BringIT

I'm getting detonation and need some ideas on what may be causing it..
JRSC 6psi stock b18c1 motor
dsm 450's
190lph pump
bkr7e plugs
Techtom tuned.

When I unplug the o2 sensor everything is perfect no detonation.. drove around for 3 days without the o2 plugged in and no problems. So I thought my o2 is leaning me out.. so I swapped it with a new o2 and it still detonates.

Plugs were replaced less than 5000kms

Bit of detonation on plug 3

BringIT

forgot to mention that I brought the car to my tuner because I thought the tune was messed up. We hooked up his laptop to do some runs.. wide band o2 etc.. and could not for the life of me repeat the detonation.. once I put my oem o2 back in, there was slight detonation.

this is what led to thinking the o2 was going.. but it's not.

Also, I only use 94 octane.. that's the highest I can get.. car was tuned for 94.
Thought it may have been bad gas.. but this is like the 6th tank from various sources..

MachAF

retard your timing a bit.

What engine management are you using?

BringIT

Techtom custom tuned.

I spent 4hrs on the dyno, partial throttle and wot tuned. My tuner doesn't think it's the map.. since it's perfect without the o2.. I kept dragging up and down the street and not a hint of detonation.. his wide band o2 shows good a/f ..

anything else to try? don't really want to mess with the map unless there's nothing else to check..

Jim Truett

Pull some timing. At your boost level I wouldn't tune a daily driver for the highest octane gas you can find. Go one step down for safety. That would only cost a few HP for a huge increase in reliability.

BringIT

Maybe what I'm looking for is an explaination why there isn't any detonation when the o2 is unplugged..

Chris F

Your engine will go into limp/safe mode with no o2 sensor. Rich and retarded.

Maybe you're tuning with hot air, and on the street it gets hotter and runs leaner?

-Chris

Chris F

Oh yeah, your car won't use o2 sensor readings at WOT anyway, so it likely isn't related to the sensor if you have problems at WOT.

BringIT

my car doesn't go into safe mode with the o2 unplugged.. its very strong.. dunno if it's suppose to go into limp mode but mine doesn't seem to.. vtec kicks in as usual.. and as a matter of fact it still took out a s2k last night easily..

the detonation seems to be happening at partial throttle .. in 2 spots..
3rd gear .. 70-90km/hr (3/4 throttle)

and

4th gear partial throttle (3/4 throttle) gradually accelerating from 80km/hr to 120km/hr

once I pass 120.. it's perfect again..

without the o2 in.. it sweeps over the whole area without any detonation .. I could romp on it all I want without any detonation???

i took the car out 3 times tonight with the o2 plugged in and it happens in the same spot each time.. then I unplugged it and nothing..

this is very odd..

Jim Truett

Sounds like VSS based fuel correction to me. With the o2 sensor disconnected the ECU goes into open loop, and it runs strictly off of the programming. You will need to pull some timing or correct your maps with a 3rd and 4th gear pull on the dyno.

BringIT

anyone else have any suggestions?
I drove into work this morning with the o2 unplugged.. the car feels great.. I'm thinking of just keeping it off.. shouldn't hurt anything since it's running from the ecu program anyways. Just the annoying light.

mrx

Hi,

i have the same problem, when driving in Closed Loop the ecu leans the mixture out when driving in part throttle (but with boost) on higher rpms (i.e. highway)

when i hit boost the mixture leans out a bit until the ecu goes in open loop... this can cause detonations when the timing if too much on the limit... on openloop this problem don't occure becuase not leaning out...

when you are at your tuner and hoocked up the wideband, do you still connected the stock o2 to the ecu or was it disconnected?

try to tune the car with the stock o2 enabled with a wideband or try to retard the igniton a bit (i.e. 2°) to avoid detonation when leaning out... but i think first method is better because retarding don't fix the leaning out problem which can be a problem too...

maybe i can tell you more when i see your maps (fuel and ignition) what ECU do you have?

Greets
Malte.

BringIT

Hi Malte,

My car is a 98 obd2 Integra GSR. I'm running a obd1 p28. I believe the base map is from an obd1 gsr.

At the tuners he removes my o2 and uses his wideband so that we can get an accurate A/F reading. I spoke to him today and he said we can back the timing a bit.. but I will lose power.

How do you keep the stock o2 and use a wideband o2?

He said we really have two options.. either back the timing to lose power .. or just drive in open loop. He said if we back the timing.. the ecu may still lean out the car under boost.

I would love to show you the maps but I don't have them. I can see if I can get the techtom file.

It's good to know I'm not the only one experiencing these problems..

KingDsi

Like everyone says, the car is running in open loop without an O2. The one thing with the JRSC is tip in detonation. The A/F usually is to lean for the compressed air initially. This usually happens when you go to the bigger injectors and remove the JR FMU and stock injectors. I had the same problem. I used to have the JR MAP controller with the stock injectors and JR FMU, no detonation. As soon as I went with the bigger injectors, problem. Even when I went with the P28 chipped for boost, I still had a problem. With good timing and fuel maps, I still had that minor detonation. I just upped the fuel a little and a slight retard.
What happens with the O2 disconnected obviously is it runs rich, good and rich, before boost. This conquers the detonation because it is RICH going into boost. You will probably see crappy, crappy gas mileage.

mrx

Hallo,

some widebands have the ability to make an 1volt output for the ecu... this can be put into the original ecu and the ecu runs in open loop with the wideband sensor.

the other way to get a wideband under closed loop is to drill a secons o2 sensor hole in the downpipe.

your tuner is right, wen you retard the timing you will loose power... but in your situation i take 10hp less to get rid of the detonations ;-)

the ther way is to tune the basemap so that the leanout of the closed loop is not so big (to do this make the basemap in the detonation area a lot richer) but this destroy the consistancy of the maps and the driveability will be not so good...

for me i don't find a solution until now... i drive with a good tuned basemap in open loop and have a great gas milage (aprox.: 8-9 Liter per 100km when crousing... i think thats good for a B16 in open loop... in closed loop i have 0,5liter less but thats ok for me... because now i'am not running lean under boost.

As far as i have a solution i will post it to you ;-)

Hope you can finde one for you too

Greets
Malte.

BringIT

I'm going to drive around for awhile in open loop first to see how bad the milage really is. If it's not too far off, then I'm going to do stay in OL..

Probably just take out the o2 sensor and find something to block the bung so that my sensor doesn't go bad from running a bit rich.

Last resort will be to back out the timing..

The things we do for more power..

BringIT

Hi Malte,

My car is a 98 obd2 Integra GSR. I'm running a obd1 p28. I believe the base map is from an obd1 gsr.

At the tuners he removes my o2 and uses his wideband so that we can get an accurate A/F reading. I spoke to him today and he said we can back the timing a bit.. but I will lose power.

How do you keep the stock o2 and use a wideband o2?

He said we really have two options.. either back the timing to lose power .. or just drive in open loop. He said if we back the timing.. the ecu may still lean out the car under boost.

I would love to show you the maps but I don't have them. I can see if I can get the techtom file.

It's good to know I'm not the only one experiencing these problems..