Was just driving along went over a speed bump(very slowly) and my car just died. Now on the PFC in the sensors section; PIM, VTA1 & VTA2 is highlighted with 0.01v!!
I tried adjusting the MAP sensor but the values don\'t change, only when I unplug it completely the voltage goes to 4.48ish.
Any ideas what could be the problem?
Id been checking ecu and harness plugs mate.
Checked them visually and they seem to be ok. Will have another look tomorrow.
If there all seated...fuses....then earths. Fd elec drawings on here somewhere worth a look.
fingers x summit simple.
Which earth is used for the +5v for the map & tps sensor. Is it the one which bolts to the intake manifold?
Time to find the drawings mate...there on the net somewhere ( prob rx7 club)
Need the pin outs on the ecu for the 5v pos. check this ok and work through drawings.
As these car are getting old could be a fractured wire in the loom i use a safety pin poke through the insulation onto the wire inside to check for power. Ackward but works.
If youve got 5 v on the pin out then wiring...if not then ecu....have you got your standard ecu to try?
A guy was having a similiar prob on a rewire a couple of weeks ago and the earth is at the ecu pin...so need to check this also.
Drawings time me thinks.
Ok so checked the ecu, turns out my power fc is not giving out the 5v for the tps sensor. I also found a bad ground caused by the window wiper motor. Was actually making the ground point hot!
Anyway, I put a 5v source on the tps output and sensor reading fine, this mean my ecu is fried!
Which pin is the earth for the tps?
http://www.mazdarotaryclub.com/forums/showthread.php?t=81626
pin 4d...drawings here.
Ok ground is good, multimeter showed continuity between the br/b wire off the tps sensor and chassis. Any other ideas,
when I run a 5v source to pin 3i the pim shows highlighted 4.99v and tps voltage is fine. Shouldn\'t the map sensor voltage be ok, can\'t think why it would still be reading wrong.
Looking at the wiring diagram it seems the map & tps sensors share the same 5v(ecu pin 3i) & ground at ecu pin 4d.
yes from 3I...but x05 is a connector...can you check this?
Hi mate absolutely shed loads of info on the rx7club website. how to check a map sensor diagrams etc. Not wishing to send you away from here but fixing your 7 priority.
Hi mate checked 3i, no 5v coming out of ecu. Also checked for continuity for this wire and it\'s fine.
Browsed all over Inc posting on the rx7 club website too. Reading from one post, a guy with a similar prob figured it to be a resistor problem in the power fc that blown due to a short on the ground.
I had a short from the window wiper that was making the ground source very hot and that shared with the everything ( 5no ground connectors at slam panel). Maybe it\'s fried!
Not good bud! Hoping the map was duff and taking the 5v down! Have you got the standard ecu still at least get it up and running?
Maybe send for repair? dont know who though....circa £450 2nd hand eek!
I\'ll try my mates first....if a grounds gets hot that\'s a lot of resistance right
If the map was gone, the 5v signal should still continue to tps right
Similar scenario to mine: http://m.rx7club.com/showthread.php?t=966924
Might attempt to open and take a look at the board
If it had a short it would drag the 5v down to 0v. The fact the tps, map are grounded to the ecu at 4D the wiper earth should not effect as separate circuits . With the map disconnected recheck for 5 V on 3I. there was a thread how to check map with resistance.
Hot earth= bad connection high resistance more current.
mmm..reading that id hold off on putting your mates apexi in ! You gotta start looking for shorts. Unfortunately the 5v is not fuse protected so simply fitting another will solve until this burns out as well. multi meter time...
See if 5V on 3i with map disconnected? Disconnect all sensors etc and see if 5v present ? reconnect each sensor in turn and see if goes off.
If it was my car i would go to 3I at ecu harness. power off ....with 30mm ish from harness cut cable. strip ecu side and test here to 4D with power on....all sensors connectors wires etc seperated of circuit and see if 5V present. If not defo ecu fried.
Also test other end of 3I to 4D with power off in resitance and see what resistance reading you got. )0 ohms would be a defo short...
cuts out the head scratching and cable can be resoldered.
Bloomin genius.....I cut off 3i and I got 5v coming out of the ecu. Resistance between 3i and 4d is .436.
So what\'s next step, installing each sensor one by one and testing volts.
Does this mean there is a sensor problem on that circuit or a grounding issue.
Sweet... ecu good so sensor wiring or connector taking the 5v down...i think a short mate...this is where the funs starts. Goona have to seperate sensors from loom test with resistance and check ok against values of good 1s which is where your mates car may come in handy.
Then if they all test good wiring. Again resistance test but with sensor connected etc.
Edit. Test wiring with sensors dis connected after sensor test. Need to protect the apexi now as this could still burn the voltage regulator out.
So on this 5v circuit there is map, tps, egr, omp & powertrain control module (autos only).
I have no egr & disabled omp. My car is also a manual. So leaves it down to the tps or map sensor or omp plug(not cut this off the loom).
Yes. Poss short on 1 of them but still could be a connector in loom...
So first plug in sensor at a time and check voltage at ecu. Then if that not showing check wiring resistance from the sensor connector to the ecu input
Me off to bed now. Good luck...use resistance test protect that apexi.
The wiring for this is only on the engine harness right. But the short is only within them few sensors supplied from 3i off the ecu?
Ok cheers mate, keep u posted tomorrow.
Quote from: ttpower;879083The wiring for this is only on the engine harness right. But the short is only within them few sensors supplied from 3i off the ecu?
Yes mate by resistance testing 3i to 4d youve found the short...but the sensors are in parallel so now gotta find which 1.or short on cable...so multi connector etc.
Just a thought...your omp is disabled but presuming switch still plugged in ?
Hi, so the resistance of.436 is good between 3i and 4d.
My omp is blocked off and connector just disconnected.
0.436 ohms? I would say no its nearly 0 ohms which is a dead short. tempting to dis connect all sensor on this circuit and see if 5 V present but not sure how much more that voltage regulator can take.
That disconnected plug will have 5v feed ov ground to ecu and switch init...id check that for moisture in the end...ideally that wants sealing up though as a precaution if not the prob. Somewhere in this circuit the 5v is touching the 0V ground. As its an ecu ground it MAY be seperated from the chassis ground but no 100% on that. Its a control circuit not a power circuit so very low amps and v low resistance so need sensor resistances.
As a side note also any recent works on car that may have disturbed something?
Any joy Mate?
Ok, got back from work late.
Reconnecting the ecu wire 3i with all the sensors disconnected gives me 5v, although if I test 3i with 4d I get around 3v. If I plug in either the map sensor or tps sensor the volts drop to 0.3v.
Seems with any sensor plugged in its drawing the current pretty much completely and not enough for both, so that a short I think?
Short yes but should be 5v 3I and 4D on loom. which makes me think connector short rather than sensor fault...have you look at that omp connector yet...
youve got 2 v drop just connecting loom...loom me thinks.
Id be happy with 5v on the loom then look at the sensors. With 3v they wont have enough power to work...so im thinking loom!
Would having the omp disconnected reduce the voltage, should I chassis ground the omp ground wire
No it worked disconnected...check up inside the plug for debris moisture...id be inclined to seperate 5v and ground from this plug...
how id tackle this is.
1. disconnect all sensor from plugs...remove 3I again and check 5v...yes.
2. Connect and confirm 2 v drop and seeing 3v. yes. disconnect.
3. so confirms loom and/or plugs has a short.
4. As omp plug has been hangin down disconnected and all others are sealed this would be the logical place to start. I would identify from drawings 5v feed and ground. 30mm back from plug. cut and tap up. then reconnect 3I and see if 5v.
5. If not then leave taped up..choose another plug repeat process.
thes ecan be soldered and heat sleeved once fault is found.
if this does not re-instate 5v...where looking at cable in the loom
The voltage at the ecu is the same when 3i and 4d is disconnected and connected. There is 5v when I ground to the chassis with the multimeter rather then 4d.
All connectors being map, tps and omp have 5v when disconnected, as soon as any is plugged in all sensor connector voltages drop to 0.1
Traced the ground off the map sensor, goes to front of car, splits in two where one goes the fuel pump relay and the other to the egi relay where the main fuses are.
Could a relay be causing this, I can\'t see a relay in the drawings though
This would suggest then the voltage regulator is failing under load....so no short circuit although resistance test between 3i and 4d is low! you got 3v or 5v test at any plug end 5v and ecu ground?
no relays no fuses 5v circuit, test at plug end mate pls.
just checking this is defo a 5v circuit?
yes just confirmed...can we run a separate earth wire from 1 plug end back to 4d to make sure we have not got a bad earth? if that dont work then looks like 5v failing under load.
Yeah we have 5v at all the connectors but only when they plugged out
Ok so I connected only the map sensor connector directly to the ecu via pin 3i and 4d. Voltage without connector installed drops to 2.8v and when plugged in 0.4v??
Confused now? Any thoughts?
Could the ground for the ecu be bad. Checked for resistance of 4d and showing 0 which is good I think?
Looks like voltage regulator is failing on load. Time to try your mates apexi.
The reason for the 5v circuit having its own earth at the ecu is to seperate from power circuits for protection. Id be inclined now to
1 final test....cut 4d resistance between 3i and 4d no sensor in and ohms....what value? Should be open circuit ? Switch to continuity beep test..should be no beep.
2.Remove yours and covers off and be looking at a dry joint on pin 4d .
1.Small earth wire from chassis to ecu cage.
3.Try your mates apexi.
Ok so....
1 - cut wires 3i & 4d at ecu and tested resistance, showing 0. No continuity/beeping between 3i & 4d.
2- looking at the board the pins look good and 4d shows continuity. However part 3050c (board of15) looks burnt browny colour at the connectors and has some flacky stuff around the pins on both sides of the board.
3- tried my mates apexi and working perfect. Showing 5v at ecu, at connector and at connector when plugged in.
Anybody in UK who can fix this or should I be looking at a new fc
Happy no short and that 5v failing under load gave us the runaround. Dont know if can be fixed in uk.
least when you get a replacement youll know a wiring fault not gonna take it out.
Do you recon it was the window motor that was shorting that ground caused it to short out. I think its damaged that component which lowers the voltage 3050C.
Definitely a runaround but found wires that need seeing to as well.
Is there any way to test a ground to the chassis. Is it that it should just read 0 on the resistance test.
It shouldnt have because it has its own earth wire all the way back to the ecu...that component is probably the voltage regulator....prob about 79p from maplins! All your earths should 0 ohms...or very low from each other back to the battery neg.
I think the earth wire is also part of the same batch of earting connectors. Just want to make sure that theproblem is fixed prior to fitting another ecu. Yeah it says it\'s a voltage regulator, might give it a go and see.
If one earth is bad on the chassis would that cause it to effect the whole circuit
Looking at a better drawing it has a shield as well so not sure where that is earthed prob the 1 you found.
if you did a beep test on continuity and no beep should not be a short. Unsure what your multi meter is reading on ohms test when open circuit. Need to test with probes touched and untouched.
Best to sort that hot earth anyway probably connection. Doubt your wipers have a short else fuse would go
When I tested the earth for the wiper motor when it was plugged in wasn\'t showing continuity with the ground, only when I unplugged it then it showed continuity. The wiper motor body was also red hot.
Open circuit earth to earth is showing 0.
Ive got a similar problem on my car. The same sensors are not reading plus the water buzzer is going off. When I unplug them they read voltage on pfc. Ive checked all the grounds and they seem fine. Don\'t know what to try next.
Pop your apexi open and see if youve got the same component burn Voltage reg failing when on load.
Popped the apexi open and all looks good. Can\'t see anything burnt out. Will have to try it in a mates car to see if it works. Then it will indicate a problem with the loom, not the ECU (PFC).
Hi Dre, u need to get a multi meter on the loom connectors and check voltage. See what the voltage is on ecu pin 3i & 4d, then check connectors when plugged out and plugged in. Also check your grounds on the slam panel (collection of grounds) and ensure each one has continuity to the chassis
Thanks mate. I have checked all the grounds on the car. I cleaned them and tightened them up. I\'ll recheck the one\'s on the front slam panel. I have bought a multi meter. How do you check the voltage at the ecu 4d and 3i? Is this done with the ecu plugged in or out? Sorry if it\'s a stupid question.
How are you getting on with the fault on yours? Have you managed to eliminate if its ecu or loom/sensor related?
http://www.ebay.co.uk/itm/DC-DC-Converter-Regulator-12V-Stepdown-to-5V-3A-15W-Car-Power-Supply-Module-/230821091424?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item35be025860
id be inclined to install this.
You need to check ot with the ecu plugged in and with the ignition in the on position. Just slightly splice the wire or poke a safety pin in. You need to be checking the voltage between pins 3i & 4d with all connectors in and plugged out.
Mine turned out to be the ecu. The voltage step down regulator wasn\'t holding current under load, plus ecu chip 3050 looked fried. But best guess it was caused by my wiper motor shorting out the ground at the slam panel where I believe pin 4d shares a ground (traced it here from the map sensor)
Ain\'t this the same as sanken 3050c already installed in the ecu.
Quote from: boosted;879248http://www.ebay.co.uk/itm/DC-DC-Converter-Regulator-12V-Stepdown-to-5V-3A-15W-Car-Power-Supply-Module-/230821091424?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item35be025860
id be inclined to install this.
Its 5vdc power supply..power up 3i and 4d loom...NOT ecu and ground shield wire on to 5v negative. Fuse the 12v feed with a 3amp blade fuse from an ignition switched live.Worth ago for fiver.
Fuse the ecu live, ain\'t that 1a & 1b
I think 1a already is on a 7.5amp fuse
Ah you mean elimate the ecu power up and use the 5v dc step down. So could still use my ecu
So four wires on the 5v dc step down chip.... Red to 12v source with inline fuse, black to chassis ground, yellow to 3i direct and other black to 4d. (direct to loom, pin 3i & 4d removed from ecu)
No run a seperate switch live to power the new regulator....fuse that. Power the effected sensors from this
Leave the ecu power supply alone...sensor get power and 0to5v signals into ecu.
As your last post yes.
Would this be ok http://m.ebay.co.uk/itm/320910878846?cmd=VIDESC&gxo=true
Yes mate...its worth a try for a fiver...
Yes...bit more power and has protection...
As it has short circuit overcurrent protection etc if there is still a problem in your loom if will just turn off. So either fix it or highlight there is still a problem.
So don\'t touch the wires at the ecu. Go from the new regulator direct to the map & tps sensor.
So the 5a 25w is not too much power. What would the max current be on the sensors.
Quote from: ttpower;879294So don\'t touch the wires at the ecu. Go from the new regulator direct to the map & tps sensor.
On my laptop now....
yes leave those ecu 3i and 4d unconnected. . connect the reg to loom 3i and 4d...fuse 12v power supply.
Unsure of the amps will be low so both easily able to cope.
sensor will draw what they need 5A is the max.
Cool will give it a go. The 3050c component arrived today, gonna give this a try too and replace it first.
(http://s16.postimg.org/rhdcyp12t/IMAG4341.jpg)
That\'s the 3050c chip.
And corroded terminals (top 5 pins)...
(http://s28.postimg.org/ahcx2hwb1/IMAG4347.jpg)
even better, didnt realise you\'d ordered 1...proper fix....
Yeah got the part from sanken, they have a base here and order from Japan or can get from their distributors.
New voltage regulator installed ...
(http://s24.postimg.org/vsddpbfjp/IMAG4357.jpg)
fingers x all sorted! do the same checks again..make sure you got 5V before connecting to loom.:Thumbs-up
Ok so changing that part didn\'t help, soon as I plug in any of the sensors the voltage is dropping so wasn\'tthat 3050 chip. would it be a capacitor that holds the load. Anyone have a schematic diagram for the pfc?
Did sanken have a description for the chip?
found the pdf on sanken site...its a voltage reg alright ! What happens if you try your ecu in your mates?
yes got the data sheet also for the 3050. With my mates ecu works perfectly
ecu doesnt work in my mates car, same problem
there must be a capacitor that holds the voltage
I tried my ecu in my mates car and it had the same senors reading in error. Have now taken the ecu to my local electrical repair store. Hopefully they can fix it for me. Will keep you posted.
Yeah let us know what the problem is if they can find it. Sure there is a capacitor which much help the load.
Just picked up ecu from electrical shop and they couldn\'t find a fault with it. TBH I don\'t think they even looked at it. Apparently could not test it as they can\'t put power to it.
Going to have a search on the net and see if there is anyone else local that can look at it.
The only company that i can think of would be bba.reman. but thats a long shot.