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Discussion Starter · #1 ·
Hi Guys,

I actually posted a similar thread to this one a while back on the 400 forum.

Strange things are happenin' to my beloved Rover and I'm at a loss to explain. I'm hoping any of these symptoms some of you may recognise and be able to offer a solution.

I bought my second hand '98 420 Sdi a couple weeks back. When i first got it I immediately noticed a problem with the accelerator pedal. I had to push it a good half way before the engine responded. I figured it might be a cable problem and seeing how I'd booked it in for a service and a cambelt change, I asked the mechanic to take a look at it.

All the filters were changed, but the mechanic told me he was unable to 'resolve' the pedal issue as it seemed to be connected somehow to ECU and he wasn't sure what the problem was.

Bit miffed he couldn't sort it, on driving away from the garage I noticed instantly the car was pulling much better- it felt like there WAS a turbo in there somewhere, but it didn't seem to me to be performing how it should.

About a week later, one late night I nipped out to the garage for some smokes, and it was like stepping into a different car! The pedal had gone from feeling quite stiff to being almost loose, and the engine was revving with such ease it was unnerving. Basically it went like **** off a shovel and i was so chuffed the problem had resolved itself. I attributed this to the mechanic telling me he had put some injector treatment in the tank after doing the service, I just figured it must have finally cleared some blockage somewhere.

That was a week ago, now it's driving slower than ever, again like there isn't a turbo, the rev's build very slowly and there is about half the power there was that night. I'm at a loss to explain it, as such a dramatic shift in performance is really strange. The only thing I can remember about that night was it was very cold. I don't know if that had anything to do with it?

The car cruises at 70 mph as it is now but has next to no torque or acceleration and I detected a slight 'missing' from the engine on the motorway. This is my first diesel car so I can only use the word 'missing' as that's what it feels like when a petrol car needs it's spark plugs changing or something.

I was also thinking of buying one of Ron's kits as I've read so much about them on here, but i need to get to the root of this problem first before i do.

TBH a guy told me that these models wern't (and I quote) 'a ball of fire' like the golf tdi's or mondeo's etc, but quite honestly, that night i have to say it was extremely rapid, i know it's just not running how it should.

I read on here somewhere something about a MAF sensor but I'm not entirely sure what this is is or where it is, or what it does, but could that be my problem?

As you can probably tell I'm a total novice when it comes to cars, I've been driving them for 17 years, but I leave all things mechanical to those who know what they're doing.

Any help at all much appreciated. Thanks.

Matt
 

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mg_zt
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I guess it could be your turbo isn't working properly, or the fuel pump is doing something wrong. I'm no expert either, the only thing I can think to do is find a way to check eg turbo boost, or the fuel pump (reconditioning it).

I guess what you want to know is how to trouble shoot some possible issues, maybe someone else can help out.
 

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Disconnect the EGR valve (actually you may need to remove the valve and reseat it or blank it off if it is stuck open) and see if that helps. If you are getting lots of black smoke then this could well be the cause.

Also do all the usual checks, unplug the MAF sensor (this only controls the EGR valve so it doesn't do anything very useful), check for split intercooler hoses and check the wiring to number 1 injector, as all of these are common faults.

Then move onto the accelerator pedal. It is possible that the throttle position sensor is duff, but they aren't a common fault. The throttle is connected to this which then electronically controls the fuel pump. It could be something as simple as a dodgy throttle cable or something getting trapped in the mechanism so check all these out. Lastly you could try swapping one from a scrap car (new ones are expensive). You have to set it up correctly though otherwise the ECU sulks.
 

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Discussion Starter · #5 ·
Disconnect the EGR valve (actually you may need to remove the valve and reseat it or blank it off if it is stuck open) and see if that helps. If you are getting lots of black smoke then this could well be the cause.

Also do all the usual checks, unplug the MAF sensor (this only controls the EGR valve so it doesn't do anything very useful), check for split intercooler hoses and check the wiring to number 1 injector, as all of these are common faults.

Then move onto the accelerator pedal. It is possible that the throttle position sensor is duff, but they aren't a common fault. The throttle is connected to this which then electronically controls the fuel pump. It could be something as simple as a dodgy throttle cable or something getting trapped in the mechanism so check all these out. Lastly you could try swapping one from a scrap car (new ones are expensive). You have to set it up correctly though otherwise the ECU sulks.




Thanks mate that gives me some things to go on, I'm gonna ring my mechanic and tell him what to check for.

I'll post back when I know anything further, cheers!

Btw, Does the TU1 make a big difference? Is it necessary to uprate things like brakes and clutch with the extra bhp? Just wondering.
 

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If it is just rons box then no you don't really need up uprate anything else. But yes it does make a big difference. It ups the power a little, but it is the drivability and torque where I think it makes the biggest difference. That will-I won't-I make it moment on the roundabout is a thing of the past. I'd certainly recommend it.
 

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Discussion Starter · #8 · (Edited)
Ok problem solved.

Turns out after all the checks it was a 4 inch tear in the top intercooler hose.

There was some slack in the cable also, so even though it's still not perfect it's way better than it was.

It's worthwhile to note that the hose wasn't replaced to begin with he just patched it up. Then about 10 mins after picking the car up from him i took it for a blast down the Mway and ripped it another 4 inch tear further up.

Got myself a part worn hose from a breakers for a tenner, fitted it and everything is fine, it goes very very well I must say i'm very pleased with the performance.

Now that's sorted can anyone tell me if these Tu1's are easy enough to fit for a general mechanic, and should they be used in conjunction with an induction filter? If so which one would you recommend.

Thanks again, especially to E_T_V for the tips.

Matt
 

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Yes they are simple to fit. You can DIY it if you can use a pair of pliers. (or a soldering iron if you want to solder the connections instead of use the scothloks provided).
 

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I'd recommend using a soldering iron. I tried using the scotchlocks and didn't work, even after stripping the wires a bit.

Not difficult though, if you are comfortable taking off air hoses I'm sure you can manage. Hardest thing for me was locating the sensor!
 
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