Misfire 945 1997 230FT

[360beast]

Yeah that's the one, when you swapped it did you remove just the module pr the module and heatsink together? If you remove the module from the heatsink there should be a white paste between the two.

Once you've gapped the plugs and put some heat sink compound on it pull fuse 1 for 30 seconds to reset the ECU and see how it goes then.

[jlawler]

I didn't remove it from the aluminium heat sink but I'll do that.
Luckily I have some heat sink compound.

[TonyS9]

If the ingnition amplifier is not working well you should see something in the rev counter. The needle will be jumpy or something. It is triggered from the back EMF from the coil primary, which is also the output of the ignition amplifier.

Generally you need to stop swapping parts and start doing some diagnosis. The spark check is a good diagnosis, but you could also have distributor problems.

They are prone to oil leaks in the distributor which at least causes hesitation. Its hard to change the oil seals, you need a special tool.

[jlawler]

Ok still not working but a little wiser

So checked all the plug gaps (some were a bit big) and did the thermal paste on the heat sink.

Went to start it and nothing, tried several times. Took a plug out and no spark at all.

Then it suddenly started working. Nice big spark on the plug. Put it back in. No rough ignition, running smoothly.

Went for a spin down the road got 3/4mile and it died and wouldn't start again.

Got a tow home off a mate. Took another plug out and initially nothing and then it sparked.

One thing I noticed yesterday is that when I turned it over the spark on the plugs didn't appear immediately. Is this normal?

So I think we can probably say that the Plugs, leads, Dis cap, rotor arm etc are Ok otherwise it wouldn't have run smoothly for even a short while. The problem is further upstream.

[jlawler]

Originally Posted by TonyS9

If the ingnition amplifier is not working well you should see something in the rev counter. The needle will be jumpy or something. It is triggered from the back EMF from the coil primary, which is also the output of the ignition amplifier.

Generally you need to stop swapping parts and start doing some diagnosis. The spark check is a good diagnosis, but you could also have distributor problems.

They are prone to oil leaks in the distributor which at least causes hesitation. Its hard to change the oil seals, you need a special tool.

Rev counter is steady it doesn't show the glitching like I have seen with the Crankcase Hall sensor before.

I've replaced the Dis cap and rotor arm with a new one (It was on the to do list)
Not really bad as I do this regularly.

[Laird Scooby]

Originally Posted by jlawler

Ok still not working but a little wiser

So checked all the plug gaps (some were a bit big) and did the thermal paste on the heat sink.

Went to start it and nothing, tried several times. Took a plug out and no spark at all.

Then it suddenly started working. Nice big spark on the plug. Put it back in. No rough ignition, running smoothly.

Went for a spin down the road got 3/4mile and it died and wouldn't start again.

Got a tow home off a mate. Took another plug out and initially nothing and then it sparked.

One thing I noticed yesterday is that when I turned it over the spark on the plugs didn't appear immediately. Is this normal?

So I think we can probably say that the Plugs, leads, Dis cap, rotor arm etc are Ok otherwise it wouldn't have run smoothly for even a short while. The problem is further upstream.

It takes a couple of turns of the crankshaft before the ignition wakes up and starts firing - as the CPS only has two places on the flywheel where it senses a gap it takes a couple of turns to work out whre the engine is before letting the sparks fly.

Might be worth checking your RSR (Radio Suppression Relay), if you have an electric cooling fan on your car the fan uses the same type of relay so you can swap them to see if the fault changes. On later cars (96 on i think) the RSR not only feeds the injectors but also the ignition amplifier module.

[360beast]

Originally Posted by TonyS9

If the ingnition amplifier is not working well you should see something in the rev counter. The needle will be jumpy or something. It is triggered from the back EMF from the coil primary, which is also the output of the ignition amplifier.

Generally you need to stop swapping parts and start doing some diagnosis. The spark check is a good diagnosis, but you could also have distributor problems.

They are prone to oil leaks in the distributor which at least causes hesitation. Its hard to change the oil seals, you need a special tool.

Which special tool do you need? I just did it on an engine on the floor in about 15 minutes with no special tools at all.

See post #23

https://www.volvoforums.org.uk/showt...=311775&page=3

[jlawler]

Is the Radio Suppression Relay the big one beside the Ignition Amplifier?

[jlawler]

Originally Posted by 360beast

Which special tool do you need? I just did it on an engine on the floor in about 15 minutes with no special tools at all.

See post #23

https://www.volvoforums.org.uk/showt...=311775&page=3

Thanks for the link, handy post. I've only had to this once on my old 740 (RIP).
It was straight forward enough.

I've get better at the dis cap with practice pain to take it on an off. I noticed some of the newer replacements don't have hex bolts but just philips screws (which would be impossible). I keep stealing them from the old cap.

[Laird Scooby]

Originally Posted by jlawler

Is the Radio Suppression Relay the big one beside the Ignition Amplifier?

Don't know.

Volvo in their infinite wisdom put them in a variety of locations according to year, model, aspiration and the results of a sacrificial troll.

A photo of what you think may be the RSR and also it depends what you call "big". It's slightly larger than a generic 4-pin automotive relay but not by much. I don't have a pic of mine which lives on a bracket next to the cooling fan relay and the bracket clips on just in front of the coolant expansion tank.

That isn't necessarily a guide to its location as mine is a V6 so not even a red block. It's also about 10 years older than yours and n/asp (no turbo - not that it needs one!) so again, reasons for it to be in a different place.