AFR pegs lean when trying to get going..

markiii · August 5, 2008, 05:12

so this is now twice you've mocked up teyh CC and twice that afterwards you have had this issue

during mock up how much did you remove? everything to teh TB? or just to teh MAF?

aaronjb · August 5, 2008, 09:24

Everything to the TB - from turbo outlet to throttle body - was off.

markiii · August 5, 2008, 09:50

since your going to put teh cc on soon, I would install it now and leave it just without water, it won;t hurt

see if teh problem is still there

if not it proves it is with the hoses/clamps or pipe

at least that way we are fixing from teh point you will be using anyway

aaronjb · August 5, 2008, 10:43

Surely that's just going to be complicating matters, though s:? :? s:?

I've already replaced the two lengths of silicone between the MAF and TB with new stuff, and had the clamps off and on a thousand times.. nothing makes any difference.

I'll try the stock airbox, stock injectors and stock ECU if/when it stops raining.. if that works.. meh, I'll be tempted to put the stock exhaust manifold and stock exhaust back on, I think.

loadswine · August 5, 2008, 11:36

I doubt I can offer much except for support mate, but you don't have a bov on yet do you? Just wondered.
Don't give up on it Aaron, its a cracking install so far and I bet its something that you find and go ....... "D'oh!"

aaronjb · August 5, 2008, 11:47

Nope, no BOV yet..

It seems for all the world like a vac leak.. and yet that should affect idle much more than it does (as we proved yesterday - pull the 3mm wastegate hose off and the idle jumps up appreciably).

I'm completely stumped.. and I've never been stumped by a car before s:(

s:(

I was just looking at S2k's on Autotrader, shame they're still so expensive s:? :? s:?

Anonymous · August 5, 2008, 13:08

A bad injector also sounds reasonable. One could have just gone bad. "Less fuel" would behave just like "more air". You seem to have covered all of the easy to check possibilities for "more air".

Your first post covered just about everything it could possibly, by the way. I can hear my brake booster working through the firewall. I didn't even know I had one before making an access panel and removing the padding back there. Step on the brake (at least when going fast) and there's a hiss.

If you want to get your car running, couldn't you just bump up the values in the base map?

aaronjb · August 5, 2008, 13:31

Thing is, if it was an injector, I'd expect to be going really, really lean under boost too - and it's not s:? :? s:?

I did try bumping the base map - in fact, I told the PFC it had stock 260cc injectors instead of the 65% sizing and it is still lean when you're trying to get on the throttle, which is weird.. that should be dumping in some 35% more fuel and it's still not right.

markiii · August 5, 2008, 16:29

I'd be suspecting a dodgy wideband at this point if you had 02 feedback turned on

Anonymous · August 5, 2008, 21:55

What makes no sense to me is it not getting richer when you bump the base map. You added to the cells, wrote the map, and there was not change in AFR? If so, it sure looks like one or more injectors isn't responding to SMALL changes yet responds OK to LARGE changes.... is this possible? Do dodgy injectors do that? Maybe. I'd just swap 'em out.

Tem · August 5, 2008, 23:21

Quote from: "Beanie"What makes no sense to me is it not getting richer when you bump the base map. You added to the cells, wrote the map, and there was not change in AFR? If so, it sure looks like one or more injectors isn't responding to SMALL changes yet responds OK to LARGE changes.... is this possible? Do dodgy injectors do that? Maybe. I'd just swap 'em out.

Injectors can fail in many ways and one of them if getting "slower", so a short pulse might not open it anymore.

But I can't imagine that happening to all 4 injectors at once. s:shock: :shock: s:shock:

Aaron, if you still have your stock injectors, you could try them. After that you might wanna try the stock MAF pipe with the stock ECU. If it's ok, then swap in the PFC with default map and see if that's ok. Then swap the injectors back. Then the MAF. You're bound to catch the issue.

aaronjb · August 5, 2008, 23:45

I struggle to imagine all the injectors going at once too - plus it was fine for 100 miles down to my folks before the issue started, and I'd expect them to go out more gradually than that.

I could see them being OK at the start of the drive, and crapping out by the end of it.. but not fine, stop the car, fiddle with the pipework, start the car BAM issue s:? :? s:?

I triple checked the PCV bung (pre throttle place) today and it's definitely sealing s:? :? s:? So that only leaves.. the krankvents, maybe, as a potential air leak, and/or the brake booster.

Then yep, I'll have to try and revert back to stock then slowly go back to how it is now.

A pain in the ass s:(

s:( I suspect I may end up buying a runaround while I try to fix this.

Anonymous · August 6, 2008, 00:34

If only one injector was bad it would affect the AFR. It still seems like the most logical explanaion is a vacuum leak even though you've checked all that, particularly since you were changing parts around before it happened. Good luck.

ChrisGB · August 6, 2008, 01:35

To eliminate air leaks form vacuum ancillaries and venting, I would just plug all the vacuum takeoffs for testing purposes.

The more I read here, the more I think the issue is possibly not an air leak. You have tried bumping up the base map up but that makes no difference. So my question is:

Does the PFC run in closed loop mode at any time? If so, is the PFC getting the correct information about the fuelling outcome?

So as Mark suggested, is the Wideband Fubared? On the other hand, if the wideband is telling the PFC that the mixture is EDIT : Lean, why is the PFC not dumping extra fuel in to compensate?

Good luck!

Chris

aaronjb · August 6, 2008, 08:26

Quote from: "ChrisGB"Does the PFC run in closed loop mode at any time? If so, is the PFC getting the correct information about the fuelling outcome?

Nope, it's in open loop 100% of the time (O2 feedback is disabled)

Tem · August 6, 2008, 10:28

Quote from: "aaronjb"Then yep, I'll have to try and revert back to stock then slowly go back to how it is now.

A pain in the ass s:( s:(

It's not as bad as it sounds. s;)

s;)

Injectors are easy, you just need to remove the plastic cover, if you still have it on and then the fuel rail has only two bolts. Should take few mins.

ECU...depends what you have blocking it. I don't have the doors, nor the "floor", so it's bloody quick to swap the 4 connectors.

Intake, just leave the turbo and the suction side as it is. You only need the 90degree part from the TB and then the upper part of the filter box, where the MAF is. If you're going to drive on dusty roads, might wanna do the lower part of the filter box too and the filter, but no need to bolt them down anyway.

You can do it all in 30 mins, if you just get to it. s;)

s;)

aaronjb · August 6, 2008, 10:51

I'll be trying it out tonight - though I'm not sure I'd want to drive anywhere with the turbo blowing out to fresh air.. I'd want to disconnect the actuator or wire the wastegate open, at least (shame it's on the back of the turbo on the TS, or that would be easy too).

Having fat hands doesn't help s:lol: :lol: s:lol:

aaronjb · August 6, 2008, 20:18

What's that Sherlock Holmes quote? When you eliminate all of the likely possibilities, the remainder, no matter how unlikely, must be the reason.. or something like that.

Well, I disconnected the hose that runs from intake manifold to KrankVent tonight, and stuffed a bolt down the hose (the only one I had to hand was some 6 inches long s:lol: :lol: s:lol: ), tightened the clamp and started the car (bearing in mind the map I had loaded was richened up some 30% to try and fix it).

It was so rich, it was off the scale of the XD-16...

So I loaded the normal map and bam, nice normal idle.

Went for a drive down the road (left my front door wide open! s:oops: :oops: s:oops: ) and there are a couple of lean spots that could be either the bolt not sealing properly or Stu's MAF having a slightly different voltage curve to mine, but... it cruised just fine - off boost was OK, on boost was OK, idle was OK.

So, I think I might have found the culprit - the only things in that vac circuit are (in order) IM -> KrankVent -> catch can -> PCV valve. One of those must have sprung a leak... I'm betting KV or PCV, as the problem changes with engine RPM..

markiii · August 6, 2008, 20:23

doubt it's the pcv as it's designed to open to allow crankcase to vent

however no try removing one item at a time and see which fits

ChrisGB · August 6, 2008, 22:42

Quote from: "ChrisGB"Hmm, rich under boost, lean under vacuum? First thing to do is plug all the vacuum and breather / PCV takeoffs to see if you get any improvement.

Start with the obvious and easy bits!

Chris

Anonymous · August 7, 2008, 01:44

That beats a cracked intake manifold any day. I got where you were coming from looking at other cars. I did the same thing after my cooling system sprang a leak, which was right on the heels of an alternator failure. Nursing an "old" car back to health isn't my cup of tea, either. But luckily with these Toyotas, problems are few and far between.

Hope you're back on the road soon.

Anonymous · August 7, 2008, 16:08

Glad you're 99% of the way there now mate s:bounce: :bounce: s:bounce:

aaronjb · August 7, 2008, 16:37

Cheers guys - going to continue with the lifts to & from work till the weekend, then hack at it and see what happens..

It's got two chances s;)

s;)

markiii · August 7, 2008, 16:41

so is it running enough to get it to mine on saturday?

aaronjb · August 8, 2008, 11:54

I don't know yet - I wouldn't want to drive it with it flipping lean like it is at the moment, so I need to try swapping the original MAF back in and re-blocking the vac hose with something a little more suitable (rather than the spare 6" long idler pully bolt that's now flapping around the engine bay).. Hopefully I can do that tonight and it'll be OK for saturday morning.

I'll let you know.