Hopping at low speed in 1st

Dlish · Post by **Dlish** » February 10th, 2006, 1:13 pm

Hi there,

I have an MX3 v6 and it has developed an odd problem over the last few days. When I'm in slow traffic I did just used to just put the car in 1st gear and it would pull along no problem with my foot off the gas at 500rpm. For the last few days when I try this as soon as it gets below 1000rpm the engine starts hopping and the revs cycle from 500 to about 1200 and won't just settle down. The problem is also there in 2nd gear but it’s not so noticeable. Apart from that the car seems to be running fine, the idle is OK and it picks up speed like it always did so I'm a bit puzzled.

The car also had new plugs at the last service if that’s any help.

Any ideas?

Cheers in advance

Juans_93_MX3 · Post by **Juans_93_MX3** » February 11th, 2006, 1:33 am

I seem to have the same type of problem

jschrauwen · Post by **jschrauwen** » February 11th, 2006, 11:15 am

My first thought when you mentioned the revs cycling from 500 to 1200 rpm was that it's a TPS problem. Since this started as a gradual thing I'm now thinking that this may be also tied to the rubber intake tube between the TB the the VAF. There is a correlation between the 2. There is good info on both in the FAQ's and in past threads to deal with this. First and easiest would be the verification of the integrity of that intake tube. Using the butane refill bottle method as I descibed in other threads would help here. Your looking to make sure there is absolutely no cracks or breaks in that tubing and the butane will help find it if there is one not readily visable. Secondly, there's an elaborate step by step for TPS adjust/verification in the FAQ. g/l
John

Meep · Post by **Meep** » February 12th, 2006, 11:18 pm

Yeah listen to John on this one. I had the same problem. I had my oil changed and got my air filter changed a few months back. Immediately afterwards, my car started buckling particularly in 1st and 2nd gear. Turned out to be a crack in the rubber tubing between the TB and VAF (as the aforementioned suggested checking). It was dry rotted (being so old and all) and very easily split when the air filter was changed.

vozaday2000 · Post by **vozaday2000** » February 13th, 2006, 9:31 pm

and check you coolant level. that was my problem. i had a rip in one of the coolant caps and it was allowing air into the cai causing it to constantly jump.

Dlish · Post by **Dlish** » February 14th, 2006, 8:26 am

Thanks for all the help guys.

I've found the thread on checking the TB to VAF tube (eventually!) so I'll test that as soon as I get a chance and I'll let you know how I get on. From what you say it does sound like that is the problem - maybe it was damaged when I got my spacers fitted and it's finally split. Here's hopeing anyway.

Thanks Again

Darren

Dlish · Post by **Dlish** » February 18th, 2006, 9:28 am

Well, I finally managed to have a look at the vacuum hoses and they all seem OK but I haven’t tested them yet. I need to convince my wife to sit in the car whilst I spray butane on them – not an easy job!

What I did notice though is that the concertina part of the air intake hose is has a 2” split in one of the troughs of the concertina, so do you think this could be causing the problem? I’m going to patch it with electricians tape as best I can to see if that is any better so I’ll post back to let you know.

Cheers again for all the advice, all the best.

Darren

Dlish · Post by **Dlish** » February 18th, 2006, 9:32 am

Sorry Guys,

Just read the message for John again and this is the tube he was talking about not the small ventilation ones I was looking at.

Well fingers crossed it looks like I've found the problem.

Thanks again

petekav · Post by **petekav** » February 20th, 2006, 9:36 am

Hey Dlish, can you send you post the link for the thread that you found please? Save me from doing the leg-work...

Thanks, Pete.

Dlish · Post by **Dlish** » February 20th, 2006, 5:22 pm

Here it is mate. Just look for the orange "check" and "butane" in the text. Hope this helps.

http://www.mx-3.com/phpbb2/viewtopic.ph ... eck+cheque

Just taped over the crack in my intake (for the time being) and the car is back to normal so a big thank you to John for the help.

Just in case anyone is interested I ordered a replacement pipe from my local Mazda and its 63GBP! A bit steep but hey ho if it does the trick it's a small price to pay.

Mazda_Powered · Post by **Mazda_Powered** » February 22nd, 2006, 1:07 pm

you dont need a 2nd person to be in the car to rev it, unless your car stalls. all i've done in the past is just start the car, wait 5 mins or so, go out with some Quickstart and started to spray certain parts that could have a leak in them, so intake pipe, intake manifold, vacuum lines, etc.

good luck

JACK

jschrauwen · Post by **jschrauwen** » February 22nd, 2006, 2:04 pm

Mazda_Powered wrote:you dont need a 2nd person to be in the car to rev it, unless your car stalls. all i've done in the past is just start the car, wait 5 mins or so, go out with some Quickstart and started to spray certain parts that could have a leak in them, so intake pipe, intake manifold, vacuum lines, etc.
good luck
JACK

5 posts in 5 minutes. And a dramatic increase of late with posts that are of little substance. Is this a prelude to posting in the Buy and Sell Forum? If that's your intent, than you obviously know that Forum's rules/restrictions. That said, why not save a lot of us from superfluous posts and ask the admin staff directly your request wrt the 30 post requirement. This is what appears to be the case at this point in time.

Mazda_Powered · Post by **Mazda_Powered** » February 23rd, 2006, 1:02 am

well thats not the reason i posted so many in so little time. i usually just scan thru posts to see if i can give advice or help.

JACK

PWRD_BY_HKS · Post by **PWRD_BY_HKS** » February 24th, 2006, 3:16 am

WHICH HOSES ARE THOSE MANN IM LOST