Camper van with 1.9tdi Passat engine - Barty
S.O.S new to site.In need of help.PLEASE

Hi, Barty here.I've got a camper van thats had a 1.9 tdi passat engine put in it. It seems to pul very well in 3rd on short hills but in 4th on the motorway it loses power at around 50-60 mph and just dies on hills. Also when first starting sometimes theres no turbo at all but if I rev hard say in 2nd it suddenly cuts in or if I stop then restart it sometimes comes straight back. I've read other peoples postings on the same problem but being a complete dougnut when it comes to anything but driving the thing I don't understand what AFN, ECU,EGR IIRC or any of that means so if anyone could explain what I should try to resolve this problem I would be eternally grateful.Cheers

Yours ( a complete dougnut on vehicles) Barty

{Subject header amended, as per one of the sticky messages at the top of the page - DD}
Camper van with 1.9tdi Passat engine - Screwloose

Don't worry about your lack of knowledge about what's going on under the bonnet; I haven't got a clue either - and I have to fix 'em!

OK; lets establish exactly what we've got here. Firstly; what year and make/model is this camper? What engine was it originally fitted with? Have a look at the cover on the front [fan-belt end] of the engine and see if there's a bar-code label still stuck to the top of it. If so; the all-important engine code [1Z: AFN: ALE: AHH; AHU; AVG etc. etc. will be among the letters printed on it. There are literally dozens of 1.9TDi units, all with subtly different control systems.

Your symptoms would suggest a number of common faults like a fouled MAF [airflow] sensor; but the re-setting after switching on-and-off doesn't quite fit the classic fault profile. Without knowing the quality of this retro-fit installation, it's going to be tricky to advise. Randomly changing parts to try and fix it can get very expensive; so getting a suitably-equipped garage to read any stored fault-codes in the ECU [Engine Control Unit - the "black box"] could be the best first course of action.
Camper van with 1.9tdi Passat engine - adverse camber
Has it ever wotked properly since the engine was fitted or is it a recent problem ?

AFN - one of several possible engine codes for a 1.9tdi
EGR - exhaust gas recirculation valve - anti pollutant system that recirculates some exhaust gas - more trouble than its worth imho (in my humble opinion)
ECU - the engine control unit - the computer that manages the fuel and ignition system,
iirc - if i remember correctly
maf - mass air flow meter - measures the amount of air going into the engine so that the ecu can calculate the correct amount of fuel to inject.

hth - hope that helps
Camper van with 1.9tdi Passat engine - Barty
Thanks for the reply mark99

Not rely ,had a nightmare with the company that fitted it took it back loads of time but got no joy from them and they've relocated to Cornwall so no chance. Any advise would be gratefully recieved.Cheers Barty

Camper van with 1.9tdi Passat engine - Barty
Thanks for the reply.

I've had a look at the engine but cannot find a number but its a 1998 engine from a passat. AFN springs to mind from a guy that took a look at it a while ago. The fitting of the engine was carried out by a company that has done serveral of these conversions. But having said that I had a nightmare with the firm and took it back several times due to it not running properly but got very little joy from them.They have since relocated to cornwall. My camper is a T25 C plate 1986 and was originally a striaght 1.6 diesel(very slow) .
I've had the thing plugged into various diagnostic units from the main dealer to garages that have bought the software from them. The main V W dealer does not want to know because its a conversion so it seems that if a machine can't tell them whats wrong thier stuffed and have'nt got a clue. Haveing said that the diagnostic units show no fault because under no load sat in a garage the thing runs fine. The vehicle is basically reliable, does not breakdown and always starts its just this lose of power and thats a major problem in a touring vehicle. I'm willing to try pretty much anything as I am looking to upgrade to a newer camper but I would not sell it to someone unless it was right. So any help at all would be apprieciated. Cheers Screwloose.
Camper van with 1.9tdi Passat engine - Screwloose

Oh dear! So this engine has never worked properly then? Retro-fitting all the TDi engine's plethora of power and control circuitry to a vehicle that had none of it as standard would be a massive job and quite uneconomic. Where did the garages even plug their code-readers in; the vehicle didn't have any self-diagnosis circuitry fitted from new? Assuming it's a 110bhp AFN unit; did they really install custom-built "fly-by-wire" throttle controls, brake and clutch pedal position sensors, adequate intercooler, bigger exhaust and the full EGR [exhaust recirculation] and turbo control system and vacuum solenoids? Or did they maybe just fit the bare minimum to get it to run and then "bodgit and leggit?"

If it was a properly engineered installation [c.£5000-ish?] then there should be a fault code stored; particularly if the system had resorted to using a "safety mode" [that resets after re-starting] as described in your original post. The previously mentioned MAF sensor fault rarely causes that "limp-home" mode to occur and thus doesn't leave a code. It's a long-shot; but if I had to play a hunch, I'd still go for that MAF sensor first. Try test-running with it disconnected [that will leave a code!] and see if it performs any better. Other than that; exhaust restriction of some sort might be worth a thought. Without knowing how well the conversion was done, it's extremely difficult to say what might be wrong; it even may not be a faulty component at all - it could well be a faulty installation.
Camper van with 1.9tdi Passat engine - Barty

Not rely ,but i've driven it all over the country (lakedistrict north wales etc I live in Bournemouth) and i just live with it. When the engine was put in the exhaust, wiring loom,clutch,throttle was changed and the little black box they plug in to is in the cupboard in the back so I assume it's all there.
I've just driven it about 5 miles with the MAF disconnected and it was flat all the way,reconnected it and the boost came back through all gears, raced up to 60 and then it went flat and would not go any faster. I pretty sure the turbo is still spinning but theres just no more power. The gearbox was changed but it's still only a 4 speed, would this make a difference its just that at 60 (when it goes flat ) its does not sound like its over revving. What would you try next or am I flogging a dead horse. Thanks for your help

Camper van with 1.9tdi Passat engine - Screwloose

I'm loath to play hunches, particularly when it's never run properly; but if you really just want to try "something," then that MAF sensor would be high on my list of tests if this were a normal factory-fit installation. They're around £75-80 from the dealers; [take the number off the old one] and they take five minutes to fit - no coding or adaption required.

A preferrable course would be to explore the many diagnostic tests that can be run on the extensive live-data coming from the ECU to check how well the engine's working under load at speed - I'm perplexed as to why someone hasn't already carried these out? At the very least, checking the MAF sensor's flow rate and the boost pressure while driving would seem to be essential first steps.

Difficult to say whether the gearing is part of the problem; but it would have to be very strangely geared to be hitting the rev-limiter at 60!

Ashok Leyland

Twenty-odd years ago [before the rheumatism killed my hands] I did indeed own a garage; but these days I just stick to autoelectronic diagnostics - mostly for other garages. [Some of them main dealers. Having access to all the kit doesn't seem to make them any better at using their brains!]
Camper van with 1.9tdi Passat engine - Barty
Cheers Screwloose

I've taken the number and i'm going to change the MAF and see what happens. To test it under load am I right in thinking that you plug into the ECU via a lap top and drive it and monitor the readings while driving or does it record a certain journey i.e clear its memory drive it then plug in as soon as the vehicle returns and look at the results. If its the former then I don't think anyone has done that. I must have taken it to 4 different so called VW specialist and they all seem like its to much of a problem for them to deal with ( they just want the easy money) even though I said do what you need to do I just want it right.

Anyway i'll change the MAF out and let you know as soon as I drive it what the results are. Probably be after this weekend. Thanks again screwlooe

Camper van with 1.9tdi Passat engine - Hamsafar
Screwloose, do you run a garage?
If so, I'd like to come to it as you sound more knowledgable than my dealer.
Camper van with 1.9tdi Passat engine - adverse camber

If you dont have it already and you have any intention of keeping a vag group car, a copy of vag-com is an excellent investment.

It is software that runs on a pc (laptop) and mimics the functionality of the vag ecu tools. I bought it from the makers (cheap cables on ebay from £20 will give limitd functionality) at full list price and have easily saved the cost.

well worth considering - makers are ross-tech

Camper van with 1.9tdi Passat engine - Hamsafar
Thanks Mark, I have just received the cable, now I'm trying to convince my employer I need a laptop ;o)
In the meantime, I could put my computer on a chair at the side of the car, to carry out some things, its only an LCD and Mac Mini so very small, I have looked at cheap second hand laptops but they mostly say the battery doesn't hold it's charge, which would be OK if I found a cigar lighter charger or invertor!
I really would like to get into the VAG COM scene, as it's right up my street.

Camper van with 1.9tdi Passat engine - adverse camber
Ive used usb externison cables to do 10m.
mac mini - I think the software is windows only - they may do a mac version but I wouldnt bet on it. There are some freeware testers available that run on linux though...
cigar lighter inverters are easily obtained on ebay.
Camper van with 1.9tdi Passat engine - Hamsafar
Mac Mini Intel - New macs are Intel PCs with DRM and can run Windows.
On Ross Tech, it says it runs fine in XP on a Mac.
Camper van with 1.9tdi Passat engine - Screwloose

The strange thing is; most scanning tools [and laptop based ones] are 12volt powered and portable. Only the big dealers kit needs to be permanently connected to Germany down a landline for "Guided Fault Finding." If a problem only occurs at speed, then that's where you have to examine it. It's obviously easier to have two people, but road-testing [using a flight-recorder - if necessary] is an essential part of diagnostics. How were any of the garages going to find your fault in a nice warm workshop??

Under full throttle acceleration at 3,000 revs, the MAF sensor should be reading around 750-950 mg/H [mg per cycle]: if the reading "sticks" at 550 then that's usually - another - duff one. It's not conclusive - nothing in this field is - but [assuming a clear exhaust, correct pump timing etc.] it's usually enough to risk trying a new one.

I don't blame your garages for being a bit reluctant to get involved. Jobs that someone else has bodged and then left as a mess for you to sort out are not exactly deeply motivating. It's very, very easy for work like this to spiral out of control and end in acrimony. Although there are many good ones, most garages with a scantool are working on - or over - the limit of their competance. Blame the manufacturers - in five years, we're all finished. Cars will be unfixable: they'll last 5-7 years [mostly under warranty] and then they'll have to be scrapped at the first major problem. It's already here with high-tech diesels.

Ask Honest John

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