumping. Took about 40 pumps or more before it started to register a vacuum. Got it up to about 14psi before I stopped. Took about 40 pumps for each pound of pressure but it held vacuum. Had a good seal before I started, just didnt know it took so much pumping to start registering pressure.
So with that test it seems like the booster is OK.
Has there ever been such a problem vehicle?

Hey Karl

Pleased to hear your brake-less trip went ok, pheww.
Annoying about the vacuum (KY jelly? Makes you wonder what Ron gets up to LOL)

At least you can strike that one of your list now

Has there ever been such a problem vehicle?
Yep, you just keep going.. A problem is only the beginning of a solution

Just one little observation.. The hose with the pen top in it looks kinda tired(perished).
If that one is like that, your other ones might be the same. You are sure that they seal eh?!

Did you try spraying throttle body cleaner on the whole vacuum system including over the injector mounts while running the motor? The rubber seals around those could be perished...

One other thing. On my car I could not see what type O2 sensor I had apart from there being only one wire (I should have measured it of course...). The shop gave me the wrong type with the pulses rather then the graduated reading (bloody murphy's law). This gave me an engine light and no savings.
Then I put the proper type in and the result was instant, much better performance, mileage and no light.
So in short, did you put the correct type in? Does your engine light come on?

What next Ron? Engine just too tired??

Just one little observation.. The hose with the pen top in it looks kinda tired(perished).
If that one is like that, your other ones might be the same. You are sure that they seal eh?!

Yes I noticed that also so I taped off the hole in the TB dynamic side that lead to that hose to see if that line was a problem. Had no change in performance so I deducted that that line is not the problem.

When doing a vacuum test on that booster in pic, I attached the device to the know in pic for the vacuum. When engine is running, does it not have pressure on the booster instead of vacuum?
The reason why I ask is that the nipple/check valve I attached it to moves. A vaccum may have sealed the movement where the device attaches to the booster with the washer seating but pressure may blow the device outward thus creating a leak. This sounds wacky and may not apply but trying to apply as much logic I know as a naive owner/mechanic to figure things out

Did you try spraying throttle body cleaner on the whole vacuum system including over the injector mounts while running the motor? The rubber seals around those could be perished...

I sprayed a whole can of carb cleaner over all the places on dynamic side that I thought could leak.
Doesnt mean I may have missed something. So when I brought it to the mechanic I know for a vacuum test running, he also sprayed over places he though could leak with no results. Even sprayed some places/hoses passive side that looked old but none seemed to be leaking there.

One other thing. On my car I could not see what type O2 sensor I had apart from there being only one wire (I should have measured it of course...). The shop gave me the wrong type with the pulses rather then the graduated reading (bloody murphy's law). This gave me an engine light and no savings.
Then I put the proper type in and the result was instant, much better performance, mileage and no light.
So in short, did you put the correct type in? Does your engine light come on?


The engine light came on with p0107 code before changing 02 so changed 02. Before putting in I checked to see if everything looked the same with wires and head configuration since I have heard of this common mistake before. Everything looked the same with 4 wires and head shape. Didnt make a difference and light is still on. Will clear the code again and see if it comes on again. There are multiple possible reasons for the 0107 code so I guess time will show me which it is.
As for Murphys law, it seems to be manifesting itself with my truck for sure.
Getting kinda tired with this. Too much effort with no progress in sight.