I've been unable to find a suitable substitute for the Bosch fuel distributor (my late 88 and current 87 are CIS). There was a recent sale of a used CIS unit on eBay a few months back, but definitely few and far between those sales.

The roughness may be due to uneven spray from the mechanical injectors - that may be an easier fix by having them cleaned. You can do it yourself by soaking in carb cleaner or sending out to a service that knows how to clean CIS injectors. There are Delorean shops that might be able to do it - I can't remember names at this time, but know definitely available.

There was also a guy selling new Bosch injectors on eBay for $400 - I think he used to be on this forum, but his injectors are modified versions of another Bosch injector. Bosch had a near identical spec injector for a VW but it was lacking in a machined groove and the 'hat' that is unique to the Esprit.

Search for the MRDANGERUS thread on CIS - very comprehensive thread on all things Bosch CIS

 

First of all,



If you are experiencing idle issues, the first and easiest step would be to replace the single-contact relays in the control box (rear engine wall). The three on the bottom (Fast warmup, ACU control, and ACU changeover), and the Idle Changeover relay on top, carry current through their normally closed contacts, and best operation comes when these parts are 'fresh'. (For the record, I replaced mine at about 83K miles and it cured an inconsistent idle speed issue I was having.)


But as sleekgt mentioned, injector cleanliness (spray patterns) can have a lot to do with idle smoothness. (This is a relative term, as the generous valve overlap of the Esprit engine does NOT provide a Camry-like idle.) I had a local Forum member clean mine, and verify opening pressure, and the idle was noticeably smoother for 5000 miles or so, but now its about the same as it was the previous 20 years.

Of course, overall fuel pressure and Warm Up Regulator operation come into play here, too. Bosch CIS is a 'system' and has many components that must work as designed. Valve clearance is another factor.



As far as replacing the FD, I think that JAE has one or two that they obtained when Lotus Cars USA moved to Michigan and liquidated their parts stock. But, you MAY want to be sitting down when they quote the price. :crazyeyes

Alternatively, DeLorean Auto Parts in Texas (formerly Special-T auto) deals in refurbished Fuel Distributors, as does Fuel Injection Corporation in California. I repeat the URLs just for anyone that comes across this Topic on a search:


https://www.deloreanautoparts.com/index.html

Fuel Injection Corporation

If anyone has their FDs done at these places, post the price and results! :up:

For sure, take some pics of those SAAB FD covers just to compare...
++++++++++++

Footnote: Yes, those reworked-to-Lotus-spec fuel injectors were arraigned for, by MrDangerUS here. :bow:

 

[snip]
If you are experiencing idle issues, the first and easiest step would be to replace the single-contact relays in the control box (rear engine wall). The three on the bottom (Fast warmup, ACU control, and ACU changeover), and the Idle Changeover relay on top, carry current through their normally closed contacts, and best operation comes when these parts are 'fresh'. (For the record, I replaced mine at about 83K miles and it cured an inconsistent idle speed issue I was having.)

[snip]

I bought the new relay set that was recommended for this. However, I haven't installed yet because the car runs 'fine' (for a 30 year old car).

And I'm old school - the recommended relays are higher capacity but they are unbranded vendor origin. The thought of putting no-name brand 'upgraded' relays in the loop of the engine management circuit gives me pause.

I'm considering just keeping them onboard as spares since 'if ain't broke, don't fix it' is a scenario that is all too familiar.

Hmm...maybe I'll install them and keep the old relays onboard for backup - assumes the new relays will improve the smoother operational behavior :scratchhead:

 

It also doesn't hurt to run a can of Techron through the system once in a while. To get the idle as smooth as possible EVERYTHING must be perfect and each cylinder must be adjusted as close to each other as possible and have compression #'s within 5% of each other.
David Teitelbaum

 

"The roughness may be due to uneven spray from the mechanical injectors - that may be an easier fix by having them cleaned. You can do it yourself by soaking in carb cleaner or sending out to a service that knows how to clean CIS injectors. There are Delorean shops that might be able to do it - I can't remember names at this time, but know definitely available.

There was also a guy selling new Bosch injectors on eBay for $400 - I think he used to be on this forum, but his injectors are modified versions of another Bosch injector. Bosch had a near identical spec injector for a VW but it was lacking in a machined groove and the 'hat' that is unique to the Esprit."

Yeah, I replaced all of mine from the guy on ebay, his name is IMSSERVICE, he's been good to me with Esprit parts and help. I think he takes Mercedes injectors and modifies them, he grinds off the part number, I figure so you don't get confused in the future and try to replace them with the wrong part. I flow tested them like the manual says and they were all within the percentage range.

"If you are experiencing idle issues, the first and easiest step would be to replace the single-contact relays in the control box (rear engine wall). The three on the bottom (Fast warmup, ACU control, and ACU changeover), and the Idle Changeover relay on top, carry current through their normally closed contacts, and best operation comes when these parts are 'fresh'."

I have disconnected every relay, fuse, and bosch connection and sprayed it with deoxit D100, which has in the past saved parts I thought were garbage, It never occurred to me that replacing a working relay could improve running, but if there's high resistance in them it makes sense. Especially since the trunk area is kinda open to the environment. I always thought it was weird how warm to the touch my fuel pump relays get while running.

"Of course, overall fuel pressure and Warm Up Regulator operation come into play here, too. Bosch CIS is a 'system' and has many components that must work as designed. Valve clearance is another factor."

I got a re-manufactured WUR and it fixed a running issue for me. I have tested it and the readings I got were right at the very top end of the spec according to the workshop manual. It took a lot longer than the 60 seconds the manual says for the warm pressures to stabilize though. Maybe 5 minutes. I never considered valve clearances. One thing I hate about my car is, I know both previous owners. And the first owner of the car blew up multiple engines and transmissions. And I know he got a 2 stroke boat mechanic to do all the work on the car. So maybe checking valve clearances would be a good idea.

I'm heading off to the junkyard to grab one of the Saab FD's, if they look the same I'll stick them together and see if the car runs and I'll report back.

Thanks for your input so far guys.

 

Be careful using parts from other cars. All of the Bosch parts have #'s on them and many (if not all) are application specific. The size of the internal passages, the springs, orifices, all can vary according to the car the part is supposed to be used on. That's not to say you can't modify things and some parts may actually be identical. Just be sure to thoroughly check it against your old, correct part. Another point, taking an old part off of another old car doesn't mean that part is any better than your old part. It could be worse. It could be the reason the car is in the junkyard! BTW some parts are application specific only because of the connections, they will operate the same, you just have to figure out how to connect to it. Some newer parts are more adjustable like the fuel distributor. They have little screws to adjust the fuel flow. There are charts you can consult as to what parts were used on what cars, it may help you figure out what can and can't be swapped.
David Teitelbaum

 

Yeah, the junkyard closed at 1pm today and I was too late to pick one up, It seems like it's the less critical of the two halves, I was going to measure everything I could with calipers and visually compare the two before trying it. I know with the WUR's that you can't swap around part numbers, but I have read you can adjust some to be within lotus spec, and I imagine some parts would be interchangeable between others. The saab FD is really a long shot, but it seems worth a peak to me.

I don't know how much travel the diaphragm has, but if it could seal at a slightly lower level you could dress the pitted face back to smooth and shiny. Perhaps a rotary tool (with a mandrel sized to fit in the cavity?) could clean up the face without changing the dimensions excessively?

Assuming the pits cause enough leakage to matter... I'm not a CIS guy, don't know the critical dimensions or pressure differentials across the seal.

Unobtainium parts lead to drastic measures- TIG in some new material to build it up and machine back to match the other chambers?

I was thinking someone out there with a milling machine probably could weld a little aluminum in there and machine it back to spec, but I really wouldn't know where to even look, and I have no idea what that would really cost.
I think any leaking into the chamber would have the biggest effect at low flow, like at idle. And as it is opened up it probably becomes negligible, which would explain why my flow at each injectors was close with the air plate fully open.

I really don't have a working understanding of what's going on inside though, Pretty much all my knowledge comes from this video

.

 

I don't know how much travel the diaphragm has, but if it could seal at a slightly lower level you could dress the pitted face back to smooth and shiny. Perhaps a rotary tool (with a mandrel sized to fit in the cavity?) could clean up the face without changing the dimensions excessively?

Assuming the pits cause enough leakage to matter... I'm not a CIS guy, don't know the critical dimensions or pressure differentials across the seal.

Unobtainium parts lead to drastic measures- TIG in some new material to build it up and machine back to match the other chambers?

 

My late 88 Esprit ran for 50K miles/49 months with Bosch CIS - in that time, I was always looking for spare parts, equivalent new parts, etc.

From my hazy memory since 2011, here's what I recall:

1. The Bosch Fuel Distributor is Lotus Esprit-specific - some Esprits were discovered to be running VW and Saab fuel distributors and nowhere near correct.
2. The Warm Up Regulators - there were 'hacks' to WURs that involved drilling holes into them and manually tweaking the heating elements, etc. There are also aftermarket WURs that are adjustable to work for Esprit, but require YOU to adjust accordingly
3. The Bosch CIS injectors - I have a post somewhere on this difficult-to-navigate site that mentions a Bosch catalog number for a VW injector that has same specifications as the Esprit injectors. But they miss the groove and the 'hat' for the injector.
FOUND IT - > http://www.lotustalk.com/forums/f164/bosch-0437502031-cis-injectors-max-flow-106047/#post1909753

4. Ebay has the rebuild kits that you have one - not many have used them but not much choice since few fuel distributors out there at all.
5. One forum member reported the original plastic fuel lines are very strong; he replaced his because of leaks, but mentioned to me that if it wasn't leaking, they seem very strong and would not have replaced them despite the nearly 30 year age. My experience is in line with this too.


So it sounds like you're on top with what's currently out there for your car.

I've gone one step further - The Lotus Forums were doing another 'last' buy circa 2014 (?) of Lotus parts being sold off. I have a factory brand new 88 Bosch CIS 'ECU' (the calculator-class electronic controller) that I kept for my late 88 Esprit (but applicable (I hope) to my 87). As I was formerly a daily driver of an 88 Esprit with Bosch CIS, you can understand why I did what I did.

You may want to try to put requests in the For Sale Wanted section for a fuel distributor. There are some folks that converted 87 and 88 Bosch CIS Esprits to MegaSquirt EFI and may have a fuel distributor lying about.

You'll unlikely find them in California because the smog requirements don't allow MegaSquirt - only original Bosch CIS is legal here.

Lastly, if you need a catalytic converters, there are CA CARB exempt catalytic converters )Magnaflow) still available for 4 cyl Esprits on eBay. Still a good but dwindling supply of Bosch CIS friendly parts for now.

 

My advice:
switch to ethanol free petrol and replace all silver-ish (aluminum casings) relays with reputable Bosch or Beuler parts. Replace "double contact" relays with 2x20A parts from... eBay.
FYI: Fuel Injection Corporation - Fuel Distributors

http://www.fuelinjectioncorp.com/testing.php
.

 

Well, some news on the other fuel distributors anyway.
I got both the Saab FD's (PN 0 438 100 058) I was talking about, they're not aluminum like the Esprit's and they use a metal diaphragm with different springs and plates.
Since the two halves were definitely incompatible I stuck an entire FD on the car just to see what it would do. The car idled pretty well at 1,000, but the second I touched the throttle it would die. I imagine it's got something to do with different air meters having different travel distances for different amounts of fuel.
I also bought a Mercedes FD (PN 0 438 101 012) and some 4 cyl turbo volvo one (PN 0 438 100 114) (which was interestingly a 6cyl FD, but only 4 of the chambers were machined.) Just to take a peak inside them.
None of the internals of either looked anything like the one on the esprit.

I'm going to replace relays to see if it makes a difference, and talk to Fuel Injection corp and see what they think about my FD.
There was a guy on ebay parting an 88 esprit a week or so ago, the entire engine was $2,000. I guess he sold everything, I was going to ask him about the FD if it were a CIS car but I can't find any of his listings in my view history.

 

Have you guys tried Larry at CIS Flowtech? 251 929 3771

He is the only US Bosch authorized repair in the US...he did my Porsche Bosch WUR (CIS element) and it is fantastic now....he does Fuel heads and can usually exchange/core if you want it quickly...I am not 100% poss if he does these parts but he may.....worth a shot.
If a fuel head has been Bosch rebuilt odds are he did it...Bosch Germany sends him fuel heads to rebuild.

 

If the diaphragm seals/meters on the center outlet to the injector, and if there are no passages to/from the annular area around the pitted face, does that face affect fuel metering? System pressure below the diaphragm, and fuel from the metering rod into the cavity surrounding the center outlet should seem to be doing the work and any fuel in the annular area would just be standing by. Maybe that face just keeps the diaphragm square to the injector outlet when closed, and the FD would be working OK as-is.

-still not a CIS guy, just curious and can't see the rest of the parts, but maybe the idle issue is something else that you can get parts for-

 

If he repairs/rebuilds Bosch parts he may have some parts or be able to modify something to make it work for you.
David Teitelbaum