Car Wont Rev Properly

[2000peanut]

i had a problem with the hazards not working on my 2000 toyota bb ( its based on a yaris 1.5)

i took out and checked all the fuses under dash and under the bonnet its sorted now

but now my car wont rev properly it starts and ticks over as nice as ever but down on power wont rev

even out of gear what the hell have i done worked great before i removed and replaced the fuses

[Mooly]

Try disconnecting the Battery negative terminal. Leave it isolated for 15 minutes and while it is disconnected press the brake pedal (to apply a "short" across the electrical system). Reconnect the Battery smartly, tighten the clamp and test.

[2000peanut]

that didnot work the car will rev if you press the pedal slowly but just bogs down when you drive normaly

all i have done is removed and replaced the fuses

[Mooly]

So disconnecting the Battery didn't help.

In post #1 you say all you did was "remove and replace fuses" Were any found to be blown ? Is it possible any fuses have been refitted to an incorrect location (there are often a lot of blank spaces), and that a required fuse is missing.

Beyond things like that and I think you are going to have to seek professional help resolving the issue.

[2000peanut]

no fuses were blown and they all when back in were they come from 1 at a time (no blank spaces)

i wish i never started it ,it had been 100% before i need the car for work tomorrow

just been out and redid everything again but no joy

[Mooly]

I can't really think of anything else, other than perhaps doing the "Battery disconnect" again and this time leaving it a lot longer, perhaps several hours.

I was just puzzled as to what you did to fix the original lights problem if no fuses were blown etc. Everything (based on what you say) points to something having corrupted/ or put into a limp mode the engine management system.

[2000peanut]

long story grab a coffee

ok i wanted to change the jap import radio for a uk spec 1

when i took out the double din radio there looked like another plug on same link on the harness it had a plastic cap on it

it looked like a radio ISO but it was not i did not bother putting this cap back on so i put the radio and dash back together and ordered a ISO patch lead

came to lock the car later and no central locking looked further no hazards

so thinking i had blown a fuse pulled all the fuses out etc etc

when this did not work i took the dash /radio back out to see it i had missed anything

then i remembered this plastic cap thought i would put it back on while it was apart looked at it and it had metal pins in it

and when i put the dash ect together locking /hazards now worked

thinking my troubles were over locked the car went for dinner

3 hours later started the car up and no power no revs

if i let the car heat up it will drive but down on power bit of missfire but once passed 3500 revs seems ok

its a automatic so very crap to drive wont drive at all cold

i have taken it apart again ( getting good at that ) checked everthing / left Battery off

had it connected to 3 different OB11 hand helds and a lap top but they all come out with error wont read anything

poss jap import not compatable i rearly dont know what to do now wished i had left it alone it was working great

loved it to bits after working all weekend on it still no uk radio fitted and now this

[Mooly]

Long story indeed. Afraid I've no real answers for you either...

So the mystery plug and its end cap appears to have had "shorting links" in it. No cap fitted, so missing connections to the loom, hence the lights/locking problem. Refit cap and those problems resolve. I assume its the original radio that is back in place at the moment ? Reason for asking that is you just don't know what inter-dependency there might be with the radio and the wiring loom.

So if its all back to original spec, and its not right, and no fault codes showing, then you probably have to attack this from looking at it as a pure engine running problem and see where that leads, which probably means professional help.

I just wonder whether working on the electrical system has "spiked" or corrupted the ECU in some way. If its all back as it was and you're sure nothing has been disturbed (plug forgotten/broken lead etc) then I can't come up with much else tbh.

Hope you get it sorted... be interesting to know what the actual problem is.

[Geoff Peace]

long story grab a coffee

ok i wanted to change the jap import radio for a uk spec 1

when i took out the double din radio there looked like another plug on same link on the harness it had a plastic cap on it

it looked like a radio ISO but it was not i did not bother putting this cap back on so i put the radio and dash back together and ordered a ISO patch lead

came to lock the car later and no central locking looked further no hazards

so thinking i had blown a fuse pulled all the fuses out etc etc

when this did not work i took the dash /radio back out to see it i had missed anything

then i remembered this plastic cap thought i would put it back on while it was apart looked at it and it had metal pins in it

and when i put the dash ect together locking /hazards now worked

thinking my troubles were over locked the car went for dinner

3 hours later started the car up and no power no revs

if i let the car heat up it will drive but down on power bit of missfire but once passed 3500 revs seems ok

its a automatic so very crap to drive wont drive at all cold

i have taken it apart again ( getting good at that ) checked everthing / left battery off

had it connected to 3 different OB11 hand helds and a lap top but they all come out with error wont read anything

poss jap import not compatable i rearly dont know what to do now wished i had left it alone it was working great

loved it to bits after working all weekend on it still no uk radio fitted and now this

Check the room fuse. Remove for a couple of minutes and replace.

Regards Geoff Peace.

[2000peanut]

i have disconected the Battery at the moment going to leave it off all night see what happens in the morning

if not i will have to take it to a garage

dont like doing that i have not taken a car to a garage for anything other than MOTS for 25/26 years

i like to do my own repairs i am a bit of a tight wad

[Mooly]

Good luck, and let us know how it all works out.

[MikeSh]

Bit of a long shot, but can the cap that wasn't replaced be put on the wrong way round? Unlikely, but just might be asymmetric links in it.

Otherwise it does sound a bit like the ECU is in safe mode.

[2000peanut]

cap only fits one way

[2000peanut]

update

the purple box is back

turns out it was the air flow meter senser at fault nothing to do with anything that i had done at all ( talk about bad timing)

the garage tried to sell me 1 for £216 with vat and fitting

but i took the car home with it disconected it only revs to 3000 rpm took the senser apart and cleaned it with carb cleaner

( told you i was a tight wad ) and now the car is back to normal

thank for all your help

steve

[Mooly]

Thanks for the update, that's an excellent result, well done. A real coincidence or what :)