Grandpa's old M100 (White)

[TRAK]

Sorry for going MIA, I have completed some projects.

Since my last post I have done a smoke test on the engine and fixed a few leaks. I'm surprised the engine was getting any air after seeing how much smoke came out of the tube connecting the air filter box to the turbo. Tuga had the right idea about the bugger of a tube underneath the plenum, thankfully my hands were small enough to fix it.
My MAP sensor readings are still showing 1.75v which tells me there is still a leak somewhere that I have not yet found.

I replaced the ECTS with a new one and am getting much better coolant scans and a better idle, but the idle is still not perfect. Will update post with ES charts later tonight. EDIT: While there still is the early coolant dip, I’m not too worried about this with 110F summer right around the corner. Very pleased to see more stable readings compared to my previous scans.

My O2 sensor is very degraded, the new one (BOSCH 15701, direct replacement with what I removed) arrives on 5/2.
-Sidenote: Before I experienced the rough idle, I used Gumout Foaming Intake Valve and Turbo cleaner. In hindsight, this might have damaged the O2 sensor although I don't have any scans prior to the cleaning to compare.

Once the O2 sensor comes in, I'm hoping it will fix the idle issue since I haven't seen smoke coming from any other ports.

I disconnected the EGR tube since it is not needed in my situation. I'm curious if anybody has capped off the EGR as a simple delete solution? Could the lean reading on the MAP be from the EGR being disconnected and uncapped?

[chrism]

TRAK, recently I thought my Denso O2 sensor was knackered - it turned out to be a disconnect in the m/plug behind the wheel arch - and I blew carb cleaner in it, soaked it in white spirit overnight, scrubbed it with a toothbrush etc...absolutely abused it...

I tried it back in the car later on, when I'd fixed the circuit break (and bought a new sensor), and it worked absolutely fine. In fact, I've now put it back in to see how quickly it warms up (cos I found the Denso to be a significantly higher resistance than the Walker and Bosch 15701 that I've measured) and it takes only ~10/20s longer depending on the ambient temp. My thoughts are higher ohms = less current = less power consumed and a saving of about 14W continuous from the alternator output (~1/2) and possibly less wear on something that's a 'blighter' to service.

(Yeah I know radio, lights etc eat into this but... )

So try cleaning up your old sensor and give it whirl with EScan. If it's okay it can be kept as a spare and help a fellow LEC-er out of trouble, perhaps?

[TRAK]

Oh very interesting! I will definitely try this while I wait for the new one to arrive.

I’m happy to help out any LEC-ers! I have a respectable inventory of interior bolts and those pesky red door lock tabs. Keep in mind I am located in Nevada, USA so especially happy to help lower the shipping costs for anyone on this side of the pond. The Lotus Club out here hasn’t shown any activity since 2014, although I have driven past a few strangers looking very excited to see an M100 on the road.

Sidenote: When I first started working on these cars I drove it to the Lotus store here in Las Vegas and noticed quite a few employees looking from the second floor window. While they couldn’t help me, the parts manager was very pleased to see the Elan in person for the first time.

[Tuga2112]

you said you still have vacum leaks. the o2 sensor may help. but any vacum leak still present will continue to affect the idle. i would suggest another smoke test and plug all the leaks you can find.

i need a smoke tester myself need to eventually look into making or buying one

[TRAK]

Chrism: I tried cleaning the old O2, admittedly not with as much effort as you did, and still found that the sensor is degraded. I'm happy to send this "degraded" O2 to anyone in need, as long as they take care of the shipping cost.

Tuga: My friend has a standard fog machine from a party store and we've used it to test a handful of different makes and models without any issues. I'm sure you've seen the clips on YouTube of people using a cigar to smoke their engine Personally, I feel the residue from the cigar would be more detrimental than the fog machine (if any), not to mention a waste of a good stick!

While I wait for my friend to bring over the smoke machine, I checked that all the vacuum hoses were connected (minus EGR), took the O2 (Bosch 15701) from my Red (not starting at the moment) and installed it in the White to test it. Red's O2 is working correctly, aside from the expected signs of a vacuum leak. I believe that all of the hoses are properly connected although, am looking to replace some old hoses for a better seal.

I have a set of fuel injectors arriving this week (purchased on fleabay from big dawg diesel) https://www.ebay.com/itm/116085849998which will hopefully solve the issue of the rough idle, as long as I can truly fix this vacuum leak...

Do you all think the uncapped EGR could be causing a leak/high (1.75v) reading from the MAP?

[RobertC]

Trak

It's been a while since this thread was first started but there is a mention at the top about the fuel pipe from the pump to the filter.
If you've not fixed / sorted this yet the following may be of interest

See 'Pump-to-filter fuel pipe' in 'Elan Products For Sale (new and used products either custom made or upgraded versions of stock items) - Elan Products for Sale (New Products for Sale)'.