So clean, impressive work.
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Awesome quality build, looks factory. Whole car looks great!Comment
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this is how Nissan should have made these at the factory. well done on a tops car.
+many internets to youOriginally posted by RdynoOriginally posted by TripperComment
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hngh... +++Originally posted by psi999 View PostSo got this out onto the street this afternoon, ended up doing about 200km's of road tuning (in 30deg heat so about as hot as it'll ever see :D)
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With all this talk of 6-cylinder S15's I remembered I owned on as well :D
Over the past month myself and a mate have been tuning this up on the street, and in the process written a whole new VQ map for the MAF with great success.
But over the course of time had noticed that the timing tended to jump around a bit.... especially at idle. We put it down to the lumpy cams and low voltage to the MAF (pulls just over 0.80v at idle).... I had the guys at Nistune locate the 'low voltage AFM' setting in the ECU and had this added to the tunable parameters to the ECU.
This setting stock was set at 1.00v so for the most part at idle the ECU has been in semi limp mode.... This setting was changed to 0.70v and basically made no difference (other than running a tad leaner) - the timing was still inexplicably jumping around.
Running back to back logging we also noticed that the RPM also tended to jump around a little as well, we hadnt picked this up before.
So putting two and two together we went hunting for some type of electronic magnetic interface issue. Wires were moved around and items removed from around the magnetic ECU pickups. All made zero difference until i thought there may have been some issue around the braided clutch line running to my clutch slave cylinder.
Clutch slave removed the issue all but went away - this was able to be repeated by moving the slave cylinder in and out.... EMI issue it is!
So weather it is a faulty CAS or wiring it was decided to change both - CAS wired directly to the ECU and new sensor.
.... thinking i mustn't have been the only bloke to discover this issue before i then went to the web to confirm my thoughts, and found this:
350Z Crank Angle Signal Integrity
During the development of the APS Intercooled Twin Turbo High Output System, a problem was encountered with the tuning of the engine. The problem manifested itself as ignition timing scatter under conditions that were intermittent, transient and at times occurred for only fractions of a second. In other words, the ignition timing would vary in a manner that was inconsistent with the engine RPM and engine load - and was not repeatable under identical operating conditions. In addition, due to the short period of time when the issue presented itself, very difficult to diagnose. The problem never the less did continue to appear on the APS engineering vehicle from time to time.
Tests were also conducted on a number of other 350 Z vehicles and whilst it was never encountered on those vehicles, the intermittent and erratic nature of the problem made it impossible to replicate without sustained long term testing of those vehicles. That is not to say that the problem does not occur on other vehicles, but it was an issue that did need addressing.
APS embarked on an exhaustive testing and engineering program to identify the cause of the problem and then deliver a solution that would be cost effective and practical.
After a great deal of data logging of the variety of sensor signals leading to the engine management computer, it was noticed that the signal quality from the crank angle sensor at times became erratic. The crank angle sensor is a vital component that informs the engine management computer of the exact position of the engine crankshaft and is used throughout the engine management program to control a variety of functions - in particular the ignition timing (when each spark plugs fires to ignite the air/fuel mixture inside the combustion chamber).
When the signal from the crank angle sensor becomes erratic, so does the ignition timing (in addition to other functions).
Ignition timing is a vital tuning parameter particularly in forced induction applications. If the ignition timing becomes retarded from the optimum point, the engine will produce less power and torque. However, and most alarming is when the ignition timing becomes advanced from the optimum point, pre-ignition and detonation may occur. Detonation places extremely high loads upon a variety of engine components such as pistons, conrods, bearings etc and the chance of failure of each or all of those components becomes very high.
With the intermittent and erratic behaviour of the crank angle sensor signal, either scenario was possible.
The engineering process continued at APS and the entire crank angle sensor circuit was painstakingly checked and verified using a variety of sophisticated electronic testing equipment. The circuit was found to be quite robust and electrically sound, however it did become susceptible to electromagnetic interference commonly found in a modern motor vehicle.
The solution was relatively simple (all the best solutions are!) and involved amongst other things, replacing the existing cabling from the crank angle sensor with robust shielded cable (and effectively earthed).
The entire crank angle sensor solution is included with each APS Intercooled Turbo system complete with factory connectors for a truly plug-in application.
After long term and demanding testing of the APS Intercooled Turbo system with the crank angle sensor solution installed, we are pleased to report that the timing scatter problems experienced with the APS engineering vehicle have never again occurred. Nor have they on any of the other 350Z vehicles APS has tested since.
A final point to consider is that the timing scatter problem was only ever encountered on the APS engineering vehicle. It may indeed have been a problem on that vehicle only when used with a forced induction system. The problem may not be present on other 350Z vehicles with other forced induction systems, be they turbocharged or supercharged, however due to the intermittent and transient nature of the problem, APS was not prepared to take the risk of assuming that it was a one-off occurrence - hence inclusion of the APS solution with all APS 350Z Intercooled Turbo Systems.
(LOL at two useless shitcunts and no fancy testing equipment Vs APS 'exhaustive testing and engineering using a variety of sophisticated electronic testing equipment' :D)
New sensor on its way - hopefully once we have that nailed it'll be off to dyno.
...glad we found this before lunching a motor!Comment
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It's probably a lot more common than most people think. It's a massive deal in drag cars with 200 amp magnetos and the smallest thing can cause it (like a lead moving with the airflow over the car). PRICK to troubleshoot.Comment
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CAS failure is common on all Nissan of that age with 3 wire sensors. Last time I replaced one they had changed the sensor design completely. They are a proximity hall sensor, not a vr sensor.
The problem may be related to crank thrust also, something that the cima vq30 wouldn't have ever had to account for.David Fraser - Automotive Historian!
Originally posted by bigmuzComment
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Is this flood damaged yetComment
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updates statComment
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Well the 350Z CAS arrived – it didn’t fit. Slight difference in the casting of the VQ30 and 35 in that area…. So back to square one.Originally posted by denmaster View Post
Managed to pick up a couple of spare sensors and chucked one in, it seemed to resolve the issue - took the car for a drive with the logger connected and it didn’t seem to throw any weird readings.
But this is where the good times stopped.
Trying to sort out hot start has been very trying, the car seems to start OK with around 2ms injector cold but on hot start I can’t get it to inject less than 4.5ms due to load somehow skipping halfway across the map and referencing those values…. Doesn’t seem to have this problem at cold start (Confirmed with logger).
4ms wets the spark plugs almost immediately (1000cc injectors, twin pumps and 45psi base pressure)
So pulled out all the ‘hot start’ offset values and still couldn’t seem to get this value down.
I thought it may have been the MAF (as it’s a massive thing so thought it could have been feeding faulty figures to the ECU) so connected the stock MAF, still the same…. Even with no MAF connected, same load skip issue.
So there is obviously a setting that I am unable to change (or has yet to be found in the ECU). Have had a couple of people look at it with me as well and all commented that this has to be the case – it’s just not logical what its doing now.
…. And unfortunately while testing my random timing / RPM issue re-appeared, engine stopped logger reporting the ECU is sensing 100, 50, 125rpm etc…. Problems are starting to stack.
So had a bit of a think about it for a week and have made the decision to fix my problems with the following:
Hopefully it proves to be the right decision
Was originally going to source a Platinum Sprint 500 but a Sport 1000 came up at the right price and will run my 4-wire idle solenoid, log internally and in general will also provide a much better solution to my thermofan switching… Also may look at setting the 2nd pump to run on load. Switch off on light loads.
I’m very disappointed that this isn’t tuned yet, has been mind fucking me for the past 6 weeks :DComment
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If you need/want, I can chuck a scope on your CAS and work out what is going on. Let me know, I've got it in my car for another PF lad atm anyway!Jason Broadhurst
Someone once asked me if they could use my mower. I said "sure, so long as it doesn't leave my yard"Comment
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I didn't think a multimeter and a laptop were sophisticated electronic testing equipment.Originally posted by psi999 View Post
Though sounds like the APS solution is a couple of meters of this http://www.ebay.com/itm/15-Feet-2-Co...-/310399623899
Did you end up rerunning the CAS wiring in shielded wiring to the ECU?
Think the solution to the CAS sensor could be rerunning the wiring is 3-core twisted shielded wiring from the ECU straight to the CAS making sure it's well shielded IE ground it out at the ECU and run the sheild as far into the plug as possible. Doesn't solve the hot start issue though...Comment
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Where where you 2 weeks ago lolOriginally posted by Jason Broadhurst View Post
What i would love a hand with is setting the haltech up and getting a base tune into it... interested?
Will be all wired, just may need a hand getting it up and running with the idle motor etc
Yeah iv got a couple of meters to do it but the main reason for replacement ended up being the hot start issue being unable to be resolved.Originally posted by The Pupat View PostComment
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