Chasing a slightly lumpy idle...still

[Laird Scooby]

Originally Posted by Stephen Edwin

Thank you for digging Dave.

I have just been to the car and lifted the bonnet. That's enough work for today thank you. The amp is screwed to a substantial heat sink. So it is worth having the spare amp ready mounted on a spare heat sink....doing the job properly being prepared.

Never having changed an amp heatsink I don't know about the screws holding the heat sink to the wing. They don't look easy to get at. Are they in to captive nuts which might fail? Is serious cleaning necessary before re-fitting a heat sink to the wing or do the job again later after a roadside fitment? Will it be raining or snowing at the roadside? Will plod be rushing one along to clear the highway? Is it worth debating?

The point relevant to the 240 is, it is worth having the spare amp mounted to a spare heat sink. Saves possibly polishing and applying paste at the roadside in possibly adverse conditions or circumstance. Have I said before, be prepared.

I am curious about the fitment of the heat sink to the wing now. Clifford Pope is one of life and Volvo owner good eggs. As indeed are you Dave. I'll pick his brains on this for my own preparedness.

Moto re this: there is more than one good proper way to skin a rabbit.


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When you say the amp is screwed to a "substantial" heatsink, can you describe the dimensions please?
Also does it have fins or holes drilled in it to increase the surface area?

Also going back to my original point, it's much easier to clean the heatsink of old paste and then apply new with the replacement module than to try and clean the inner wing.

However, on the note of preventative maintenance, if the existing amp is removed, cleaned/polished on its mating faces with the inner wing/heatsink with fresh heatsink compound/paste applied, it should all but negate the necessity to carry the spare.
I'm not saying that by doing this the existing module will last forever but it will extend the service life and reduce the risk considerably.

As someone i used to know who regularly gambled on horses and was reasonably successful (he won more than he lost, albeit only by a small margin) used to say, you weigh the odds in your favour.

[Stephen Edwin]

Dave,

I'm not convinced I should use more forum space on this. Really, we are agreed about everything that matters. Cushti. And my suggestion I passed on is clearly 240 not 700/900 related.

You have my email address if you want to natter about it.

Stephen

[Stephen Edwin]

Having asked and delved just a little, I am posting this here now only in case anyone happens on this thread and needs info re the ignition amplifier and the 240 model.

The position and type of fixings that hold the heat sink to the wing on the 240 are such that the battery has to be removed to change the heat sink, unless one has a ball ended T25 torx driver/bit that can be used in a confined space. Mine is 1/4 drive on a stubby flex handled ratchet. Otherwise one could for example be horribly vulnerable on a hard shoulder in the dark &c. with no lights on the car while fixing a replacement amp. EEK. Or waiting for a breakdown service patrol.

I understand the amp doesn't fail often but when it fails it tends to fail totally. So it is worth planning. (Obviously there will be exceptions to how the amp fails.)

Best plan for the 240 is to carry the spare amp mounted to a spare heat sink, and if reasonably possible also carry the "special tool" for the heat sink screws. Belt and braces with safety net. Did I mention be prepared?

Now this really is not 700/900 section stuff. I really will stay out of this matter in this section now.


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[AllHailKingVolvo]

Thanks for the ignition amp info, gents.

I’m still chasing this issue as the car is still a bit lumpy at idle and a little “bitty” under acceleration too.

I’ve gone through the entire ignition system bar the EZK and everything seems in order. I’ve checked all vacuum hoses and sorted a couple of splits but that hasn’t really improved things. I’ve ordered a couple of metres of new vacuum hose so I can be sure though.

Could this be a fuel pressure regulator issue? I’ve checked for injector leaks and all are 100% airtight. I’m going to replace both fuel pumps just to refresh them but I don’t think it’s a fuel pump issue.

As an aside, when I tap the top of the MAF the engine note changes and idle smoothness tends to change a little. Could this be the problem?

[Stephen Edwin]

Originally Posted by AllHailKingVolvo

Thanks for the ignition amp info, gents.

I’m still chasing this issue as the car is still a bit lumpy at idle and a little “bitty” under acceleration too.

I’ve gone through the entire ignition system bar the EZK and everything seems in order. I’ve checked all vacuum hoses and sorted a couple of splits but that hasn’t really improved things. I’ve ordered a couple of metres of new vacuum hose so I can be sure though.

Could this be a fuel pressure regulator issue? I’ve checked for injector leaks and all are 100% airtight. I’m going to replace both fuel pumps just to refresh them but I don’t think it’s a fuel pump issue.

As an aside, when I tap the top of the MAF the engine note changes and idle smoothness tends to change a little. Could this be the problem?

I'm concerned for your wallet, replacing stuff....but it seems hard to get a diagnosis.

1. Yes. Quite so. That was off topic. Sorry.

2. Refresh my olde memory cell please, have you got a Lambda warning light illuminated? Have you read the LH fault codes using the little black box code reader that I expect will be on the inside nearside wing near the windscreen? Is there a code to indicate an air mass meter / MAF problem?

[AllHailKingVolvo]

Originally Posted by Stephen Edwin

I'm concerned for your wallet, replacing stuff....but it seems hard to get a diagnosis.

1. Yes. Quite so. That was off topic. Sorry.

2. Refresh my olde memory cell please, have you got a Lambda warning light illuminated? Have you read the LH fault codes using the little black box code reader that I expect will be on the inside nearside wing near the windscreen? Is there a code to indicate an air mass meter / not MAF problem?

I’ve not got a Lamba light up or any fault codes on the little black box, I’ve checked, reset ECU, driven for 80 miles and checked again and I’m not getting any codes, hence me being a little skeptical about the MAF being the issue.

It has to be a sensor or something in the fueling system I reckon. I ran a bottle of Forte trade injector cleaner through it last week which improved power and responsiveness and smoothed things out a bit, but although the grunt is still there, the lumpiness seems to have come back to some extent.

PCV is clean, vacuum system is all intact, fuel filter is new, ignition system is entirely new bar loom and EZK. I’m thinking fuel pumps, FPR or injectors are the most obvious possible culprits. I haven’t changed the knock sensor or crank speed sensor, but I’m not sure the issue points to those.

Could a blocked cat be a possible cause?

[Laird Scooby]

Silly question Phil - there's a vac hose from the inlet manifold to the EZK unit - under the dashboard - have you checked the EZK end is still attached to the stub on the EZK ECU?

[Timbo_1975]

No one has mentioned doing a compression / leak down test. You may have one weak pot.

What about valve clearances? Tightened up and very slightly holding a valve open. This would be more apparent with a cold engine than hot...

[AllHailKingVolvo]

Originally Posted by Laird Scooby

Silly question Phil - there's a vac hose from the inlet manifold to the EZK unit - under the dashboard - have you checked the EZK end is still attached to the stub on the EZK ECU?

I haven’t! That’s a good point, and not one I’d thought of until you mentioned it. Whereabouts under the dash would i find the EZK? I know the previous owner went dash mining to replace the stereo head unit, so maybe he dislodged it.

Timbo, I haven’t checked valve clearances or done a compression test yet but I will do in due course. I’m working through the car section by section and replacing any consumable bits that may fail due to age or wear as part of recommissioning the car. Ignition system is nearly done, fuel system is next and then setup stuff like valve clearances etc after that. The car runs and pulls well, but the slightly lumpy idle and intermittent misfire when driving is virtually identical whether hot or cold.

[Laird Scooby]

Originally Posted by AllHailKingVolvo

I haven’t! That’s a good point, and not one I’d thought of until you mentioned it. Whereabouts under the dash would i find the EZK? I know the previous owner went dash mining to replace the stereo head unit, so maybe he dislodged it.

The car runs and pulls well, but the slightly lumpy idle and intermittent misfire when driving is virtually identical whether hot or cold.

He almost certainly did then Phil! I can't remember exactly where it was on mine, it's about 6 years ago now and as i was crawling backwards on my back into the footwell (after removing the trim) with a torch i got confused over what was left and what was right.

If i was pushed to say where it was, i'd probably say between the clutch and brake pedals as a general area but bear in mind Volvo sometimes move these things on a whim and mine was the B230E so no fuel ECU, just the spark (EZK ECU) and i actually found it when i suddenly noticed this "spare" vacuum hose dangling in the breeze when i was bypassing the audio amp with a bypass loom from fleabay.

That said, mine had been running like a sack of spanners for a while at the time, rough idle, hesitancy/flat spot on acceleration, thirstier than it should have been and not as lively either. However, i put a lot of that down to a manky dizzy cap etc as i hadn't had it long at the time, scraped it through the MoT (emissions were the stumbling block - can't think why!) and like you are now doing, was working through its various problems.

Once i found the EZK unit and the stub (with no hose attached) i put 2 and 2 together and fitted the hose back on and on a road test later found it was the cause of the running problems.

As you can see, i wasn't trying to trace the rough running at the time but bypass the audio amp so i didn't pay as much attention as i maybe should have done.

If you have a spare door mirror glass or can "borrow" one of your wifes make-up compacts (preferably an empty one so that she doesn't moan you've left oily pawprints in her favourite foundation and also that same foundation doesn't end up pawprinted around the car!) and a torch, remove the underdash trim and save your neck, back etc by using the torch and mirror to find the EZK unit.

Hopefully this will be the final piece of your jigsaw puzzle, for now at least! You might also find you don't need to go to the expense of changing the fuel pumps yet too and save those for another time.