Hi All, my first technical post so apologies in advance for any errors.

I have a May 1992 Volvo 940SE which while running very well it does have an occasional problem after a longish drive and the ngine compartment is very warm. Vehicle has been running smoothly without a problem and I pull in to a rest halt for example. Switch off the engine, go to the rest room, purchase a burger or whatever come back to the car, insert keys and turn on engine - nothing!

All warning lights are illuminated battery has full power and all light are operative. Turn the ignition key again - silence but all lights still solid on dash. Switch off all is dark as it should be. Turn ignition key - dash lights on but silence, no engagement of starter motor nothing!

Open the bonnet (hood) and sit back patiently for a few minutes, up to 30 minutes worst case, and after turning the ignition key every few minutes (all dash lights appear each time) and all of a sudden the ignition connects and engine starts,

The car can run problen free for weeks then for no reason it decides again not to start.

The silence of it all and the fact that lights are on gives me a feeling that the car has become immobilised, as I say it won't start.

I have a Volvo alarm fitted, best of those available in September 1992, and made by Scorpion according to the key pad. This works fine and on occasions I have switched off the alarm with provided key in the engine compartment. Car immobilses whether alarm is activated or not.

I have been advised that it could the alarm that is the problem. I have found a alarm engineer that will professionally disable the alarm but he warns that this may not be the problem and all that he would be doing is getting rid of a potential area of problen and the original problem may still be with me.

So please has anyone else had a similar problem or even better advice on where the problem may lie.

Many thanks

Bryan

 

I vote for the hall pickup in the distrubutor if you have one or the speed sensor connected to the bellhousing. Check for failed connection or frayed wires. the connector on the distributor is easily broken. You can use freeze spray on component to see if that is what is causing your hot no start. I will get a link for you.

http://www.brickboard.com/FAQ/700-90...nosisandRepair

 

Does the keypad also operate the central locking? I have not heard of Volvo using Scorpion alarms on UK Volvos. They are either the Volvo Basic System Alarmor the Volvo Guard Alarm 11. Usually Scorpion is an aftermarket fit which seems to be borne out by your having a May 1992 car with a September 1992 alarm.

 

Bill. many thanks for the reply.

Yes the keypad does operate the central locking and yes also it was an aftermarket fit. It was a Volvo alarm, maybe Volvo Guard Alarm I think and it was the best of two models available at Speeds Volvo Beeston, sadly long gone. It was the service receptionist at Stratstone Volvo Derby who suggested the alrm problem and the fact that it was manufactured by Scorpion for Volvo. It has blue Volvo security sticker on the window and it was a Volvo instruction booklet that came with the alarm and handed to me when fitted.

So Volvo Guard Alarm sounds good?

 

wojeepster, Sorry but I am not aware of what the hall pickup is so will have to check.

As to the sensor on the bellhousing I was having intermittent speedo/trip problems where the speedo which just die and stay dead for days then start again and would be OK for weeks. Stratstone Volvo Derby first of all cleaned and checked the existing sensor. It lasted for about 2 miles before speedo again died on me. They ordered a new sensor and had it fitted and whilst testing it was fine but about 7 miles later it again died. Next option was a speedo head but Volvo cost made me decide on try to find one at a breakers yard and in the meantime I bought a TomTom Go so at least I new what speed I was going. (I needed anexcuse for one anyway!)

Would you believe the day after purchasing the TomTom Go the speedo started working again and did not hiccup until Sunday last, which is about 6 months after purchasing the satNav!

So effectively I had the original sensor cleaned and cables checked by Volvo engineer and a new sensor fitted by another Volvo engineer. The immobilising (what it appears like) was happening on both the original and new sensor?

Apologies if this is none technical for I am not a vehicle engineer?

 

No apology needed, neither am I.

You threw me by saying it was a Scorpion, it made me think it was just an add-on.

It probably is the Guard Alarm, but staying non-technical does your remote have two buttons side by side - 'Lock' & 'Unlock'? This will definitelyindicate which alarm it is.

 

Bill,

again many thanks. No buttons I'm afraid it is lozenge shape 2" x 1 3/16" x 1/2" thick. On the front it is blue with a red beam effect starting with small clear red covered hole which lights when it is squeezed to activate the small pressure switch inside. The spare which replaced a dead one after a while says "Scorpion" on the front. One the reverse they both have printed:

MPT 1340
W.T LICENCE
EXEMPT

As I say it was the Volvo chap at Stratstone Derby that mentioned there were two manufactures involved in supplying these Volvo alarms, cannot remember the other but he dis say this, even though Volvo badged was made by Scorpion, maybe born out by the Scorpion badged replacement key pad/remote. (no buttons)

I can take a photo of the key remote and the alarm inside the engine compartment and upload tomorrow if this would help.

It was definately a Volvo Alarm which has the immobilser and two interior sensors mounted to the left and right of the rear view mirror and locks/unlocks the car and sets/unsets the system when the remote is squeezed. It also came with a circular hollow key to switch off the alarm system. As mentioned this fault occurs whether the alarm is live or off and their is no pattern apart from the fact that the engine, and compartment, is hot.

I have yet to check on whether this has a hall pickup as mentioned by wojeepster, if I can recognise it???

Again Bill, many thanks for your help.

Bryan

 

The photographs would be helpful but the only diagnostics I have are for the Volvo Guard Alarm 11 and the Volvo Basic Alarm. There is no indication as to the manufacturer.Both of them have the functions you mention.

 

The only real way to diagnose a no-start is if the engine stays dead! That way, conditions remain constant. Go to www.stepbystepvolvo.com for a free diagnosis guide to 740/940s.

For gremlins, another good choice to try is the fuel injection relay. See above guide.

 

I'd strongly suspect the ignition switch, it is possible it acts up on occasion and causes this. I've seen the switches begin to cause crazy problems onVolvos with high miles, such as the one you are describing.