MrGorsky · Jun 11, 2015

Morning all,

My wife was dropping the kids off at Beavers the other night, and when she came out of the hall the car won't even crank.

It's a 1998MY Gems.

I thought the battery might be flat, she thought she may have left the lights on for an hour but I've tried another known good battery and jump starting from another car and it's not even trying to crank with either method.

Switching the ignition to pos 2 brings the car to life, usual whirrings and beeps etc. There is an audible click from under the bonnet somewhere, but turning to pos 3 does absolutely nothing.

The car locks and unlocks fine with the remote fobs.

I have the latest RF MK3 receiver installed.

I have a Nanocom.

I thought perhaps I've lost BECM sync? The GEMS immobiliser inhibits cranking so the symptoms are correct, but the engine check light comes on, and Google suggests this is what you want. If you've lost sync then it DOESN'T come on.

I've got the battery out and back home trickle charging now, and I'll take the Nanocom with me when I go to put the battery back in. Perhaps it is just flat, but....

What else should I be checking/trying?

What is the fault when you're parked next to a phone transmitter? It could be that. Can anyone remind me what causes that problem?

Datatek · Jun 11, 2015

If you can lock/unlock with the FOB, it's not stray RF interfering. sounds like loss of sync to me but I'm no expert on the V8. Otherwise duff fuse/relay or bad connections. If the battery is flat, the dash lights will go out when you try to crank.

wammers · Jun 11, 2015

Have a look at Maxi fuse 2 and relay 16. On Gems if engine lamp comes on it in sync.

Saint.V8 · Jun 11, 2015

Starter or its solenoid??

(Gems Starter on the 4.6 and 4.0 are the same if it helps...also the when I put the 4.0 starter back in, I used Hex Head bolts rather than the Socket Caps which can collect gunge and strip)

Rick-the-Pick · Jun 11, 2015

Easy test on this one.

If the doors are unlocking ok, on the fob or the key, then when key is in key position 2 in the ignition, (Dash lights on) you should see a " Check Engine " light appear on the bottom left of binnacle. If this " Check Engine" light isn't appearing then the link between the engine ecu & the becm has failed.
A sync-mate will sort that out for you if no access to proper diagnostics.

Rick-the-Pick · Jun 11, 2015

Forgive me, the check engine light appears on the bottom RIGHT of binnacle, & NOT the left as previously stated.

wammers · Jun 11, 2015

Rick-the-Pick said:
Forgive me, the check engine light appears on the bottom RIGHT of binnacle, & NOT the left as previously stated.

Not if you are looking through a mirror.

MrGorsky · Jun 11, 2015

Cheers chaps.

The engine light is on, so I can assume I have sync.

I'll check the fuses and relay when I go and have a look later. Any idea which relay it is? And can I swap it out with another to test it? I have a Nanocom so can put it in learn mode if I have to.

The battery (according to my cheap charger) was half dead when I started charging it last night, and was fully charged this morning so it was at least a bit flat.

Maybe the car I was using to attempt the jump start from just wasn't up to the job....?

Datatek · Jun 11, 2015

MrGorsky said:
Cheers chaps.

The engine light is on, so I can assume I have sync.

I'll check the fuses and relay when I go and have a look later. Any idea which relay it is? And can I swap it out with another to test it? I have a Nanocom so can put it in learn mode if I have to.

The battery (according to my cheap charger) was half dead when I started charging it last night, and was fully charged this morning so it was at least a bit flat.

Maybe the car I was using to attempt the jump start from just wasn't up to the job....?

Could be as simple as the battery dying under load.

MrGorsky · Jun 11, 2015

Lets hope so Datatek!

I've just been running through the tests to do for a non cranking engine in RAVE.

Those starter solenoid connections don't look easy to get at….

Grrrrrr · Jun 11, 2015

Is it running now?

MrGorsky · Jun 12, 2015

Going to look at it tonight.

Can someone remind me what voltages I should be getting from the battery when switched off, and when the engine is running.

Assuming I can get it running that is!

Grrrrrr · Jun 12, 2015

Battery should be over 12.5V really. You have the bigger alternator so should have 14.2V or more when engine is running.

Datatek · Jun 12, 2015

Grrrrrr said:
Battery should be over 12.5V really. You have the bigger alternator so should have 14.2V or more when engine is running.

14.5 volts if it's a 4.6V8.

MrGorsky · Jun 12, 2015

Well it's home. And thanks for all your help in diagnosing it.

Connected up the battery and nothing. Checked Fuse 2 and it's blown, so first prize goes to Wammers for suggesting that.

I borrowed the ABS maxi fuse to get it started, it did start, but then the fuse blew almost straight away, so now I've got to find out why the starter motor fuse is blowing.

And replace some fuses.

Also, according to the Nanocom "GEMS Instruments" page, I've got 16v at the battery. I haven't checked this with my multimeter, but does that sound too high?

odyssey · Jun 12, 2015

The 16v thing is not correct, I have the same reading on the nanocom for my '98 4.6 Gems. As far as I remember it was something in either early engine ECU (or BECM? not sure), but I read somewhere - poss the nanocom manual - that it always shows the 16v no matter what.

I'll try and find it . . .

A

odyssey · Jun 12, 2015

Found it - on the nanocom forum here:- Forum

Bad batch of engine ECUs around 95/96 apparently, maybe mine's been replaced with an older one at some stage

MrGorsky · Jun 12, 2015

Thank's for that Odyssey. Unfortunately I can't see the forum because I'm not a member!

Looking about I think it's my EAS compressor causing the problems. The fuse only blew after I closed all the doors, that would normally make the car level and start the compressor so i think that's where I'll look first.

Hopefully I might have access to a spare….

urena · Jun 12, 2015

you should not jump start with out serge protection
get battery drop tested could be starter motor ####ed that will earth your battery out
use a multi meter check voltage can be bought for £10

MrGorsky · Jun 13, 2015

Just to draw a close to this, it looks like the EAS compressor was at fault.

The flat battery was a red herring. The fuse was always blown, but because my wife thought she'd left the lights on I assumed the battery was at fault when it wasn't. There's a lesson to learn in there somewhere!

I've disconnected the EAS compressor and the fuse has stopped blowing. I'll swap it out with a spare and refurbish this one if I can.

Do we have a "preferred supplier" of compressor refurb kits. I'll always go for quality over price.

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