Map Sensor Car Running Way Too Rich !

[West]

Hi,

I've got an EP82 Toyota starlet. Like most imported cars, these things run rich straight out of factory. I recently wack a SS mainfold, SR20 turbo in it. Car runs beautiful on boost but off boost is an issue......

It runs way too rich off boost (from 2000rpm to 3500rpm) to a point where it created mis-fire sometime. I've checked everything, thermal switch works, watertemp sensor works, O2 sensor works, engine light don't come up, change sparkies, change igintion leads.......ect still won't fix the problem.

Long shot here on this forums but someone might have an answer,

Thanks

[Rolls]

Get an aftermarket ECU and tune it properly? Of course its not going to run properly. It would be expecting the tiny turbo to be on boost much sooner so thats probably why its overfueling down low. Could be running lean on boost as well. Seriously get it tuned with a copgy back fuel controller or a full ecu asap before you break it.

Edited October 20, 2009 by Rolls

[West]

Get an aftermarket ECU and tune it properly? Of course its not going to run properly. It would be expecting the tiny turbo to be on boost much sooner so thats probably why its overfueling down low. Could be running lean on boost as well. Seriously get it tuned with a copgy back fuel controller or a full ecu asap before you break it.

Thanks,

What i thought but i also thought that it should be able to sense boost pressure, when boost kick in and such but i guess not . SAFC it is.

[Rolls]

Thanks,

What i thought but i also thought that it should be able to sense boost pressure, when boost kick in and such but i guess not . SAFC it is.

It will but who knows what the max level the stock map sensor can handle? Its probably reaching load points its not meant to and running wrong size injectors etc. I'd be betting the stock computer is just going wtf and not knowing what to do.

[West]

I'm running standard injectors still but bigger ones is on the card. Thanks for your help, cheers.

[Akis]

I had a Starlet once, and you do not need a remap, the map sensor reads until 1,25 bar. Stock injectors will make 200hp for sure.

Check your vaccum hoses, it is VERY possible tha this is the cause.

[Rolls]

I had a Starlet once, and you do not need a remap, the map sensor reads until 1,25 bar. Stock injectors will make 200hp for sure.

Check your vaccum hoses, it is VERY possible tha this is the cause.

Just because it can sense that much doesn't mean it knows what to do with the values. How do we know what the manafactures had in mind when they programmed the computer? If it exceeds load cells and the max pressure it expects to run it could just dump fuel and retard timing all over the board for a preset amount of time. There's no way to know.

[West]

I had a Starlet once, and you do not need a remap, the map sensor reads until 1,25 bar. Stock injectors will make 200hp for sure.

Check your vaccum hoses, it is VERY possible tha this is the cause.

Yeah, i've been told about Vacum hoses, has done lots of checking but not on the dyno so can't really tell while its under pressure.

[MBS206]

Turbo A and Turbo B can both be at the same boost pressure... The difference is, they're flowing different amounts of air.

This is why the tune is up the shit.

Go and get it tuned. Nothing else to be said.

[West]

Although giving a tune is critical, it shouldn't be doing what its' doing at all. My friend has the same set up, except for a TD04 instead of a T25 like mine and his car is running fine. Its gotta be one of the stupid sensors that fail.

[TiTAN]

cars with map sensors work on volumetric efficiency, any changes you make that effect that (ie changing the turbo) can mess up the tune massively.

[T04GTR]

because the factory tuning thinks its got more air coming in from the standard turbs. only way to fix it is re tune.

[West]

Cheers!

[West]

Guys,

I did a stupid test , ran the car with the O2 sensor un-plug and guess what...........it ran faultlessly lol. Does that mean the O2 sensor shat itself?

[Rolls]

Guys,

I did a stupid test , ran the car with the O2 sensor un-plug and guess what...........it ran faultlessly lol. Does that mean the O2 sensor shat itself?

Quite likely, I would still put it on a dyno, you don't want to pop your motor because its pinging/running lean/rich. Only cost you $50 or so.

[West]

Quite likely, I would still put it on a dyno, you don't want to pop your motor because its pinging/running lean/rich. Only cost you $50 or so.

Oh yeah i'm still going to run it on a dyno first just to be safe but i think at least i've got to the bottom of it.....phew.

[Akis]

Guys it was making problems OFF BOOST, there was no problem when on boost, nothing to do with tune when off boost. 4EFTE's are very rich from the factory they handle EXTREMELY well at 0.6 boost with OEM setup, Trust me i had one with 315hp and searched a lot.

[West]

Cheers guys, thanks for your help !