The latest pain. The car (MY04 Aero) has always been a prompt starter but at the weekend I noted that it took longer than usual to fire. It was fine on warm restarts and I forgot about it. But then today it took even longer. I backed off the first try (5 seconds?) and it went after a bit on the second try. Again warm restarts fine, and runs fine.
It didn't seem particularly sluggish - turned over but reluctant to fire as promptly as customary.
Battery giving an early warning? I thought they just tended to fail these days. I've checked and it's 3.5 years old, measured 80% at last service (May).
I assume if it was other suspects - starter motor, alternator, fuel pump, injectors - the symptoms would be a bit different? Any thoughts gratefully received.
Is the cold start improved if you turn on the ignition and wait a bit before starting? If so the fuel pump may be slow to pressure up. Tip the back seat up and listen to the pump.
You often need an accomplice as the pump may only run for a brief period. But, if the pump is OK, a blocked fuel filter might cause a slow build up of pressure.
From Off to On and before St - difficult to be very clear because all of the bongs - and with seats and bonnet up:
I can't hear the fuel pump doing anything.
There are some rapid clicks which then stop; they sound like they're coming from the back / central of the engine bay. The car then starts fine if I proceed to try, as it's still warm.
The pump is under the back seat.
Aye I lifted the rear seats but couldn't hear it doing anything. I assume if it was acting up I'd have problems when driving? The car drives completely normally once started.
I'm wondering about starter solenoid.
There's a strange rapid but finite click at On.
Lots of clicking could be a failing relay.
That was my thought. I also wonder whether this coming on after the welding was done is a diagnostic clue - a bit of Googling made me wonder about the ground wire.
I'm not a welder. but I understand that a welder would disconnect the battery, etc, if he's using an arc welder. But i'm happy to be corrected!
Sigh, it's getting more complicated ...
Swung by Cartech today and the car was completely normal; I couldn't reproduce the rapid clicking between Off and On (and since it was warm it started fine). So I headed to my destination. Got back in the car 90 mins later and again while it turned over briskly it was very slow to catch; and moreover there's a completely new symptom, a loud click/clunk which you can feel through the gear shifter (auto) when you touch the brake pedal in Park. Google says shift lock solenoid. It's like I've got some migrating electrical gremlin.
The click/clunk when hitting the brake pedal is indeed the shift lock solenoid releasing. It's what stops you pulling the selector back from "P" until you put your foot on the brake. It's normal. My old car had a noisy solenoid.
But is there some reason it would go overnight from a barely audible click to a loud clunk? I mean, I would have expected something like that to get imperceptibly louder over time but it's a dramatic shift.
Not really. The switch itself may have come loose. I was worried about the noise on my old9-5, but the garage listened and said that it was "normal".
Shift lock solenoid back to normal (inaudible). So, that was weird.
Still turns over briskly but only fires on the second or third turn. Idles fine. I was starting to convince myself that hard acceleration was slightly under par.
So, although hot starts are ok for the moment, I'm starting to wonder about [1] the CPS, which seems to generate various issues, or [2] the fuel check valve, which a bit of Googling suggests can cause my issue, i.e. difficult cold starts but fine thereafter.
If it's slow to start, but is OK once running then I would be looking at the fuel pump ability to get the fuel rail to the required pressure
CPS risk of failure normally shows when the engine is hot, not cold
No error codes ?
Indeed, hot starting is fine which doesn't square with the usual CPS issue.
No CEL.
I've read that with the check valve problem, if you prime it two or three times rather than the once, and it then fires as normal, that's that an indicator.
Went out to see what it would do from a cold start last night, in particular whether the tacho flickered while it cranked (if not then CPS, if so maybe fuel check valve). For about a second I thought "it isn't flickering, aha, CPS" and then it started completely normally. And then ran fine. So I'm baffled but if it keeps behaving like that I'm happy to stay baffled.
OK well we have a verdict I think - on the day I have to get Heathrow it won't fire at all [aaaaaaaaaaaaaaaaaagh]. Multiple cranks, but won't start, and tacho not flickering. So CPS I assume, noting that the symptoms really weren't the standard ones.
If you have the means of checking the resistance. Two of the pins should show a resistance across them. It should be between 770 ohms and 950 ohms. Usually fails on the high side.
Also:
Are you sure this isn't a different (perhaps new) problem.... like fuel pump failure
They can fail suddenly
I'm not sure of that no - but I thought that the tacho not moving was the sure sign of CPS? Wouldn't it flicker if the fuel pump was the culprit?
I'm afraid measuring the resistance is beyond me. A new CPS is in the post, though I'll need a mobile mechanic to fit it ...
Googling does disclose instances of people replacing the CPS cos the tacho wasn't flickering, only to find it was the fuel pump.
I've lost all confidence in my own diagnosis now so I have added HomeStart to my AA cover and will call them (when it's active). If they say it's the CPS, yay, I've got one; if it's something else at least I know and they can either fix it or tow me.
Take the DI cartridge off,
Let the engine it crank over for 5-10 seconds or so
Remove plug(s)
Wet / smelling of petrol, fuel pump is OK
Alternatively
Remove DI & plugs
Place DI upside down on the block, reconnect & place plugs in holder. Use jump leads to earth plugs to battery / good engine earth (a couple will be fine)
Get someone to crank the engine, watch / listen for a spark from the earthed plugs
Many thanks for your counsel carrera. That's beyond my confidence / competence, so I'll get the AA to determine that - and report back!
Extensively Googling I do note (at least) two things:
1] I thought that unmoving rev counter simply meant CPS - and of course it often does - but plenty of people have replaced a CPS on that basis only then to find that it was indeed the fuel pump, or a relay.
2] We all know about hot-start difficulties being a sign of CPS failure - and of course it often is - but plenty of people have had cold-start only difficulties too. The CPS is a bit of a maverick ...
More when I have it.
Well, if anyone's interested - and I'm pretty bored with this saga myself - it was indeed the CPS.
So I'd warn anyone thinking that hot starts are the red flag that for me it was purely cold starts. Before it failed it would only fire on the second or third attempt despite fast cranking. Warm re-starts were never a problem. Then when it failed it was a cold start, just cranking not firing. The rev counter not moving at all is the key.
Glad it's sorted, and hopefully you are a little more confident in your diagnostic abilities
Before I started to strip the 9-5 today, I went shopping. The car refused to start after the first shop, only half a mile along the road. It started eventually and the rev counter was moving a bit, so at a bit of a loss to diagnose. It hasn't done the non-start since the Pyrenees over a year ago. Starting hasn't been really sharp for all that time, and some time before that.
It was thanks to this forum that I had any clue really. I told the AA guy what I thought; he didn't do any diagnostics, just said "it sounds like you know what you're talking about [!], so if you've got a crank sensor let's change it and see", and it worked yay.
Seems like a fix! :)
As my 9-5 is off the road waiting for parts, I may change my CPS and see if it makes a difference to the starting.
I think mine is idling better now too. It could be a bit uneven but it seems a little happier and smoother at idle.