Warm up fuel pressure reg dismantling

Having got my spare fuel warm up reg yesterday (secondhand unit), I thought it might be an idea to dismantle and clean it up first before putting it on, the logic being it should help to put off the time I need to do this again to some point in the future when hopefully I can afford a new one  :wink: .

Anyway, I have kind of fallen at the first hurdle so to speak as I can't undo the 4 slot headed screws that hold the bottom plate on. For those of you that don't know what I mean the base cover of the reg is held on with 4 slotted screws (one at each corner). These pass through the main casing and out the other side into nuts that are held "captive" in nut shaped recesses in the casing.

I have already nearly damaged one of the slotted screws trying to remove it (with the correct size bladed screw driver I might add).

Tried soaking the offending screw areas in WD40 overnight and then just tried appling heat with a small blowtorch and the pesky barstewards won't budge  

Have been considering an air powered impact wrench for a few other jobs - is now the time to buy one? Can they be used for things as small as this (i.e. can they use screwdriver type attachments)?

Other alternative is an impact screwdriver (I think I have one in my toolbox somewhere), but I don't fancy hammering seven shades of sh*t out of it in case I damage anything……

What about trying something stronger than WD40 - carb cleaner maybe?

Suggestions on a postcard please…….

Cheers,

Chris

Well, it seems perseverance (and a large mallet and impact driver) is the way to go  :wink:

I now have the sucker opened and disassembled:



Only thing is the mesh filter thing seems to be part of the housing and not removeable  :? . I had wanted to take this apart to clean out any crud that might be lurking in there. Anyone got any tips on removal / cleaning?



I have blown it through with an airline, but would like to clean it up a bit better.

Whats recommended for cleaning up fuel system parts like this. Want something to lift off the grime without damaging any of the rubber seals - paraffin do you think?

Also does anyone know if Bosch still supply replacement gaskets or service kits for these warm up regs? Seems they were pretty widely used, and not just by VAG. Was looking at a review of an early 80's Porker 928 in this months Classic Car mag and lo and behold the warm up reg in there looked identical to the one on my golf  8O

Any help with the questions above appreciated.

Cheers,

Chris

More of a gen commen Chris so dont know if any help but a mate in my village who's ramp I use from time-to-time has family bus company. I was surprised how many VW Golf bits were used on some of their VW group buses! (my ignition starter switch is out of a bus!)

I snapped one of the internal screws on mine.

If I was you I wouldn't take it apart. Oh, too late!!

KJet ran on loads of cars, volvos, porsches etc etc.

some of the later warm up regs had vacum control aswell so they are no good.

Peter.

Not really any help to you but could you help me?

What does this warm up fuel reg do (or does it do exactly what it says on the tin)?  How do you know when it is busted?  My 82 gti hesitates really badly when warmed up, I've put in a new fuel pump, sparks and rotor arm, should this fuel reg be next?

Cheers, Tom.

Always happy to help where I can  

Pete - with hindsight I am thinking maybe I shouldn't have opened it up, but I always was an inquisitive so and so  :wink:

I reckon it should be possible to get service parts for it (rubber gasket, clips and maybe the metallic strip). I might try and find a Bosch service / parts centre near me (anyone know of a good one in SE London / Kent?).

Tom - I am still not clear on whether it is a valve that closes completely like the cold start valve or whether it just varies the fuel pressure.

Basically its designed to allow more fuel to the engine when its cold. There is a bimetallic strip in there that is gradually heated up by a current supplied via the electrical connector, this operates a small valve in the regulator.

I believe after 5 mins it should be closed / at maximum deflection. I suspect that due to its location on the engine block it as also heated by heat coming directly from the block.

See my other thread and Crazyquiffs starting problems thread for some descriptions of the symptoms.

With my car it would start fine from completely cold and run for a few minutes (until the temp gauge needle started moving), then it would just die. No amount of turning over would restart it until the engine had cooled completely again.

I checked the cold start injector (another device for adding extra fuel briefly on start up), the thermotime switch (controls the cold start injector), plus the throttle mixture screw and these all checked out OK. I also check the cold air valve at the rear of the inlet manifold and that seems OK.

My current diagnosis is that the warm up reg is faulty and is not reducing the fuel flow once the engine has warmed up. This leads to the mixture being too rich and the engine just dies and won't restart. This would also explain why the engine seems to start fine once truly cold again as the richer mixture would not be a problem then.

Until I get my hands on a fuel pressure test gauge (hopefully at the end of this month) its nearly impossible to diagnose the fuel system any further. Even Haynes says that without a test gauge you are pretty stuffed beyond checking the basics.

All you can test on the warm up reg is the impedence of the electrical connector and maybe blow through the connection with an airline.

I'm interested to find out if service parts are available from Bosch as the only other reliable alternative is a new unit which is about 150 quid exchange from the likes of GSF (although I think its a Bosch unit).

Going to go and put the casing in a jar of carb cleaner over night to try and clean off some of the gunk, then will re-assemble tomorrow. Doubt I will have it going before the Kent meet on Sunday though to be honest  :roll:

Got a whole load of bits from my VW dealer today that I had been waiting on including some replacement fuel lines and banjo (or banto as ETKA lists them   ) bolts and washers - some of mine are well past their best…..


I actually have a fair few parts to put on the car now including new seals for the oil filter head and tubing and bulkhead grommets to replace some of the heater ones that have seen better days.

Will have to get it all sorted next week I think and maybe even get the tunes sorted out finally.

Taking bets with myself on what the next likely thing to fail on the car is  :roll: Current fave is one of the front wheel bearings as I thought I heard the telltale "rumble" starting last time I had it out on the road…

Chris

chris!

when the car cuts out/dies will it rev when u apply throttle or will it not have any of it??

mine starts from cold and dies after 3-4 mins too. still havent worked it out yet wot restart again until the car cools down :cry:

Ok thanks for the info, it doesn't sound like that's the problem for me as it always starts on the button and doesn't stall.  Thanks, I will keep trawling the archives.

Good luck Tom - if its a fuel related problem it can be a right pain to diagnose. A good search through the forums should tuen up a lot of possibles.

There are a fair few diagnostic checks you can do before spending any cash though. I would check the Cold Start Injector, thermo time switch, cold start air valve (back of inlet manifold), check for leaks in the piping using carn cleaner as described elsewhere.

If the fuel filter hasn't been changed in a while I'd also do that - its only a tenner.

Prowler has a good guide for checking your injectors are up to snuff. The warm up reg and metering head ontop of the airbox are about the priciest bits to replace in the fuel system I think, so hopefully it won't be that.

If you have 60 - 80 quid or so to spare its probably worth a trip to your local Bosch service centre. They should be able to give you a good idea of what might be causing the problems.

George - if you really floor it and keep cranking it you can sometimes keep it going, but not even full throttle will always keep it going and it makes me wince trying it!! I think the reason it might work occasionaly at full throttle is that the extra fuel the warm up reg is incorrectly supplying is a smaller proportion of the fuel at full throttle, so maybe the mixture gets lean enough to allow the engine to run?

Anyway, cheapest way to rule out warm-up reg is probably to get a SH spare and swap it out. Thats what I did and it only cost me about 20 quid.

Will post more info once I have tried the swap. If it cures the problem I will probably save up for a new reg. I feel I'm on borrowed time even if the spare reg works - after all its nearlt the same age as the current one.

Hope that helps,

Chris

Basically there is a thick needle in the centre of your fuel distributor with slots in it that line up with outlets to the injectors, the higher the needle is forced to go by the air flow meter the further the slots open and more fuel is delivered. Above this needle is a chamber with petrol at fuel pressure, there is a pipe from this chamber to the regulator and from there back to the tank. If the regulator restricts the flow to the tank it increases the pressure over the fuel metering needle, the airflow meter has less effect and the mixture is weakened, this would be with a warm engine. Starting from cold the pressure is lowered by the regulator allowing more fuel to return to the tank and therefore the airflow meter has more effect on the needle and the mixture is made richer.

If I can borrow a camera I will post a picture of my pressure gauge, I had it made up by a hydraulic firm for aboiut ?25. The threads are not an exact match but perfectly good enough to do the tests. Cheers.

cedar - any pics / info on the gauge you had made up would be great  

Hi There

I made a fuel pressure tester many years ago i'll try do dig it out, Chris u can borrow it when i find it

Cheers Wellsy

or

  http://cgi.ebay.com/eb…_top" href="" rel=""></a>

Ah Wellsy mate that would be grand  

George - that auction looks like a quality item, but a little too pricey for me  :wink:  

I'm hoping the JCWhitney 60 USD one will be back in stock soon, so I'll probably order one of those.

Cheers,

Chris

Arsen Wenger…. JCWhitney have just emailed me to say manufacturer has told them the fuel pressure test kit is on back order now until mid March  

I think I am going to have to go down the DIY route, so any detailed instructions anyone has would be appreciated, especially with regards to where to get the parts.

Back to my warm up reg adventures  :wink: …. the latest installment <cue 20's syle Chaplin-esque silent movie piano accompanyment>

So I decide I may as well get the current (possibly suspect) warm up reg off the car whilst the replacement one is soaking in a jar of carb cleaner….

Hopefully the following info will save someone some time, as it took me about 4 times longer than it should have  :evil: . First things first:

REMOVE THE BATTERY COMPLETELY FROM THE CAR!!!!!!!

A lot of the fuel lines that need to be undone are not far from the battery and the last thing you want is your pride and joy (and also yourself) doing the whole fireball thing… trust me on this one it may be a pain, but it just ain't worth the risk…

Once battery removed and safely put out of the way, extinguish all cigarettes or other sources of combustion and you are ready to…..

Remove the Warm up reg

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- Undo the fuel cap on the petrol tank to release any pressure that may be in there.

- DON YOUR EYE PROTECTION (no one wants to get petrol in their eyes - v. v. bad news)

- Top tip number 1 - before attempting to remove the reg from the car, you probably want to make sure those fuel line banjo bolts in the top of the reg are at least slightly loosened. Don't wait until you have painstakingly removed the allen head bolts from the block and the reg, only to realise there is no way the fuel line bolts will undo without some leverage  

- So, undo the bolts very SLOWLY - AND BE CAREFUL as fuel in there is under pressure and will start to leak out as soon as they start to work loose. Once each bolt has been loosened then retighten slighly to stop fuel coming out. We just need to get them to budge intially so we can undo them later.

- If as on my reg the larger fuel banjo bolt is right against the electrical connector on the reg you will have to undo the fuel bolt anyway to remove the electrical connector.

- Once you have been able to loosen the fuel bolts on top of the reg and unplug the electrical connector, you can now undo the two allen head bolts (one on each side of the reg in the middle). These were a right pain in the butt to remove for me as access was very restricted, but they do come out eventually!!

- You should now be able to thread the reg and attached fuel lines out from under the heater hoses to a more workable position on top of the radiator. At this point VERY SLOWLY undo the fuel bolts holding the reg over a petrol proof container to catch any spillage.

- Watch out for the copper washers, one on either side of the fuel pipe connectors - you should renew these on re-assembly.

- Where the large fuel bolt came out of the reg there is a small mesh filter in the hole - if like on mine there is some debris in there you need to clean it out with an airline. Again PLEASE USE EYE PROTECTION when doing this!

- So now the reg is off the car - unless you are fitting a replacement straight away I would recommend bagging up the end of the exposed fuel lines to stop any crud getting in there.

So flushed with success I though I may as well get the fuel filter off at the same time so I can put a new one on along with some other new fuel pipes I have ordered. I mean fuel filter is a service item right so should be easy to remove….. so the theory goes anyway  :evil:

Removing fuel filter

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- On my car the banjo fuel bolts going into each end of the filter were on real TIGHT.

-  Wear EYE PROTECTION as before and try undoing the one at the exit (battery) side of the filter first. This is a 17mm bolt. Main problem is the braket holding the fuel filter to the airbox is a bit too flexible so it moves around a lot  :cry:

- After a bit of WD40 and a few goes it eventually comes loose - MAKE SURE YOU HAVE YOUR TRUSTY CONTAINER HANDY TO CATCH ANY FUEL SPILLAGE.

- So front bolt off, not too bad I hear you say  :twisted: . Dream on sonny, the rear bolt is the real barsteward. The bracket flexes too much to use it as leverage for undoing the rear bolt and looks like it might break off…..  8O

- The only solution I found was to use one of the adjustable 3 claw type oil filter wrenches that fit onto your socket handle (Clarke make them or you can get them in Halfrauds for about a tenner iirc). Anyway you need to fit this over the end of the fuel filter where you have already removed the fuel bolt and then put a 19mm ring spanner over the other fuel filter bolt (the one you are trying to remove). Only this way with a lot of grunting and superhuman effort was I able to finally free the rear fuel bolt.

Thats it pretty much. Its vital to replace all copper / aluminium washers with new ones come assembly time to avoid leaks.

The only slightly worrying thing for me is that having measured the impedance accross both my "replacement" warm up reg and the one I have just removed from the car, the both read about 20Ohms, which is fine according to Haynes. This suggests that if there is anything wrong with the current reg, its not the bi-metallic strip playing up.

Bit concerned about the small bits of crud on the gauze in the reg on there at the moment. I am hoping these were maybe from before the filler neck was replaced, or have just accumulated over 20 odd years.

I will check the injector pattern and delivery though to be doubly sure.

Slightly concerned that if there is a small amount of debris in the warm up reg then it may also have got into the metering head too.

Fuel filter looked very clean from what I could see though….

So, once I get the spare washers I need I will re-assemble with the new warm up reg and see if that makes any difference. If it doesn't and in the absence of a fuel pressure test gauge I'm a bit stumped as to why the car won't run.

I still feel it HAS to be a cold start issue givejn the previous behavior, although today the battery was getting low and it wouldn't start at all  :roll: .

Battery is now on charge, so hopefully I will be good to try again tomorrow.

Phew - long post!!!!

Chris

Chris,

Did your filter not have hex ends to counter grip with? VW filters have this if yours does not. Makes life easier though they are still tight!

Cheers
Rajan

Yeah filter had hex ends on both sides, but the filter casing was very soft metal and the connections were very tight  :? . In my case the hex ends just stripped / deformed and so were pretty useless!

Need to make sure I use the correct torque settings on re-assembly to avoid this in future….

Cheers,

Chris

Chris

As dubboy says, if filter has been fitted correctly should be able to do it with the hex ends and two spanners. If the hex ends are rounded off is a good sign that someone has over-tightened the fuel filter in the past, from my experience dodgy garages not bothering to renew the washers have overtightened to prevent leaks  :roll: .

Cheers

Having now dismantled the filter connections it looks to me as though whoever fitted it last time didn't fit new washers, which is maybe why they were done up so tight.

Anyway, I collected a few bags of the correct washers from my local mainstealer today and so am ready to reassemble with the replacement warm up reg, new fuel filter, new washers and some banjo bolts and a freshly charged battery   . Interestingly some of the replacement washers do seem to have rubber inserts and all the rest look to be aluminium rather than copper (they look like mini sump plug washers). I guess the aluminium is deformable so makes a good seal.

Anyone know what the torque settings should be for the fuel banjo bolts onto the filter and the bolts into the top of the warm up reg?

Wondering if while the system is fairly empty of fuel I should take off the fuel metering head and blow it though with compressed air and maybe give the injectors a clean too…… all takes time, but at least I would know its all clean I guess.

Also took the spark plugs out to have a look and they were all pretty black and sooty - this confirms the rich mixture hypothesis - right?

Chris

Chris,
I've sometimes found that an impact driver is the only way. I's a bit brutal - but it usually works!