code 45 , rich exhaust

[wardy2]

Hi Gents
My car is an Se to which I fitted mountain chip and closed loop modification.
Sometimes after a run when the engine is hot I have difficulty starting and have very rough running with missfire.
If I let the car cool down it starts perfectly and will run ok for many miles with good power and good fuel consumption.
suspecting it was a fuel supply problem I checked out the pump flow ( ok at 3ltr per min ), fitted a new filter and pressure regulator.
This problem has been ongoing for a long time but may only occur after 500 or 600 miles and then go away again.
When the above happens I never got an engine alarm but just returning from a 600 mile trip I momenteraly had an engine check alarm and at the next engine stop The problem was there. The code was 45 -- rich exhaust.
Has anyone had a similar problem after going closed loop? --- I would welcome any opinions on other possible causes -- intermittant CAS signal --- fuel injector problems ---
etc
Thanks
Wardy 2

[Brit-Car-Nut]

The most common culprit I have seen from watching posts about others with similar issues is the injectors are very suspect. Early on, most get theirs cleaned and tested and that often helps for a while, but eventually they buy replacements which seem to end their problems.

I am assuming that you have verified that the coils and Ignition Control Module are functioning correctly.

If one injector has been "breaking down", if often drags the other one it is paired with down too.

Both the ignition (spark) and injection (squirt) fire Two Cylinders at each cycle. The ignition fires 1- 4 and 2 - 3 while the injectors squirt 1- 3 and 2- 4.

If you can identify which cylinder is lame, you can try swapping the plug wires at the coil and see if the misfire moves to the paired cylinder, then you know you have a failing coil.

If you disconnect one injector at a time, you might see an improvement in the misfire as a bad injector activating coil will shunt BOTH injectors.

If you decide to replace the injectors, they have become expensive again now that the surplus stocks have been liquidated. You can get an affordable set from a seller on eBay:

http://www.ebay.com/itm/191637275013

If you want the retaining clips, you will need to make sure you request them when you order the injectors otherwise they just send the four injectors.

Good luck.

[lotusflasherman]

If you are running rich it doesn't make much sense to me to be cleaning injectors to get more fuel to go in ...

I'd check that the Coolant Temperature Sensor is giving the correct info to the ECU for correct decisions on mixture to be made. At cold it should be about 100k ohms and it reduces to be about 70 ohms at hot (130°C).
If it's not getting down to low values below 100 ohm the ECU might be thinking the engine is cooler than it is...

My car would start and run fine for about 2 miles and them start coughing and shortly after splutter to a stop due to over rich mixture (Code 45) . Wouldn't start again until engine had got cold again. Found CTS had lost it's ability to give low readings.

[Brit-Car-Nut]

My injectors were never closing completely (car sat for 5 years after wreck), so mixture was always rich. I sent them off to be cleaned and even though I cleaned out the rest of the fuel system (I even washed the inside of the tank with solvent and then soap & water), the injectors sometimes still were over-injecting, so I replaced them and it has been fine since then.

Testing the temp sensor is definitely a good thing to do first. The M100 sensor is the same as the one used on the Fiero and other GM cars (25036979) and is less expensive than the M100 version (A100E6373S).

I think there is another Lotus sensor (Esprit?) that is also less expensive: A910E6928F Lotus price book says it is now discontinued but it fit the Esprit (1996-2004), so looking for that might be less costly.

[wardy2]

Hi again
I have removed the temp sender and carried out a resistance check against temperature all the way through the range.
It was good and followed the "book" values.
The fault is very intermittent and can disappear for months. When it does ocur it has not been in a situation where I can do much investigation ie just boarded a ferry or in busy traffic and so I have not been able to much fault finding.
BCT -- thank you for the info re the injectors-- after reading about the possibility of one dodgy injector pulling down its mate I have ordered a set from the site you mentioned.
Its possible that one injector coil is breaking down after heat soak.
Regards
Wardy2

[lotusflasherman]

If you are running closed loop there is also the possibility that the O2 sensor is starting to play up..

[HJ2]

Indeed!
No exhaust leaks by any chance?

[wardy2]

Hi Brit Car Nut,

Just wanted to tell you my father has been a little quiet the forum because last Monday he suffered a stroke.

He's recovering now and making good progress.

Dad says he followed your advice and will be having fitted new cam angle sensor and fuel injectors.

Myself (his son Philip and a friend) we be fitted these over the coming weeks.

Thanks for your help we will keep your posted!

Philip

[HJ2]

All the best to your dad!

[Brit-Car-Nut]

Likewise: I wish your DAD AND you the best and don't be afraid to ask questions on LEC if you run into anything you don't understand.

Use the link at the bottom of my post to get to the manuals for your M100.