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Discussion Starter · #1 ·
Well after a nice tune up and replacing the vacuum lines/fixing the vac pump this 76 245 with CIS continues to be a hassel. I took it to some knowledgable guys who say the fuel pressure regulator is shot and it is "dumping fuel" meaning way too much into the system. Says the part is 600 bucks. Should I trust this assessment or take it back home and try some things on my own? Thanks.
 

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Hi George,

It is bad advice you got

but what exactly are the problems - like cold/warm/hot start, rought idle etc etc???

The SYSTEM pressure is regulated to 70 psi by a simple relief valve on the side of the fuel distributor [and it can be adjusted by shims] but I doubt that is the problem

the "dumping" would infer it is stuck and is therefore dumping fuel back to tank - but how would they KNOW that - and what is CONTROL pressure ??? [far more impt]

so please tell us what are problems and I will advise on probable causes [and I will say here now I bet it is WUR]
 

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Discussion Starter · #3 ·
Hey Doc.

It is running very rich and has trouble with idle at start. After starting I need to apply throttle for several minutes until it will run without pedal. Sometimes I need to shut off and then turn back on with the problem vanishing. Anyway, I went out to discuss with the mechanic and he pointed out the WUR as the culprit and says it is 600 bucks which is not true. He says that even after replace of this there is likely a lurking problem with the fuel distributor that could emerge soon after replace of the WUR. Is the WUR easy to replace? I see they are not too expensive on the volvo site... Thanks, George
 

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warm up problem sounds like WUR not doing its job and this sounds exactly same as mine was - problem was simply that the tiny filter on the inlet to the WUR was totally blocked meaning the WUR was not doing any reg at all, which is why you need to wait till engine warmed up

however if it is blocked that means the vacuum [and altitude] regulation are not working either once it is warmed up [yes it is badly named as WUR as it does far more]

hence I would say someone has made an adjustment on the fuel distributor [the Allen key down the guts] to make it richer

so I would clean out the WUR and once start problem fixed then adjust mixture [small anti clockwise say 20 deg only at a time]

and check vacuum and 12V connections work

and once fixed it will be idle at 2000 rpm or so - so adjust to 800 once heated up
 

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Discussion Starter · #5 ·
Doc,

Thank you for the advice. I am going to pick up the car over the weekend and will pull the WUR/check the screen. Again, thank you for your advice. I will let you know how it shakes out. George
 

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Discussion Starter · #7 ·
Doc,

I pulled the WUR or otherwise referred to by Haynes as the control pressure regulator. The tiny screen does have a small amount of debris. How do you recommend to clean and also, should I take the unit apart? Not sure if I should open that can of worms... Where is that allen adjustment on the distributor? Thank you-George
 

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well cant go past best way to do overall check as per Bosch book ie a gauge with a T piece to check the SYSTEM press and CONTROL press

and yes CPR is far better description

not too many worms inside ie compared to taking the fuel distributor apart which is hairy

there is a heater on a bi metal strip and a spring loaded bleed off valve hanging off it so a normal kitchen table job and hard to even see if filter blocked let alone clean it if you dont take the sucker apart

frankly I would prise out the gauze filter and chuck away - it can only cause problems - I mean I did clean and replace mine but I have gauges inside car so I keep an eye on both pressures
 

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Discussion Starter · #9 ·
Doc,

This thing is exactly as you described inside but how to go about actually getting that screen out of there. Do I just scrape it out of the inject port or is there a cleaner way. Also, Where is that adjustment you referred to on the fuel distributor? Thank you, George
 

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Discussion Starter · #10 ·
Doc nevermind that last post. I scraped it out and found three screens and one gauze/cloth filter. Replaced one of the screens and put everything back. Should one screen be okay? That distributor adjustment...?
 

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Discussion Starter · #11 ·
Doc,

I put everything back together and started it up. It idles a hint better but running very rich. I did not assembe the air clean unit and there appears to be fuel leaking out of the duct connect on the air distributor unit. I assume this is bad? Thanks for any advice. George
 

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did you check bi metal has 12 volts and is not burnt out because when you say it idles better - remember that the bi metal steps in way before the engine itself gets hot and heats the WUR metal to metal

looking at my gauge it goes from 10 psi to 45 psi in about a minute [for cold climate the bi metal may start at 2 psi thus giving far richer at start]

my problem was blocked filter so always at 70 psi [so even in tropics it took a mile to get any power at all and spluttering bad] but if heater no work then it will be rich all the time

as for adjust on distrib, dont touch it unless you first prove SYSTEM press not about 70 psi
 

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Discussion Starter · #13 ·
Doc,

It appears the bi metal is fried so I have ordered a new WUR. Good price on thevolvosite.com. Anyway would the bad WUR explain gas coming out of the air intake port on the fuel dist? Also, how important is it to have the round plate in the dist perfectly even. I also noticed a reference in Haynes to make sure it is not scratched. Why is this? Thanks, George
 

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not sure what you mean re gas coming from dist

the dist only has fuel connections in/out

can you be more specific

but to explain, the air valve is the casting with the flapper plate about 4 inches diam [and for sure make certain it is totally free to move and not hitting one side]

it is balanced by suction of engine to lift it up [and as it lifts it exposes slits in the fuel dist via the centre spindle, increasing the fuel to the inject]

then there is a COUNTER force on top of the spindle and that is the back pressure from the WUR

so at start up counter press is low so mixture is rich - then bimetal quickly raises the press in the WUR so after a few minutes the mixture is "normal" ie the setting done manually via that allen key slot

also when you plant foot the vacuum hose to the WUR drops pressure a bit so you get sudden richening for overtake
 

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Discussion Starter · #15 ·
Doc,

The gas leaks out from where the air intake duct connects to the distributor housing. The rebuilt wur arrived today-wasn't advertised as rebuild aaarrrggghhh! Anyway, any guesses on the gas leak?
 

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the high pressure connect to dist is on the side [and another going from dist to start up injector] - so make sure they are tight

if leak is from dist itself, man you have a big bill for a new dist [the one I got off the old car and took apart did that], seems cast iron warps when taken apart and prob need a surface grinding to get flat again [which is prob why Bosch quote over a grand to recondition]

recon WUR should be OK
 

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Discussion Starter · #17 ·
Put on the new WUR and it ran nice for a few minutes then back to the same old garbage. Running very rich and now high idle. I will check out pressure lines tomorrow. Thanks for all of your advice. George
 

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Discussion Starter · #20 ·
Doc,

I decided not to monkey with that allen adjust just yet. Found that the 02 sensor is maybe the wrong one and poorly crammed in there there is only one prong on it but appears to be two wires there and one just hanging. Any hints?
 
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