Stalling at idle

[Malakaone]

Hey everyone.

I am just looking for some reassurance, but since I installed my header, high flow cat, and exhaust I got a CEL. To eliminate the CEL I used this product:

http://bigdaddiesgarage.com/angled-cel-fix.html

It got rid of the CEL perfectly, but I am experience some occasional stalling at idle. For instance after cruising around at 50 MPH and I cost to a light, at the light and fully stopped the car's oil pressure will dip and the engine shuts off.

I figure it is the ECU trying to find the sweet spot especially with the eliminator. Your thoughts?

Thanks!

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[Stink Star]

i doubt its due to the eliminator as the 2nd o2 sensor doesnt really control the car, it just monitors the converter operation. more likely is that the engine just isnt used to the free flow of the exhaust and cant compensate. sounds like you may need a tune

 

[Malakaone]

Kind of figured something like that. Since the ECU "learn" on my car do you think it may fix itself? I don't think anyone in our area is a tuning expert for Elise's.

BTW thanks!

 

[Stink Star]

honestly i dont know. does it still use a toyota ecu? sounds weird but you might wanna find some scion guys and see what they say

 

[Malakaone]

It uses a Lotus specific ECU.

Thanks for the help.

 

[redevo58]

It uses a Lotus specific ECU.

Thanks for the help.

Did you disconnect the battery to reset the fuel trims?

 

[Malakaone]

No I did not. I'll try that. Thanks Dan.

 

[Turbocharged400sbc]

is the vehicle equipped with a low oil pressure Fuel pump kill?

clean maf thermisters, clean iac pintle/port/throttle blade...it may be coked up enoughthat the iac cant open far enough for the airflow to run the engine at decel

 

[GTwolf]

If you can't find a tuner anywhere around check out a lotus board and see who'se out there. Maybe someone can send you a tuned ECU and you can just send back your core.

 

[bluzohh6]

Actually don't listen to ANYONE who tells you the secondary O2 doesn't do anything. My secondary o2 on my Type R has been a thorn in my side ever since I eliminated my cats. Secondary o2 does more than you think.

 

[Mook]

i havent run a secondary o2 on ANY of my cars with the exception of the mazda. never a problem.

 

[bluzohh6]

you know the issues ive had with secondary o2

 

[Malakaone]

How does the ECU know it is providing the correct A/F without using both O2 sensors, just trying to learn.

 

[Stink Star]

It uses the first one to run the car. The 2nd one only lets the computer know how the cat is performing. Look at cars made before 1996, they don't even have post cat O2 sensors.

 

[KagA152]

downstream O2 has an influence on fuel trims, the computer wants to do whatever it can to lower emissions by keeping the cat at the right temp.

 

[Stink Star]

Then how do cars run with the rear O2's eliminated?

 

[KagA152]

it either sets a code and runs off the upstream, or an emulator sets it at .5v or whatever the PCM wants to be happy

 

[Stink Star]

so lets say my car has a P0420 code set, why doesn't it die at idle like this lotus? and if im using a simulator or have it tuned out completely, why doesn't my car die or idle badly?

 

[HILROD]

Some manufacturers use the rear O2 differently. Most GM cars can easily have the cats and the rear O2s removed easily, others not so much. It's all in the tune.

 

[Stink Star]

I did some research and found that the rear o2 in a GM car contributes less than 1% to fuel trims. In fact the highestvi could find was Toyota at less than 3%

 

[KagA152]

i never said it would make it die, i said it influences fuel trims. like redevo said it would be a good idea to reset keep alive memory of whatever term lotus/toyota uses, the two combined could cause a stall. im not going to get in a pissing match with you because i know youre a gm tech. otherwise like james said check the intake for leaks post maf and vacuum.

the best thing to do would get a scan tool so you can monitor whats going on when it dies

 

[CrunkMaro]

is the vehicle equipped with a low oil pressure Fuel pump kill?

clean maf thermisters, clean iac pintle/port/throttle blade...it may be coked up enoughthat the iac cant open far enough for the airflow to run the engine at decel

this guys put in the only worthwhile suggestions.

do you have a k/n filter?
that oil effs up maf sensors
and your maf is fucking finnicky.
it should read 4.5ish
bet you at warmup its right around 3
check into that.


and that thread you posted in is a good start.
seems like a tune is key.

 

[Malakaone]

I do not have a KN filter.

I disconnected the battery for awhile yesterday and did not have any issues today. Is it possible that as oil temperature rises (thereby reducing oil pressure) could have the vehicle stall? Whenever the stall would happen the oil temperature was higher. I did not get the oil temperature that high today.

 

[Turbocharged400sbc]

y/m/m/engine? ill see what i can find diagram wise towards a low oil pressure FP interlock circuit

 

[Malakaone]

^^^ Huh? That is definitely above my head.

2007/1.8L 2ZZGE Engine