The V8 Owners Forum -

I spent a day with Dale Bladen last week on his rolling road (and I rate him highly). Whilst checking things, he noticed my injectors were wired incorrectly with the +ve and -ve wires swapped. I'm puzzled as my RV8 wiring diagrams show the Orange and Brown wire as the 12v supply so I had it connected to the what I thought was the +ve terminal of the JT connector. But on his tester it said it I had connected it to the -ve. It was originally a standard Hotwire loom (with official Landrover sticker too!) and had never altered the JT wiring.

We swapped the wires so now the Orange and Brown wire is split and goes to each bank control on the ECU but as the injectors seem to work both ways, does it actually matter if they were swapped?

Don't think it matters. It's in effect just a solenoid.

However, if you remove the rubber boot from the Timer connector, the pins are marked 1&2 on the body. 1 is Yellow/* and 2 Brown/*

DaveEFI wrote:However, if you remove the rubber boot from the Timer connector, the pins are marked 1&2 on the body. 1 is Yellow/* and 2 Brown/*

Dave,

Mine were originally the reverse of this so 1 = Brown + Orange and 2 Yellow _ Blue (DVR side).

So, LR loom must have been incorrect at the factory but as you say, may not have made any difference.

Interesting. I got the information from a hotwire loom I have here which looks to be untouched. None of the schematics I have number the pins on those connectors, but do on other things. So I'd guess it doesn't matter.

Some are marked, most arent.

Cant imagine it making any difference really. I know on some cars I have switched wiring that wasnt as per markings. Never made any difference though

Had a look at the slightly different connectors used on the flapper, and can't find any terminal numbers on those at all. Although of course the connectors are still polarised.

As a matter of interest, what ended up being changed with your rolling road session - and is it much improved? I've long fancied having mine done too - but never heard a recommendation for a RR place close to London who knows MS.

DaveEFI wrote:As a matter of interest, what ended up being changed with your rolling road session - and is it much improved? I've long fancied having mine done too - but never heard a recommendation for a RR place close to London who knows MS.

Loads - Dale knew his stuff. Among the problems were timing way out, running very rich, plug gaps too big (although specified as that by my supplier), map completely out, wrong fuel return regulator (LR one, not TVR one) so too low fuel pressure and countless MS settings.

Dale is in Ironbridge, near Telford so not close to London but a very good value day.

As it happens, I suffered my recurring cooling problems on the way there and during session so did not make the final power runs so need to go back to finish off the job.

Had you used the auto-tune facility in Tuner Studio? And it was still massively out?

As regards the fuel pressure, what is the difference between the LR one and TVR? I'd have though the correct pressure to use would depend on the injectors and fuel pump, and provided the reg adjusts for manifold depression, normal mapping with cope with a slight difference? Obviously you need the pressure required for maximum injector demand.

Dave,

Autotune yes and way out or no where near enough re-mapping. Don't forget Dale mapped whole table, not just a few rev ranges through driving. I'm not blaming Autotune at all.

LR return valve rated at 2.5 bar, TVR supposedly 3 bar. In the end using the vice trick managed to get pressure up to just over 40 psi. Still not enough but now good to 5,000 rpm. It was running very lean at standard pressure.

Fuel pump is Syrtec rated at same as the original Bosch one.

All interesting stuff. 2.5 bar (36 psi) is IIRC the same as my SD1. 3 bar is close to what my standard pump can achieve. Wonder if TVR used a different one? (Many other systems run at a higher pressure)

I have an adjustable reg (non rising rate type) with pressure gauge so can easily see what's happening there.

However, I'm curious about the under fuelling at high loads. That suggests the injectors are too small, if it can't be mapped round. Have you looked at the injector duty cycle log?

Seems it is 3.5 bar.
http://www.racetechdirect.co.uk/l0171-t ... ulator.asp

Cannot really answer the injector question, sorry but as I understand it there was not enough pressure so not enough fuel was injected. I seem to remember that initially the AFR gauge was showing hig 20s at around 29 until Dale increased the pressure to 40 psi or so.

The pump on my SD1 won't make 50 psi (3.5 bar) It's all out at about 45. Fairly new, too. Perhaps TVR use a different pump?

When you first install MS it's usual to calculate the Req. Fuel, using the supplied calculator. You enter injector flow, from the likes of this site and use their calculator if not using the 'normal' pressure, to get the actual flow rate.

http://users.erols.com/srweiss/tableifc.htm

The Tuner Studio calculator needs engine size and injector flow to give req.fuel. Once set, it wouldn't normally need altering.

Stock TVR used stock LR 2.5 bar FPR a few cars that have been modded may have had the squash treatment to the reg but certainly not from the factory if you need to increase the poundage/uprate slightly your injectors far better to use a 3 BAR 80's BMW reg IMO

Pressure regulator really shouldnt matter provided you have adequate injector, and adequate pump.

But I personally would prefer 3 bar or more base pressure. But the fact it had a 2.5 bar regulator is not a problem, it is not wrong and it is not a cause of lean mixtures, unless the ecu has never been tuned correctly either. In which case the blame still lies with the mapping.

But lower pressure is certainly not to be blamed for lean mixtures when you have a programmable ecu that has been mapped.
Unless the reduced pressure itself is actually a fault that occurred over previous higher levels.

Almost any Bosch efi pump will easily be able to make, 40, 50, 60psi. Other brands I couldnt comment. As for the Sytec Bosch copies ( pretty sure they sell Bosch too though ), again hard to comment.