1996 Rav2 2.0 Auto - Won't Start - Blowing 20A Am2 Fuse

[riscyrich]

Some help please if you wouldn't mind forum :-)

My old man's Rav4 wouldn’t start this morning, got home from work last night and all seemed well. Came to the car this morning and it wouldn't start, didn't even turn over.

So I started with some quick visual/audio checks. All lights on dash are on, gear selector in 'P' position. Operation of ignition key to 'start' position results in no action at all i.e. no attempt to bring in starter contact, no relay clicks can be heard etc. Clock goes out as it normally does during engine start.

Had a quick check under centre console for any obvious switch faults but remembered that the selector position switch is on the gearbox. Popped it in reverse and rear lights came on so I am assuming that it was working somewhat.

After all this I stopped (coffee break), woke up and went to where I should have in the first place - the fuse box !

Spotted a 20A fuse labelled 'AM2' blown. So I replaced that and turned ignition on (not to start position). Fuse popped straight away; so something down wind of the AM2 fuse must have a short.

Just to be 100% sure it wasn't Battery, starter, solenoid related I managed to carefully remove the lid of the small purple starter relay and mechanically operate it - the engine turned over but failed to start as expected.

So my question is can anyone tell me what might be on the 20A AM2 fuse might be giving me trouble?

My best guess is its fuel pump related, only because there was a fault with the fuel sender (well a fuel leak) which we had replaced a while back. A short time after that I noticed the gear selector illumination had failed but didn't really connect the two until now. He also today informed me he had smelled fuel again recently :censor:

Anyone think the AM2 fuse might feed the fuel pump? I have tommorrow off work so I thought I'd give it a go in the morning before getting it towed to the garage. Just not looking forward to dropping the fuel tank off in this crappy weahther

Any help is much appreciated so thanks in advance.

Rich

[bothwell_buyer]

First reaction would be to check that the earth lead onto the bodywork is sound. If a dicky connection onto earth exists, it will be enough to connect light use but will not allow power up of starter etc. I say this based on the age of car. Its worth checking or replacing the earth connection, or even adding another connection as well... engine to bodywork to Battery.

On the fuel, I would check the fuel tank breather pipe in the rear nearside wheel well. These rust as they are only protected by a plastic shroud which acts to trap road muck etc against the breather pipe and the filler pipe.

[riscyrich]

Hi bothwell_buyer

Thanks for the reply. Have checked earths etc, all are sound to my knowledge. The car is able to turn over strongly when I operate starter motor relay so am pretty sure its not that.

I will get it up on the ramps in the morning and have a look - thanks for the heads up

ATB

Rich

[bothwell_buyer]

OK

Has the immobiliser kicked in somehow?

[junebug1701]

I think this schematic is for a 2001, but it should be similar. The AM2 fuse feeds the alternator through the charge warning light on the dash. Seems if it were a problem downstream the 10 amp IG2 fuse would have blown. That leads me to believe it's a bad ignition switch (the electrical switch, not the mechanical lock cylinder) or a wire shorting to the frame.

[riscyrich]

Hi junebug1701

Thanks ever so much for posting the wiring diagram - very helpful.

I had a little scout round and did stumble across the ignition switch problem a few times, it's well worth a change before I go to the trouble of dropping the fuel tank. Would also go some way to explaining why he got home and then found it faulty next day. I'll see if I can get one local and swap it out.

Thank again.

ATB

Rich

[riscyrich]

Turning out to be a right pain trying to get one of the ignition switches. Looks like I'm going to have to bite the bullet and head off down to Toyota. Probably going to have to drag my wallet kicking and screaming there though - they want nearly £80 for it !

ATB

Rich

[Joylove]

Can you pull the connector and probe the pins for shorts? and probe the wiring for shorts?

[riscyrich]

Unfortunately I've not had the time to look at the car in any real diagnostic fashion as of yet due to work, weather and lack of workshop space. Might have to wait till weekend now unless I can get an early dart from work one day. Have ordered the switch from Toyota in Leeds. I will try diagnostics before fitting so I can always take back if not required. It does kind of fit the fault though, it being ok one min and not the next.

I'll keep my progress posted...

ATB

Rich

[anchorman]

There was some autos that had the wiring loom chaf through on top of the gearbox. Just move the wires and see if it clears it.

[riscyrich]

Hi Anchorman

Thanks for the heads up; I will have a look tonight, certainly sounds like another candidate for the fault.

Think I need to man up and get my head into some proper diagnostics rather than just chancing my arm at faults.

Thanks again.

ATB,

Rich

[riscyrich]

Well had a look round and lifted/moved all the wiring trunks, fault still there.

The hunt continues...

ATB

RIch

[riscyrich]

Well had a bit of a mess around this evening. Have moved some of the wiring trunks around and swapped out the ignition switch. The switch didn't present any faults but had some rattle noises to it so I swapped out just in case. But alas the fault is still there :ffs:

Managed to find the wiring diagrams for the car after an hour of hunting around the web. Electrical wiring diagram (EWD) is here if anyone wants it:

http://www.filehosting.org/file/details/287440/EWD.pdf

I think all my messing around has drained the Battery (showing 11v no load) so I have that on charge. It hasn't even got the juice to 'pop' the fuse anymore, just made it glow till it eventually went.

New wiring diagram was helpful - as the fuse only blows when the key is turned to ignition position I'm thinking the fault lies down the IG2 path. This complicates matters somewhat as the EWD shows it connects to the whole ignition system which is going to be pain. There are rumblings of a noise suppression capacitor in the ignition system that can short out but I can't see that its fitted to this car.

Not sure whether to carry on or give up and hand over to a good mobile auto electrician - if I can find a good one

I know the guys down at Viaduct Auto's in Leeds have a good one they can bring in but means getting car recovered at further expense. Wished this happened during the summer so I could have a good crack at it...

ATB

Rich

[mnl]

Thanks for posting the EWD for a 4.1 (even if the spambots now have my email address )

The usual trick of jumping the fuse with a headlight bulb whilst looking for a short likely won't work as the ignition normal load will be too high, I suppose you could put both beams on in parallel.

Try whipping off the kick panel and seeing if the problem is water ingress beneath the screen running down the A pillar that has filled up something and caused a short

[riscyrich]

Hi Mnl

Yeah I had the same thought about the problem with the lamp test method. Suppose if I did parallel them up I could get it to pull enough to show the difference between fault and normal load current. Getting the time during daylight hours is the problem at the moment as have no access to the garage.

I was in the footwell a fair bit this evening and didn't notice any signs of water ingress but I will double check in the morning.

ATB

Rich

[Joylove]

Can anyone post the EWD as an attachment or host it on somewhere that doesn't need an email address like rapidshare or megaupload please?

[riscyrich]

Hi Joylove

Yeah, I think that is the next step. Time to dust off the multimeter

Now I have a clear wiring diagram it doesn't look as bad as I thought. Might see if I can have a look in the morning before work...

ATB

Rich

[riscyrich]

Joylove - I will find a better host soon - I have spare webspace somewhere . Just wanted to get it up for discussion quickly etc.

ATB

Rich

[riscyrich]

Well believe it or not I've still not managed to get this Rav4 back on the road. Called out an autoelectrician but with all the bad weather we had he struggled to get enough time on the car to get to the bottom of the fault. He dropped round on Christmas Eve and spent an hour on the car and got close to the fault.

Anyway, once he had localised the fault I was able to diagnose the problem myself as being the noise suppression capacitor inside the distributor housing. I had previously eliminated this from the diagnostics as I had disconnected the unit and the fault still existed, turns out there are two connectors to the distributor one of which is stashed right at the back under a wiring trunk :censor:

Upon opening the unit it was immediately obvious that the capacitor had blow and spat out all its dielectric.

Only problem is now replacing the capacitor as there are no markings on the component itself. What I’m going to do instead is bring out a wire from the ignition coil (where the capacitor was connected) so I can substitute capacitors in when I understand the type and rating I should replace it with.

Does anyone have any ideas what the rating of the capacitor may be? I've had a good look through the manuals but not come up with anything useful.

ATB

Rich

[riscyrich]

I've found the part:

http://www.napaonline.com/Catalog/CatalogItemDetail.aspx?R=ECHRC102_0213206262

Anyone know where I might get this in the UK ?

Cheers

Rich

[crofter]

Hi Rich,there is an Aladdin's cave in Derby that I have used in the past with some success and after checking their website they stock Napa parts,and the counter staff know the biz.

I offer this in the hope they can help.

R.F.POTTS Electronics

66-68 Babington Lane

Derby

DE1 1SX

01332 343 469

Other than a past customer I have no other connection with this Co.

Del

[riscyrich]

Hi Del

Ended up getting it from Toyota in Leeds. I would have gone to the one in Bradford as it's near where I work, but in my experience of their parts dept and customer service the one in Leeds wins hands down every time.

I will definitely keep a note of it for the future - I ended up paying nine quid for a what seems to be a (at best) £2 capacitor in a shiny Shell. Had I been able to determine the rating of the capacitor I would have just relocated a generic one outside the distributor.

I have taken a few pictures which I will upload when I get my web space back up and running. I'll get a full description of the fault et all up soon too. Then at least if anyone has this in the future they are in with a fighting chance of getting to the bottom of it quickly.

ATB

Rich