No definative results Mark, the clutch just gave up so im zedless again I will be back onto this thread in a few months though
base idle hey i had the same problem it turned out to be the base idle on the IACV valve was set way too low disonnect the connector and see what the z revs at with it off should be approx 750rpm in Neutral. if not then adjust the screw until it is this fixed my stalling problem at low speed and when on high boost and backing off..
Totally unrelated. He's not stalling on back-off he's dropping all cylinders under positive pressure aka...BOOST. Rollin, the fuel cut-out or "air-flow limit" is part of the ecu, and should be changed whenever a tune is done. Here's an cut and paste from ztech's ecu tuning page. Here's the link as well http://www.ztechz.net/id10.html If you want I can send you a tune in a *bin file that you can get an electrical engineer or someone in your neck of the woods to burn onto a chip which will eliminate it as an issue, I can make one here, I unfortunately am away for work for the next week so I can't burn one for you.
Thanks for all your insight andy. Is there someone i can send my ECU to that could tell me if it has been disabled?
I spoke to a EFI guru today and he also favoured the diea of reaching a maximum load value in the ecu. He suggested that i introduce some air into the intake downstream of the AFM to allow unmetered air into the system. This will allow the motor to take in the air it needs without all of it going through the AFM. Ill do this with a wideband or the exhaust gas machine connected so dont worry about the possible lean mixture. This should prove or disprove the theory. As for why it didnt do it 3 months ago? maybe the colder ambient air temps we have now?
Sounds dangerous to me, un-metered air is just not cool, and not constant either. Take out your chip, take it to an electrical engineer and ask them to rip it to a file and email to me. You'll know then if your hitting the air-flow limit.
If yours is a stock TT manual BIN file, I have one here Andy can edit I got out of my stock Nissan ECU. OR I have a BIN of a TUNE from Top secret I got out of a TOP Secret ECU last week. The MAPS look better up the top end. BUT dude you have to be careful here cause if your injectors are maxing out. You will fry your engine pushing it to 18 PSI ( or anywhere above 14 PSI actually) I had a guy here last week who ws running 18 PSI on stock injectors. I put consult on and the injectors where pegged out at 13 PSI. Told him to turn it down. He came back 3 weeks later with 555's to put in. I did a compression test and the engine was stuffed. 5 cylinders at 125 and 1 at 60. He hammered it at 18 PSI for 2 years. That is what comes from running lean and not having enough fuel.
Yeah I've got the stock files here, but i think he has a chipped ecu so to be sure It'd be best to have a look and see if there's anything funky going on, otherwise I'd just write another one with the air-flow limit increased, and a few other tweaks and get him to test it. 2 years on maxed out injectors?! I would have given him 2 days.
Any electrical engineer firm should be able to do it....theoretically, but most likely another member in brisvegas should be able to do it. Theres normally a few floating around in each city who can do it. Either that or send it to ZRATED or MYSELF, catch is you'll be without a zed for a week or so unless you just trust us to write a tweaked tune for you.
More information. Swapped out a working CAS, AFM and another 2 PTU's . repeatedly cleaned the connection and no change unfortunately. i removed the boost controller and ran on 6 psi. The problem inly occurs quite rarely now. But it does still happen if you load it up in 2nd on the brake . This leads me to belive that it is not the maximum load thing in the ECU.
How bout fuel quality? You got plenty of fuel volume (as per gauge), what about its quality? Seems to be one of the few culprits left... existing tank fuel contaminated with water or other crap and/or low octane could present similar results. Worth a shot to drain contents into a container (for possible reuse) and fill up a small amount of V-Power or Ultimate at a high volume turnover servo...? (Apologies if this has been suggested and eliminated already)
This is the fix for the air flow limiter nail, from ztz. 7960 796F Air Flow Limiter This is the Air Flow Limiter aka the Boost Cut J and is involved with the VQ Table. It is one the simplest and most valuable areas to adjust in the ecu. Lets first take a look at the values in 7960-7961 which are 80 and 80. These values are also read as word data so they are seen a one four digit value, 8080hex. When enough air passes by the MAF sensor - to send a 4.08v signal - which references the 52nd block in the VQ Table - which value is 8219hex the air flow limit is exceeded. The ecu will now take steps to prevent the engine from sucking in any more air. That stops our car from accelerating which trips our fun limiter causing us to cuss and possibly our wallets to bleed money profusely. One of the problems with add-on AFCs and boost controllers is that somewhere along the yellow brick road to making hp you will hit the boost cut and no piggy back system can cure this. This IMHO is the biggest reason for having the ecu tuned. Here is the fix - By setting all the values to FFFF the problem is solved and the Boost Cut has left the building, thankyouverymuch.
more info After 4 hours of diagnostic work with a knowledgeable mechanic i have one more clue. By disconnecting the tps or removing it and manually winding it to max then connecting it, the car runs real well, its very strong and rarely breaks down. The confusing thing is that doing a snap test on the potentiometer side, it reads fine, no breaks in the voltage signal.
Are the pin outs correct on the 3 wires ? I'd tell you mine but they have been soldered on to the tps so i dont know if they are right :bash:
more clues Its definately spark cut. Would a badly faulty coilpack cause the ecu to shit itself ? because its not just cutting one coil, its all of em. then it will miss badly on one, but it clears before i can isolate which one is cactus.
