Can You Help me with My loss of Power investigation?

[Rincewind]

I was very disappointed with the performance of my Terrano during my recent caravanning holiday to southern France. Is seemed to lack power on hill climbs and even lost speed on the slightest incline, on the main auto routes I was down to third a lot of the time.

Since returning I have not had a lot of chance to look into this much, but last weekend I had to do a fair old run up north mainly motorway and dual carriageway (This time without the caravan). Again I felt there were times, particularly on some of the uphill sections where the old girl just did not seem to have anymore left in her. After the round trip I did a check on the economy. Over for that round trip she was down to 26 mpg, I have done the same trip before (about a year ago) and returned over 30mpg.

Also I have found that the engine miss fires and blows light coloured smoke when revved hard with the clutch in, although i have not noticed any lumpiness or hesitation when pulling away from a stand still.

So I have done some investigation.


1) Mini Filter
Followed the Workshop, I don't have one, its built into the bolt and its clear.

2) ERG Valve
Followed the workshop, Can't find one (does my model have one fitted?)

3) MAF
Followed the workshop, Checked that everything was clear/clean. All electrical checks produced the expected results. The only slight problem I notices was that the large "o" ring between the Air filter flange (the bit that actually clips on to the end of the air filter housing, and the air flow meter assembly (where it bolts onto the air filter flange) had been mis positioned and as a result had got nipped in a couple of places. Although as it is positioned in front of the airflow meter I don't think it would have caused too much of a problem.

Anyway the only conclusive result I have found, so far, is that with the MAF disconnected the engine revs freely without mis firing and there is no light smoke discharge. I have compared this with the engine hot and cold with the same results.

MAF Connected = Misfire and light blue/grey smoke
MAF disconnected = Smooth revin and no visible smoke.

I cant say so far if there is any discernable performance difference when driving with or without the MAF connected. Even though I have tried both.

Is it possible that the MAF is working correctly (hence the correct electrical readings) but not sensing correctly due to external factors or perhaps a build-up of dirt etc on the MAF itself (possible caused by the ill fitting "o" ring? In which case how do I go about cleaning the sensor?

Can anyone here give me any advice on what to do next?

Sorry id this post is a bit like "War & Peace" but I wanted to give as much info as possible to help with the diagnosis.

Cheers
Ricewind

 

[Jocky]

If its a Bosch MAF change it. A few members have did the electrical checks and not found a problem, including me. Them you put in a new MAF and the car flies :smile:

get it changed only costs about £30ish now

:smile:

If there is no difference with the MAF disconnected its knackered.

 

[Rincewind]

Thanks Gego for the reply

If its a Bosch MAF change it. A few members have did the electrical checks and not found a problem, including me. Them you put in a new MAF and the car flies :smile:

get it changed only costs about £30ish now

:smile:

Well it is a Bosh, So I guess it would be worth replacing it, can anyone let me know where I can get a good price on one?

If there is no difference with the MAF disconnected its knackered.

There is a difference with the MAF disconnected, it appears to rev cleaner and smoother.

I have got to do the yorkshire run again tomorrow. 360miles round trip, would there be anything to gain (either performance wise, or a better understanding of the effect the MAF is having and if it is US) by disconnecting the MAF for the journey/half journey etc or is running that far without it going to be counter productive?

Cheers
Ricncewind

 

[Deleted Member S]

I've often wondered about my maf unit so disconected it & it reved about the same but prehaps a bit smother, but on the road it was like driving with the hand brake on :roll: I ended up cleaning the maf unit with some electric contact cleaner & it was a bit better.
I don't know if it's just a T2/Mav thing but mine hates going up hills as the speed just drops off :? But going down is another matter :lol:

 

[Jocky]

I'll be straight to the point here. If there is no noticable difference driving it when it is disconnected its U/S. Waist time money and fuel trying to clean it if you like.!!!!!!!!

These Bosch units are crap.
Ask Arthur he's went through 2 in 18 months.

If its not running right with it plugged in, "its had it"

:smile:

 

[Rincewind]

Thanks Gego for the straight talking. I will start looking for a new one.

Rincewind

 

[Jocky]

No Problem :smile:

Phone round a couple of Nissan Dealers.

Some will still charge you the old price of £80ish, if it is old stock :twisted:

If they have to order you one it should cost about £30+vat.

When i got mine I changed it in the dealers car park and I drove out in what felt like a new car :smile:

:smile:

 

[Rincewind]

I have contacted my local Nissan Dealer today who initially quoted me £94.43 including VAT for a new MAF.

He then asked me if I'd had a quote from elswhere, I told him that I could definatly get one for £55 (I had seen them on ebay, at this price, today, but i did not tell him that). I also mentianed that other club members had got them for £34. and in one case as low as £26.01 + vat.

He then went on to tell me that there was no retail price for these items (i guess another term for "we (insert your Nissan dealer name here) can charge what we (insert your Nissan dealer name here)want for them") and the £34 figure would have been the warranty cost price, but they have to make somthing on them so he would match the £55inc price as the other dealer must have failed to put the price back up when the Terrano's wnt out of warranty. Then told me how other terranos cost hundreds as do most other cars, which is what they base their selling price on etc (blah, blah, blah)

Is £55 a fair price? or should I keep looking. I don't want to spennd weeks looking and miles travleing just to save a few quid, but on the other hand I don't want to pay £55 for somthing I could get £20 cheeper with just a little time and effort.

Rincewind

 

[Jocky]

I would phone other dealers. There having a laugh.

Also try Ford as the Mav Bosch MAF is the same, they get it off nissan and charge you less cash. Tell them its off a Mav and give them the Bosch part number. Its worth a try.

:smile:

 

[Rincewind]

Here is the good news, I replaced my MAF sensor yesterday morning. So far it seems to have done the trick 8) . She accelerated better, and even at 80mph (that’s the speedo reading, the GPS says it is only around 70mph), she still has more to give. I even tried it for a short spin with the MAF disconnected to compare and make sure it was not just wishful thinking on my part. But sure enough the New MAF is making a noticeable difference. I am hoping that the improvement in acceleration will equate to more grunt when towing, but it may be a while before I can test this after my little incident with the caravan a few weeks ago, but that’s a different story.

Here is the bad news. I ended up paying £55 (inc vat) for it . Having tried 4 out of the 5 Nissan dealers (one just never seemed to answer the phone) in a 40mile radius, I had been quoted between £104.77 and £110.47 plus vat. None had them in stock and none were prepared to drop their quoted price. So I gave it up as a bad job. I Know i have probably been ripped off but I neither had the time or the inclination to travel that far to look any further afield. One of them even offered to fit it for me for £42 + vat 8O (4 clips on the air filter, I jubilee on the pipe and 4 nuts to remove and bolt on the new part, it took me 7 minute to do the job and that included getting my tool box out of the garage,£42 worth? nice work if you can get it).

The other possible disappointment is that the New MAF has not cured the revving problem . She still misses and blows blue/grey smoke when revved hard from idle, and it always seems to be at around the same revs that she misses and smokes, but if I rev her up slowly with the engine off-load she does not seem to miss a beat. Also there does not appear to be any flat spots or rough areas when accelerating hard under load, so should I be worried about this and investigate further?

Would it be worth starting a new thrasd under the mechanical section, regarding this?

Rincewind

 

[Jocky]

PM Toolbox.
I seem to remember something about swapping 2 wires round to solve or reduce this problem. I think it was the wireing to the pump??????? or injectors??????

Have a seach on misfire and see if you can find it.

Glad the MAF is doing the job :smile:

:smile:

 

[Deleted Member S]

Mine also dose this(missfire) I was told it may be a small blockage in the pump :roll: but thay wanted £1k + vat to sort it out, but they were'nt sure :evil:

 

[Toolbox]

There is a common problem with a miss fire when free revving and many do it, mine included. I would not worry about it, if all is ok when driving.

There is a very strong possibility, if you go down the road of trying to correct it, you could end up spending a lot of money with no result at the end.

 

[Rincewind]

Thanks everyone for you help

There is a very strong possibility, if you go down the road of trying to correct it, you could end up spending a lot of money with no result at the end.

That is what I was afraid of, so i will take your advise and leave well alone for now especially as the new MAF seems to have cured the original problem. As it is a comon issue hopefuly it won't develop into anything more worrying.

Thnx
Rincewind

 

[Philwmn]

Hi. Am new to the owners club. Having followed this topic, you've saved me a lot of pennies. I'm so grateful. My garage had told me that my problem was down to the fuel pump. The symptoms described here were identical to mine. I replaced the MAF today and new air filter at same time. I now have to be careful with the accelerator because the car has become so responsive. What a brilliant thing this club is! Am now feeling really positive about tackling the other lesser problems. Thank you! It cost £50 plus VAT (Bosch type from Nissan). Didn't want to hunt around. :lol: