75ZT Community

My 75 has me and Russ flummuxed.

Recently I had a failed Under Bonnet Pump and then replaced this with a known good secondhand unit, which has subsequently failed some 3 weeks later. It was working intermittently so I had my 75 on Russ' T4 (Testbook version 4.Computer Diagnostic System) and this showed low pressure (94KPa) on the low pressure side (minimum of 121KPa required).

So have bought a new pump and am now getting very good pressure (350+KPa) on the low pressure side. Problem solved we thought, but no. Have good pressure on the low and high pressure side but car won't start.

ECU (Engine Control Unit) has not got wet, or at least are no signs it has, and T4 can communicate with it and get real time readings from it.

Tried starting on easy start (well was actually contact cleaner but should have worked) and no joy, almost fired but not quite.

Cam sensor replaced with known good one, from Russ' Tourer, no difference.

No fault codes on the T4

Have to say I didn't pay any attention to the tacho to see if it was moving during cranking but am fairly certain rpm was showing on T4 when cranking.

Car is located long way from home. Am going back over tomorrow so looking for any ideas as to what to try next?

A long time ago, Tim had a problem with his diesel. Similar problem tried everything but no joy.

I got some odd but inconclusive readings from capacitor voltage using a testbook (old version of T4) so the ECU was sent off to the ECU doctor and worked OK when returned.

His car just died suddenly. It had been wet perviously but had not died then and was dry at the time of 'death'. Did Russ look at the capacitor voltages? I never found out what the root of the problem was but I suspect a component was allowing the voltage to drain away and the ECU doctor replaced this.

Thanks Duncan

Yes Russ looked at the voltages and they were spot on.

Every reading on the T4 was spot on where it should be but it won't fire.

Russ has pm'd me to say that everything is pointing to the ECU even though it seems to be functioning.

We're gonna have another look at it tomorrow.

Double check the contacts on the ECU. One of my pals was having cold start problems. After spending loads and having Duncan put it on T4 to no avail, turned out to be corroded contact /s.

Thanks Mick will have a look at those when we get over to her later.

Russ is planning on forcing an ECU error, by pulling the relay I think. Russ says this will mean the car will allow him to fit another ECU to it in order to try fire it from that. Something about this function being built in order to allow a mechanic to rule out the ECU as the cause.

He had to re-programme the ECU while we there today as it managed to get itself into programming mode while we fiddling.

If it is the ECU I'm going to have to do some serious thinking. My 75 has continuously made a considerable dent in my fragile finances am not sure how much longer that can go on.

Tis a nice sunny day and Russ is on his way over to mine.

Will let you know what the cause was, assuming we find it!!

Keep your fingers crossed.

What about crankshaft sensor?

Even the core plugs can cause silly problems, even though they shouldn't be causing a problem!

Me and Russ finally got to the bottom of the problem on Sunday, but were unable to sort it until Monday.

The under bonnet pump was my initial failure but the terrential rain on Thursday had it seems managed to cause water to build up in my plenum high enough to get the ECU wet. We opened up the ECU on Sunday and it had a couple of drops of water still in it and signs of water damage and a previous poor repair.

My drains were working, but one was not fully clear and we feel it may not have allowed the water to clear fast enough.

Russ tried various fixes, including fitting a known good ECU, which interestingly caused T4 to realise that it didn't have the X-Power upgrade on and therefore applied it automatically. However nothing we tried worked so we decided that the only course of action was to get a matching used ECU and EWS (Engine immobiliser (EWS from the German, Elektronik WegfahrSicherung)) from another CDT and see if that sorted it and thankfully it did. I came out of work at 3pm on Monday to find my 75 merrily chugging away with Russ stood next to her. Apparently she started 1st turn of the key.

There are still a few issues with her and I am seriously considering purchasing a Tourer and possibly breaking this one as she is not long from needing an awful lot of work. At least if I do break her her parts can ensure that many other 75's stay on the road. If I sell her she will only be run into the ground as a cheap hack.

I can't thank Russ enough, he has been truly amazing. He came over to my house, some 5 or 6 miles from his and ferried me over to my work some 20 miles away and back as we tried to work out what had gone wrong on 3 separate occasions. Also he went over to Doncaster on Monday to pick up the ECU and EWS and brought it to me at work for us to fit and I can assure you that Donnie to that part of Huddersfield is a pig of a drive.

Russ has always bent over backwards to help members. Well done Mate.

You may well need the matching Speedo etc or a new one.

Good show Russ. Glad it got sorted in the end.

JohnDotCom wrote:Russ has always bent over backwards to help members. Well done Mate.

You may well need the matching Speedo etc or a new one.

We don't think we will as haven't changed the light module and the mileage on key matches the light module as we just took the transponder off the donor car's key.

Hope we're right.

Been over at Russ' again this evening and it is clear there are still some issues.

Strangely the VIN (Vehicle Identification Number) in the donor EWS and ECU do not match but they seem to work together. The VINs were 52 apart.

The X-Power upgrade is back on and other options back where they were before all of this occurred.

Hi over the past month or so ,at least three times the dame has failed to start, once when cold, the other two..after about an hour after turning off ignition. They have eventually cranked over but at the time it was a tad disconcerting.

I have read about crank sensor and hope to hell its not that, I have listened to both fuel pumps ( bloody back seat is a nightmare to get back on innit) they both sound as if they are doing something...should I be praying its glow plugs, they look easy enough to replace ... what with winter coming I am getting worried.

Never ever in nearly 4 years of ownership has she missed a beat and failed to start.

one time when it was still warm I had to crank it in gear and she started up....hhmmmmmmmm???

AAAAAARRRRRRRGGGGGHHHH
Twice yesterday cold starting = failed to start initially, cranking over and almost firing.

last two occasions including this afternoon...almost flattened battery. when jump started it fired up straight away, I will get battery checked tomorrow, hope ist that or plugs and nowt technical.

PS i only do running around , very short journeys , so am wondering is my battery actually getting charged up, I suspect not...will keep anyone thats interested posted ..lol

Have you checked you have no water in the plenum chambers and that there are no signs of water - look at the filter, does it have a tide mark on it?

That was the give away on mine. No signs of water but a tide mark on the cabin filter.

Glow plugs will not be the cause. I have run mine with them disconnected due to a faulty relay in the depths of winter and I live 1200 feet up.

Could be leak back from one or more injectors and just because the pumps are running doesn't mean they are working correctly. My under bonnet pump was running but not giving enough pressure so the ECU was telling the engine not to pump fuel to the injectors and therefore not to start.

If you can, get yours to either BigRuss, West Yorkshire or Marina Brian, North East. They both have a T4 and don't charge the earth to have a good look at it for you. I can definitely vouch for Russ, he was fantastic with mine. Unfortunately I have had to take mine off the road and am breaking her to pay for the tourer I've bought as her replacement.

Chris

Hiya MrB,

I always check my chambers...clear as bell they are. With regards to the filter which one would that be...(the pollen filter)???? oh god i hope its not ECU or pumps....I have read they can cost a fortune ...

just before christmas...thats all i need!

Marina Brian sounds like a decent chap..... newcastle is only up the road....is he in the phonebook do you know??

very much appreciate the response by the way mate.

ned

well i charged battery up, borrowed next doors ..charger thingamebob reckoned it needed doing...its been starting first thing...still need to get battery checked , worse case scenario...its up to newcastle

ned1 wrote:Hiya MrB,

I always check my chambers...clear as bell they are. With regards to the filter which one would that be...(the pollen filter)???? oh god i hope its not ECU or pumps....I have read they can cost a fortune ...

just before christmas...thats all i need!

Marina Brian sounds like a decent chap..... newcastle is only up the road....is he in the phonebook do you know??

very much appreciate the response by the way mate.

ned

Yes, it's the pollen filter behind the ECU. Mine had a clear water mark on it.

Sounds like maybe your battery is on the way out and finding it hard to stay at its optimum in the cold?