[71type65]

After owning my 2003 Esprit V8 for a few weeks I noticed a rapid repeating noise that seemed to be coming from directly behind the driver's head. Not sure why I would not have noticed it sooner, but am thinking it may have started after I found a hose was unplugged from the right side air filter housing and plugged it back in. Coincidentally (or not) the car had a previous history of setting the CEL. I think it was Code P0442 "Evaporative System Malfunction, Small Leak" and was a simple matter to clear the code with an OBD-II tool, but it would reappear at unpredictable intervals. After I plugged in the hose the CEL/fault code has not reappeared in over 3 months and 3,000 miles of driving.

Anyway, the noise occurs only intermittently and the frequency definitely does not change with either road speed or RPM. After reading a few blogs I am pretty convinced it is the the evap canister purge solenoid operating, which has been described as a ~4hz "clicking" (that is one loud "click" believe me, but I can't come up with a better word for it), and that the noise is normal. It's not unbearable but it is a little annoying.

Wondering what the side effects would be of disconnecting the electrical connector from the purge solenoid so that it doesn't operate. CEL? Fault codes? Any drivability or potential engine damage concerns?

Just toying with the idea, the car runs great so I am reluctant to tempt fate and disturb the equilibrium. But still would welcome any insights or theories. Thanks in advance.

 

[carbuff]

Hey Steve, you might get another CEL if the purge pump fails its self-check. (I'm sure that @jtrealty might agree.)

EVAP codes will not cause drivability issues but if you need the code 'off' for inpection in your state, you may want to fix it properly. Perhaps (after being open to the air due to the broken hose) it just needs a drop of oil? Post a picture of it.

 

[jtrealty]

When you do a smoke test you must take into consideration any valving. If the valve is closed the smoke cannot pass through it, of course. You must either reconnect the smoke past the valve or use a short piece of hose to "jump" past it. When looking for leaks in the evap system you are looking for really tiny ones and they can be temperature dependent meaning if everything is cold you may not find it because it only leaks when everything gets hot. On one car I worked on (not a Lotus) when you accelerated and the motor moved ever so slightly, a fitting leaked. It can be very difficult to find such tiny leaks even with smoke. That means it can can take a while and that means it can be expensive to fix if you have to pay a shop charging by the hour. As Carbuff says, to pass emissions you must set your readiness monitors and even if the evap system isn't throwing a code, the monitor may not have set so even without the check engine light on you may not pass. Clearing the code doesn't set the monitor, it just erases the code. Depends on your State, some States don't require every monitor to be set at inspection.
David Teitelbaum

 

[71type65]

Thanks guys, much appreciated! My state does a tailpipe test only and the car passed no problem (I had reset the code beforehand). The CEL was occurring frequently before the hose reconnection and has not reoccured since so I am thinking the leak is now actually fixed, guess that time will tell.

Haven't physically seen the canister/solenoid yet, supposedly it's behind a cover in the LR wheel well that is accessed by removing the wheel. Had a quick look but did not even see the cover in the wheel well. Will have to dig deeper, the idea of lubricating the solenoid sounds promising.

I haven't found a diagram yet showing that hose routed to the right side airbox so I am still curious about the actual connections.

 

[71type65]

My service manual PDF has the parts list and diagram for section 44.05 V8 evap system. But it only has the parts list for section 44.05a USA V8 evap system, the diagram is missing. Figures doesn't it?

The parts lists are different between versions and I'm thinking the 44.05a diagram would shed some light.

Any idea where I could locate the 44.05a diagram?

 

[carbuff]

Were you looking at the S4s section?

The V8 section only has a 44.05 AFAIK. I think you are looking for #22, but I was interested in a picture of where it actually 'sits' in the car...

 

[71type65]

Progress! I dug a little deeper, and here's what I found. You may want to settle in and get comfortable, this could take a while….

Am looking at V8 not 4cyl in the manual. The 44.05 diagram and parts list are for pre-2000MY V8. The manual I have shows the 44.05 pages and also a 44.05a parts list that is applicable to USA 2000MY V8, but it's missing the 44.05a diagram. Apparently someone skipped a page when they were scanning the manual or Lotus was just deficient in their pubs dept, probably the former. After much digging I finally located the 44.05a diagram, image is at the end of this post.

Service notes section EMM2V describes evap system theory of operation and shows the pre-2000MY canister location with its protective cover in the LR wheel well. See attached EMM2V pages.

It turns out there are several differences between the pre-2000MY 44.05 and the USA 2000MY 44.05a. Where the earlier cars have a cylindrical evap canister (44.05 item #1) with integral purge solenoid, the later cars have a rectangular canister (44.05a item #4) with separate purge solenoid (item #10). Also the mounting locations are different. In either case, the purge solenoid when activated opens a port allowing vapor to be drawn from the canister to the engine intake plenum (via the EGR manifold).

Item #22 on the 44.05 parts list is the canister vent close valve, which is mounted on a tab near the engine bay fwd bulkhead upper left side as shown in the EMM2V illustration. The vent close valve is item #7 on the 44.05a parts list, although they are identical part numbers. This valve allows the flow of fresh air into the canister to assist purging, or shuts it off as needed.

Evidently starting with USA 2000MY the canister was changed as well as moved from the wheel well to the area outboard of the LH air filter housing. It's the black box with 3 hoses attached to the left in the first photo below, aft (left) of the round vacuum reservoir, seen through the access panel inboard of the LH rear quarter window. Second photo shows the separate purge solenoid mounted on the tab that is attached to the metal header rail along the top of the engine fwd bulkhead near the center. The last photo shows the solenoid and tab, the non-return valve (NRV) between the 2 white clips, and the hose leading to a grommet where it passes through a bulkhead to connect with the canister. Also the canister vent close valve is visible below the NRV and behind the LH cam cover breather hose.

Just FYI the link below has factory pics of the last V8's during buildup on the production line and these help show the later configuration (excellent resource site BTW!!):

Esprit V8 Build: Body Build

A Photographic Build Record of the Lotus Esprit V8

www.espritv8build.co.uk

Also found an update package for the service parts manual although it is applicable to a later version of the manual than what I have currently:

https://meinlotus.files.wordpress.com/2014/03/1996-04_gt3_v8_partslist_ul_ot4_s.pdf

From a documentation standpoint I think what I really need is service parts manual N082T0325J which covers the 1996-2004 V8, together with the corresponding latest service notes manual. Then along with the update package it would be a fairly comprehensive set.

Turns out the hose I reconnected to the RH air filter housing is the RH cam cover breather vent (pic below), it is item #17 on diagram 42.01. Not completely clear to me how this would have triggered the evap leak code 0442, but I guess it's possible since ultimately it ties back in to engine areas that are also connected to the evap system.

For anyone that hasn't nodded off and is still reading there is an end to this saga I promise. Getting back to the original noise issue (which I almost forgot about in digging through all this), I confirmed it is the purge solenoid. It slides onto the metal tab that is bolted to the aforementioned metal frame rail along the upper fwd engine bulkhead so it makes sense that rapid repeating "clicking" noise (kind of a thumping actually) is transmitted to the cabin. Plus the bracket attaching hardware was slightly loose, adding to the percussion symphony. Anyway I inserted a washer between the bracket and the rail which helps prevent actual contact between the solenoid and the rail, then snugged it up. Still can hear/sense it but it's softer. Seems to me this design is abusing not just my ears, but also the poor solenoid by constantly cycling it so rapidly...hey at least it's an easy replacement if it ever fails. Again, it's better now and maybe at some point I'll try a more involved isolation measure. Or just chalk it up to the fact that she is continually informing me of system functionality i.e. I know when we are purging. Not that I particularly care to know.

To maneuver the solenoid during this exercise I had to temporarily disconnect the hose that leads to the intake plenum. Upon engine start I got…wait for it….a CEL !#/@?&! Codes were the familiar P0442 Evap System Small Leak and a new one, P0108 MAP/Baro Pressure Circuit High. Reset the codes and did a test drive - no codes. So I suppose just disconnecting that purge/plenum hose for a short time (yes the engine was NOT running) triggered the fault. All good for now, will continue to monitor the situation.

Thanks for the assist and for tolerating my diatribe. Hopefully it could help save someone a couple steps if they encounter a similar situation.