Hey Guys,

So the past two times I started my car my gauge shows the car running lean and while it is heating up the engine shakes and it feel as if the car is going to turn off. After about 5 minutes, the gauge goes up in the stoich region where it should be and the car is idling fine.

What can be the problem?


thanks

 

lean numbers? wideband or narrowband?

 

Not sure what the numbers are. My A/f gauge is with colors. After I drive it around it seems fine and it is on the border of stoich and rich at a red light.

 

What are the mods on the car? It may just need some work on the water temp correction tables as its warming up.

 

that sounds like a narrowband , please do your car and yourself a favor and get rid of it asap and get a wideband in its place

Now like was stated before what mods are on the car . during startup , the accelerated warmup / air pump feeds air into the cats in order to heat them up quickly . during this time that air messes with air fuel ratios ,

So has the car ALWAYS done this ? or is this a new thing ?

I ask because I've read about it , But I've never ran a stock ecu , an air pump , or a cat for that matter .

 

I am not sure exactly what mods are done on the car because I have had it for about a month now. The engine shaking just started a couple of days ago. I asked around and I was told by a rotary mechanic that it is normal for it to show lean since the car is not at operating temp. He said that after i start driving it around then I will see it in the rich section. That is exactly what happened, but I am still concerned about the engine shaking and the engine almost turning off.

I just had a compression test done (110 each rotor), spark plugs changed, radiator flush done, brake and clutch fluid changed, and sea foamed the engine.

Tem120: Will the wideband sensor go into the same hole as the narrowband or do I need to make another hole somewhere for the wideband?

Thanks guys

 

same hole but the car may not run correctly IF it is using the O2 sensor for closed loop driving . and you replace it with a wideband sensor . if your downpipe has 2 holes already 1 is being used for hte narrowband , and the other for the O2 sensor , then you can replace the narrowband sensor with a wideband and everything will be fine .

Also it would be good to knwo what is done , because tomany flow mods intake / exhaust and tomuch air may be flowing for the stock ECU to handle correctly .

do you have an aftermarket ECU??

also the air pump . when you start the car at first does the car rev to about 3000 for a few seconds? or does it just idle normally?

 

if the wideband can emulate a narrowband signal you can rewire the signal wire to the original engine harness and have both closed loop and a wideband you can read, such as the innovate LC-1.

 

I did not know this , that is pretty awesome.

 

Is your airpump still connected?

-Geoff

 

Engine sounds healthy. Why don't you take it over to your rotary mechanic to have him check out the other issues?

Who is your rotary mechanic?

 

Okay, if you're running the stock ECU and air pump, that makes this a bit easier to diagnose. Attempt to pull some fault codes and see what you get.

FD's usually run RICH upon startup, as the ECU takes the place of a conventional choke, intentionally raising cold start rpm, and adding more fuel until the stock coolant temp sensor registers 60C. Then the cold start richness should begin to go away and the idle rpm will begin to come back down.

Yours is not doing this. There is a signal somewhere that is not within spec. If you attempt to pull some fault codes, you should narrow down which sensor is the culprit or is failing. My bet, based on your description, is the coolant temp sensor is having issues. They are at that age now, where 20 years is about their useful service life used up.

Please pull the codes, verify you have read them correctly and then post back here with what you found.

Alternatively if you do not have a stock ECU but a Power FC, you cannot pull codes. You will need to navigate to the 'Sensor Check' screen of the Power FC hand controller and verify that all sensors are present and accounted for. Post back with what you find. Taking it to a mechanic for these steps should not be necessary. You're a new owner, so no better time than the present to learn.

 

i read the op and no other posts so if this has already been mentioned then forgive me...

widebands need time to warm up before they start reading properly. i forget where i read that but when i was putting my uego in my crx, that little bit of information was brought up in my research. i dont know what to tell you about the shakes youre getting but as far as the readings on your wideband, thats how it goes.