Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Whistle from throttle body.

More sage advice needed please.

I recently did some mods which involved removing the throttle body, iac valve, and airfilter. This also involved some moving/manipulation of the hoses that attaches to these parts.

Went for a run this morning and it has developed a whistle sound when driving. It sounds like it's coming from the throttle body area. The only difference to this area was a new throttle plate gasket which is a white plasticy type substance. All bolts seem to snug as well as everything else. I also have a MIL for code p0174, which is a lean mixture on bank 2.

This might be a coincidence as I had this code recently after the mot, but cleared the code and it hadn't come back despite several spirited drive.

Any ideas?

When balancing carbs or trying to find the location of air leaks I use a lenth of flexible tube. The diameter is not critical but something that is easily held close to the ear, long and flexible enough to be able to follow round the flanges etc that perform the supposedly air tight seal... You might hopefully be surprised just how effective it can be..?

Good luck.

I'll see if I can do something like that, but feel like it's internal for some reason.
With the engine relatively warm I started it up after repositioning the jubilee clips holding rhe hose to the TB and airfilter housing, and the whistle, which sounds more like a constant squeak, with stays when holding a steady throttle. There was a smell of petrol from the engine bay on start up but went after a few seconds of idling, but not sure if that's normal. There was, when I turned the engine off after a minutes idle, what I would describe as a relief valve going off as if letting pressure out. It used to be like a whooshing sound but has now turned to a raspy sound like you get when letting air out of a balloon.

Another alternative is to apply some light oil such as 3 in 1 or even a squirt of WD40 to every pipe union. If air is being sucked in at any point, the oil will be sucked in as well and temporarily stop the whistle..

Good tip. Failing that, I'll return to the old gasket after its had a good clean and see if that cures it. I read on a Honda forum that someone developed a whistle when they upgraded their TB and used a thermal gasket as well. It may be that there's a slight over hang into the chamber as is causing a resonance when it's opened.

All cured.
I have installed the original gasket along with the new one as the profile of the new one was slightly diffetent. Although the gasket sealed the hole, as you can see from the below images the is a weak point in a channel which could provide a route in for air, unless torqued down massively.

Either way, the whistle is gone.

The lean mixture codes kept coming up on my S1 Roadster . I never did crack it. I did find the fibreglass was crcked on the air filter housing after the MAF sensor & repiared that. I replaced hoses all over. One was PCV vlavle to inlet hose. I bought a cheap one on ebay & it would collapse making a whistling sound on engine stop. Repelced by the original and it went away.