75ZT Community

jonjon77 · Posted 07 Jun 2010, 13:07 #1

the car drives great round town with plenty of go but with a slight delay in reaction from pressing the throttle pedal to the car responding.in 5th gear the 50 to 70 time is above 10 seconds even with synergy 2,pierburg maf,intercooler seals,pvc filter,mk2 intake,egr cleaned,checked the boost sensor for blockage all clear.l went round to see bigruss yesterday to check the car with his T4 (Testbook version 4.Computer Diagnostic System) and do a couple of options(cheers russ)and found that the pierburg maf while ok at idle was out of spec at 3000rpm by about 100mlg per stroke.l put the original bosch maf back on and found that the delay from the throttle had gone but the 50 to 70 time is no better.the air filter is less than 12 month old and hasnt done 10k yet but l will change this.does anyone know of anything else l can check?

JohnDotCom · Posted 07 Jun 2010, 13:42 #2

The first thing that jumped to mind was the MAF (Mass Air Flow Sensor),
but having done what you have and the test that Russ has done on T4 this should have shown itself up.
You could try just up[lugging the MAF and she if she improves.

If the Turbo is coming in OK and is working fine we are only left with a Faulty Injector or two but the balance of them should have shown up on T4 and if faulty or out Russ would have said so.
A leak-back test is still a good option if everything else has failed.

jonjon77 · Posted 07 Jun 2010, 14:34 #3

cheers for the reply.the figures on the screen showing the injector balance were,lowest 0.2 and the highest was 0.4 russ said that was fine.russ drove the car and said bellow 3000rpm it picked up a bit better than his car but over that rpm it was not as good.lve just found the receipt for the pierburg maf and it is only 9month old so l think a call to roverron is in order

DeuxGazoles · Posted 07 Jun 2010, 15:23 #4

Another thing which came to light when I was having troubles was the little gauze filter on the input side of the HP pump, not saying that's it but you seem to have covered almost everything else. I'm assuming the car starts ok & runs well otherwise

jonjon77 · Posted 07 Jun 2010, 16:29 #5

ah,l remember reading something that before.how do you check that? lve never had any starting or running problems with the car in the 12 months lve owned it.my mates 130 tdci mondeo estate(dirty words l know)is quicker 50 to 70mph than mine which l find very offensive :mad1:

much to his amusement after everything lve done to the car and all hes done his is change the oil.lve just read the trouble youve had with your car,makes me realise mine isnt a problem more of an annoyance

Russ · Posted 07 Jun 2010, 18:40 #6

We can have a look and check what's happening on T4 with the maf and airflow figures once the air filter has been changed, then look at different settings on the Synergy.

I'll also do a leakback test on the injectors to see if there's any problems, not that it seems likely but you never know for sure until it's been checked. (if nothing else it'll give me another chance to use my new leakback test kit)

Russ

JohnDotCom · Posted 07 Jun 2010, 18:42 #7

Glad you have your new kit now Russ to play with.

jonjon77 · Posted 07 Jun 2010, 19:57 #8

cheers russ your a star.theres nothing more fun than playing with a new toy.l will get another air filter in the morning and a fuel filter(just to rule it out) put them on and pop round and see if you are in to have a look.l think l need to order one of them egr bypass thingys too.

FROGGY · Posted 07 Jun 2010, 21:05 #9

Would have thought that 50 -70 in 5th gear was asking a bit much if you want it to fly. At 50, if I remember correctly, you are doing around 1650 rpm in 5th, which is at the very bottom end of the torque curve for a Ronbox equipped diesel. Try it in 4th and see what the time is.

Mick

James.uk · Posted 07 Jun 2010, 22:09 #10

If I tread hard on the go faster pedal at 50 mph the car will kick down to 3rd and orf it will go. To get it to go from 50 to 70 in top I would have to be very gentle on the pedal, so my times would be worse than yours, and there's nothing wrong with my car.

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To check your best 50 to 70 time you have to use the gears!

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jonjon77 · Posted 07 Jun 2010, 22:28 #11

maybe l am expecting to much from it in 5th.lm just not happy about being beaten by a car that has a van engine in it.it picked up fine in 4th last time l tried.it hardly kicks out any black smoke when your making progress

JohnDotCom · Posted 07 Jun 2010, 22:34 #12

Being in a Auto I cannot really say as if I floor it she will generally drop down to 3rd or 4th gear.

jonjon77 · Posted 08 Jun 2010, 12:14 #13

put bother filters on this morning and l cant feel any change so l can rule them out.l phoned roverron for some advice and he was really helpfull and he said the same as russ,dump the egr valve.l also told him there wasnt much change between setting 5 and 10 with the pierbrug maf,he said l shouldnt use 5 but l should have noticed a differance when l changed to 10.lm sending the pierburg back and hes going to replace it

just ordered a egr bypass from ebay Ã‚Â£24.50 with free p&p from 199andy(l dont know how to do a link)he has good feed back from people who have bought one

James.uk · Posted 08 Jun 2010, 14:21 #14

Hi JonJon. I really don't think you are going to improve your 50 to 70 mph times without using your gearbox, no matter what changes you make to your car..

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jonjon77 · Posted 08 Jun 2010, 15:53 #15

hi james,l had a go at in 4th gear after ld done the filters and was suprised at the lack of surge from it if you know what l mean.once the revs get to 3000 it starts to loose interest untill you get to 4000 and then you feel it pull a bit (when the power kicks in)but then its time to change gear.its as though the torque is tailing off 500rpm before it should do.when lm om the motorway following a truck at 60mph,l pull out to over take it and the car accelerates like my old 620 petrol(no surge of torque)it just gets faster in the way a none turbo petrol does.

James.uk · Posted 08 Jun 2010, 16:37 #16

Hmmm, interesting. At 3000 revs you should have a lot of power available..

Are you sure your tubo's working? I'm not sure how you can test it though, hopefully someone on here will be able to tell you..

My 50 to 70 mph time was about 6.5 secs timed by a passenger on his posh watch.. 8-)

But the car dropped to 3rd as soon as I "floored" it and I cant remeber whether or not it went up into 4th before reaching 70

It would be borderline I think as in 3rd 70 mph would be around 4000 revs and dropping off it's best power curve.. :roll:

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jonjon77 · Posted 08 Jun 2010, 17:52 #17

after looking on the other other side it seems lm not the only one with these symptoms.one blokes car is doing the same as mine but his car is a standard 131 bhp the others have done similar mods to me.the only common link so far is we all still have the egr valve in place.l will be happy if l can just get a bit more urge from it

Russ · Posted 09 Jun 2010, 20:22 #18

The turbo's working fine, let's see what happens with the egr removed and the new maf.

There's a definate reluctance to rev for some reason although I don't think it's quite as bad as others have reported with theirs.

Russ

jonjon77 · Posted 10 Jun 2010, 11:58 #19

egr fitted and the response and pull from low revs has improved with a little improvement over 3000rpm,if the new maf makes a similar improvement to the higher revs then l will be happy with it.

James.uk · Posted 10 Jun 2010, 14:26 #20

Have you actually established a "fixed datum" so you know you have improved things? or is it just that you think its going faster now? I know the MAF changes can make a big diff if they they prove faulty, but I have yet to be convinced about the EGR (Exhaust Gas Recirculation Valve) mod.. I am always open to persuasion though..

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