Mazda Rotary Club

Cars by Model Type => 3rd generation RX-7's => Topic started by: Jeffers_21 on October 18, 2008, 01:56:13 PM

Title: Engine problems
Post by: Jeffers_21 on October 18, 2008, 01:56:13 PM
I need some help with my rx. i had it 3 months and in that time i have done the following mod\'s. blitz nur spec, air filters, boost controller and a mines ecu (thinking the mines was a big mistake) anyway ive had issues with boost which i think is the rats nest so i have been running it with low boost (0.25bar) as i was getting rubish spikes and stuff when the 2nd turbo kicked in along with it sometimes not kicking in atall. anyway to the point
 
i was driving along the other day and i put my foot down a bit, it picked up fine (well as fine as it would with not much boost) then started to splutter i lifted off the pedal and all went back to nomal didnt notice any diffrence so i put my foot back on this time there was a constant miss and lots of unburnt fuel coming out the back, i mean it was clouds of black smoke. i pulled over and it was missing quite bad, i limped it home whihc was a bout 3 mins away turned her off and had a look around, i checked the oil and could smell petrol in it.
 
im thinking maybe one of my side seals has gone but i want to know some check\'s i can do before i take the plundge and get the engine out. i have changed the plugs with in the last month and the leads. i have had a look to see if the leads have come loose or anything but cant see anything wrong
 
any guidence would be very healpfull
 
Josh
Title: Engine problems
Post by: Hi RX7 on October 18, 2008, 04:00:17 PM
Well you\'re not too far away from Re-Worx who are based in Portsmouth if you get stuck.
Title: Engine problems
Post by: rx jamie on October 18, 2008, 05:41:50 PM
if it was missing it wouldnt have been black i wouldnt have thought, more of a white fuel mist. black smoke is massive over fuelling.
Title: Engine problems
Post by: Jeffers_21 on October 18, 2008, 06:09:16 PM
well if its missing it will be not burning the fuel hench the black smoke?
Title: Engine problems
Post by: Carl on October 18, 2008, 06:15:04 PM
Check the boost hose to the MAP sensor on the firewheel just behind the throttle,if it has come off then that will run really rough and rich.
Regards
Carl
Title: Engine problems
Post by: Jeffers_21 on October 18, 2008, 08:08:56 PM
ive checked the map hose, all looks fine. anything else to check?
Title: Engine problems
Post by: rx jamie on October 19, 2008, 08:44:23 AM
Quote from: Jeffers_21;545749well if its missing it will be not burning the fuel hench the black smoke?


no fella. black smoke means its been ignited. missing means it has no spark. no fire without spark. just fuel haze.
my pulsar does it alot when condy gets on a particular earth. i always **** myself thinking the headgasket has gone because of the white cloud behind me ha ha. bloody datsuns.

definately sounds sensor or boost related to me. possible a leak in the system somewhere. im sure there is a vacuum/boost leak tester thread on here somewhere. do a search for it.
Title: Engine problems
Post by: Jeffers_21 on October 19, 2008, 02:43:46 PM
righty i have moved on a little with this today. ive started her up and it is wite smoke out the back you can smell the fuel in it. ive had the spark plug\'s out and the 2 front ones were quite black were as the 2 rears looked quite clean. i bunged some old plaugs i had back in to see if it made a diffrence and nothing changed. there is a deffinet missfire as it sounds like a dragster.
 
neaxt thing on the list is to put in my old ecu to make sure its not the new one crapping out. anything else i should be looking at. maybe coil packs?
 
i did have a look at the map sensor and unplugged it when it was running which made a huge diffrence the car didnt want to run at all so i quickly plugged that back in. ive checked all the little funky valves around the place and they all seam fine. to me its sounding more like an ignition problem.
 
what else could cause it to miss?
Title: Engine problems
Post by: FDAsh on October 19, 2008, 02:58:33 PM
What are your coolant levels like?

If you run the engine at idle and take the oil cap off, do you get a steam train-esque chuffing? I had this when my side seal stuck, but no white smoke. White is usually coolant.

And its known for rotary engine oil to take on a fuelly smell in some cases, I\'m not sure why it is, but it happens.

This is what mine sounded like:

http://uk.youtube.com/watch?v=0NXwlDcglgA
Title: Engine problems
Post by: Jeffers_21 on October 19, 2008, 04:54:19 PM
i have checked the coolant levels and took the oil cap off as you sugested and there is nothing wrong there, no steam or anything coming from the filler, and coolant levels are the same as they have always been.
 
i have now checked the ecu, which made seamed to cut down the over fueling. but no diff with the missing. ive also changed the plugs and leads and still the same. ive been keeping an eye on my boost guage and that is nice and steady same goes for my oil presure guage and oil temp guage, water temp seams to be normal too.
 
the more ive been running it the less white smoke there is, its more of a lite mist.
 
i dont know where to go from here really. ill do a ecu code check in a min but anyother ideas would be awsome
Title: Engine problems
Post by: Jeffers_21 on October 19, 2008, 05:09:43 PM
ok ive just checked the codes and im not getting anything come up. im getting confused with it all lol
Title: Engine problems
Post by: BlitzBoy on October 19, 2008, 05:30:56 PM
have you tried it with the stock ECU and removed the Mines ECU yet?
Title: Engine problems
Post by: Jeffers_21 on October 19, 2008, 05:34:08 PM
yeh have tried that matey. it stoped the car from overfueling as much but made no real differance
Title: Engine problems
Post by: BlitzBoy on October 19, 2008, 05:41:01 PM
you say you have managed to set it to .025 Bar, this is only possible if you have a boost leak this would cause you symtoms of over fuelling, even if you have rats nest problem, the minimum boost you can run is 0.5 Bar and no lower as thats what the wastegate spring is setup to.

Check the intercooler piping for leaks and the rubber couplings as these hide small tears around the jubilee clips
Title: Engine problems
Post by: Jeffers_21 on October 19, 2008, 06:06:37 PM
sorry was getting confused with that bit, on the apexi avcr its set to 0.25 but yeh your right it boost\'s around 0.5. ive been having boost problems since i have had the car with the 2nd turbo notting kicking in sometimes. but i have replaced all the vac tube\'s bar the rats nest.
 
as for the over fueling that was more down to the map on the mine\'s, im just getting the white fuely mist from the exhaust coz of the miss.
 
im really leaning towards it being a dead coil pack. i wouldnt have thought a vacuum leak would have cause it to missfire like it is. would it help if i took a vid of it tomorrow to show you all whats going on?
Title: Engine problems
Post by: BlitzBoy on October 20, 2008, 12:23:23 AM
check for boost leaks anyways as this would/could cause the 2nd turbo not to come on line.
I see you are from the Isle of Wight, Reworx are nearby in Portsmouth so if you cant find the fault in the end they are very good garage to take your rotary to
Title: Engine problems
Post by: Jeffers_21 on October 20, 2008, 01:03:15 PM
yeh i have sent geff an email already, its just a pain to get it over there as the tax has now run out and also the ferry\'s a stupidly expensive, oh how i wish there was a bridge lol

i wanna keep trying things before i take it to someone. i really want to know some more test\'s to do to find out if its a tip gone or something
Title: Engine problems
Post by: BlitzBoy on October 20, 2008, 01:25:29 PM
you can check for a tip problem if yyou have a boost gauge, if at idle the needle goes up and down quite a bit in vacuum then most likely a tip.
No from your symptoms sounds like aboost leak or a fuelling issue
Title: Engine problems
Post by: Jeffers_21 on October 20, 2008, 01:29:44 PM
yeh my boost guage is nice and steady at idle.
Title: Engine problems
Post by: BlitzBoy on October 20, 2008, 01:40:28 PM
good news well you dont have tip damage so you can rule out an engine problem,when I popped my engine the engine could hardly pull any vacuum at idel the boost gauge would go up and down like a good un, yep its either solenoid,fuel or electrical problem
Title: Engine problems
Post by: FDAsh on October 20, 2008, 05:25:51 PM
My side seal going showed no vacuum fluctuation at idle, either on the boost gauge or PFC.

The only way to really know is to take it to an expert, you can spend lots of time and money as I did, trying to diagnose and treat the symptoms.
Title: Engine problems
Post by: Jeffers_21 on October 21, 2008, 01:16:15 PM
what other symptoms did you have?
Title: Engine problems
Post by: Silverstone Autosport on October 21, 2008, 02:09:41 PM
Hi, its Ben from lindop motorsport, were currently doing free compression test\'s for this month and next if any one wants to pop down for a test,we can also do a print out for you to prove your engines health (also available in graph form) we are located in the chester area, opening times are 8:30 till 5:30
Title: Engine problems
Post by: Jeffers_21 on October 21, 2008, 03:34:00 PM
i would take you up on the offer ben, but its a little far for me to pop over lol. i find it hard to get off the isle of wight at the best of times
Title: Engine problems
Post by: Jeffers_21 on October 21, 2008, 07:12:16 PM
ive got a further with this today. ive checked the spark from my coil packs and the trailing on the 1st rotor seams to be very weak and a bit erratic. so im almsot postive this is my problem.
 
so bring me to my next question where can i get a set of coil pack\'s, i want to do all of them just so i know they have been done.
 
ive only manged to find the leading pack at the mo not the trailing ones
Title: Engine problems
Post by: FDAsh on October 21, 2008, 07:31:56 PM
Quote from: Jeffers_21;546404what other symptoms did you have?
BIG flatspot on WOT, fluttering noise on boost, otherwise normal. Sparks burning clean as usual.
Title: Engine problems
Post by: Jeffers_21 on October 21, 2008, 07:37:56 PM
overall it seams like it has less power not as responsive but not actull flat spots, and no fluttering noise\'s. but like i said im pretty sure its that ignition coil. fingers crossed. i just need to find someone that sells the dam things lol
Title: Engine problems
Post by: Jeffers_21 on October 22, 2008, 12:38:11 PM
im really having issue\'s trying to find these sodding coil packs, someone must have got new one\'s before from somehwere?
Title: Engine problems
Post by: obie81 on October 22, 2008, 02:54:38 PM
You can always get new ones from mazda but its always pricey and you have to wait for them to pitch up from Japan. Best thing you can do is get a 2nd hand set to diagnose the problem. RX motors are always good for parts mate or find someone breaking a Rex on e bizzle! lol