What causes richness

[Redlyne_mr2]

Im experiencing ignition break up at higher RPMs, I'm wondering what causes this? I was at around 13.5 psi, upped the boost and didnt make anymore power because of the igntion breakup. It looks as if my coolant temps are dropping as well during boost which means bad temp sensor.

Here is what I am currently doing to try and fix the issue.
- Replace densor platinum plugs gapped at about .035 with ngk iridums gapped at .028
- Replace coolant temp sensor

Any other suggestions? It's a gen 3 3sgte so it's a map based system.

I was also running on the stock ecu at the time.

thanks

[crxcel]

what kind of gas are you running? I was runing Mohawk 91 and soon as i turned up the boost it gave me issues. I have changed to shell and now it seems to be clearing up. Also whats your a/f in boost?

[Mr_ET]

What kind of shape is your ignition system in? Plug wires good, distributor? If I remember you're not making crazy power anyway so it sounds like it's ignition related.

Where the old plugs fouled or very white at the tip?


No seriously now richness is caused by hard work and perseverance;)

[ercchry]

Originally posted by Mr_ET
No seriously now richness is caused by hard work and perseverance;)

:rofl: i was thinking the samething


with my car running 12psi over 5k it would sound like it was missing and be really rough, i changed the plugs and it was fine after

[Redlyne_mr2]

Originally posted by Mr_ET
What kind of shape is your ignition system in? Plug wires good, distributor? If I remember you're not making crazy power anyway so it sounds like it's ignition related.

Where the old plugs fouled or very white at the tip?


No seriously now richness is caused by hard work and perseverance;)
All ignition components were brand new, plugs looked a bit black .. no white at all. The ignition system is good for around 500hp so I should be seeing any issues, I put down 285whp at 13psi... once I upped it to 16 psi I made less hp. I aint rich I just floss alot.

Im really thinking it was the plugs.. but we will see.. again the temp sensor could be the issue as well if the car is running cold all the time.

[ercchry]

hmm what size turbo? maybe you have reached its max?

[Redlyne_mr2]

Originally posted by ercchry
hmm what size turbo? maybe you have reached its max?
It should still be able to go up to 17psi.. it's a Blitz KKK turbo.. k26 or k27.. dont know all the specs on it unfortunately...its similar in size and spool to a t3/t4..so I should be good for 350-400whp.

[benyl]

You sure you don't have a boost leak?

[Supa Dexta]

A few things;

what were the plugs? gap should be right on, but sometimes iridiums cause issues, and regular old ngks work wonders.

Cooling during boost can be headgasket troubles, any loss of coolant, or pushing coolant into the over flow?

What was the wideband saying? Not hitting fuel cut are you? I know you said richness, but I didn't see mention of wideband readings.

[962 kid]

Originally posted by benyl
You sure you don't have a boost leak?

wouldn't cause richness on a MAP based system. Ryan, what are you using for fuel management?

[Redlyne_mr2]

Originally posted by 962 kid


wouldn't cause richness on a MAP based system. Ryan, what are you using for fuel management?
I had the stock ecu hooked up for this run..wanted to try and max it out before hooking up the pfc but that didnt happen.. it was running big rich from 5500rpm on..

[Redlyne_mr2]

Originally posted by Supa Dexta
A few things;

what were the plugs? gap should be right on, but sometimes iridiums cause issues, and regular old ngks work wonders.

Cooling during boost can be headgasket troubles, any loss of coolant, or pushing coolant into the over flow?

What was the wideband saying? Not hitting fuel cut are you? I know you said richness, but I didn't see mention of wideband readings.
hmm.. for some reason I didnt think a bad HG would cause cooling during boost.. hope thats not the issue. Fuel cut isnt until 17psi so no issues there... from what I can tell no loss of coolant, Ill verify tonight. Wideband was saying rich..

[dj_honda]

are temp sensors expensive? if you are running rich it would make sense that your engine run cooler.

that gap seems big for boost, but i don't know what the norm is for mr2s....i run .028 gap on my turbo honda and i run upwards of 16psi. so i would change the plugs first.

last but not least, i think you should get your car tuned and not run stock ecu.

[Tripz]

Try to lower the gap on your plugs. I was breaking up on the upper rpm range as well, and when I lowered the gap with copper plugs...it ran much smoother. Also try a colder plug?

[Supa Dexta]

He said he's at .28, thats fine for him. I wouldn't run iridium's myself though.

[m10-power]

What is 'big rich' over 5500rpms mean :dunno: 10:1 :dunno:

Could be too rich to fire off properly

My richness comes from good investing :rofl:

[Kavy]

I saw this thread and came here for a 89coupe joke.

I was sadly let down.

I 3rd the comment on staying away from Iridiums.

Temp sensor sounds right but the breaking up would come sooner would it not?

[dblpostwhore]

no one is questioning the tune? who tuned it? and why is it dumping fuel.

post up your dyno maps most intrested in your fuel curve.

are you running a wideband or just an expensive lightshow?

[dawson13]

my friends rb26 had problems running rich we changed out injectors and it brought it down
(factory - factory swap)

[Redlyne_mr2]

hmm what were the issues with the injectors?

[stevo 27]

ryan how rich is rich 10:1, 9:1??

get rid of the iridiums my trac ran like shit with them they foul up after the first start up pretty much:thumbsdow

do you have an afpr or is it the stock one or ats's juiced one?

injectors stock 540cc?