Cutting out...

[pgoldsmith]

Thanks Ben,
I'll 'go a hunting' for it this evening. Had a combination of left foot braking, using the handbrake and blipping the throttle this morning trying in vain to keep her going....

I am currently looking in to the over boost cut out valve and its relay, as mine decided to cut out on the 3rd and 4th laps going round Donnington on the sunday. Sorry to anyone who was behind me on the right hand bends and suffered from plooms of petrol and flames when it decided to run agian! Appently the over boost switch will cut every thing out if its not working properly. Im just trying to figure out how to check it....?

No, the overboost switch is built into the ecu, and is not relay based. When the map sensor sees over 4.96v then it cuts ignition.

The map sensor has an earth, 5v feed, and a return to the ecu from 0-5v. Now, if the return and feed wires short out against eachother or the map sensor is faulty, then the ecu could be fooled into thinking its had a signal over 4.98v and cut the ignition cut.

Are you sure Ben, when you fitted your map boost gauge module, none of the wires could be touching together?

Definately not crossed any wires there. Besides that the cutting out problem was happening long before the new boost gauge...

The guy at Donnington (can't remember his name - Blue GTA with Azev C's and bucket seats) said the over boost cut out switch is the the round thing located just in front of the map sensor. He said it then tells the a relay under the dash to cut the engine when the boost gets too high.
He also told me that it could be the rev limiter cutting the engine if thats not working properly. Im a bit scared to try the limiter if its not working, as i don't want things to pop! I have never had it cut in though and it has had some hammer. Is there any other way to check this other than 7000 rpm? And where is this located to check the wiring?

Thanks for the photos (Blue Alpine with bucket seats at Donnington )

I think David is getting mixed up with the rev limiter, the over boost switch is just a switch. This operates relay number 6 under the dash.
This relay in turn supplies the energy to the fuel pump relay and the injector relay situated under the ECU between the rear seats.

I didn't notice if your car was an early car or not, if it's an 86 or 87 check the main terminal block on the right hand ride rear of the car under the hatch. The contacts in this block corrodes when you start the car everything is ok, but after a few miles because the contacrts are poor they heat up and break circuit. If you then switch off the ignition the contacts cool and make again. This can be a niggly intermittant fault so either clean the contacts or replace the block.

If you would like to contact me on 01492 533430, I can point you in a few other places to look. I've dealt with most problems that an Alpine owner can experience, this comes from owning an Alpine for over 12 years.

Andrew.

[Alpineandy]

I think David is getting mixed up

That's what booze does to you.
David, hope your having fun on your hols!

Thanks Andrew.

The car is at an auto electricians in Lincoln today. I have asked them to have a look at the cutting out problem as well as loads of other minor electrics. They said it might be a bit over there head, so ill be probably be ringing you when i get it back... I have had a good look at the contacts in the main engine connector block, but ill have another look and get some contact cleaner on it. It is an 86 car.

The over boost sensor seems the most likely problem, as the symtems you told me decribe it perfectly.

lol,

There is no overboost switch on the GTA Turbo...



The round cylinder is the sender for the dash boost gauge, the one next to it is a dummy blank unit (the only cars fitted with a cut out switch here are the R25 V6 turbo, and Lemans, and Swiss D502 only, (this is what Andrew is talking about) and the other black unit is the map sensor which connects to the ecu and monitors the boost and does the cutout at peak map voltage.

My boost upgrade module raises the boost level, and this wires to the ecu. If there was a boost cutout switch, I would have to modify this too...

lol,

There is no overboost switch on the GTA Turbo...

Hi David,

My 86 GTA Turbo has an overboost switch. In the PR1132, it's part n°2 on page 17.401.
I've simply disconnected it.... because the boost in my inlet manifold is 1050 mbars. The ECU is also modified.

Double lol!

On the fiche the cut out switch is listed, but I have not seen one UK D501 with this fitted. It was only fitted to cars upto VIN plate number 1730, which most are abroad (and lemans, D502 etc..)

I have three GTA turbo's and all three do not have this cut out switch fitted, nor do they have the T piece in the feed to the MAP sensor to go to the cut out switch.

Even if you do have a cut out switch fitted on a GTA, and remove it, the cutout is also still built into the ecu at 1 bar of boost.

Renault no longer fitted the cutout switch on D501 and issued a technical update to remove any such system (same as used on 21T and 5 GT - but deemed unreliable) because the cut out inside the ecu was adequate. The T piece was then replaced with a straight adaptor which had a small restrictor in place to slightly raise the boost cutout limit.

[pgoldsmith]

So I've now cleaned the idle valve - though it wasnt that gunky - and checked the vaccum pipe to the Map sensor to ensure it's not clogged up.
However, I'm still experiencing the engine dying at when cold.
Apart from these two points is there anything else it could be ?
I'm thinking maybe the idle valve is actually faulty.
If I come coast to a halt when its cold it stays alive , its the sudden switch from 'in gear, throttle on' to 'out of gear, no throttle' that causes it die.

At all other times it's fine and when its warm / hot it's ok too.

[pgoldsmith]

So I've now cleaned the idle valve - though it wasnt that gunky - and checked the vaccum pipe to the Map sensor to ensure it's not clogged up.
However, I'm still experiencing the engine dying when cold.
Apart from these two points is there anything else it could be ?
I'm thinking maybe the idle valve is actually faulty.
If I coast to a halt when its cold it stays alive , its the sudden switch from 'in gear, throttle on' to 'out of gear, no throttle' that causes it die.

At all other times it's fine and when its warm / hot it's ok too.



[ version without the appalling grammer!]

There is a cold start temperature switch (located on the left hand side of the thermostat), have you tried replacing that?

Mine wouldn't idle properly and stalled from cold until i replaced that. Think it cost less than £20 from Renault....

If its only when cold then it could be fueling related. It may be that the c/o pot level is set to low. I had this on a car I bought, it had trouble starting when cold, when it finally ran, if you gave it revs it was fine, if you pulled up to a stop, and just touched the throttle, it stalled.

C/O voltage was all the way on minimum. Set it to the correct amount and it was fine.

Other thing could be low fuel pressure/regulator/fiter.

[pgoldsmith]

It starts fine, it will idle ok and I can move off the drive down to the main road and its still ok.
I then travel say half a mile, approaching the traffic lights, clutch in, throttle off to change down a gear and revs fall to zero.

The thing is it doesnt occur all the time only some of the time.
If I coast to a halt its ok and once I've stopped it will idle fine, and whilst stopped if I touch the throttle its fine i.e. it doesnt die.
It's as though the sudden fright of the car still moving with no throttle kills the engine.

If this idle valve is faulty could it sticking on / off ?
Is it an expensive item ?