 Re: Engine is gradually getting richer over time |
| yea, this issue is usefull
ty TS |
| |
| Re: Engine is gradually getting richer over time |
Very good and informative thread!
I will try to remember this when I am unlucky enough to experience similar issues.  |
| |
| Re: Engine is gradually getting richer over time |
| I found the problem.
I went over all the vacuum lines from the throttle bodies to the manifold pressure sensor & spotted a pin hole. So I ran the engine while watching the data & then covered the hole with my finger & sure enough the AFR went up.
You would think that a vacuum leak would cause a lean condition, but because there was a vacuum drop getting through to the IAP sensor it was causing the ECU to think the engine was under more load than it was & thus richening the mixture (using fueling from the wrong IAP cells).
When I looked at the data originally I obviously didn't look close enough at the IAP readings because under the same conditions after replacing the hose the IAP readings showed approx 5-7inches more vacuum at cruise.
The leak had obviously been getting worse over a period of time.
Lesson learned - don't just assume the data is good because it looks ok at a glance. Check the raw numbers. If I compared the specific IAP values between recent logs & earlier logs like I had with the AFR readings I could have saved myself a bit of time.
I hope this info may be of use to others in the future. |
| |
| Re: Engine is gradually getting richer over time |
| Have you checked your valves? |
| |
| Engine is gradually getting richer over time |
| Any advice anyone could offer would be greatly appreciated.
I have a K7 GSXR750 that is gradually getting richer over time. I've not changed the tune at all during this time. I don't know why it's doing this.
Does any one have any ideas what might be going on?
Symptoms:
Bike is starting to surge slightly at idle.
Getting approx 30-40kms less mileage per tank.
AFR ratio in the logs has dropped
This has gradually got worse over the last 2 months. There hasn't been one definite point where it's happened. The logs show it slowly getting worse over time.
On average AFR has dropped by about 1.5:1, so gone from 13:1 down to 11.5:1 across the rev range, not just idle.
Nothing to do with filtering as I can see it clearly using data viewer.
If it were getting leaner I could understand, but seems weird that it would get richer. TPS signal is good, so are STPS, ECT, atmospheric & intake manifold pressure readings. Logbox won't show IAT readings so I don't know what it's at, but doubt it would cause that much of a difference.
The only things that I would think that would cause this are:
1. blocked air filter (I've tested without the filter in)
2. blocked exhaust (the exhaust is definitely not blocked)
3. leaking injector (all 4 spark plugs are equally carboned up)
4. excessive blow-by (have checked & also noticed still rich without airbox on)
5. fuel pressure too high (haven't test yet because I don't have a gauge), but I would think if there was a problem with the fuel pressure regulator getting stuck it would have happened all of a sudden instead of slowly getting worse.
I wouldn't think valve clearances tightening up could affect AFR.
Has anybody got an ideas on what could be happening? |
| |
| |
| View Topic on the Woolich Racing Forums |