Mazda Rotary Club

General => General Technical => Anything Engine/Performance/Tuning related => Topic started by: Welsh Dan on February 06, 2005, 08:38:00 PM

Title: Oh dear - Lost a tip?
Post by: Welsh Dan on February 06, 2005, 08:38:00 PM
Hi all.

Driving back taking it easy on the motorway (sticking to the speed limits), I gave it a gentle bit of throttle and there was some wierd noise and backed off. At this point, the car seemed to be fine.

However, when we came off the motorway and pulled up to the traffic lights, the engine idle seemed to be very lumpy. I turned it off and tried to restart it and it was much harder to restart than normal. It sounds fine at more than 2500 rpm and it didn\'t appear to have lost any vast amounts of power.

I have checked the boost gauges at 1500rpm, and they seem to be pretty stable and not much fluctuation. Also, if we give it a bit of revs, it sounds fine but then dies down and sounds like its going to stall, before the revs rise and it idles lumpily again.

Any suggestions as to what else it could be? I\'ve not had chance to take the plugs out yet and test the compression that way. Another possibility was the inlet manifold gasket, but that appears to be fine too (at least as far as I can see). There also appears to be no smoke that I can see? I\'ve also noticed that it has sounded a bit tappy over the last few days. The ECU isn\'t showing any problems either and theres no lights lit up or anything?
Title: Oh dear - Lost a tip?
Post by: Mazdarotaryparts on February 06, 2005, 10:29:05 PM
Hi Dan,

From what you have explained it sounds a bit strange if you have lost a tip, if you have a boost gauge is it reading any vacuum.

And also have a look to check the pipe hasn\'t fallen of the Map sensor ( small square box on the n/s bulkhead)
Title: Oh dear - Lost a tip?
Post by: Welsh Dan on February 06, 2005, 11:57:25 PM
Righto, a bit more info may be of use, as well as an update.

Its running non-sequential turbos, intake, downpipe, decat, full system, AVC-R and PowerFC.

I\'ve already checked both the MAP sensors and they\'re connected properly (i\'ve already had this problem once this week). As far as I can see, all vacuum hoses are connected fine. I\'ve also checked most of the other sensors, and they appear to be fine too. The PowerFC doesn\'t indicate anything out of the normal.

When i\'m sat in the car, with the windows up there appears to be a tappy sort of noise from the engine bay. Peering into the engine bay, it looks like its coming from the turbo side of the engine, possibly by the lower intake manifold rather than both sides ( I presume that a worn or broken tip would make a noise both sides of the engine rather than just on one side). The car hunts between 1k to 1.5k, before finally settling at 800rpm (ish) after about 20 seconds. At idle, the vacuum reads a steady 12.5 inch/hg (about 320 mm/hg), which from what I can see on RX7Club.com is about right? It idles without me having to use throttle at all.

I\'ve taken it for a drive, and it boosts exactly the same way as before, no visible smoke and is fine apart from in the lower revs, where it sounds a bit rough (sounds slightly like a misfiring car, but apart from a slight shudder, runs ok).

Is it possible that its a leaking inlet gasket, or a slightly knackered turbo?
Title: Oh dear - Lost a tip?
Post by: 20B_boy on February 07, 2005, 08:24:45 AM
Is there zero boost gauge fluctuation at idle or not?

Lower inlet manifold? Symptons aound a bit extreme though, e.g. not starting well etc
Title: Oh dear - Lost a tip?
Post by: Welsh Dan on February 07, 2005, 08:46:23 AM
Once its idling and has settled down, theres no fluctuation on the boost gauge.
Title: Oh dear - Lost a tip?
Post by: Martiny on February 07, 2005, 10:44:09 AM
I thought the vacuum was supposed to read about 17?  Mine goes to 20 sometimes.

I suspect a leaking inlet manifold gasket. Old ones were paper, newer one is metal.

A long job, (turbos must come off), but it can be done at home.
Title: Oh dear - Lost a tip?
Post by: Welsh Dan on February 07, 2005, 05:14:15 PM
Not too worried about doing the inlet gasket, as we\'ve only just taken off and replaced the turbos.

However, that is the least of my worries now as I crashed the car this afternoon :(

(http://www.cruisesouthwest.co.uk/modules.php?name=Forums&file=download&id=3804)
Title: Oh dear - Lost a tip?
Post by: Big Stu on February 07, 2005, 05:15:31 PM
What Happened?? Looks like a bit of a hard front end smash!!
Title: Oh dear - Lost a tip?
Post by: Welsh Dan on February 07, 2005, 05:23:09 PM
Someone stopped quickly in traffic and I drove in to the back of them at about 15mph. However, I have caused more damage by there being a complete lack of a crash bar behind the bumper, hence all the damage.

We\'ve removed all the bits that are knackered, and can probably get it back on the road in a few days.

(http://www.cruisesouthwest.co.uk/modules.php?name=Forums&file=download&id=3803)

(http://www.cruisesouthwest.co.uk/modules.php?name=Forums&file=download&id=3806)

(http://www.cruisesouthwest.co.uk/modules.php?name=Forums&file=download&id=3808)

(http://www.cruisesouthwest.co.uk/modules.php?name=Forums&file=download&id=3807)
Title: Oh dear - Lost a tip?
Post by: Big Stu on February 07, 2005, 05:25:56 PM
All that from 15 MPH, bloody hell.

But you think you can repair it pretty quickly though?
Title: Oh dear - Lost a tip?
Post by: Welsh Dan on February 07, 2005, 05:52:20 PM
Looking at it, the bonnet is repairable although i\'m looking around for a carbon bonnet. It needs a new front bumper - i\'m going to visit Dragon and have a look at some of the ones he has and get an aftermarket one. The passenger side wing again should be ok. Will have to get hold of a new radiator, fans and AC rad. I don\'t need new lights really, just the covers, but I suppose its as good a time as any to get flush headlamps. The slam panel needs to be done properly, which I suppose is that part that will take the most time to be done properly.

It looks like it has been in a minor shunt before, hence the complete lack of a cross bar behind the bumper, which would have taken the brunt of it.
Title: Oh dear - Lost a tip?
Post by: babz_audio on February 07, 2005, 11:51:12 PM
sorry to hear about the crash mate, i am gettin more and more scared by the day...hope i dont get problems with mine...hate that feeling of thinking something is gonna go wrong with it :mad:
Title: Oh dear - Lost a tip?
Post by: J.j. on February 08, 2005, 12:24:33 AM
Sorry to hear that Dan.
Look at the bright side, luckly it wasnt serious and also you hadn\'t done any mods yet.  Now you finally have all the excuses to do the upgrades you\'d have wanted to do anyway.  
Lack of the cross crash bar??  How did that happened??  
Anyway, can you check if you actually have one on the car without taking the front nose cone off?
Is this the same crash bar Fish mentioned in another thread regarding fitting 99 nose cones onto pre 99 cars??

Cheers
Title: Oh dear - Lost a tip?
Post by: Welsh Dan on February 08, 2005, 12:29:27 AM
QuoteOriginally posted by J.j.
Sorry to hear that Dan.
Look at the bright side, luckly it wasnt serious and also you hadn\'t done any mods yet.  Now you finally have all the excuses to do the upgrades you\'d have wanted to do anyway.  
Lack of the cross crash bar??  How did that happened??  
Anyway, can you check if you actually have one on the car without taking the front nose cone off?
Is this the same crash bar Fish mentioned in another thread regarding fitting 99 nose cones onto pre 99 cars??

Cheers

No mods bodywise, plenty engine wise. The crash bar sits behind the bumper, but i\'m guessing that it was removed after a previous bump (before I had the car).
Title: Oh dear - Lost a tip?
Post by: J.j. on February 08, 2005, 12:43:35 AM
Doh!!  
Hope those mods arent damaged.......
I think Re Worx\'s having a huge discount right now on uprated Radiators.  Maybe it\'s worth checking it out??  
I wrote my FD off last year.  Put the car into crash barrier at about 50 m/h.  However, my engine bay looked more intact than yours(15 m/h).  Guess that crash bar does work then.......
Will definately have that checked out on my next car.
Most importantly you are ok, hope you\'ll be back in your car soon.
Title: Oh dear - Lost a tip?
Post by: Gerry M on February 08, 2005, 07:18:39 AM
cross bar might of been removed if its had a big FMIC in the past
Title: Oh dear - Lost a tip?
Post by: Mazdarotaryparts on February 08, 2005, 07:49:30 AM
Hi Dan,

Real real sad to hear you had this on top of what you had going on as well  

I have always found it scary that people remove the composite crash bar from under the nose, particularly when they fit 99 spec noses, l found that with a bit of cutting you can still keep the bar in place.
( also most proper I.C.\'s will fit with it in place but people leave em out)

If you want to know if you guys have a bar behind, just push on the nose and see if it pushes in as it also supports the nose , if it "boings in" it aint.

Don\'t know if this would help but we can sort you a direct replacement all alloy rad for 325+ VAT or an O.E. rad.


__________________
Title: Oh dear - Lost a tip?
Post by: 20B_boy on February 08, 2005, 01:59:30 PM
QuoteOriginally posted by J.j.
I think Re Worx\'s having a huge discount right now on uprated Radiators.
Indeed, in stock ready to ship immediately :)

Details here:
http://www.mazdarotaryclub.com/forums/showthread.php?s=&threadid=12295

Please mention the MRC ad to ensure you get the \'right\' price...
Title: Oh dear - Lost a tip?
Post by: Welsh Dan on April 06, 2005, 07:20:17 PM
Righto, car is back on the road now, so back to the initial problem. It doesn\'t seem to be as quick to start as it did before (now takes 1 or 2 seconds longer), although it does still start when hot (again, taking a few seconds longer than before). We have noticed a few small plumes of smoke coming from deep within the engine bay and scorch marks around the exhaust manifold area. Is it possible that the exhaust manifold needs replacing and could be causing these symptoms. Car still runs absolutely fine as such, pulls with no problems and no apparent lack of boost, no smoke, doesn\'t lose coolant etc. It does appear to be slightly noisier which sounds like something is possibly blowing and there seems to be a tapping noise coming from the front end somewhere.

Could the exhaust manifold gasket make it harder to start at all? I priced one up at £120 +VAT, so hopefully its not that, but if so, are there any places that would do it cheaper than Mazda?
Title: Oh dear - Lost a tip?
Post by: Brett on April 07, 2005, 08:35:32 AM
I had a similar tapping to the one you described when my manifold was cracked, hence you may find there is a crack in the manifold from exhaust to turbo. I wouldnt expect scorching if it was just the gasket.