Engine: 2.8 F/Inj B28E: B28 V6 won't idle or rev

[stinky]

I originally posted this on the 700 pages but as this engine is more popular in the 200 Volvo's I reckon I'm better off asking here:

See what you think to this B28 engine problem.
I seem to be getting closer to getting this car running again, but...

The engine will start up and idle albeit roughly. You can accelerate but there is no power, the engine will rev but slowly and roughly and the air flow sensor plate moves down but seems to shudder; if I use my hand to push it down smoothly as I move the throttle linkage the engine revs quickly and smoothly.

I’m hoping this is due to fuel pressure being too high and preventing the control plunger from moving properly but I’m not sure.

I can't find any vacuum problems anywhere and I've pressure tested the fuel system and it looks A1 (it was iffy but after cleaning seems OK now).
I've tested the idle control valve and actually tried another one, no difference.

Like I say though if I move the air flow sensor plate by hand at the same time as moving the throttle linkage the engine seems to rev nicely.

what do you think?

[TheJoyOfSix]

Are all the pipes connected properly to the air bypass valve? They do have a habit of falling off.

[Mister T]

Stinky,
Can you tell us what as been done to the engine or when this problem started, this sounds like a control pressure problem, (to high) this cannot be tested without the proper fittings for the fuel pressure tester.
However its possible that a fuel pipe fitting maybe installed in the wrong place causing the control pressure to be blocked, post back with some history and I will try to help.
Mister T.

[stinky]

Hello,
I've check all the pipes and they look good.
This car broke down many weeks ago and seeing as I'm in a very remote location I've had a hard time getting hold of testing gear and parts, but..

I recently got hold of all the pressure testing gear I needed and I discovered that the pressure was too high due to a blocked control pressure regulator (warm-up regulator). I took this off and cleaned it (an internal gauze filter was blocked by fuel varnish) I only had a certain amount of success cleaning it (trust me it wasn't easy) and after putting it back together it worked but the pressure was still a little high. To compensate I adjusted the bimetal strip fittings inside until the pressure showed as correct. I don't trust it though and have ordered a new control pressure regulator to try.

So here's the thing, I thought this problem was due to control pressure which is why I have a new regulator on order but I wasn't sure because the existing regulator now shows the correct pressure.

I just want to be sure, so I thought I'd run by you whilst I'm waiting for the part to arrive (one week).

I'm pleased you think it's pressure too, guess I'll find out when the new part arrives.

If you or anyone can think of any other reason though I'll give it a shot.

[Rich 264]

Thats sounds very interesting, I had very similar problems with the V6 in my 262, part of the reason i eventually ripped it out and am replacing (not necessarily permanently) with a B23.
(Main reasons being cost of parts, difficulty of getting parts and complete allergic reaction to these engines from engine "specialists" and mechanics)

My car had been vandalised with paint in the fuel tank some years before i had it, so I presumed the problems were likely to be lack of fuel getting through along with blockages everywhere so i assumed insufficient pressure! Reading this thread it could well be that the CPR was blocked up as yours appears to be hence excessive fuel pressure! In hindsight it smelt rich rather than lean, although there was also a strong smell of cellulose masking the petrol fumes! Whilst struggling with this I picked up a tip for unblocking the injectors of depressing the plate fully whilst cranking (so full pressure fuel reaches the injectors instead of 'idle' pressure) sounds like you are already there with that one though.

Best of luck and keep us informed how you go on.
Cheers
Rich

[cywprof]

Hi ,
Think Rich 264 has a point. My 262C has the infamous Renault/Peugeot/Volvo engine. As Rich stated, most mechanics avoid it. I did find one generalist who gave it a try. After checking out the fuel system & rebuilding the vacuum pump the simple solution was to disconnect the vacuum hose. Gets a little noisy every once in a while, but otherwise no problems. Car has lots of power to spare. Must have been driving it for over a year now in that condition. Like Rich I too thought of replacing the motor. In North America there are several 200 series Volvos running with Ford small V/8s. There was a conversion fad a few years back. Apparently there was a demand for a faster & safer solid sedan. Mind you I think that the motors removed were the standard 4's. After all the V/6 in the 262 has a poor cousin in the stainless steel De Lorean.

Until my 262C gives me grief I'll stick with the V/6, even if it is over engineered. It doesn't hesitate to pull away fairly fast @ most traffic lights. Much to the surprise of drivers in the lanes besides me.
Good luck.
Bill

[stinky]

OK so I've now changed the warm-up (pressure) regulator at great expense (it really looked like that was the problem) and it hasn't fixed the problem; if anything it has made the engine run a little smoother but it is still rough but essentially there's no power.

It will start and run reasonably OK and rev fairly well but when trying to drive the car there is practically no power. The car will pick up and drive but I managed 15mph max and a slight hill caused a stall.

It's as rough as a badgers arse, so with all other things considered I'm really looking for advice.

My current line of thought is timing either ignition or valve timing.
As the fault initially occurred suddenly I'm wondering if a timing chain has slipped. How on earth do I check for that?

Help please guys.

[Rich 264]

Stumped! Had a problem on my 740 once, the sender lead from the dizzy (very small wire) had a 'fracture' and basically if i even breathed on the accelerator pedal would cause the engine to stall. I was able to just drive home by frantic regular gear changing and barely touching the accelerator pedal the whole way! Any attempt to accelerate by pressing the pedal and the engine just cut out. Would be easier to check the ignition out thoroughly than the timing chains, I can't think of any other way to do this without having all the timing covers off.

[Rich 264]

Forgot to ask, have you checked the in-tank pump is working?

[Mister T]

Stinky,
If this happened suddenly a broken timing chain on the left bank is a possibility, I have seen this a few times when this engine was in current use , you can check this easily by removing the small plate at the back of the cylinder head and seeing if the cam rotates .
Regards Mister T.