Poor starting after inlet mods

[Jim Bob]

I run a 3.5 V8 with stage three heads, hot cam, Hotwire EFI from a 3.9 RR and a multi point LPG system in my Triumph TRV8. Recently a reknowned Range Rover / Land Rover specialist fitted a modified (enlarged) plenum, a 45mm trumpet set and also relocated the IACV (stepper motor) to the offside face of the plenum (see photo).

However, since these mod's were made, the car really struggles to start on both petrol and gas. The engine spins for ages and will eventually fire if you pump the throttle (before the mods, the engine fired without problems).

The specialist thinks that the ECU will need to be remapped but their Hotwire specialist has left the company and they do not have anyone who can carry out the remapping. To give them there due, they are trying to find someone who can do the work for me but so far they have not succeeded.

So, can anyone on this forum suggest a reliable company who knows the hotwire system and can remap the ECU? One local to where I live would be great (Basingstoke, Hampshire).

Thanks

Rob

[Snooper]

I run a 3.5 V8 with stage three heads, hot cam, Hotwire EFI from a 3.9 RR and a multi point LPG system in my Triumph TRV8. Recently a reknowned Range Rover / Land Rover specialist fitted a modified (enlarged) plenum, a 45mm trumpet set and also relocated the IACV (stepper motor) to the offside face of the plenum (see photo).

However, since these mod's were made, the car really struggles to start on both petrol and gas. The engine spins for ages and will eventually fire if you pump the throttle (before the mods, the engine fired without problems).

The specialist thinks that the ECU will need to be remapped but their Hotwire specialist has left the company and they do not have anyone who can carry out the remapping. To give them there due, they are trying to find someone who can do the work for me but so far they have not succeeded.

So, can anyone on this forum suggest a reliable company who knows the hotwire system and can remap the ECU? One local to where I live would be great (Basingstoke, Hampshire).

Thanks

Rob

Hello Rob, I can understand that replacing the plenum/trumpets will "upset"the air mixture and the ecu may need tweeking regarding fuel/air ratio.I would first check basics when the engine is running i.e. exhaust CO reading at idle / check for airleaks ( I know the work was carried out by a reputable garage but it can happen to the best of us)

Relocation of the IACV should make no noticeable differance , try clamping the hose leading to it when the engine is running to see if you can achieve a smoother idle. If so then a suspect IACV could be the problem.

As for a company to remap your ECU I am sure a quick look at the web will come up with remapping garges near you ,they may even have rolling road facilities which is really a requirement to set all the ECU paramiters.

Hope you resolve your issue.

Snooper.

[David Sparkes]

I'm not a V8 person at all, but isn't Mark Adams the man for this?

An enthusiast about what he does, very knowledgeable, very friendly. I'm sure he would be interested in a slightly different problem like this.

Seems to sell through ebay at the moment, but don't let that put you off contacting him about individual requirements. http://stores.ebay.co.uk/v8performance

He is very much a one man band, so don't despair if he is slow to respond to emails etc.

If you do try phoning, do it first thing (office hours, naturally) and have some time to spare yourself - he can chat to Olympic standard!!

These details are a few years old, but I'm hoping they are still current.

contact details for Mark:

email: mark@tornadosystems.com

tel: 01694 720 144

You might find previous reference to him if you search 'Mark Adams' on this forum, or Google 'Mark Adams V8'.

HTH

[SteveRK]

Stating the engine should not be affected at all by plenum changes as the volume of air being sucked in is tiny (with the throttle closed as is normal for starting) will have no effect whatsoever. I would suggest that the problem is somewhere else and not directly affected by a performance plenum itself.

[FridgeFreezer]

A big vote here for our very own Nige - www.megasquirt-v8.co.uk

That'll keep him out of trouble for ages

[Hybrid_From_Hell]

The specialist thinks that the ECU will need to be remapped

No S**t Sherlock

Yes it will defo need a remap, some specialist, it will run very weak on WOT so avoid acceleration and high RPM

Prob is you will need a EPROM and that a goodly few hundred quid, then a Rolling road, and then payment for that.

Remap and rolling road best guess £600-£1000, and you still have lucarse HW system, F knopws why he ha moved the steeper mount,

but all in all THEY need to sort you out IMVHO as that engine with the mods is not fit for purpose and you can dmage it in its current state

in very quick time.

Dare I say Fit Mega.................. eeek

Nige

PS No, I do not wnat to get involved ina EPROM Refit / remap thankyou

[mad_pete]

I agree, I don't see how the changes have messed up starting. Is the ECU showing any fault codes ?

[Hybrid_From_Hell]

Starting wil be messed up as more air will be allowed in = weak

ASE and WUE Tables are very delicate and a small % change will wreek havoc with a ROM Chiped ECU

Nige

[mad_pete]

So the closed throttle position is now letting in more air as the larger plenum has a larger intake ?

[iomlt]

If you need a 3.9 ecu with a tornado chip in then i have one going cheap currently fueled for a 4.6 but could be remapped if need be. let me know

[Jim Bob]

HI everyone and thanks for the advice.

The mods were made by JE Engineering in Coventry so they should know this unit and the injection system well enough. However, their ECU man left recently to join Jaguar/Land Rover so whilst the remaining members of staff were able to swap the hardware they did not give a second thought about remapping the fuelling to account for the extra air flow. This has left a bitter taste in my mouth as I thought I had picked my supplier well enough.

They are trying to find someone who can remap the ECU but four weeks on they have not resolved the problem; hence my request for potential (and reliable) suppliers but it would seem that there is not a long list (if any) to choose from.

If anyone knows of an experienced company who can (and is willing) to fix this problem do please let me know.

Thanks

Rob

PS- the IACV was moved as in its original position, it fouled the bonnet catch mechanism of the Triumph!!

[iomlt]

Rpi, i have their ecu chip etc.......

http://www.v8engines.com/

[iomlt]

or spend the extra cash on megaquirt then do it yourself..

[FridgeFreezer]

Rpi, i have their ecu chip etc.......

http://www.v8engines.com/

Oh hell no, don't do it.

The problem with all of the "chip" solutions is that they are only ever a best-guess for a generic model of what your engine is, not accounting for vehicle-to-vehicle variations, age, tweaks, etc. They're also still just a new program for some shonky 30-year-old Lucarse EFI hardware that's obsolete.

MS lets you tune YOUR ECU to your engine, and re-tune / tweak if you change anything. It's also far easier to fault-find as you can see everything on a laptop with free software.

The chip solution will be plug-and-play (although still not guaranteed to help), the MS requires a bit of work but I very much believe the rewards are worth it.

[iomlt]

no exactly 100% above, best ring them RPi and have a chat if dont want to go the MS route.

[FridgeFreezer]

Sorry but RPi will just try to take your money for a load of old tat, they mix a good knowledge of RV8's with a load of misguided sales bull which can be quite misleading.

[Jim Bob]

Having considered the advise I have read up on Megasquirt and made contact with www.v8developments.co.uk for some advice. I will let you know how I get on...

Thanks to everyone- I appreciate the pointers

[SteveRK]

Hang on- at least try retarding the timing or making some basic adjustments to see if it resolves the problem before ripping it all apart and fitting all new items/parts. I know on mine if i advance the timing it runs better at idle but can be reluctant to start when warm so theres one thing to check before spending more money. Do some radical changes like plug breather and vacuum pipes that connect to the inlet manifold o see if it makes any difference etc. I say this because its possible that during the work carried out something might have got disconnected/split/detached etc. and is causing the starting issue.

[Ally V8]

I cant see why the mods should affect starting - something else is wrong,an engine in good health ought to fire away from cranking speed after a few turns,even if it runs like a bag of nails when it does go.

The Hotwire system will allow for a larger airflow to an extent and put in more fuel to match.But with the other mods its a bit of a blunt tool.You mention LPG,what system is it and do you have any means of mapping the ignition when its on gas ?

If that was my car I'd be putting a pair of wide band oxygen sensors and AFR gauges on it,then you would have a constant view of whats going on - rather than a short glimpse on a rolling road.Make any further changes and you can see their effects immediately.If as with most v8's you only use the petrol for starting and back up,you ought to be able to use the LPG software to tune the engine perfectly well,piggybacking off the Hotwire with the help of a pair of AFR gauges.

The only reason I say this is because I have done it,and the other point I would make is that Hotwire is very capable,if well looked after - even after 120,000m, its more accurate than you would think.

[Jim Bob]

I have had a good look at all of the vacuum pipes and although the pipe to brake servo looked a bit pinched under the jubilee clip, upon removal it had not pierced the hose. I cut off the end of the hose and reconnected it. I also tightened all of the grub screws that hold down the plenum and also those that hold the repositioned IACV and the blanking plate used to seal the old IACV mount.

None of this made any difference.

Then I thought about the comment about the engine starting on petrol then flipping to gas. The car is set up to start either on gas or on petrol- I can select manually what fuel type and the starting problem is there irrespective of what fuel type I select. If the problem of poor starting is caused by the ECU needing to be remapped as JE suggest then BOTH ECUs would need to be mapped wouldnt they? As the problem is just as pronounced on either fuel type does this not suggest that the starting is NOT ECU related? BTW, the LPG system is an OMVL multipoint.

During the time spent investigating all of the hoses and connections, I did notice that the powder coating on the plenum had been damaged on a housing that contained a grub screw to the right of the throttle body, (it looks like the sort of damage caused by a lever being used).

I have trawled the web and I think that this grub screw is the 'base idle adjustment' and as the tamper cover is no longer there it probably means that this has been adjusted. If this has been adjusted could this be contributing to the problem?

[SteveRK]

Yes it looks like the base idle adjuster. I'm constantly adjusting mine and it doesnt affect starting but can have an effect on how high it revs on initial starting.

Have your tried making some big adjustments to the ignition timing - advanced then retard to see if it has any effect?

[SteveRK]

One other thing to check is whether fuel pressure is correct and whether its up to pressure during cranking.

[geoffbeaumont]

Not sure how the LPG ECU will operate at starting, but most multipoint LPG systems work by monitoring the voltages on the petrol injectors (while isolating the actual injectors) and using the pulse width to calculate LPG fuelling, so in theory a badly mapped petrol ECU could still be the problem.

[FridgeFreezer]

Ally V8 is on the right track although I don't entirely agree with his approach - even a badly tuned ECU + ignition should be close enough to start a V8, so look for obvious problems. The hotwire system is by no means *bad* on a standard engine, but the outlay for tuning it to something non-standard is disproportionate compared to the MS&EDIS solution, and you have no real diagnostics from it. I don't think wideband lambdas are really necessary for fault finding, they're only a "nice to have" for tuning, any fault big enough to stop the engine from starting should be findable with only basic diagnostics (Mk1 eyeball, brain) rather than hundreds of pounds of specialist gear.

Hell, you could install MS for the price of twin widebands and probably spot the fault just as quickly...

The screw you found is indeed the idle screw, no harm comes from adjusting it, it just lets air past the throttle plate.

Geoff is bang on about LPG ECU's, they just "steal" the injector pulsewidth from the main ECU and pass it on with minor adjustment to the LPG injectors.

[Ally V8]

Ally V8 is on the right track although I don't entirely agree with his approach - even a badly tuned ECU + ignition should be close enough to start a V8, so look for obvious problems. The hotwire system is by no means *bad* on a standard engine, but the outlay for tuning it to something non-standard is disproportionate compared to the MS&EDIS solution, and you have no real diagnostics from it. I don't think wideband lambdas are really necessary for fault finding, they're only a "nice to have" for tuning, any fault big enough to stop the engine from starting should be findable with only basic diagnostics (Mk1 eyeball, brain) rather than hundreds of pounds of specialist gear.

Hell, you could install MS for the price of twin widebands and probably spot the fault just as quickly...

The screw you found is indeed the idle screw, no harm comes from adjusting it, it just lets air past the throttle plate.

Geoff is bang on about LPG ECU's, they just "steal" the injector pulsewidth from the main ECU and pass it on with minor adjustment to the LPG injectors.

No,you couldnt possibly agree could you - I stated in my first paragraph that something else must be wrong for the poor starting issue,other than a bad fuel map.If it was not PERFECTLY clear I then went on to say that a pair of AFR gauges would be a really useful tool to map the LPG,which is doing most of the work - if its not why bother having it ?

BTW, seeing as we are being so petty,the base idle screw does not let air past the throttle plate,it allows it to bypass it.With a hot engine the correct adjustment is to clamp it off and adjust the idle speed to 450-500rpm all loads off.

Jim, when you have sorted the starting problem,look here; http://cgi.ebay.co.uk/INNOVATE-MTX-L-AFR-Wideband-Air-Fuel-Ratio-Gauge-3844-/300506017816?ept=UK_CarsParts_Vehicles_CarParts_SM&hash=item45f78df018 £300 and you have a constant veiw of what your fuel mixtures are doing,as I said the Hotwire is a good enough base for the LPG to piggyback from - you can tweak the LPG from it,including up to 20% balance from bank to bank.The AFR gauges are also very good at showing a misfire situation long before you can hear/feel it.

They are only doubted by people who have never used them.