TD5 lack of power

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R

Robcod

Member
Posts
51
Location
Downham Market
Hi Guys

Driving along the other day the cars seemed to of lost power and not rev of 2500-3000. Ive looked through the other threads and have my own theory. I think its the CAT. For a while now theres been a sort of rattel at ideal that sounds like the exhaust but was hard to locate as it sounded as though it was coming from the engine bay area. I checked to see if it was a knocking manifold cover or something but nothing. Since the loss of power the knockings gone. Ive checked the ngine bay plugs and leads for signs of oil but generally the car is in really good nick (late 2002) and hasnt led a hard life. I was thinking about buying a de-cat pipe. What do you think does this sound feasible? are the de-cat pipes eay to fit??

Thanks

Rob
 
Is there any smoke? Is the engine misfiring? Is it like the engine is holding back or more like it's maxing out?

Get someone to rev the engine while you hold your hand at the back of the exhaust pipe. Can you feel prickles on your hand? Are there any sparks? is there a burning smell?
 
decat pipe dead easy to fit, dont buy custom made one, go to your local exhaust place and get front pipe for 98-01 disco 2.
i agree with ratty about cat put hand on back exit from exhaust if tooo hot cat fkd
i had the similar problem to you but it was my egr vacum block which was blocked, again a common problem according to autodata
 
im getting it looked at friday so ill keep you posted.
The exhaust was *!* hot when i held it over the end and that was shortly after start up from cold. I have got a EGR blanking plate fitted. Talking to the garage about that they reckon theyre not worth fittign as the engine is designed to be over aired anyway so you wont make any gains. Except i guess unless you go the whole performance hog with improved intercooler exhaust etc
 
Robcod said:
I have got a EGR blanking plate fitted. Talking to the garage about that they reckon theyre not worth fittign as the engine is designed to be over aired anyway so you wont make any gains. Except i guess unless you go the whole performance hog with improved intercooler exhaust etc
Click to expand...

Your garage is talking utter rubbish!

"Designed to be over-aired" indeed ... ! Sheer CRAP!

All diesels are "over-aired" up to the stage where the black smoke starts trailing out the exhaust pipe..

The more air you can ram into a diesel engine the more efficient it becomes, and the more power you can extract. That is what all turbos do - they ram in extra air, usually about DOUBLE what the engine could suck in without the turbo.

And you pay money to this garage to "look after" your car?

CharlesY
 
CharlesY said:
Your garage is talking utter rubbish!

"Designed to be over-aired" indeed ... ! Sheer CRAP!

All diesels are "over-aired" up to the stage where the black smoke starts trailing out the exhaust pipe..

The more air you can ram into a diesel engine the more efficient it becomes, and the more power you can extract. That is what all turbos do - they ram in extra air, usually about DOUBLE what the engine could suck in without the turbo.

And you pay money to this garage to "look after" your car?

CharlesY
Click to expand...
Charles,you ought to be careful in your rantings - black smoke is caused by an excess of fuel or a lack of air.
I think what the garage was trying to say is that diesels are designed to run with an excess of oxygen - not at or near stoich as on a petrol.
 
eightinavee said:
Charles,you ought to be careful in your rantings - black smoke is caused by an excess of fuel or a lack of air.
I think what the garage was trying to say is that diesels are designed to run with an excess of oxygen - not at or near stoich as on a petrol.
Click to expand...

Stochiometric ratio has nowt to do with it unless the diesel has a problem, as you say, too much juice or not enough air.

What he said his garage said was that a diesel could have too much air.

I think as I have been "ranting" I will take a holiday for a few weeks.

Back about the end of June if I remember to come back.

Bye .....

CharlesY
 
Last edited:
I think the garage guy was saying that taking out the EGR butterly valve section didnt make any difference as the air supply pipe was over sized any way and thus no power increase, something like that.

I thrashed it last night to see how it was and it seemed fine at first, 10 mins later and being warmer and it started to lose power. It would rev over 3000 even up to 4000 but didnt seem to have any oopmh.
No sigh of any smoke out the back. I wondering if its the fuel filter thats the problem as i dont think its been changed for ages even though it was apparently serviced when i brought it. The MAF thing was clean when i looked at it.
I'll let you know how it goes tommorrow
 
Robcod said:
I think the garage guy was saying that taking out the EGR butterly valve section didnt make any difference as the air supply pipe was over sized any way and thus no power increase, something like that.

I thrashed it last night to see how it was and it seemed fine at first, 10 mins later and being warmer and it started to lose power. It would rev over 3000 even up to 4000 but didnt seem to have any oopmh.
No sigh of any smoke out the back. I wondering if its the fuel filter thats the problem as i dont think its been changed for ages even though it was apparently serviced when i brought it. The MAF thing was clean when i looked at it.
I'll let you know how it goes tommorrow
Click to expand...

Try a new temperature sensor. Thay are about £15. I have had 2 feck up in less than 9 months.

Also try plugging it back in on the diagnostic. It is going into limp mode. Temp sensors don't show up as faulty on the diagnostic. Turbo wastegate sticking is the other common fault. Mine is forever playing up cos of the wading I do. Turbo wastegate does show up on the diagnostic.
 
ratty said:
Try a new temperature sensor. Thay are about £15. I have had 2 feck up in less than 9 months.

Also try plugging it back in on the diagnostic. It is going into limp mode. Temp sensors don't show up as faulty on the diagnostic. Turbo wastegate sticking is the other common fault. Mine is forever playing up cos of the wading I do. Turbo wastegate does show up on the diagnostic.
Click to expand...



RATTY
you tried that fuel cooler i gave ya yet !!!
 
robint said:
RATTY
you tried that fuel cooler i gave ya yet !!!
Click to expand...


erm.......:eek:.....Nope.......:eek:. I haven't had a chance to finish flushing the system out before fitting it. I gotta crack on with some work on it from friday onwards as I desperately need to get it in for it's mot. At least with my hours cut I'll have extra time on my hands.:(
 
Robcod said:
I think the garage guy was saying that taking out the EGR butterly valve section didnt make any difference as the air supply pipe was over sized any way and thus no power increase, something like that.

I thrashed it last night to see how it was and it seemed fine at first, 10 mins later and being warmer and it started to lose power. It would rev over 3000 even up to 4000 but didnt seem to have any oopmh.
No sigh of any smoke out the back. I wondering if its the fuel filter thats the problem as i dont think its been changed for ages even though it was apparently serviced when i brought it. The MAF thing was clean when i looked at it.
I'll let you know how it goes tommorrow
Click to expand...

Most mafs give a zero or very low reading when fecked. I plugged Buckshots TD5 into the diagnostic several times after he suffered flat exceleration. Everytime we did it the MAf showed the airflow fine. The dealer fitted a new maf to test see what would happen and the power came back. It could be your maf.
 
ratty said:
Try a new temperature sensor. Thay are about £15. I have had 2 feck up in less than 9 months.

Also try plugging it back in on the diagnostic. It is going into limp mode. Temp sensors don't show up as faulty on the diagnostic. Turbo wastegate sticking is the other common fault. Mine is forever playing up cos of the wading I do. Turbo wastegate does show up on the diagnostic.
Click to expand...

what are the symptoms of a naff temp sensor? can the resistance be checked using a meter? mine has a habbit of being gutless one min and then power comes back
 
jsbholden said:
what are the symptoms of a naff temp sensor? can the resistance be checked using a meter? mine has a habbit of being gutless one min and then power comes back
Click to expand...

No. the resistance will come up as ok. I only found out cos I drive with my diagnostic plugged in. On a days laning my temp went from around 80 degs to 150 degs in split second. It only flicks the temp for a second or two and then back to normal. It did this twice. A new temp sensor and power was restored.
 
Seem to be having a similar problem, do you mean the air temp sensor on the air box?

John
 
Well the plot thickens.............

After having it checked at the garage and them finding some oil in the ecu and them wanting to clean it up and then move onto replacing the MAF. I got it home thought id do it myself.
Sadly the red cable on the ecu was quite oily so i cleaned it up, and then did it again this morning and i really cant of got it all. I used some damp start this morning which seemed to clean the oil out nicely. Since last night however I had removed the front section of pipe in anticipation of getting a de-cat pipe monday and as i had asked the missus to get a new MAF sensor for me we she got home i was itching to try it. I though id cracked it until after it had warmed up after 5 mins of driving the power went again????????????? I not giving up just yet as the exhaust is knocking like a hoare house thanks to a suspected buggered cat and im hoping thats what is really behind this loss of power. Its strange as it goes fine then after 5 mins or so when im doing 60 it wont go any faster hardly. Im getting well paranoid now as i think there is a slight whistle on the turbo that wasnt there before. To top it all the vauxhall main dealer failed our vectra on discs, pad, tyres, broken spring and want £850 to sort it. I told the missus to bring the car home and id sort it for less and the garage didnt like that one bit. Personally i think there just after the work. I hate cars!
 
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