Yet another problem.....

[Bahnstormer]

So, another week another problem with the PS13.

This is an odd one, so bear with me if the explanation doesn't quite make sense.....

My journey home usually involves sitting in very slow moving/stationary traffic. The last two days the car has happily been rolling along in first until we come to a complete stop. When I try to pull away again, the revs bounce between idle (around 750-800 revs) and 2000 revs. It does this even if my foot is planted to the floor. If I take my foot off the throttle it idles perfectly. The only way I can get it moving again is to limp the car to the side of the road, then switch off and wait a couple of minutes before restarting. It doesn't do it every time I try to pull away, just randomly (It did it twice this evening in the space of about 10 minutes).

Any ideas on this? I'm thinking maybe TPS is on it's way out?

[Dastardly]

I don't know much about SR but can you not pull codes out Ecu like you can on Ca?

[Bahnstormer]

I think you can normally yes, but my ECU is chipped which I've heard (could be wrong though) can stop the LED functioning properly?

[skyshack]

Massive air leak?

2000rpm is ECU limp home mode limit (CA), that could point to AFM plug having a poor connection but also to massive air leak. Yes I've driven off having forgotten to clamp up all the inlet hoses. Oddest was the "pop off valve", hose to IC wasn't tight, hit boost it expanded and leaked, engine tries to cut out until rpm 2000rpm, sudden loss of boost allowed hose to seal and then it surged away only to cut as it regained boost.

I thought all SR's had 16 bit ECU with Consult.

[raddy.]

So, another week another problem with the PS13.

This is an odd one, so bear with me if the explanation doesn't quite make sense.....

My journey home usually involves sitting in very slow moving/stationary traffic. The last two days the car has happily been rolling along in first until we come to a complete stop. When I try to pull away again, the revs bounce between idle (around 750-800 revs) and 2000 revs. It does this even if my foot is planted to the floor. If I take my foot off the throttle it idles perfectly. The only way I can get it moving again is to limp the car to the side of the road, then switch off and wait a couple of minutes before restarting. It doesn't do it every time I try to pull away, just randomly (It did it twice this evening in the space of about 10 minutes).

Any ideas on this? I'm thinking maybe TPS is on it's way out?

I would say that it looks like intermittent AFM failure, as 2000rpm rev limit is applied in case of AFM casue DTC error in the ECU... Check AFM connector and cables for loose contact, moisture, oxidation etc...can be also AFM failing itself... TPS should not cause that dramatic effects.

[sx rider]

coilpack on its way out perhaps.

[green_rs13]

AFM trouble for sure.

take it off and spray the element with either carb cleaner/brake cleaner/electrical cleaner.

[R3K1355]

Do the revs bounce around by themselves or is it under control of the throttle.
2000rpm limit is the AFM failure mode, but you can dive the car perfectly find between idle and 2000rpm.

I managed to do a good half mile with my AFM disconnected without even noticing, the car drove perfectly normal.

[Bahnstormer]

The revs only bounce if my foot is on the throttle. It doesn't matter how much throttle I give it, it goes no higher than 2k and at a rate of about 1 bounce per second. The car will drive, but very very slowly and even when the car is moving the revs bounce. If I take my foot off the throttle it idles perfectly. I did wonder about an air leak, but surely it would do it all the time not just randomly? And it'll only do it if I've come to complete stop and then try to pull away again. I've checked the MAF plug and it's in securely, but I'll whip the MAF out later and make sure it all clean etc.

Thanks for the suggestions so far guys!

[Bahnstormer]

Just driven it home from work and it didn't miss a beat! I've managed to get out of work early tomorrow, so I'm going to inspect the plug and harness to make sure there are no breaks or other damage and check that the signal is reaching the ECU. I'll also pull the MAF and make sure it's clean, but thinking about it, I gave it a clean last week when I was having other problems with the car (which turned out to be unrelated to the MAF).

[skyshack]

So it's simply a failure to properly plug it in.

[green_rs13]

unplug it and see if it replicates the problem. then you will know the solution for when it plays up again!!!

[Bahnstormer]

So it's simply a failure to properly plug it in.

Not sure what you mean? It's always been plugged in properly, it just didn't play up today.

[Jonny Wilkinson]

If its not pushed fully home you'll get intermittent issues. That is what is being suggested.

If you've been messing with the MAF then not pushed home would be a good guess as to the cause.

[Bahnstormer]

Ah I see! It's definitely fully home, the first time it did it I unplugged it then pushed the plug on all the way until the little spring clip clicked. Drove it to work this morning and it was fine again, so I'll give it a once over when I get back and keep an eye on it.

[R3K1355]

Any noticeable corrosion on the pins or the socket on the plug?

[Bahnstormer]

No, none at all. I guess if it's not a wiring/plug problem then the MAF itself could be dying? For now though, it seems to be ok. Like I said, I'll check the harness etc over this evening and report back.