Got a bit of a problem.
Engine runs fine and then around 5 minutes of driving it\'ll stop want to rev. and feels like its misfiring on anything but light throttle. It starts doing this when your on the throttle. Stop turn off the car and restart it i\'ll work fine for about 5 minutes and then start doing the same.
It seems like an electrical problem to me with it being temporally solved with a restart.
Now am I being blind and thick here... But I can\'t see the check engine light. I\'ve seen a video that shows the cel next to the clock, but on mine it\'s a fog lamp indicator.
This seems like pretty much the same problem that I have been having recently... It feels like fuel starvation to me though... so when the weather brightens up again I\'m going to investigate the wiring and pump...
I\'m assuming that the pump isn\'t keeping the fuel pressure high enough and it eventually gets to the point where nowhere near enough fuel is being injected.... But at the moment this is pure speculation
The car revs smoothly to 7000rpm under load before misbehaving. It doesn\'t really feel like fuel starvation to me.
Been having a bit of a think. Car sometimes struggles to turn over the starter. This morning it was really playing up and had to flick the ignition on a off to get it to turn over. I\'ve not started for a couple of weeks due to waiting for parts. It\'s seems like the starter isn\'t getting enough power to turn over the engine. I\'m starting to think it could be bad earths around the car that\'s not helping. It did go funny after hard braking this morning come to think of it. I\'ve cleaned up all the factory earthing points that I can find but they don\'t seem at there best even after cleaning.
Also when accelerating hard it felt like I hit fuel cut once. The car has a decat pipe and the last owner had a recon turbo fitted. Maybe I\'m getting boost creep as the wastegate can\'t cope as it wasn\'t ported?
I\'ve checked the resistance of the TPS. It\'s a little high on closed throttle but at full it\'s within limits. There is a smooth increase in resistance and no dead spots from what I can tell.
I\'ve tried shorting out the wire to get the cel light to give me the fault codes. But there is definitely no flashing cel in the car... well that i can see.
I think I\'m going to try running new earthing cables to the engine and also one to the ECU mount. See if that solve the issue as I think it\'ll be the cheapest solution.
When did you change the plugs and HT leads - they are both perishable items.
It\'s quite possible it\'s going into limp mode... You can hook a lamp up to a spare pin on the ECU and it will flash the codes.
Brett that\'s great. Can it go to any spare pin or a specific one?
Why didn\'t Mazda put the CEL light in the dash like they do on the US cars.
I think this might work to get the cel off the car, as I have the green connector in the engine bay?
http://fc3spro.com/TECH/HOWTO/ERRORCODES/ZENKI/zerror.html
Just been out to check the connector which is the same as the one in the above link. But it only has three wires going into it. So guess thats not the way to get the CEL codes off a turbo 2.
Is there a correct guide on how to do this anywhere?
Im pretty sure there is a port in the engine bay labeled \'diagnostics\'
I just had another look around for a diagnostics port, but there is nothing in my engine bay.
There\'s a pin out diagram in the FSM, I don\'t have the info to hand though....
Figured out how to get the codes out of the car using the connector in the engine bay. No codes.
But I\'m pretty sure the TPS needs adjusting and should solve the problem.
You have new plugs and HT leads already though yeah?
Nope not changed plugs or leads yet. But if it was these I don\'t think the problem would go away as soon as you turn the car off and back on?
I\'ve been having a go at setting up the TPS today. I\'ve set it up so you only get one 12v out of the test connector. It\'s a very narrow band from having one 12v to two 12v from the test connector. Sometimes you go for quick drive and when you come back they will both be giving out 12V again.
If found when driving along put the car in 3rd and accelerate with constant throttle it\'ll hick up at around 3000rpm and then the throttle doesn\'t work properly and anything over very light throttle the car will splutter and not want to rev. But it will go funny at any RPM and speed. It doesn\'t seem to go wrong whist sitting on the drive and will rev to the red line on full throttle and not go wrong.
I\'ve checked for fault codes out of MIL (CEL) connector. But if it\'s logging a fault it\'s cleared as soon as you turn the car off. If it was a faulty TPS wouldn\'t log and save this as a fault?
I\'ve tested the resistance on the TPS and it\'s a smooth increase on both censors. No steps or dead points.
Could it be a coil pack going down? But the car idles fine and drives on very light throttle just fine.
Could it be a bad speed signal to the ECU? Would this course a problem? As the problem doesn\'t show it\'s self when the car hasn\'t gone any where.
I did notice the idle isn\'t rock solid and will slightly hick up every so often and when I lights are on they\'ll dim for a split second then the car hick ups.
This is a very useful thread for anyone experiencing the same problems as me. The car is going to limp mode as duff oil metering pump has more than likely fried the ECU.
http://www.rx7club.com/2nd-generation-specific-1986-1992-17/s5-mop-ecu-failure-diagnosis-710938/
My TII cab started doing this on the way back from Brooklands at the weekend (although mine seems to run for longer than 5 minutes normally before going into limp home mode).
Are we saying from the thread you highlighted that the only real fix is to source a new OMP and ECU?
The car doesn\'t go into limp mode until the car is fully warmed up as some of the sensors are by pasted until then. Restarting the car put\'s it back into warm up mode for a short time then back to limp mode.
You\'ll need to use the FSM for some of this. http://www.rotaryheads.com/PDF/2nd_gen/
See what fault codes the car has stored. You\'ll need an analog multi meter to read the pulses from the ECU. Down near the battery and leading coil pack there are two green connectors. Ground the single one to the negative on the battery. Then plug the multi meter into the larger connector. One of the connectors is ground (top middle) then top left is positive and that is the ECU fault output. The bottom middle point is to test another control unit. Once all connected up turn the ignition on. Multi meter will display 3 second pulse then it\'ll display the fault codes. 1 long pulse is 10 (2 long pulses is 20) then you\'ll get short pulses, 1 pulse is one (5 short is 5) that code would = 25. The FSM gives all the fault codes in fuelling the part.
If the OMP shows as a fault. Unplug the two connectors and check resistance of the OMP. This will show if it\'s the pump or bad wiring back to the ECU. All is explained in lubrication on the FSM
The ECU doesn\'t always fry it depends how the pump has failed. My stepper motor had a short and this burned the OMP part of the ECU. Your ECU might be fine. I could smell my ECU frying itself, when I first got the car running again. Check the picture in the previous link that I posted. It shows you what part of the ECU burns out. Or just fit a new OMP and then take the car for a good drive if no limp mode the ECU is fine.
I bought my OMP off Tim at RXmotors for a tenner. ECU is going to be £50. So not too bad.
Great advice thanks
If it is the OMP, it\'s basically a stepper motor and the likely hood is that the insulation on one of the coils has failed and it\'s shorted. This is basically bad news as it toasts a transistor pack in the ECU as the outputs aren\'t really short circuit protected. The part is no longer available (typical) but could be replaced by a 4 discreete power transistors - bit of a bodge but will work. I did go through an excersize a couple of years back to see if I could find a pin compatible pack that could be used - but drew a blank.
Having said that,
I had similar \'under load\' issues like mis firing and loss of power when accelerating and it was caused by a lose alternator belt - since this is such a quick check and a cheap fix - it\'s worth ruling out - and you\'ll get no error codes from it either !
Cheers Prof, looks like I\'ll have to get my hands dirty for once. Shame you missed Brooklands but definitely not the place to be if you had a cold!
I did find these for sale. http://www.plccenter.co.uk/Buy/TOSHIBA/TMP4501
I might have a go at repairing the ECU at some point but looking at buying that Pansport ECU thats up for sale. As the car has had the cat removed and I don\'t think the turbo wastegate will have been ported. I\'m guessing that with the increased boost of the pansport ECU the car will less likely over boost and hit fuel cut. Also I\'m guessing the car will run a bit richer which has got to better than lean. Or it\'ll just blow up!
Quote from: Mazzyrx7;853809I did find these for sale. http://www.plccenter.co.uk/Buy/TOSHIBA/TMP4501
I might have a go at repairing the ECU at some point but looking at buying that Pansport ECU thats up for sale. As the car has had the cat removed and I don\'t think the turbo wastegate will have been ported. I\'m guessing that with the increased boost of the pansport ECU the car will less likely over boost and hit fuel cut. Also I\'m guessing the car will run a bit richer which has got to better than lean. Or it\'ll just blow up!
You\'ll probably still get boost creep - but at least the ECU will be mapped for it and avoid the dreaded fuel cut. The Boost creep is much worse if you change the air filter as well as the exhaust, and a boost controller won\'t stop it either.
Oh and good find on the Tosh\' transistors - if you have to order a bulk load, i\'ll take a couple. could never find anyone who had stock when I looked for them.
mmm this is interesting, my fc is giving the same problem. thanks for shedding a bit of light on this for me. hopefully my redom ecu isnt fried!eep
this is almost certainly an EOMP fault if s5 car and the best solution is quite likely the US rtek chipped ECU which will ignore the EOMP and thus allow you to set it at fixed rate and supplement premix
in my experience the initial fault is sometimes oil built up around the plug socket on the pump itself or also in the feedback sender
.. a few times the issue has been in the wiring pigtail up to the water pump neck
and it is no good swapping the ecu for another until you track this fault down , as some of the faults can ruin the new ECU
as for the self protect , the ecu does do a resistance check.. but should log this fault .. if its not logging it then the fault is often in the feedback sender or wiring
the other options the OP have are the obvious full standalone ECU .. some of which can use the EOMP in a modded output format ... consider that your EOMP needs to be checked still for faults
cheaper ECUs wont do it as it ties up too many outs and one input .. but there is the eomp controller that will run off a map sensor or a mapped ecu output
( should you wish to run in from a custom 2 or 3D table )
NB
a similar 3000 rpm / load fault is in the s4 cars,, but has nothing to do with limp mode or a restart
.. the issue relates to engine and sensor grounds and is quite often a fault in the loom just out from the ECU plug where all these earth,, and the shield wiring ties together in two metal crimps
adding supplementary ground to chassis from here,, and resoldering the joints will sort that issue
To conclude my problem. New ECU fitted today and car is running perfectly.
Just got a few more small jobs to do and get an MOT on it. Found insurance for £200 for the year which I think is pretty good.