Lexus Sc430 Turns Over But No Start, Birmingham. May 2014.

Terminator Guy · May 26, 2014

Hello,

Have you any suggestions as to why my 2002 SC430 didn't start yesterday evening ? I'm dead in the water parked up at a friends house in Barston, near Solihull and Birmingham International Airport

The engine turns over as normal, I can smell the unburnt fuel out the exhaust. I can hear the fuel pump working etc. It gives a slight cough upon first turn of the key but will not come near firing up properly. The engine turns over at speed from the starter but without any further signs of ignition.
The car's key is unlocking the car with the remote on the key as normal so I don't think it's an immmobiliser issue. The Battery is fully charged and turned the engine over for about 5 minutes in total during the hour I tried to start her in so there is no Battery voltage problem.

A strong side issue is that the heater fan started to switch on and off by itself yesterday, and this morning stopped altogether on the drive home. Another thing is that the heater fan briefly turns for one tenth of a second when switching the car off, even when selected to off on the climate control screen.

I disconnected the Battery, checked all visible fuses, pulled out the ECU to check for visible problems on the connectors like corrosion, damp etc but found none. The earth straps in the engine area all seem good, a I've pulled and re-installed all the visable engine bay fuses, but nothing improved. No big fuses are blown that I can see. The cars remains a non-starter and the heater fan still won't operate as normal.

Lastly, the boot / trunk area seems to be quite damp so I let it open for a while to dry out tonight.
Stuff like this is not supposed to happen to a Lexus !!

Morning Edit:
Now I found elsewhere after a bit of searching primarily on Clublexus in the LS430 section that the fuel pump relay will give the starting symptoms I've described, so I think I'll replace that first, but I'm still at a loss to find a cause of the heater blower fans erratic behaviour and I'm still suspicious that both issues are connected....

I found these part number for a Fan Blower control module: 87165-22050. and this for the fuel pump relay: 90987-03003.

I'll still suspicious that both items are related to some common point as it's like lightning striking twice for the starting and blower issue to happen within 24 hours of each other.

That ignition key has always worked normally for 3 years now and I've never ever had an issue like this before, not even for a second. I don't think it's the key. As an aside I've only one key for this car since I've had it.... but it's as good a suggestion as any, and will be investigated in due course. The car does provide spark, but not for long enough to fire up the engine. It sparks for less than 1/3 a second and then stops again.

My own feeling is that I have an earthing point or a relay somewhere not functioning normally. Second guess is fuel pump, fuel relay, fuel pressure regulator, etc. I've no tooling to be able to confirm any of this.

I got a loan of an OBDII scan tool and there are no fault codes detectable by this tool stored in the ECU, I checked with those 10 pound Bluetooth OBDII tools along with the "Torque" app. The ECU seemed to communicate well with the scan tool though I have my doubts that it actually communicated at all.

I brought the Battery close to discharged this morning after all the cranking attempts since last night and the few more this morning, so it's charging up now with a Battery charger, with the Battery earth strap disconnected.

At this point I feel a trip on a tow truck to an independent Lexus service centre is due now.
I've checked all the easy stuff at this stage. It's not helped by the fact that I'm currently in England but am normally resident in Ireland and I've no contacts over here and am not a member of the AA (my reasoning being that a well serviced V8 Lexus will never ever break down, famous last words ha ha).
Any recommendations as to a garage local in the Midlands that might be able to fix her up at a reasonable cost ?

Boring picture of her getting charged up this morning.

http://i.imgur.com/L6e8K3A.jpg

steve2006 · May 26, 2014

Hello,welcome to the LOC and sorry to hear of your problems with the SC430.

Strange no codes came up but they don't always.

Not entirely sure here but there may be a black rectangular diagnostics socket mounted in the engine bay normal attached to the top passenger side of the engine under the engine cover.

If you have this fitted lift up the top and look for +B and FP connections, if you bridge these together it will force the fuel pump to run constantly then see if the car will start. DO NOT leave the link in place it is ONLY for diagnostic purposes.

Another cause of complete non start is the crank angle sensor but I would have expected this to have shown up on OBDII.

What you really need to accertain is whether the cause is fuel or spark related.

Terminator Guy · May 26, 2014

If you have this fitted lift up the top and look for +B and FP connections, if you bridge these together it will force the fuel pump to run constantly then see if the car will start. DO NOT leave the link in place it is ONLY for diagnostic purposes.

Thanks for this tip Steve2006, I'll get a pic of this port and bridge those connections soon. Hopefully it will help decide if it's fuel or sparks.

Just having a look around on the 'net and can't find that port on a 2002 SC430 so far... I'll keep looking.

Terminator Guy · May 26, 2014

I had the Battery disconnected today, and put it back on in the evening, opened and closed the doors with the button on the key no problem, and she fires up and runs properly. As a bonus the heater fan rely thingy is working normally too, so full normal service resumed ! I had the boot open all day as it seemed a bit damp yesterday pulled and reseated all the fuses in the engine bay again this morning, so I suppose (and I hope) I'll never find out what happened.

Thanks for the advice Steve2006.

PS I couldn't find that diagnostic port under the engine cover of the SC430 so I took a photo of the engine bay, I hope you can spot it as I couldn't.

http://i.imgur.com/4rcGDzil.jpg