Another B230 idle problem thread

OdinsRedblock · 2022-02-06T11:31:10+00:00

The distributer and the tape covers wiring are obvious to me whenever anything gets wet....

OdinsRedblock

So the pro parts catalogue lists the two items for the 700 series. One has a much wider flare on the arched piece though and that’s the one I got. The little key inside is maybe like 1/3rd of the size.

Major Ledfoot

I avoid ProParts whereever possible; it's often junk. Their application list certainly is, since 740s had head-mounted dizzys from about 1986 on, and head mount rotor buttons and caps are very different from block mounted rotor buttons and caps. Also, B234 dizzys have nothing in common with any (factory) 240s, but according to their list.....

FCP sell a genuine Bosch for not a lot of money. The correct rotor button for rear mount distributors is OE p/n 1346787.

Does anyone know if there are different styles of rotor button for 740?

Yeah, one type fits the block-mounted contraption on early 740s and on B23 turbos; it uses a 240-type cap and rotor. The rear mount things all use the same cap and rotor, but the guts of the LH2.2 dizzy have a Hall sensor in 'em. The LH 2.4 rear-mount unit is a simpler version.

But what is it about washing the engine bay that would cause a cap and rotor that is performing perfectly well to stop functioning? I mean obviously getting wet.. but if I pull it and dry it and clean it, shouldn’t it run again? Well at least similarly to how it was before I washed it?

IMHO it would not have been running perfectly; it would have been barely running. Waterlogging the thing was its last straw, and then cleaning it removed the little particles of metal on which it ran.

The 780 had a similar problem, where a crusty rotor and cap contributed to an irritating situation where the car would start and initially run fine, then misfire and stall, and finally stall when warm and no restart. Some clever soul on Oz Volvo with experience of the B280 engine pointed out how cap and rotor were the likely culprits, as he'd had the same thing happen. B280 dizzys are mounted at the front of the head, and a a pig to R&R the cap and rotor. But the old ones were rusty AF inside.

OdinsRedblock

Okay so the plot thickens.

I called up GLT at the crack of dawn and they confirmed only one rotor button for my application as far as they know. They’ve been using the pro parts item for 10 years without any issue. I trust GLT. They said just bring the whole dizzy down and they will check it out.

So I called the ‘other workshop’ and asked if they could pull the dizzy. They also let me know they’d had my injectors cleaned as I’d asked and 2 were at 90%, one was 80% and one was 75%.

He had the dizzy sitting there waiting for me. I pulled out the new rotor button and he said “oh you’ve got the new rotor button.. give it here” and so I did and he pulled the old button off and went sat the newer one on and said “see.. it just won’t fit correctly.. it just spins”.

I asked if I could have a look and applied a little pressure and the rotor snapped on. I said “gee it seems to be on there pretty tightly now” and he’s like “oh well um, it is likely to just spin off and cause the same issue”. And I reminded him that they had told me it was faulty in the first place because it wouldn’t fit on the rotor at all and wouldn’t even start. The rotor not fitting tightly onto the dizzy shaft at all and the rotor falling off the dizzy shaft were different problems. I gave it a good tug and it seemed to be on there pretty tight.

I asked for some spanners and said I’d go try it myself. So I went and fitted it up and sure enough, it fired straight up. Idled rough as it was. Ran for a minute or so. Started to give it a bit of throttle, revs died down and motor cut out. Exactly the same as it was before.

Alas, I don’t think the cap and rotor were my problem. I didn’t think they were.

So I’ll leave the car with them to have the exhaust completed. And if they want to have a bit more of a poke they can but I don’t have much faith in them now.

Major Ledfoot

Ummmmmm..... just wondering - are all the plug leads connected in the correct order? It's amazing how these engines can still run at all when 2 leads are reversed, but sometimes they can. Firing order is 1-3-4-2.

Robert DIY to the rescue - again.

https://www.youtube.com/watch?v=_KG4TLEG4xg

OdinsRedblock

Major Ledfoot
Ummmmmm..... just wondering - are all the plug leads connected in the correct order? It's amazing how these engines can still run at all when 2 leads are reversed, but sometimes they can. Firing order is 1-3-4-2.
Robert DIY to the rescue - again.
https://www.youtube.com/watch?v=_KG4TLEG4xg

Hang on, you said 1-3-4-2.. but Mr Spinner says 4-3-1-2. Have I missed something?

OdinsRedblock

4-3-1-2 from drivers side to passenger side so yeah, that’s all good.

Major Ledfoot

^ Have a look at your old cap. It's a weird-arsed setup.

We are both correct - the firing order is 1-3-4-2, but the cap and leads run 4-3-1-2, like he said. Which is the same firing order, except he's pointing out how the #4 lead connects to the cap in the position it does.

And remember which way the dizzy spins.

OdinsRedblock

Oh yeah because the firing order is in the order of the way the rotor spins rather than the way the leads are positioned on the cap.

This has become relevant because the cap has been off but the car was running well before the pressure wash and I don’t think the wash shuffled my leads around haha

You know, another member has suggested maybe a faulty ECU. They had suffered similar issues with a hunting idle and poor running.

Now that I think about it, the way the car was running when it turned up was fairly similar to after the pressure wash. I did a bunch of work on the car and had it running well so I’d just assumed it was from the new plugs, leads, air filter, vacuum hoses, hose clamps, cleaned MAF and idle valve. But maybe it is an intermittent issue that raised it’s head when exposed to some moisture. It had been raining ALOT in the week before the car turned up too.

Where is the ECU on these cars?

And does anyone know if I would run into trouble putting a late model 940ECU in the car? A 9xx model. I’m thinking in particular with immobilisers.

Major Ledfoot

Where is the ECU on these cars?

On the RH side lower kick panel - in OZ-market cars, the kick panel next to the throttle pedal. You'll need to remove a couple of Torx screws and lift the door seal (and part of the trim plastic along the floor) to get that trim cover off. Above it and well hidden is the cruise control module.

As for the EZ-K? Ugggh.... it's tucked away in the dash, behind the instrument cluster and above the pedal box. Don't confuse the EZ-K with the ABS module.

Bill's List might be of use to you in determining which ECU you have, or what you need.

http://www.nuceng.ca/bill/volvo/database/ecu.htm

But IMESHO it would appear that unwanted water could be the problem here, rather than ECU issues. Unless the ECU is throwing codes.

FWIW, the code list is on this site, along with much good info.

https://www.volvoclub.org.uk/faq/FAQSummary1.html

OdinsRedblock

As for the EZ-K? Ugggh.... it's tucked away in the dash, behind the instrument cluster and above the pedal box. Don't confuse the EZ-K with the ABS module.

Hmm.. I did have the cluster out a couple of times before this problem arose. I wonder if I could have dislodged something?

Would there be any worth in just cleaning the connections on the ECU and or EZK or should I just inspect for secure connections and water encroachment?

If this workshop tested spark and it was getting good spark on 2 cylinders, and poor spark on 2, is it possible there is an issue with the ignition module? Bearing in mind, apparently spark at the coil was strong.

Bill's List might be of use to you in determining which ECU you have, or what you need.

I checked the list and for the ECU I’m interested in - 977, it says unsure if it’s EGR or not. Also doesn’t mention anything about immobiliser. But I have seen some people mention issues with immobilisers on the later model 2.4 ECUs.

I am interested in the later ECUs as I’ve heard they have software revisions that can allow for better fuel economy. I don’t want to just throwing parts at the car but replacing the ECU is multi purpose.

And yeah that UK club FAQ is gold.

Major Ledfoot

If this workshop tested spark and it was getting good spark on 2 cylinders, and poor spark on 2, is it possible there is an issue with the ignition module?

Not really. Weak spark on 2 pots only points more towards the cap, rotor, or leads being the problem. Strong spark at the coil confirms the EZ-K side of things is fine.

Did you get Bougicord leads, or something else? I've never had a problem with Bougicords.

Hmm.. I did have the cluster out a couple of times before this problem arose. I wonder if I could have dislodged something?

Maybe. If the speedo connection isn't correct, it may screw with idle. 2.4 needs a VSS to determine load, and especially to transition from fuel-cutoff-on-overrun to fuel back on at idle.

I'd be checking for water ingress and an advocate for leaving things alone if they're high and dry.

OdinsRedblock

Not really. Weak spark on 2 pots only points more towards the cap, rotor, or leads being the problem. Strong spark at the coil confirms the EZ-K side of things is fine.

Did you get Bougicord leads, or something else? I've never had a problem with Bougicords.

Yeah, that’s what I thought. There probably was weak spark but I wonder if it was bad enough to cause a problem. I did notice the dizzy shaft did have a bit of end to end play though. I wonder if that could cause excessive float in the shaft and potentially create a spark issue?

Maybe. If the speedo connection isn't correct, it may screw with idle. 2.4 needs a VSS to determine load, and especially to transition from fuel-cutoff-on-overrun to fuel back on at idle.

Okay.. so this^ definitely makes me concerned I’ve connected something up wrong. There was just one random wire which I wasn’t 100% about.. and it was probably on the back of the speedo.. oh man..

OdinsRedblock

And yeah Bougicord all the way.

OdinsRedblock

I checked out RobertDIY’s cluster video and it looks like the same cluster type as mine. IIRC, the plug I wasn’t sure about went on to the connector I circled in yellow above.

The plug only went on to one spade and the other spade was left without a connection but I couldn’t see any other plugs. I wasn’t sure which spade.

Cannot remember colour of wire.

Does anyone know what this plug is for? And which is for VSS?

I suppose it’s possible any of the other plugs have slipped off as I refitted as well.

OdinsRedblock

Okay so am I looking at this right in thinking that particular connector should be a red-white wire and it’s in connection to CPS? So tach connection?

OdinsRedblock

I just had the car towed home from workshop. 2 weeks to finish an exhaust! Apparently mandrel bends in mild steel are hard to come by.

Anywho, car was doing the same thing. Head mechanic reckoned he had a little squiz yesterday arvo and played with timing and checked idle valve and whatever. Tried to tell me the idle screw was completely bottomed out but I said I don’t think this model has an idle adjustment screw. And that either way, I hadn’t touched any screw before or after it started playing up.

So I got it home and pulled the cluster and I had the red/white wire where I think it should be but I noticed I had a purple and white wire on the spade directly next to it.

I looked for another spot to place that single wire and sure enough there was another pair of spades up higher on the cluster and one of them looked clean, like there had been a wire on it. So I tried the purple and white wire and it fit like a glove.

I started it up. And the idle went up to around that 700rpm straight away. Let it idle for a bit and it seemed good. Started to give it some throttle and it was hesitating and misfiring a bit. But I persevered a bit and it seemed to smooth out and started running normally.

I tentatively backed it out and there was no hesitation or bawking. (!!!) So I took it for a lap around the block. Driving like a champ. Let it come onto boost a little bit and rears started to slip! That’s enough of that in an unregistered car.

Brought it home and let it idle. Seems to have a very slight wander in the idle but the longer I let it idle the more it seemed to smooth out. Turned it off and started it back up again and warm start seemed good. Exhaust sounds nice too. Not too loud at all but nice rumble and a bit raspy at revs.

I won’t count my chickens just yet but I think we may have gotten to the bottom of it.

Thankyou Captain.. @Major Ledfoot Your willingness to help and engage in some chitter chatter has resulted in somewhat of a serendipitous moment. Thankyou so much. As soon as you raised the issue, I had a feeling you may have found the answer. Inability to adjust AFR when coming back on idle when throttle closed seemed the ticket. How can I get a 6 pack to you?! :p

Oh and all my gauges are working too! So I must have at least done a good job on cleaning the circuit board/contacts when I pulled it the last time.

Major Ledfoot

@OdinsRedblock - Glad you got this issue sorted.

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