Mazda Rotary Club

General => General Technical => Topic started by: Doofry on December 12, 2005, 01:27:19 PM

Title: HELP I think my engine may be b*ggered!
Post by: Doofry on December 12, 2005, 01:27:19 PM
Hi guys,
          I\'m looking for some advice. I have a 55k jap FD3S, which as far as I know hasn\'t had a rebuild (I know its about that time that they go). It\'s seemed fine, always started fine, power felt fine, etc.

  The other night it all went worng. Luckily I was only about 1 mile from my home  when I\'d gave it a wee blast down to a roundabout (only to about 5-6k rpm), slowed down and when round the roundabout then went to accelerate and suddently my sweat rotary engine bogged down big time. I didn\'t fell or hear any mechanical or metallic noises and didn\'t see anything unusual coming from the exhaust in the mirror (it was night though). The best was I can describe it was of a really boggy response (i could only get to about 30mph) as if a plug lead was disconnected (though I doubt this to be the case :( ). I checked the temp guage and it was normal. So I thought if its a rotor then I\'m screwed anyway so I soldiered on and limped home. As I cam round my street I did notice a red warning ligth come on for a second, which I\'m sure said \'HEAT\'. As I said the temp guage was still normal. I let the engine cut out after this and free wheeled down the road and into my drive.

  I was looking for some advise as to how I go about diagnosing the problem. Honestly, I expect that knowing my luck its a rotor and I\'m going to need a rebuild and being in Glasgow I\'m not looking forward to trying to organise this. I\'d love to hear that it\'s maybe something less expensive like a cracked hose, etc. but I won\'t hold my breath, so....

  Should I start with trying to arrange a compression test? Would this be a good first step to see if its the rotors? Would the tips normally fail like this? I don\'t suppose there\'s anyone in the West of Scotland who\'d have the equipment and be kind enough to help me with this (I\'d pay obvoiusly) is there? If this doesn\'t look as if it\'s the problem what else should I check? And then can anyone recommend a good RX specialist in Central Scotland who could repair my baby? I\'m assuming if its a rebuild then the engine still needs to be sent down south?

  S....O....S....
Title: HELP I think my engine may be b*ggered!
Post by: Doofry on December 12, 2005, 01:53:38 PM
Sorry about the spelling in this post  :Hammer . I\'ve just re-read it and it\'s shocking....should have went to school more!
Title: HELP I think my engine may be b*ggered!
Post by: iaint on December 12, 2005, 02:37:15 PM
Could be the boost pipe to the map sensor popped off - this will make the car run really rough and quite smokey too.  Do a search for this one, there\'ll be details on how to look at it.

What ECU are you running?  If non-standard I know the Apexi uses the heat light (this is a cat heat light not engine temp) to indicate knock amongst other things.

ECU could also have gone into \'limp\' mode, maybe overboosting due to cold air?

Other vacuum hoses can case odd problems but it should run/rev okay if it were that.

Thinking about the CAT heat light coming on briefly - maybe the cat\'s blocked and the extra back-pressure would prevent the car from revving properly (would be more gradual though I think).

Probably not a boost leak - this would still rev but just no real power.

How does it run at idle now and what mods are you running?  It\'ll help \'diagnosis\'.

Maybe some of the scots members can shed some light on \'local\' garages that are FD savvy?

Iain
Title: HELP I think my engine may be b*ggered!
Post by: Doofry on December 12, 2005, 02:52:01 PM
Iain, thanks for the pointers. I\'ll check a couple of these points out tonight hopefully and then post an update. Hope it is one of these as I was hoping to get a new garage built this year rather than having my engine rebuilt.
Title: HELP I think my engine may be b*ggered!
Post by: nikp on December 12, 2005, 02:53:39 PM
QuoteThinking about the CAT heat light coming on briefly - maybe the cat\'s blocked and the extra back-pressure would prevent the car from revving properly (would be more gradual though I think).

I was thinking this one. Maybe a chunk of the cat material has fallen off. These give consistent results of complete lack of power. Dunno if you can get these tested or anything!? You could try and take the CAT off (Very easy job to do) and turn it from one end to the other - if you hear something large sounding move or rattle, then that could be the case.
Title: HELP I think my engine may be b*ggered!
Post by: Doofry on December 12, 2005, 03:04:54 PM
hmmmm....if it were the CAT, how much are you talking for one. Or should I just get a decat pipe  ;) ? I\'m assuming it still has a CAT at this point but it does have a 3" stainless zorst so it might not. Suppose I really need to get my head stuck under her....which isn\'t easy as they\'re bloody soo low. Ramps are a no no so i\'ll try my j-olley tr-ack and see if it gets under it.
Title: HELP I think my engine may be b*ggered!
Post by: iaint on December 12, 2005, 03:10:13 PM
Quote from: Doofryhmmmm....if it were the CAT, how much are you talking for one. Or should I just get a decat pipe  ;) ? I\'m assuming it still has a CAT at this point but it does have a 3" stainless zorst so it might not. Suppose I really need to get my head stuck under her....which isn\'t easy as they\'re bloody soo low. Ramps are a no no so i\'ll try my j-olley tr-ack and see if it gets under it.

A replacememnt cat would be expensive as a new part.  You may be able to get a 2nd-hand one cheaper but no gurantees on how healthy it is!  I opted for a slienced de-cat rather than streight-through pipe, makes getting on track days a little easier.

Iain
Title: HELP I think my engine may be b*ggered!
Post by: Doofry on December 12, 2005, 03:13:03 PM
Do any of you think it sounds like an f*cked rotor? Just wondering or are you all trying to be positive to begin with ;)
Title: HELP I think my engine may be b*ggered!
Post by: rx7veilside on December 12, 2005, 04:00:48 PM
if uhave blown a tip or bad compression car will be hard to start especially when warm and will idle rough..if u have a boost gge the vac reading will be fluttering as the rotor runs thru its combustion cycle
Title: HELP I think my engine may be b*ggered!
Post by: Doofry on December 12, 2005, 04:06:42 PM
Ok I\'ll check this out also. To be honest I\'ve been scared to try starting it since this happened. Thought it\'d be safer to get some facts before I did incase I possibly caused more damage.
Title: HELP I think my engine may be b*ggered!
Post by: Donato on December 12, 2005, 05:35:10 PM
hi mate, i would suggest as Iain has said, first port of call is the map sensor, then check all the other vac pipes.

If you cant find it yourself, Marc at the garage in Wishaw would probably be the closest people that could have a look at it for you/

i would offer myself but im very busy at work at the moment..

Cheers

Donato
Title: HELP I think my engine may be b*ggered!
Post by: sadgoth on December 13, 2005, 08:15:43 AM
I\'ve managed to throw a tip in a Gen 1 and my FC! The effect is sudden and quite dramatic! Similar to the effects you described in fact sudden loss of power (like the car is running on half an engine strangely!) and a bugger to start from hot (or cold for that matter). The real test is whether you can start it easily. If you have actually physically thrown a tip, it may get caught in the exhaust port causing the engine to suddenly stop (quite surprising when you are moving at 20mph!) as the seal sticks between the housing and the rotor. I\'d check all your vacuum hoses as suggested check the plugs for signs of fouling, give the CAT an check and then try and start her up. Hopefully one of the other problems is the cause.
Title: HELP I think my engine may be b*ggered!
Post by: Doofry on December 13, 2005, 04:21:17 PM
Not looking good! I tried starting her last night (very cold and dark). Took a while to \'catch\' but did eventually run under it\'s own power, but still as before As Sadgoth described felt like it was running on half an engine - which it probably is :(
Title: HELP I think my engine may be b*ggered!
Post by: iaint on December 13, 2005, 04:38:13 PM
What mods do you have installed?  Pretty rare (but not unheard of) for a stock engine to throw a tip.
Title: HELP I think my engine may be b*ggered!
Post by: sadgoth on December 13, 2005, 04:48:37 PM
Still may not be the dreaded dead engine. Is there a rich petrol smell when it\'s idling? Could indcate unburt fuel which may mean fouled plug or plugs rather than boogered apex seals (I had that recently with my FC which after having spent out a new bridgeported engine I was more than a little scared when I started losing power!) At 55k the engine may be on it\'s way out, but the circa 60k is a guideline, not an absolute.
Title: HELP I think my engine may be b*ggered!
Post by: nikp on December 13, 2005, 05:03:29 PM
And the more usual route for an 60k engine failure is water seal failure than apex seal - although, as i iain says: it can happen.
Title: HELP I think my engine may be b*ggered!
Post by: Doofry on December 14, 2005, 12:40:05 PM
Sorry I\'m not getting much info back to you guys at the moment but what with work and xmas shopping it\'ll be the weekend before I get a look at it in daylight.

I did however start it up to move it this morning. The exhaust is always very \'steamy\' (not smokey) when cold, which I assume is normal for REXs. This morning it definetly felt like it was only running on one rotor. It would tick over (very lumpy and struggling) on it\'s own. I\'ve still not heard any mechanical noises which I think I\'d expect if there was a rotor tip getting rattled around in there. The exhaust does smell of unburnt fuel I\'d say and its not the usual white steamy output but now has abit of a brown colour to it.

  Does this sound like unburnt fuel to you guys? Am i right in thinking I\'d be expecting a \'blue\' output if it was burning a lot of oil? Hopefully on Saturday I\'ll be able to check some pipes (dunno which ones are accessable from the bonnet) and pull the plugs out. Are the plugs easy to get to? Am I right in thinking there are 2 per rotor?

  What tool is required to compession test a rotary? Is it mega bucks?

Thanks again
Title: HELP I think my engine may be b*ggered!
Post by: Doofry on December 14, 2005, 12:44:05 PM
oh by the way. As far as I\'m aware the only mods to the car are a S/Steel exhaust and foam airfilter. As far as I know its running standard boost (usually only 1 bar max on guage) and still has the CAT fitted (not checked though).
Title: HELP I think my engine may be b*ggered!
Post by: sadgoth on December 14, 2005, 01:13:06 PM
getting to the plugs in a bit of a mission! Still if the plugs are clogged and not firing properly it could be the cause. If the exhaust is smelling a bit petroly and there is a blackish smoke present it could well be a sign of excess unburt fuel in the exhaust.

keeping fingers crossed for you!
Title: HELP I think my engine may be b*ggered!
Post by: nikp on December 14, 2005, 01:22:36 PM
Quoteusually only 1 bar max on guage

1 bar is not standard boost - this could may well be your problem: if you\'re getting too much boost (standard is 0.7 bar) then you could be getting engine knock (cos you won\'t get enough petrol in for that boost), and engine knock can kill apex seals!

Quotegetting to the plugs in a bit of a mission!

And getting to the spark plugs is dead easy: done from beneath, that\'s the easiest way.
Title: HELP I think my engine may be b*ggered!
Post by: Doofry on December 14, 2005, 01:24:55 PM
maybe have to get the front splitter off then to get it up on ramps to get to the plugs then, eh :(
Title: ..
Post by: wedgiekray on December 14, 2005, 01:37:45 PM
just remove the elbow and reach down, im a short arse and i can reach them fine. Take a torch with you just incase.

Editted: Meant CAN not CAN\'T :)
Title: HELP I think my engine may be b*ggered!
Post by: nikp on December 14, 2005, 02:55:18 PM
Whats wrong with a jack and axle stands?
Title: HELP I think my engine may be b*ggered!
Post by: Doofry on December 14, 2005, 02:59:14 PM
I\'ve been having a search about the forums for posts about the MAP SENSOR as originally advised by you guys. I came across this post which sounds exactly the same....fingers crossed, otherwise I will be out with the trolley jack (bit tight \'cos of my side skirts and splitter)

http://www.mazdarotaryclub.com/forums/showthread.php?t=17437&highlight=map+sensor
Title: HELP I think my engine may be b*ggered!
Post by: Doofry on December 16, 2005, 02:57:41 PM
I had a look at the MAP sensor with a torch the other night and was disappointed to see that the pipe (could only see one so assume thats all that goes to it) that goes into it seems to be fine. I\'m assuming that when this seperates it\'s at the sensor connection. It also seemed to be quite firly connected at the other end. What are the chances of this sensor actually being faulty? Does any one know how to test it with a multimeter?
  Since I\'ve now just about flattened the battery I was thinking about resetting the ECU next, incase it is in limp mode. Though from what I\'ve read the symptoms don\'t seem to match this. Then I\'ll try and pull the plugs out and have a look. Does this sound reasonable? After that should I be looking to arrange a compression test? (dunno where though. Is the compression tester for a rotary expensive?) After that its a case of emptying the piggy bank for e rebuild, eh?
  Has anyone North of the border got someone they\'d recommend for this? Whats the cost/turnaround?
Title: Open to sensible offers for my RX
Post by: Doofry on February 16, 2006, 08:50:23 AM
Right, since my last post I haven\'t looked at my RX apart to check a couple of the suggestions that were made. In the meantime I have split up with my wife and as such I don\'t really care about the RX anymore, so.....

  I\'m open to any sensible offers for her (the RX not the wife) and I mean sensible. Feel free to carry out any testing, etc you feel fit. Remember as there was noone who could do a compression test for me this has not been carried out. If you read the thread you\'ll see the discussions about the cars issue.

  At this point it is not confirmed that it is a rotor problem. I was pretty confident that it was a vacuum hose problem but it seems to be alright at the sensor end anyway.

  Also if there is someone now available that would be able to carry out a compression test on the RX over here in Glasgow let me know. I\'d pay obviously for this.

Cheers

Derek
Title: HELP I think my engine may be b*ggered!
Post by: banned advertiser on February 16, 2006, 09:03:28 AM
There is a guy called Mark who runs and garage called the Garage. He is near Edinbough I think and has worked on several RX7\'s he should be able to help
Title: HELP I think my engine may be b*ggered!
Post by: Gerry M on February 16, 2006, 09:19:30 AM
the garage is is wishaw
Title: HELP I think my engine may be b*ggered!
Post by: Doofry on November 28, 2006, 03:33:44 PM
Guys, as I split with the wife earlier in the year the rex has just sat in the drive since I last updated this thread un touched.

Would anyone be interested in purchasing her? As I\'ve lost interest and have other cars now. It\'s a real shame as she is beautiful car and has probably only done about 100miles on her MOT (which is prob about to expire now).
Title: HELP I think my engine may be b*ggered!
Post by: Jit on November 28, 2006, 03:49:16 PM
possibly interested...depends on the money really! give me a call on 07947212298 if you want?
Title: HELP I think my engine may be b*ggered!
Post by: Doofry on December 01, 2006, 02:11:51 PM
Looking for £3,000 mate