So, help me. Why does the air intake hose keep sliding off the manifold? How clamp is totally tight and do not want to crack the manifold. It is the original hose. Need ideas, fixes, etc. Thanks.

 

New clamp? Make it tighter? You won’t hurt the manifold with a hose clamp, the hose clamp will strip well before the manifold is in any danger

 

Air intake clamps to the turbo, so right away I'm a bit confused. Maybe post a picture of your setup? If it's the original hose, there's no way it's coming off unless it's seriously damaged or covered in oil.

 

Curly, my problem is not at the turbo connection. It is the connection at the intake manifold, front/top of engine on the passenger side, right before the intake control valve/throttle. Hope this helps.

 

Post some pictures, maybe we can see what's wrong. The factory charge piping is known to be excessively complex, the intercooler tiny, and piping restrictive. I can barely find a picture online of the stock piping, there's a chance yours is attached poorly to an aftermarket piece pulling it in a bad direction or ill-fitting coupler at the throttle body.

 

Make sure you are using a T-bolt clamp. Also not sure to what extent a bad motor mount would rock the engine enough to potentially be an issue.

 

guys, could this be related to the waste gate? Idling runs fine ... get on it ... hose pops, error codes (P300) appear. How test a waste gate while in the car? Thanks all for your help .. getting close to fixed.

 

It's not the waste gate, and I agree that posting a photo would be helpful.

In addition to the other suggestions, one thing to try is cleaning the two sides that get clamped together (that is, the outside of the throttle body and the inside of the charge pipe) with some kind of degreaser. Isopropyl alcohol works well.

When you have a factory-style cam breather hooked up, the inside of the intercooler/etc plumbing gets a light coating of oil on it, and when one of the couplings blows off it will spray that oil all over the surfaces that are supposed to be clamped together. This lubricates them and makes them much more likely to blow off in the future, and you need to clean that oil off before they will hold again.

Some people will use hairspray to make the coupling surfaces stickier and help to "glue" it together.

--Ian

 

Thanks guys .. appreciate the help. Here is a photo of the hose that comes off (not my car, stock photo). Still wonder if waste gate, and how to check it .. or could it be the turbo boost solenoid and how check it? I would add more info/photos but my car is at the dealer who cannot figure out why check engine light, P300 codes, keep coming on. new coils, wires, injectors, O2 sensors, cat convertor good, no exhaust blockages, no manifold leaks, IAC valve fully functioning, Now the hose popping off??? Several Mazda specialists have looked at it/consulted ... still no idea of what is wrong.

 

Does the car run and drive ok? Do you have any other codes? If it’s somehow backfiring into the intake that could definitely blow the charge pipe off lol. But also pretty unusual and unlikely on a modernish EFI OBD2 car.

You should be able to check the wastegate with a small vacuum/pressure pump like a MightyVac. But as others have stated without some sort of overboost code I don’t think that’s your issue.

Have you checked the motor mounts? If one/both have completely separated the motor may be moving excessively and pulling at that charge pipe, making it come loose.

Has the shop confirmed the camshaft timing is correct? Have they done a simple compression or leakdown test? Have they checked fuel pressure? Lots of other reasons you could be getting random misfire codes that are totally unrelated to coils, plugs, or injectors.

 

MonkeyMan, car runs OK until pipe comes off. No other codes. Fuel system checks OK, Compression is good. I'll have them look at motor mounts and check the waste gate. Thanks.

 

Bro, why cant you post your own picture?

 

car is at the dealer now. If I had it, I would post the real picks. Sorry. Since the dealer, including brought in Mazda specialists, cannot seem to fix it, I am trying to gather info to 'assist' them

 

Flyin Miata makes a tube/hose to replace that section, claiming that with increased boost levels it can pop off. https://flyinmiata.com/products/ms-tb-inlet-upgrade-kit


First thought it, higher than normal boost levels. However the OEM ECU has a boost cut. IIRC it is still possible to cause this condition prior to boost cut as the FM kit allows a slight increase in boost, below the boost cut, but above stock. Second, those MSM kits/parts have been available now for nearly 20 years. So while the original problem remains, your intake tube to the throttle body has gotten older and worn. Thus any problem people had with the MSM cars 20 years ago will be exacerbated now. I test drove an MSM and had this exact problem happen to me, I brought basic tools so I repaired it for the dealership. The clamp around the throttle body needs to be tight, about as tight as you can get with a screwdriver handled 10mm. It's possible your clamp has been stretched as well or has damaged gears and will not properly tighten. Finally I would inspect the throttle body itself on the off chance there is damage around the lip. P0300X misfire codes are likely just a result of the pipe coming off. They run very poorly when it does.


EDIT: Somehow this got posted in a For Sale thread, deleted that post and reposted here as I intended.

 

Here is a photo of my engine.

 

2ndGearRubber, very much appreciate you insight. Since I am not a mechanic and not at all well versed in the acronyms, I have questions. ECU, engine control unit .. could it be bad for just the boost cut? IIRC ... no idea what this is?? FM Kit ... again, no idea ?? Again, my thanks as I would like to get my car back from the dealer who cannot seem to fix it.

 

Spoon feeding time.

The "kit" is the Little Enchilada or maybe the Intake Package:
NB (1999-05) : Powertrain : Mazdaspeed – Flyin' Miata

My MSM came with the full FM2 Garrett conversion and an ECU that is NLA from FM. Read up on those kits and do yourself a favor. Measure the diameter of that hose and buy yourself a T-clamp instead of relying on a worm gear hose clamp. Either a T-clamp or a constant tension type that has a stack of washers. With that type you tighten enough to mostly compress the springy stack of washers and it will compensate for temp changes keeping a constant tension. Either is a HUGE upgrade to the clamp that's currently installed.

 

This issue seemed familiar so I went back and read through some of your previous threads on this car, where @curly , myself, and other members had given you suggestions prior. I see in your earlier thread that you said compression was good, but "all within 30psi" --30psi is a big range, especially as a percentage. Do you recall the circumstances under which the test was done? IE, was engine warm or cold? Removed all plugs or just the cylinder being tested? Throttle held open or not? Fully charged battery? The actual pressure readings for each cylinder would also be helpful.

Basically all the systems-management troubleshooting is gonna be chasing your tail if the engine is fundamentally unhealthy. Similarly, "fuel system checks OK"--what was the pressure with key on engine off? Engine running? Was a flow volume check done in addition to pressure? "OK" is very vague I'm sorry to say.

 

Looking at your picture, the solenoid mounted on the front of the valve cover has a clamp slightly loose, not fully seated on the hose. It is the clamp/hose facing the front of the engine. Not likely your issue, but it needs adjusted. Additionally I see modified AEM piping. How long have you owned this vehicle? If this is a new issue and you have driven the vehicle with no issues for a given time, ignore this. If you have purchased the vehicle modified and have had issues from day one there may be contributing modifications to increase boost output which could contribute to the tube coming off. Above my post people describe the intake tube kit. This was designed to correct the issue you are having when increasing boost pressure, as aftermarket venders were quick to do when the car was released. If the car is modified and running higher than stock boost pressure that is likely the root cause. It is also possible with worn clamps, or worn 20 year old intake tubes, or either being improperly secured, that this can occur at stock boost pressure.

The ECU is designed to control maximum boost pressure to a given level, I think it's 8psi. Above this pressure it is documented where the intake pipe you are describing can blow off. Additionally, if the re-circulation valve is stuck closed or sticking closed, boost pressure cannot be rerouted when the throttle plate suddenly closes, causing a larger pressure spike directly in front of the boot which is coming undone. The vender I linked sells both a more robust intake tube, and an improved bypass valve. I am sure there are other venders or DIY options, I simply linked them because I knew they still produced the parts.

This cannot be easily diagnosed remotely. As others mentioned, severely worn/broken motor mounts may be causing excess movement exacerbating the issue. If I were going to throw parts, and I do not advocate doing that, I'd replace the tube itself with an upgraded part after first attempting an upgraded clamp. IIRC the bypass valve typically stuck open causing no boost/bogging, not closed, but being stuck closed would produce a problem as you are having.



I have not had good feedback from people about having NA/NBs dealer serviced. I don't inherently consider that damning of the dealer, these are 20-35 year old vehicles and the training/memory of those who actually worked on them new is waning. Not really their business model anymore to service these cars. Many techniques and even measurement equipment used now, versus then, is very different. If you read the OEM troubleshooting trees it is honestly insane to attempt to fix cars taking Ohm measurements of harnesses or the other nonsense the engineering depts want done. But that's a different rant. I will admit I no longer work on "classics" myself, and won't work on anything pre-1990 at all.