O2 sensor problem?

I have a 2000 JRSC'd GSR with Hondata 2b. Lately I've been having this weird problem where my car will suddenly bog and my Autometer A/F gauge will go all funny. Instead of having a few LED's lit and bouncing back and forth, almost the gauge will be lit up and bouncing.

I changed my sparkplugs, and filled my tank of gas but neither helped. It's been progressively getting worse. The problem started last weekend then went away and came back this weekend.

Thanks.

You should go to a dyno and have ur fuel settings checked. A/F ratio bouncing around at a consistent throttle is either a sign of poor tuning or bad 02 sensors.

I've been using the same tune for about a year now. It was tuned on a dyno with a wideband. Is it safe to say that it is the O2 sensor then?

Is there any reason that my tune would start failing now?

Could be fuel pressure or bad injector. Either of these going bad will set off the O2 sensor.

u might be losing compression on one of the cylinders too. I've heard (not sure if this is true) that B-series motors number 3 cylinder has a history of losing compression.

My fuel pressure seems pretty stable. There's no drop when my car starts to bog or anything.

Would my compression just spontaneously fail? I mean I wasn't pushing my car hard or anything. Just cruising on the highway at about 60mph.

Here's a really stupid question. Say it was my compression failing. What do I do now? Do I need a rebuild?

Thanks.

Could a crapped out cat converter cause these problems? I've had a history of problems with my aftermarket cat.

Is it possible that the A/F gauge connections for the oxygen sensor are causing a problem for the ECU? This "intermittent" problem sounds electrical in nature.

It seems that several people are having stutter/hesitation problems with Hondata in certain applications. Myself included.

Have a look at this:

http://hondata.com/bb/viewtopic.php?t=745

Actually I think the problem may be with my fuel pump. I had the o2 sensor replaced on saturday and that didn't work. On Sunday my car ran perfectly. No hesitation or anything or the sort. Today my car ran fine too until I filled up on gas. After filling up and starting the car I could immediately tell the problem was back again. I car idled rough and lags pretty much all of the time.

Does this sound like a fuel pump problem or another part of the fuel system?

Thanks

I kind of found some reasons for my part throttle hesitation with my Hondata. I was getting a hesitation between 3000-4000 rpm, just before boost, and I thought it was fueling being a problem. It turns out it was only part of the problem. My idle for some reason is very lean and the ECU would register 0% long term fuel trim after an hour commute in mixed traffic, but according to the datalog, it began a slow ramping up of the long term fuel trim driving the last couple of miles to work off the freeway, stop lights galore. It finally leveled off at +20%!!!. Then looking at the low speed ignition table, I noticed the hesitation would occur when the trace was going through a rat's nest of curves in the region of 750 mBar absolute. Also, the injector coefficient was wrong at 0.454 for 240cc to 440cc swaps, and when I reset it to 0.545, the idle stabilized at around 14.2-15.0 a/f, vs the estimated (narrow band) 15.5-16.9. The hesitation was greatly reduced at these settings.

but I've been using the same tune for over a year now and I've only started having the problem lately.

I can't say definitively but I think most fuel pump problems are either when they are completely shot or when the cannot keep up with the power demands. I've never heard of one where it causes idle problems because they either pump or they don't. How about the fuel pressure regulator? Incorrect fuel pressure from a defective regulator could cause some of the problems you described. Can you datalog when it's running badly? It would help in diagnosing the problem and in helping to show whether it's ignition or fuel related.

I datalogged it. I don't have anywhere to post it though. If you give me your e-mail I can give it to you that way.

Thanks

Send it to me at [email protected]. Also, if you remember when in the timeline the problem was occurring, it would help so I won't have to view the entire log.

I didn't get to look at it yet -- my grandmother's funeral was last weekend... I'll look at it tonight...

I noticed the variations in the graphs after 2 min of driving as you mentioned (about the 4:30 mark) but I'm more concerned about the O2A Long Term behavior. That's the point at which the O2A Long Term begins to ramp up. It's showing over +15% at the end of the graph, which means you're running quite lean overall. I can't say what would be causing the lean running if it was fine for over a year but the lean running does seem to be contributing to the hesitation problem. You might want to check out the electrical connections throughout the car, especially the oxygen sensor connections in the harness.

This is embarassing but I found the problem. 2 of the injector clips were slightly loose. I just fully seated them again and everything is good again.

Thanks for all your help.