O2 sensor heater reads 7.5 volts / emission failed

[tomatcbl]

Great detective work - hope to post my elanscan this weekend

I had read some reports that Isuzu alternators were bigger than the Lotus ones
and would not fit. I bought a 91 impulse RS alternator from Autozone. They
had it in stock at my local store. Looking at them side by side they seemed
the same size though I did not measure them. Putting it in was no easy task.
I took off the engine mount and jacked the engine around a bit to get it in.
but the hard part is getting the cables reconnected! I'd say a timing belt is
an easier job than an alternator on a M100.

When you have the OEM alternator this is not entirely (but almost!) true
The Isuzu one is only 6 mm bigger and won't get past the suspension parts (unless one does what you did )

The OEM goes back with a little encouraging, but without the need to remove the engine support


Good that you solved the voltage problem!
Regulator packs tend to go a little early due to the hot & tight space where the alternator sits.

[Andrew99]

Just got back from my emissions test... FAILED

Was: HC 1.13 limit 1.00
CO 13.90 12.00
NOX 3.61 2.50

And now after all the work I've done:

new O2 sensor
new spark plug wires
checked spark plugs for gap and consistent color
new thermostat
cleaned throttle body and Seafoamed intake
ran a half tank of gas with a bottle of Seafoam in it
checked system for vacuum leaks
Checked PVC valve
Changed oil and washed K & N air filter
adjusted base timing
Checked ERG valve
AND swapped the alternator

My latest was:

Was: HC 1.01 limit 1.00
CO 16.35 12.00
NOX 3.34 2.50

virtually unchanged despite my efforts

The plugs and coil packs were swapped to solve a misfire years back that leaves injectors.
Should I blind swap with new and retest emissions or send them off to get measured/cleaned?

Andrew

[tomatcbl]

Sorry to hear of emission failure - I had hoped the alternator would have solved it. In MD if you spend enough on repairs ($400 I think, including $150 allowance for your own labour if you do it yourself) you get an exemption from emissions. That's what happened to me first time through.

Have sent you elanscan file directly as I couldn't upload here for some reason.

[Andrew99]

Update on my Emissions:

Removed injectors and had local shop test and clean them.

Shop said that the injectors tested fine before reconditioning them, but that
the connectors were likely corroded. I did notice that if I wiggles the injector
connector the idle would change. After cleaning the connectors with a small file
and applying some dielectric gel the car runs great while wiggling the injector
connectors.

Replaced the coil packs.

Re-soldered the Hall Effect (the Charlie way).

Checked Base Timing again. It still jumps off of 16deg a little bit, but I've measured it
many times over the years and have not seem it more stable than now.

Now Emissions are worse:

Was: HC 2.03 limit 1.00
CO 20.43 12.00
NOX 3.85 2.50

Since about every ignition part has been swapped. I'm thinking the Cat might be clogged.
Though I read somewhere that these cars can pass Emissions with the Cats removed.
So I'm not sure what to do next...

Andrew

[Brit-Car-Nut]

Andrew: Have you verified your fuel pressure? Too much pressure will wreak havoc and the early OBD can't do much to control it. Shortening the injector pulses has a limit and from what I understand the tables don't allow big adjustments. If you need them, I can supply you a new Factory Cat and I have a couple of used Pre-Cats available too.

I am fortunate that NC doesn't emmision test andy cars before OBD2, so the M100 will never be tested for that.

LGM was recently working on a fuel pressure gauge connection in the fuel rail that will make pressure testing easier than the stupid method Lotus proposes. You might send her a PM and see how far she has gotten on that.

Keep us posted on your repairs and results.

[Andrew99]

Emissions update:

Fuel Pressure Regulator:

Since there was no easy way to check the fuel pressure, I just swapped the regulator anyway since the part is cheap.
Getting the old one off was impossible "for me" without completely mangling it. Still after the swap the car runs the
same.

Installed Main Cat:

I tested the main cat with the Temp Test (IN temp is supposed to be 100 deg F lower than OUT).
The temps were the same. I cut the Cat out and it was an empty shell. Years ago I gutted the Pre cat for more
boost thinking that the Main Cat was whole. I guess Ortenburger (the original owner) gutted the main Cat
before I bought it from him. So I know that some S2's can pass MOT without Cats but I'm not sure if
a California spec M100 can pass a US style rolling Dyno Emissions test without Cats.

Has anyone done it?

Anyway with a Cat I passed Emissions easily:

HC 0.51 limit 1.00
CO 3.59 12.00
NOX 1.02 2.50

FINALLY!!!

[Brit-Car-Nut]

Thanks for the update! Sorry about the fuel pressure regulator, but I have seen several that have been way off.

[tomatcbl]

Not clear from your post - did you pass emissions before you reinstalled the main cat (suggesting it was the fuel pressure regulator) or after (suggesting it was the cat).

Emissions update:

Fuel Pressure Regulator:

Since there was no easy way to check the fuel pressure, I just swapped the regulator anyway since the part is cheap.
Getting the old one off was impossible "for me" without completely mangling it. Still after the swap the car runs the
same.

Installed Main Cat:

I tested the main cat with the Temp Test (IN temp is supposed to be 100 deg F lower than OUT).
The temps were the same. I cut the Cat out and it was an empty shell. Years ago I gutted the Pre cat for more
boost thinking that the Main Cat was whole. I guess Ortenburger (the original owner) gutted the main Cat
before I bought it from him. So I know that some S2's can pass MOT without Cats but I'm not sure if
a California spec M100 can pass a US style rolling Dyno Emissions test without Cats.

Has anyone done it?

Anyway with a Cat I passed Emissions easily:

HC 0.51 limit 1.00
CO 3.59 12.00
NOX 1.02 2.50

FINALLY!!!

[Andrew99]

I passed after installing a main Cat.

[DeanG]

Great that you passed emissions and have sweet running car again. Owning an M100 in the USA often feels like AZ has some great M100 roads. Enjoy.

[tomatcbl]

So my elan failed emissions in MD again this spring, despite lots of time trying to solve the issue with the system not going into closed loop mode. I followed Andrew99's example and took it to an exhaust place to have them replace the cat. The old cat was empty! New cat installed and passed emissions

[Andrew99]

After I had my cat installed and had passed the emissions test. I had planned to go back to the muffler shop and have them flange in a straight pipe so I could bolt the cat in and out for testing. Well it's been over 2 years now and I'm still running the cat and I don't notice a lack of boost. Or miss the noise.

Andrew