RobH

ok, it seems it's a simultaneous thing, not the most efficient of systems though...

Hi guys, I lied! This should deffo be my last post today - my brain is fried now anyway! Pulled the CAS off and tested for injector clicks, they appear to be simultaneous across all injectors, I should have counted, I guess there must be six clicks per one rotation of the CAS (logical). I thought these were supposed to be sequential rather than simultaneous!? Where's the sense in firing all injectors at every cylinder's compression stroke!?!!? How many cam rotations are there per crank rotation (2:1?)? Cheers RobH

yep, all seals replaced, actually got a complete 'known good' fuel rail with original injectors in there at the moment. Connected my 'suspect' fuel rail to the fuel lines whilst out of the engine and switched on, didn't leak a drop under pump pressure, think I can more or less rule out injectors and seals as it's performed equally badly with 2 different sets - both of which are now known not to leak.

yep, plenty of it, deffo running rich. Used £20 of fuel just sat on my drive scratching my head!

hmm...I did consider this when I first had problems, can't hear anything around the engine bay though and the engine has recently been. I'm pretty sure everything has been reconnected correctly. Actually I have a question about that, if there's some valve overlap, wouldn't it be impossible to pressurise the system unless you block up the exhausts??

Have replaced injectors, replaced ECU ROM, ECU reset, consult fault code dianosed nil defects, disconnected MAF, replaced O2 sensors, checked for injection and spark at all cylinders (present), checked fuel pressure, TPS checked etc etc, the only things I haven't done which seem possible culprits are CAS test, replace PTU (was a new series 2 about 5 years ago) and replace ECU unit as a whole and I guess a compression test wouldn't hurt (or it might)... Haven't checked for electrical continuity to ECU connectors yet, want to narrow the fault down a bit first...as it is I'm grasping at straws..

It's quite different to a knakd MAF, it will rev ok (though not great) to 4000+ when in neutral, under load (in gear) it really struggles and gets worse as more throttle is applied.

Hmm...TPS is relatively new (few years, very few miles on it) and is reading correctly. Neutral switch is a bit of an odd one though...not thought about that really, it was new when I converted to manual about 5 years ago. Doesn't seem to show up in the limited consult test I have. It will rev to 2500+ when in neutral (i.e. no load) quite different to when the MAF is disconnected so I've kind of ruled out the MAF as the problem.

Yep, I agree, problem is that the thing is running so badly that I can't get it past about 2500 rpm - difficult to hit +ve boost at this sort of engine speed - particularly when it's running so badly. If I boot it it pops and bangs and gives up.

It seems it is impossible to connect the FPR upside down - don't know what I was thinking of!? It was correct the whole time, I must have removed it and put it back on just the same - i.e. correctly. duh!

This sounds quite similar to my current probs, I have the AVC-r showing reverse of what it should for injector duty. 90%+ for idle. I have found other references to this in the US but the US car was not running badly (or at least the guy didn't say it was). I've tried all sorts, different ROM images (programmable ECU), slightly modified SE chip, different injectors (back to 370cc now), different MAF, fuel pressure, ECU reset, new O2 sensors, cleaned every connector I can find etc etc...Really scratching my head. Trond, are your plugs coming out sooty? Mine are well carbon coated. Engine sounds like it's only running on 3 or 4 cylinders most of the time, idle is very poor. Hoping to borrow a complete ECU to rule that out, damage whilst I was last soldering is a possibility. Chris, my car had also been off the road for approx 2 years Cheers H

I've been using the AVC-r successfully for years, the only change is that I pulled the engine to replace turbos and whilst it was out I cleaned up all the pipework I could, this included removing the stock boost solenoids. AVC-r was plumbed into the stock solenoid pipework previously, they were just disconnected electronically. The stock solenoids used a 3 way connection whereas the AVC-r only uses 2.

No, it's running like a bag of s***, not sure if it's because the solenoid's not working or connected wrong that it won't hit +ve boost or whether the solenoids not working because it's not hitting +ve boost - chicken/egg thing..

Pulled coil pack #1, length of HT cable with a plug cap on one end and the other end stuffed into the coil pack, sensor from the timing gun between plug cap and plug. (should be) much more reliable than the loop, which is known to cause problems. Cheers H

Hi all, Last new thread for me today (promise!). Had a problem with a stuck injector causing a hydrolock in one cylinder, enough to stop the engine from turning. Just wondering if this could have caused the cam belt to slip a tooth? Not even sure if it's possible to slip a tooth!? The timing seems to go 'out' for no apparent reason, I set it correctly (not using the loop on the PTU!), check it again at a later date and find it 10 or more degrees out! Could this be a CAS problem? Any other possible causes? Engine temperature sensor appears to be working correctly. This problem first happened to me quite some time ago when the car was otherwise running well, timing suddenly advanced 10 degrees and caused severe detonation, checked, retarded and it was fine. Thanks in advance for any help. RobH

Should the AVC-r solenoid valve run at 0% duty cycle until it hits positive boost? My engine is running badly, very little chance of hitting +ve boost so I can't actually test it. I've taken the stock boost solenoids out and am running lines directly from the wastegate actuators to the COM side of the solenoid and from the intake hardpipes to the NO side. I can't help feeling this is too simplistic and another pair of vacuum lines is needed somewhere - has anyone else set up successfully this way? Any help appreciated. Cheers RobH

Hi All, Still having over rich problems (amongst others) on my recently rebuilt TT. It runs extremely poorly and is not really usable. I've noticed an anomally, or at least i suspect it is, checking injector duty cycle on the AVC-r, it shows as 90%+ at idle and drops with throttle applied. Is this as expected? Seems to be completely the reverse of what should happen and makes me suspect a crossed connection or short somewhere. I double checked with consult and sure enough the injector time drops as throttle is applied. Whether this is not the case when the engine is under load I haven't been able to test (not really driveable). Can anyone check on their AVC-r, consult etc and let me know if they experience the same please? Cheers RobH

Hmm...confused myself a bit with this one. It seems that it's not possible to fit the FPR upside down with connections reversed...

Ok, ta, so you're saying page 16 is correct?? A couple more odd things, I've just checked the fuel pressure, pulled the fuel pump fuse to relieve the pressure, engine just kept on running, is this normal?? Pressure was around 40 psi at 'idle' (it won't currently idle with any stability), as soon as I turned the ignition off all pressure was lost within about 4 seconds - I'm pretty sure this isn't normal - any suggestions? Cheers H

Hi folks, after some confusion I thought I'd put my fuel pressure regulator on the correct way up - having looked at the manual a bit more closely it seems to show conflicting info. http://www.300zx.co.uk/cgi-bin/manual.cgi?list=efec&dir=&config=&refresh=&slide=16&cycle=off&scale=0&design=default&total=190 and http://www.300zx.co.uk/cgi-bin/manual.cgi?list=efec&dir=&config=&refresh=&slide=5&cycle=off&scale=0&design=default&total=190 These do not agree...page 16 shows the end of the sensor connects to the fuel rail, page 5 shows the end of the FPR connected to the fuel tank return. Could somebody please take a quick look under their bonnet and let me know whether the end of the FPR connects to the fuel rail or the fuel tank return?? Cheers RobH

Hi guys, I'm waiting on delivery of a fuel pressure gauge which may or may not help. I'm keeping my fingers crossed that I've damaged the regulator (!?). The point I'm trying to make about the possibility of cr*ppy or badly installed injectors is that it's extremely unlikely that they'd all be bad - hence not all plugs would be carbon fouled. If one or two were fouling then I'd definately be looking at that as a priority. Thanks for the input though. H

Hi guys, further to my problems with a non existent idle (probably due mainly to an over rich AFR), a thought has ocurred. Does removing the Aircon and cutting the lines cause an issue with the function of the IAA unit?? Does the ECU simply detect the drop in revs and then use the IAA to compensate or is it something more complicated (a signal from the aircon system for example)? TIA RobH

Hmph - apparently this wasn't the problem, still runs exactly the same!! Points of note are that K constant needs to be below 100 to make it idle (latency has very little effect, it won't rev with the K constant this low) OR the MAF has to be disconnected - it will idle with a reasonable K constant then, plugging the MAF back in stalls it, obviously can't rev it with the MAF unplugged....

Oh man!! I'm such a fkin dunce!! Think I've put the fuel pressure regulator on upside down (didn't think it was possible!!) - hence supplying the rail at pump pressure =:-O

Hi John, it was you that pointed me to Nistune in the first place - just wanted to make the point that I was happy with your suggestion and was in no way suggesting Nistune was at fault ;-) I have been thinking about the pipes etc for the pressure regulator, this and the dampener were mystery items to me when I pulled the plenum off, still not confident in my knowledge of them so am going to investigate this fully and ensure all is hooked up correctly. Looking at it slightly differently, it's evident that the engine doesn't actually idle at all, it is either about to stall (revs dropping) or the ECU is compensating by revving the engine to approx 1200 rpm - there is no inbetween although it will idle when cold (about 1200), maybe this provides a clue?? As for the MAF, checked at below 0.5V with ignition on, engine not running, at 'idle' it shows 1.8V or thereabouts - these figures look bad to me. My MAF has only 4 pins, connector has 5 wires - is this an NA MAF in a TT chassis?? There seems to be some confusion as to whether there is actually a difference between MAF sensors in TT and NA. The injectors click as expected. I think if the were drilled oversize and flowing too much then changing K and latency values would improve things to an acceptable level. Jaffa, I know where you're coming from, I was extremely careful fitting the new injectors and rings, I've kind of ruled this out as all cylinders are running over rich, if the odd one was pinched it would show when reading the plugs - v unlikely I've pinched them all(although anything is possible for me ;-)) Cheers again H