Thanks Simmo. I only have NA FICD units though, so don't know how I will go in that regard. If I get a chance today, I'll set it to 800 and see what happens.
nah its the actual idle unit that bolts onto the plenum the square area that is directly behind the plenum is different !
I dont know m8, you state the pump is starting and stopping. Thats got warning bells on it to begin with. Did you put a test light on the pump terminals to double check that the pump was getting constant power while this activity was going on? Might not be the pump at all see? Could be something to do with the fuel pump driver circuit in the ECU...... Anyway, bygones. Assuming the ignition timing is correct, Idle hunting is where there is a fuelling issue and almost exclusively a lean condition. Engine rpm falls below the "recovery" threshold and the ecu opens one of the fidle's to "catch" the engine. A primitive "stall saver". The additional air overcomes the original stumble and the rpm "flares", the fidle valve closes and the cycle repeats. Now, you say you have fitted different injectors and a "tuned" ECU. The "problem" is most likely right in front of you. So, to start with, what are your slow run AFR's. This is the first and easiest indication. Its been mentioned that the problem worsens as it warm up (leans off from cold run enrichment) and pulling the temp sensor wire will improve things somewhat. Thats a straight up indication that the slow run mixture is too lean. Too rich will settle into a rough and if excessive, smoky idle if the idle speed is adjusted and the car will be very prone to stopping the colder it is. Stick a WBo2 sensor up its bum to confirm. Dont have one? What the hell are you doing playing with tunes and injectors if you cant provide some evidence of your changes would be my first question!!! Its a crucial and indispensable tuning tool if you are going to go down the path you are going. Think what happens if this say 5% lean error extends to moderate cruise and you end up frying a valve on the 100k drive to the tuner??? E
Wow, I'm surprised that you can be so helpful and condescending at the same time. Anyway, to answer each of your points... No test light. Didn't consider it, but not a bad idea. I don't know anything about Air Fuel Ratio's. I don't know anything about tunes and tuning. The tune that's in there was provided as-is. It's a working tune from somebody else's car that just so happens to have the same size injectors. I also don't have Nistune. A friend came around with a laptop and put the tune on for me. No, don't have a Wideband O2 sensor either. (Why would I, taking the above points into consideration) I would go to a local tuner except for one thing - there isn't one. I live 65 Km's south of the Perth CBD and PZP is about another 40 Km's north of that. I asked for advice previously about a tuner down this way, but with comments like (Go here. No, don't go there, he's crap), where did that leave me? I have a couple of things to check, and then I will revisit your info. Thanks.
Well Tass is 100% correct. I have had a few people rock up with modded ECU's complaining about idle issues. to find they have stock injectors and modded ecu's. I think you have Consult? If you enter the area which lets you adjust timing. You will find you can also adjust fuel by about +/-20%. I suspect if you start fiddling with that adjustment you will find the idle smooths right out which means your ECU aint right for your injectors. Big injectors and stock ECU is enrichened by quite a lot = idle problems. Adjusted ecu and stock injectiors is leaned by quite a lot = idle problems Getting this correct will smooth a crap idle right out, not to mention save your engine from expiring. BTW the fact your fuel pump stops and starts is pretty alarming. Hope the bypass fixed that.
TT ECU with Nistune board. 740 cc injectors Stock FPR TT pump 740 cc tune GT28 Turbo's Edit: bypass made no difference Base idle runs quite smooth in comparison, with no hunting
did you swap the temp sensor, it sends a signal for the fuel mixers doesn't it? & can give bad idles.
Condecending..???, Hawhawhaw! Youd know if I was being condecending m8. It wont come thinly veiled to be interpreted in different ways. it will come straight between the eyes, mod or not. HOWEVER, I should have added a few strategic smillies in there!!!! Perhaps exclamation marks were not sufficient and this: might have helped. No need to get all pious on me. Here to help Ok. Now, 740cc injectors, roughly double stock size. Good for about 600 flywheel horsepower. Pretty large M8, and tuning resolution becomes an issue at low to moderate dwell times. Factor in dead time correction (latency) hopefully the new tune accounts for this but its on ly relevant if the injectors are EXACTLY the same as what was specified for the original tune. For some reason I was under the impression your fiddling with some smaller 450 odd cc's or whatever. So your going for roughly double stock power then? Otherwise why so large? Just creates tuning issues down low that take forever to tune out. This is why you aim for a specific HP output and work backwards to the injectors. Thing here is that a 5% error on a small injector results in a small flow error, 5% error on 740's results in double the flow error for the same tune K. What I said about fuelling issues and engine damage sharpens in focus by quite a bit. AFR (Air Fuel Ratio) is just that a ratio of air an fuel. 14.7 is most efficient for petrol but not for best power. You need to get down to about high 12's to 13 or so for powah. Its traditional to go lower on boosted engines. However increased fuel consumption and powah loss is the result. The lower the ratio, the richer the mixture is. Lambda is exactly the same except the representation is different. Lambda is calculated as a ratio of ratios or simply the current measured afr and 14.7 expressed as a ratio of its own. Your playing with some fairly large clobber. Take care with it now. E
I found and fixed a bunch of boost leaks, and it's idling much better. I know there is one more big leak, and that it has something to do with the passenger side turbo coupler (the one deep down), but I couldn't work it out with the light I had this afternoon. I should get a chance to look at it tomorrow, when I will pull that side apart and try and work out what is going wrong with that rubber coupler. It's either that or there something wrong with that turbo inlet. Pretty hard to exactly work out where the air is coming from. But it's getting closer :zlove: :br:
I decided on 740's for a couple of reasons * They were available cheaply * They were bigger than stock * I wanted bigger than stock because of the bigger turbos, and didn't want to lean it out * I wanted more power than stock because my 370 has more power than a stock TT, and it didn't make sense for my daily to have more power than my project/weekend car. I 'spoke' to Danny at Garage 101 today about getting it tuned - I have no intention of doing that myself. Maybe next week or early the week after (need the exhaust hangers put on, and then the front bar needs to be fixed up first) I also found out that my injector latency should be set to around 98mS, whereas it's probably around 75mS now. That isn't doing my AFR any favours (apparently), so once these things are all done, it should be sweet. Thanks for the advice so far, and a BIG thanks to EzzupTurbo for lending me his boost leak tester.
Yeah, it is a lot. I'm not making it up though, I got the info off twinturbo.net, specifically for the deatschwerks 740cc injectors.
Had a good look, but I'm no closer to finding it. I thought I had it when I saw the nipple on the accordion pipe, and put another cable tie on it, but no, it made no difference. I'll have to continue tomorrow.
