Anybody have any experience with changing fuel injector seals? I've got one leaking (#2) I see that IPD sells a kit anybody done this? Any tricks?

 

leaking air into the intake manifold, or leaking gas?

 

It's leaking a little bit of gas out of the manifold.

 

injector seals normally keep air out, as the manifold is normally below atmospheric pressure. any extra air that is sucked in around the injector messes with the mixture as it doesn't get metered, so it causes the engine to run too lean , its usually a bigger problem at low throttle/rpms as the amount of air taht leaks is usually quite small.

you didn't mention which year/model/nationality this is, 240/740/940 have used several different fuel injection sysstems over the years, and world market cars often differ from North American cars in a variety of ways. also, if it is a turbo or not could be an important factor.

where exactly is the fuel leaking out? between the injector and fuel rail (lh injection) or fuel line (ke injection)? or between the injector and manifold ?

 

Sorry I thought that my sig showed my car. 86 US 240 non turbo. The gas is leaking between the manifold and the injector.

 

huh, is this mostly at idle, or is it when revved up? at idle there should be a strong vacuum in the manifold (like -9 psi) such that it would be sucking air in, not dribbling fuel out.

also those air leaks make for very poor idling.

 

Seems worse when cold, but there is definite fuel leaking. Hard to say if it's worse at speed. There had always been a pretty poor negative crank pressure (doesn't suck much). Even though I've replaced oil separator/flame trap. But it does idle ok not buttery smooth but steady.

 

crankcase pressure has nothing to do with manifold vacuum.

one of my mercedes had several leaky injector seals, the symptoms were stalling when you tried to accelerate from a full stop, it required a very gentle touch on the throttle to prevent stumble-stall.

 

Doesn't the crankcase get neg pressure from the intake side?...

 

i'd have to look closely at the 240 plumbing to verify this, but most cars, the crankcase ventilation goes into the air path *before* the throttle body, but after the mass air flow meter. there's no significant vacuum before the throttle.

 

I understand never thought about it that hard. Either way I think I'm replacing the seals on the injectors. Pretty straightforward?

 

Yes, nothing to it! An untrained monkey can do it in a couple of minutes, (Youtube).

 

definitely plan on replacing all 4 injector's seals.

 

Just an update. All 4 seals in (nothing to it really) at start up looked like #2 was still leaking. Let her warm up and it looks like she's holding, though I won't be confident for a while. Just for the heck of it I pulled the plugs and #2 did look more rich than the others (nothing concerning). I also cleaned electric connections while I was there. We'll just have to wait and see.
Also the vacuum routing for the flame trap is big hose after MAS before throttle body. Little hose is right on the intake manifold. At least that's how mine is.