Engine Cutting Out

[druid]

Hi

My son has just got a zx 14i and he keeps having a problem with the engine cutting out this is a intermittent fault.

If you rev the engine to about 6000 revs the engine starts to pop and the revs start to drop and if when driving the revs will drop right down to nothing and cut the engine.

The car starts first time everytime and can be driven for a day without any problems then you go out a hour later and it starts playing up again.

It seems like a fuel problem but we have changed the fuel filter and used redex injector cleaner.

Has anyone had a simlar problem or got any ideas how to fix it.

The car had been sat for 5 months with no use and also needed a new clutch which has been done.

Many Thanks

[Guest Colin Hunter]

First thought on this one is that it's objecting to abject cruelty! Revving an elderly 1.4 engine to 6K rpm is a bit like getting your 80 year old gran to run the 100m! :blink:

 

If it's an intermittent fault it's most likely to be a dodgy connection on one of the engine management sensors. (Crankshaft position, Coolant temp, Lambda sensor, Air temp/flow and throttle position. ) On the single point engine I believe the latter two are part of the "Throttle body" Remove each plug in turn and ensure the connections are clean. Also check the Multi plug on the ECU (It lives in a box behind the battery)

If you had the engine and gearbox adrift to do the clutch you may have damaged tthe crankshaft sensor in the process or not replaced it properly.

 

Other than checking the plugs and the connections to the ignition mudule I don't think there's much more you can look at on a DIY Basis. Cheers Hope this helps. :D

[druid]

Hi Colin

Thanks for the reply.

My son did have the clutch replaced about a week before Christmas and was done by a garage.

We are not 100% sure if the problem was there before the clutch was replaced as the car was givin to my son from a friend and it was sat in a garage for 6 months due to the clutch needing doing.

When we state about the 6000 rev thing it does not matter what range of revs you use it can happen when you are just coming to a stop or when you are driving up the motorway it will splurt and stutter and sometimes the revs will drop right off and the engine will die but will re-start right away when you turn the key.

How easy is it to check the crankshaft sensor and can you check it etc with out splitting the gearbox and engine apart?

Is it a expensive part to replace and refit? In case the garage wont do anything about it.

Going back to the high rev thing the reason we took the revs so high was to see if it cut out at high revs with the gearbox in use (netural and not moving) and we then noticed that the revs will hit about 6000 and then they drop back and splurter and the engine cuts out.

Can you tell me what the crankshaft sensor does?

Many many thanks for your time.

Cheers

 

First thought on this one is that it's objecting to abject cruelty! Revving an elderly 1.4 engine to 6K rpm is a bit like getting your 80 year old gran to run the 100m! :lol:

 

If it's an intermittent fault it's most likely to be a dodgy connection on one of the engine management sensors. (Crankshaft position, Coolant temp, Lambda sensor, Air temp/flow and throttle position. ) On the single point engine I believe the latter two are part of the "Throttle body" Remove each plug in turn and ensure the connections are clean. Also check the Multi plug on the ECU (It lives in a box behind the battery)

If you had the engine and gearbox adrift to do the clutch you may have damaged tthe crankshaft sensor in the process or not replaced it properly.

 

Other than checking the plugs and the connections to the ignition mudule I don't think there's much more you can look at on a DIY Basis. Cheers Hope this helps. :(

[Guest Colin Hunter]

Yes, it's quite easy to get at the crankshaft sensor as it's on the front of the engine on the joint between the engine and gearbox. You'll see the "Lambda" sensor sticking out of the exhaust frontpipe, the crankshaft sensor is to the right of that on the casing. This is now straight from the manual (Well nearly!).

1. To remove the sensor , first disconnect the battery negative terminal (Make sure you heve the radio code before you do this)
   
2. Trace the wiring back to the connector and disconnect it.
   
3. Prise out the rubber grommet, then undo the retaining bolt and withdraw the sensor from the transmission.
   
4. Refitting is the reverse (BLah blah) etc! make sure everything is properly tightened etc!
   

I don't know how much a new one would be, or even if that's the problem, there's also a vehicle speed sensor which is part of the speedo drive but if it's doing it stood still I can't see it being that. What the crank sensor does is twofold.

1. It tells the ECU how fast the engine is going.
   
2. It senses the engine position from ( I beleive ) magnetic inserts in the flywheel which correspond to TDC on 1&4 clylinders and 2&3 cylinders.
   

The ecu can then work out the engine speed, position and amount of "Advance" to apply to the ignition. The ignition works on "Wasted spark" principle in that it fires both 1/4 and 2/3 cylinders together regardless if they are on compression or exhaust stroke. This does away with the need for a mechanical distributor.

 

Best thing to do is go out and buy a "Haynes" manual. They are very good and mostly written in language the layman would understand . They'll also cost about an average 20 mins to half an hours labour at a garage! The biggest problem with the single point injection system fitted to the ZX 1.4 is that it's completely non adjustable and if there is a problem then there IS a fault with some part of the system. The trick would be to find out which bit! If the car has been sat for that length of time it may well be that dampness has got into some of the wiring sockets and caused a bit of corrossion there. Was the car running properly BEFORE the clutch job?

 

The good news is that there are plenty of dead ZXs in breakers yards all too willing to donate parts (Quite cheaply) in order to keep their siblings on the road!

 

If you are new to Citroen cars here's a few places to look for spares and service parts

 

http://www.gsfcarparts.com/ German Swedish & French cars. Pattern parts at decent prices. Mail order from Website or check on the site if there's a branch near you.

 

http://www.partsgateway.co.uk/ Web based breakers yard.

 

http://www.pugcit.co.uk/index.html Another of the same.

 

Although the ZX you have is probably worth very little in monetary value it's a solid wee car and later ones were (Almost) fully galvanised. It's pleasant to drive and has few vices. It's probably worth trying to keep it going if it's in good nick as you have to factor in the cost of a replacement vehicle which may be no better in the end!

 

Cheers. Hope this helps. :lol:

[druid]

Hi Colin

Many thanks for your advice.

We will take a look at the sensor as you suggest.

The car is a 'R' reg and is in fact vgc and only has 63000 miles on the clock.

It has had a new lambda sensor fitted.

To be honest we dont know if the car was running ok before being stood for so long we were told that it was a bit jerky but then it was ok again not sure what work was done to make it ok again if that makes sense but like I said something was done as it has a new lambda sensor on it, I drove it to the garage to get the clutch fitted and it seemed ok but was differcult to tell 100% as the clutch was slipping really badly.

We will take the crankshaft sensor off and look at it and clean it up and put it back in again just in case the garage did not put it back right.

Do you think it is worth getting a home tune guy to connect it up to his computer and give it a good tune and see what fault if any he can find.

Its a real shame as it is his first car and just bought a house for him and his G/F so money is a little tight and he does not want to keep spending out on parts that are ok to find the fault.

Many Thanks

Graham

[druid]

Hi

I have taken out the sensor and cleaned it and the plugs etc the screw holding the sensor in was only hand tight so maybe the garage had put it back in and forgot to tighten it back up so have now tighten it right up so will just need to see if it makes any differance I will let you know.

Cheers

Graham

[Guest Colin Hunter]

As I have said before, it is not possible to adjust anything at all on the single point injection system, (It is single point I assume) so a hometune guy wouldn't be able to do anything to it except perhaps pinpoint what was wrong.

 

The best thing to do is phone a few and see what they say, also fuel injection specialists may be able to help as indeed may your local Citroen Garage. Ask them if they know any common problems which may cause the symptoms you are experiencing. They may be able to tell you right away if it's a known issue.

 

Bear in mind that it may not be the fuel side of the engine management which is causing the problem. It may be the ignition module on the end of the cylinder head. I have heard they can give bother sometimes.

 

If you've found the crakshaft sensor loose then you may have cracked it! Hope so!

 

Cheers again

[druid]

Hi Colin

Guess what?

Its still the same.

How do I know if it is a single point injection system?

Think it may have to go to a garage and let them sort it out but its a pain in the ass getting a garage to do it.

Cheers

Graham

[Guest Colin Hunter]

If it's single point it will have a 4 branch inlet manifold with a thing like a carburettor sitting on it. Multi point engines have an injector for each cylinder. These things are notoriously hard to diagnose. I've heard of places basically replacing sensors one at a time until the problem went. OK if it works after the first one! Try Citroen themselves and ask if they can do a diagnostic on it. I'm not sure if the ZX has that capability but it's worth a try. They'll be able to tell you if it's ignition or fuel related.

 

Cheers