Leaking fuel pressure valve

Site Subscriber Joined: 23 Jan 2005 Posts: 502

R1916S (V) Its French I`m Brit.
I have fuel in the rubber pipe between the fuel pressure valve on the end of the injection rack and the inlet manifold.
Could this be causing starting & idle problems.
The air valve has been replaced, but some times the idle goes up to 1500 RPM but goes back down if I restart the engine.
Planing to change the fuel valve anyway as I guess that the membrane is gone. Put a can of injector cleaner into the tank recently, hope it did`nt eat all the rubber parts inside.

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

Well the diagphram has deffo gone if theres fuel in the pipe from the regulator to the manifold.

This will be affecting things. if the regulators leaking then it will be running unregulated so fuel pressure will increase thus it will run rich.

So get a new regulator on there. There are 2 types, the very early late 90/early 91 cars had the old style regulator that sits above the rail after that the rest were the ones where its in the end of the rail

As for the idle staying high start by cleaning the throttle body. When you replaced the idle control valve was it new or 2nd hand?

I done tech articles on how to clean the ICV and Throttle body so have a look there.

It may also be poor earthing on the road speed sensor circuit.

Site Subscriber Joined: 23 Jan 2005 Posts: 502

Idle control valve is new, but I think the old one was OK until I decided to take it apart.

The car is a phase 2 end of 1992 so its on the end.

Throttle body is clean.

Had the alternator rebuilt, but now the battery light on the dash sometimes doesnt light, also the insulation on the throttle position sensor fell off so I cut off the plug put on sleaving and soldered the plug back on.

If the revs stay under 4500 the idle is nomal, but once it has gone above it goes up to 1500. switch off the engine and restart it`s back to normal.

Is the road speed sensor behind the speedo on the cable?

Will order a new regulator in the morning. The local big Renault dealer is not very helpfull - book it in in 2 weeks with a blank cheque and we will see what we can do -. they changed the cluch as the gearbox shaft was leaking oil which cost a bomb, but for small things they want to change everything. Leak on the inside rear brake (hand brake seal) they want to sell you a new caliper for Â£250 +.

Thanks

Site Subscriber Joined: 15 Oct 2004 Posts: 1139

wouldnt go 2 Renault 2 fit things m8 as there well 2 expensive as every1 knows

mabe get the parts from Renault but not fitted by them

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

sound sliek a faulty earth the idle problem. the road speed sensor is at clock end of the speedo cable.

If its dodgy or poorly earthed then you get the problems you have described.

Site Subscriber Joined: 02 Oct 2004 Posts: 1575

R1916S wrote:

R1916S (V) Its French I`m Brit.
I have fuel in the rubber pipe between the fuel pressure valve on the end of the injection rack and the inlet manifold.
Could this be causing starting & idle problems.
The air valve has been replaced, but some times the idle goes up to 1500 RPM but goes back down if I restart the engine.
Planing to change the fuel valve anyway as I guess that the membrane is gone. Put a can of injector cleaner into the tank recently, hope it did`nt eat all the rubber parts inside.

where in france are you matey Question

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

the french bit

Site Subscriber Joined: 23 Jan 2005 Posts: 502

Nice

Site Subscriber Joined: 23 Jan 2005 Posts: 502

Looking at the wiring diagram the road speed sensor wires both go strait to the ECU ?

Should get the fuel valve on Wednesday. Will fit that and see if it helps.

Must have some bad connections in there somewhere but itâ€™s finding them.

Thanks for your advice.

P S the red blob in the photo was Marcus Gronholm last Saturday - not me. ( never go that fast me )

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

theres 3 wires, 2 to the ECU and an earth. Its a hall effect sensor.

Site Subscriber Joined: 23 Jan 2005 Posts: 502

Give up, its going to Renault next week.

The road speed sensor is grounded on the black wire, +12 V on the yellow with the key on.

Fitted the new fuel valve which has fixed the hard starting.

Now it idles at 2000 from cold, settling to 1500 once it has warmed up.

Used to like tinkering around with the car but this really needs electronic diagnostic.

Pity you cant get a connection and a program for a laptop,

I like my old Renault and know its history from new but like all of us its not getting any younger.

Thanks for the advice again.

Cheers

Site Subscriber Joined: 23 Jan 2005 Posts: 502

It was the throttle position sensor. Only problem Renault could not get one as they are out of stock in France.

These cars are over 10 years old now so parts are going to starts getting hard to find, classic cars were fairly simple, but the electronics in these cars may be getting hard to find.

Got the car back from Renault as it was. After 10 or so phone calls to breakers yards found one with two of the things. â‚¬90 for the best looking one (with the throttle body as well) against â‚¬150 for the new sensor from Renault.

Fitted the sensor to my throttle body using the marks from the old washers, perfect idle at 850 â€“ 900 RPM.

Went back to Renault to cancel the order for the new sensor (they had no ideas if or when they could get one anyway) and they said that if the idle was OK and there was no warning light it must be set right in the old position.

The car is now starting OK, so I think that was the fuel pressure valve.

Site Subscriber Joined: 23 Jan 2005 Posts: 502

Back to the old idle problem.

The car was OK for almost a week with the new second hand throttle position sensor. Then after a run on the motorway itâ€™s idling at 1500 â€“ 1600 RPM again. Switching off and restarting gets it back down to 850 RPM.

Driving me mad this thing.

If I clutch in when rolling, (with the normal idle) the idle will stay at 1100 and drop down to 850 when I brake and stop. So the road speed sensor seems to be working.

If I floor the accelerator and lift off quickly without picking up speed the idle stays low.

But if I go over about 4500 RPM regardless of roadspeed it goes into high idle.

As it ran OK for a few days, I think the throttle position sensor maybe suffering from the same problem as the old one. So its back to Renault to try to find a new one as it started like this last time and it ended with a full time high idle.

Anyway I am of to sea for a month so the car will sit in the garage for a while untill I get back. After I will upgrade the engine earthing as shown in the tech article. I would also like to check the grounds infront of the fwd, doors. Does the plastic lower door suround just pull off or are there screws behind the dash?

Cheers

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

to get to the dash earths you have to remove the rest of the plastic pillars all round the car.

A new idle control valve isn;t goign to solve this problem. Theres either a mechanical fault somewhere thats either jamming the throttle slightly or the ISCV or a possible ECU driver problem, of course there could be a wiring problem , easy way for that is to waggle the loom with enthusiasm when its running.

Site Subscriber Joined: 23 Jan 2005 Posts: 502

Had a go at it today as the wife is away.

Managed to get the plastic off the door surrounds. Grounds OK some corrosion on one of the black plugs but not to bad.

Traced the wires to the rear window de-mister as it hasnâ€™t been working for awhile, broken wires in the rubber tube going into the hatch. Spliced in some new wire now itâ€™s working.

Tested the throttle position sensor with digital and analogue multimeters. It seems to be OK. Tested the old TPS which gives the same readings. So I think that may only be part of the problem. Last year I had alternator problems caused by a loose connection on the + wire. I got the thing out, but as the car has Air Con, the pump is under the alternator and it has electric power steering pump and thus a bigger alternator = a big flight to get it out. During all this the insulation fell off the TPS wires and with tape on the wires it looked a bit tired.

I do`nt believe the Renault garages story about the TPS being unavailable. I bet that they didnâ€™t want to fit one, as it may not fix the problem. Thay must have done something as the cap was off the diagnostic plug.

I think the problem most likely will be electronic as if I switch off the engine and restart the idle goes back down.

Do you think it could the ECU as they must have one in the scrap yard?

Thanks

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

ECU's are a grey area, they are usually very reliable, but sometimes they can fail. Some failures are quite strange and cause funny problems. I wouldn't condemn the ECU until everythign else has been tried.

Pin 2 on the ECU plug is an earth, check this, resistance between here and the batt neg terminal should be 0. if its ok load test it to make sure its not breaking down.

Although it dos still sound very road speed sensor biased. Unplug the sensor and drive it, you may need to be quick with the throttle as it may start cutting out everytime the clutch is dipped.

Site Subscriber Joined: 23 Jan 2005 Posts: 502

OK. I unplugged the road speed sensor and drove the car to work. It went into high idle mode but maybe 1 or 200 rpm lower. No stalling.

Pulled out the ECU, tested the number 2 pin in the plug, 0 ohms. Tested briefly with an ammeter and a 55w headlamp bulb, 4 amps (think a 21w bulb will be better but I was quick).

Decided to get under the car to unplug the lambda sensor. Now when I first got the car nearly 3 years ago, the previous owner had fitted a decat pipe and removed the lambda sensor. The cat was in a box, but no lambda. As the petrol consumption was too high, I found a sensor in a breakers yard. (From a Renault 21 with a guaranty of 3 months). Fitted the cat and lambda, fuel consumption down, less noise, still goes fast enough for me (hell Iâ€™m pushing 50, I cant drive around in a noisy car which back fires on lift-off). Any way this is getting a bit long, but as soon as the idle problem started I put the decat pipe back on to save the cat. (Wife says whatâ€™s the noise, donâ€™t miss much do they).

Take the car out, no high idle. Get on the motorway â€“ come off - idles 850 RPM. Go up to a town called Vence, (Iâ€™m in the South of France) thrash it up to the coll (700 meters straight up) stop, 850 RPM.

Think Iâ€™m looking for a lambda sensor, Renault is about Â£150, second hand around Â£70, and GSF Â£50 probably the best deal.

It looks like this was caused by several problems. If Renault could get a throttle position sensor maybe they would have found the lambda was off. Hopefully I am not going to fit a new lambda only to find it the wiring is at fault. Anyway us Muppets will have to learn a lot of s**t if we want to keep these car running as there is not a lot of professional help out there.

Keep it up.

Thanks

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

You were right to use a headlight, the halogen draws more current so its better for load testing.

The main problem is you can't just flash the DTC's, you need XR25 or some other expensive reader but trouble is getting them these days, everything is becoming standard fitment (shame the codes are all different though!).

Universal lambda probes are under Â£50 but they are not as good as a OE NTK/BOSCH sensor.