TTrax

Just curious, has anyone else noticed excessive injector noise in any of their cars? Mine has done this for awhile, and might be getting slightly worse but it's hard to tell. I was fearing the worst with possible rod or valvetrain noise, but when I checked with a stethoscope, there are no ticking noises at the bottom of the engine. At the side on the head, the noise is present but faint, but when I put the tip of the stethoscope on the fuel rail, it is the loudest. If I place it on one of the metal fuel lines a little way from the fuel rail, the noise is still pretty loud.

In the car it is pretty noticeable, seems like the ticking doubles in frequency during tip-in on throttle but goes back to the same frequency pretty quick. If I rev and hold the engine at 2500 RPM and let off the gas, the noise frequency falls with engine RPM. If I hold the throttle at 2500 RPM and turn off the key, as the engine slows RPM and stops, there is no ticking noise whatsoever.

I took a short video, if anyone is interested in hearing it.


Thanks and hope you all are having a good day!

zs&tas

Hi, injectors can be noisey , but id be suprised if they are THAT noisy . does she drive good ? Lots of power ?

TTrax

Yeah, the car drives pretty good, no weirdness or any drama when driving from the engine. The car never really felt like it had intense power from the day I got it (back in Feb of '97) but it has gotten a little weaker over the years and miles. It has finally gotten to where it is using almost a quart of oil between 3K mile oil changes but it is to be expected with the amount of mileage. I would've thought that if it was engine internal failure I would hear it more loudly in the engine bay but that is not the case. I did have someone tell me that they thought it might be a wrist pin but not sure. Still have pretty decent oil pressure, between 40 and 60 psi on the gauge depending on the temperature, and near 80 psi when pretty cold out. I use 10W-30 in it at all times. Thanks!

Gfunkill

i dunnoman, from the video, that's kind of a scary sound.

TTrax

Yeah I agree, I have thought that for several years now. By no means is this a daily driver. I did forget to mention, this car truly earned its name as "Firebird" as my wife was driving it and it caught on fire due to a fuel leak off the cold start injector line coming off the fuel rail. The fire was put out and I got off easy (distributor and wiring harness, plus one injector). It seems like the noise started after that but has gotten slightly worse over time.

RBob

iTrader: (1)

Make sure that none of the injectors bodies are in contact with the intake manifold and fuel rail.

It may also be that the fuel pulsation damper at the front of the engine has failed. I know that the '90 - '92 MPFI cars have one, not sure about the '85 - '89 cars.

RBob.

TTrax

I'm pretty sure this one doesn't have a pulsation damper, all that is up front is the regulator. I will check to make sure none of the injectors are touching the intake or fuel rail metal to metal. Probably just going to observe over time. If it blows up tomorrow, doesn't owe me a thing anyways. At 394k miles it's exceeded my expectations when I got it. Thanks for the ideas everyone!

KITT87

Sorry to commit some threadomancy, but I’m having the exact same issue with the exact same sound (just a little quieter). Did you ever resolve this? Is it normal?

tom3

Probably not a wrist pin. Usually hear this on decell when vacuum is highest. Loose spark plug?

KITT87

I checked and they’re all tight. Also checked distributor (rotor isn’t hitting cap), flexplate, pretty much anything that could be making that noise apart from a loose bolt somewhere. Put the injectors and fuel rail to my ear via screwdriver and it’s definitely coming from them.

TTrax

I didn't ever resolve it, still makes that sound but hasn't gotten quieter or louder. I'm living with it for now, possible new injectors in the future but for now I don't see a need to do so just from sound.

tom3

If you have a multi-meter you might check the resistance of the injector, compare to the others. Could be something abnormal in the coil causing the extra noise.

KITT87

Hey brother, thanks for coming back to answer this. That makes it seem like it’s not a problem really, apart from the sound. But I drive around with the radio up and the windows down, so it’s not something I’ll notice too much

KITT87

I’ll give them another check. Something I forgot to mention is that they are new from Southbay, only have about a weeks run time on them.

southbay08

which injectors are they?????

KITT87

2.8 upgrade injectors, sku 4471. I sent you guys an email too, sorry to double up by posting here too

southbay08

hmmm....that is very unusual for those injectors. Are you having any problems with them or is it just the noise?
Do you want to send them in so we can check them out for you???

KITT87

Just the noise, they’ve been great otherwise. I would send them in but it’s my daily right now and if it’s not doing anything wrong other than the noise it’s not a big deal to me.

southbay

If something comes up or you change your mind please let me know!!

TTrax

No problem, yeah pretty much the same here. I don't notice the noise until I'm sitting still and about to turn the engine off. I don't mile this thing up too crazy like I used to, its got about 10K more miles on it then when I took the video of the noise.

KITT87

Gotcha, I’m probably just gonna leave it then. I do about 10,000 a year on mine, potential more now that I’m working more. Thanks for the info! I’m really glad this turned out to not be a rod or a flexplate or something similar.