engine stethoscope (what should my injectors sound like?)
Discussion
Your stethoscope is designed for exactly that, you are listing for something different to other components, so it looks like you have found your problem. As for what the problem is, I think you need to start stripping it down if thats possible and take it from there.
What are the symptoms of what caused you to start listening to them in the first place?
What are the symptoms of what caused you to start listening to them in the first place?
thanks for reply
car start runs, idles and drives fine......except for one minor issue.
if left overnight/longer for the first 30-60 seconds of warm up. the car will have a terrible bog/hesitation between 1800-2000rpm.
it runs fine either side of this rev range during warm up too.
over this brief warm up period the problem reduces gradualy (less severe bogging) until it disappears
i can turn the car off an leave it for a fair few hours (9hr work shift) and the problem doesn't return.
ive replaced almost every engine sensor at this point. no phantom inlet vac leaks or exhaust leaks. new coil packs, spark plugs all look good/even colour. well maintained otherwise.
only got the stethoscope out for a "joke" was a cheapy amazon thing i got a year ago....might of done its job
my thinking is, hot engines mask poor spray patterns.
this one injector sounds muted and like its flowing a lot.
like the pin seat is gummed up resulting in a muted clunk and maybe its bypassing/leaking more fuel than normal, hence the wooshing.
if it is bypassing/leaking more fuel it could mean my other injectors arnt seeing as high a pressue reducing their spray pattern.
if its leaking overnight, it might pool fuel in my inlet....causing other issues.
it could just not be opening enough aswell making that one cylinder lean.
its a weird problem...the boggy 200rpm band between 1800 and 2000rpm make me think ecu/electrical i.e. a sensor fart
but as its only a cold start problem....it feels like it should be more of a mechanical/physical problem.
thanks again for the input
car start runs, idles and drives fine......except for one minor issue.
if left overnight/longer for the first 30-60 seconds of warm up. the car will have a terrible bog/hesitation between 1800-2000rpm.
it runs fine either side of this rev range during warm up too.
over this brief warm up period the problem reduces gradualy (less severe bogging) until it disappears
i can turn the car off an leave it for a fair few hours (9hr work shift) and the problem doesn't return.
ive replaced almost every engine sensor at this point. no phantom inlet vac leaks or exhaust leaks. new coil packs, spark plugs all look good/even colour. well maintained otherwise.
only got the stethoscope out for a "joke" was a cheapy amazon thing i got a year ago....might of done its job
my thinking is, hot engines mask poor spray patterns.
this one injector sounds muted and like its flowing a lot.
like the pin seat is gummed up resulting in a muted clunk and maybe its bypassing/leaking more fuel than normal, hence the wooshing.
if it is bypassing/leaking more fuel it could mean my other injectors arnt seeing as high a pressue reducing their spray pattern.
if its leaking overnight, it might pool fuel in my inlet....causing other issues.
it could just not be opening enough aswell making that one cylinder lean.
its a weird problem...the boggy 200rpm band between 1800 and 2000rpm make me think ecu/electrical i.e. a sensor fart
but as its only a cold start problem....it feels like it should be more of a mechanical/physical problem.
thanks again for the input
Years ago a good article said for running problems, start with the injectors and work out. Which can make a lot of sense....apart from injectors usually being very very reliable.
You could pull them out and send them to ASNU for a test/clean etc. At least that would rule them in or out.
You could pull them out and send them to ASNU for a test/clean etc. At least that would rule them in or out.
stevieturbo said:
Years ago a good article said for running problems, start with the injectors and work out. Which can make a lot of sense....apart from injectors usually being very very reliable.
You could pull them out and send them to ASNU for a test/clean etc. At least that would rule them in or out.
^^^^Wot 'e said.You could pull them out and send them to ASNU for a test/clean etc. At least that would rule them in or out.
That would also be my first step.
A while ago I have a Volvo v40 which would "missfire" slightly at lower revs in higher gears, actually it obviously did it all of the time but was more noticeable then.
Sent the injectors off, 1 was sub-standard. Got another.... Sorted.
stevieturbo said:
ASNU
That's the phrase I was trying to remember. Yes, a flow and leak test would probably be worth it on such old injectors, but be ready to be told they're all scrap. 
In the meantime, leave it over night, take the sparkplug out and stick an endoscope in? You'll soon see if there's a puddle of fuel in there.
Depending how convenient it is for you to take the injectors out, I'd be tempted to give it a dose of PEA based injector cleaner first and see if that helped. Also check the exhaust header temperatures when you get the stumble and see if the cylinder with the dodgy sounding injector is running cold, supporting the theory it's got a misfire. Then take that plug out and see whether it's wet or dry. (Wet just confirms that it's got a misfire, but dry might indicate it's misfiring due to insufficient fuel, which further supports your diagnosis.)
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