Advice please!

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Gilbertd
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Re: Advice please!

#241 Post by Gilbertd » Sat Aug 29, 2020 7:04 pm

This https://tinleytech.co.uk/shop/lpg-parts ... -wire-afm/ is the one I've got spare only with a 36mm choke. Inside diameter of the bit that fits over the throttle body intake (where the intake hose would normally fit) is 72mm so may fit on yours or may not be the correct size (possibly too small). Not a lot right with your current mixer, it almost looks like something is missing, like a venturi.....

You need to have the photo hosted somewhere, since Photobucket started charging most of us use Imgur.com instead which is free. Then post the URL for the image between the two img commands.
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Pinger
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Re: Advice please!

#242 Post by Pinger » Sat Aug 29, 2020 8:15 pm

Gilbertd wrote:
Sat Aug 29, 2020 7:04 pm
This https://tinleytech.co.uk/shop/lpg-parts ... -wire-afm/ is the one I've got spare only with a 36mm choke. Inside diameter of the bit that fits over the throttle body intake (where the intake hose would normally fit) is 72mm so may fit on yours or may not be the correct size (possibly too small). Not a lot right with your current mixer, it almost looks like something is missing, like a venturi.....
Thanks for the offer. The 90mm TT one will be an easier fit (as OD the same as mine) and given it looks like more of a mixer than that abomination I currently have, surely I can make it work and retain the breathing that comes with a 45mm ID.
Nothing I can do until Monday anyway so I've a few days to think about it.
That restriction on the inlet pipe of mine must be thwarting my set-up efforts when I have the actuator flowing more than the mixer will accept. Even blowing through it (by mouth) takes effort! I should be able to lower my reducer's sensitivity with something other than it. There is an attempt at a venturi but it disappears after about 5mm. To my eyes it's more turbulence generator than mixer.
Gilbertd wrote:
Sat Aug 29, 2020 7:04 pm
You need to have the photo hosted somewhere, since Photobucket started charging most of us use Imgur.com instead which is free. Then post the URL for the image between the two img commands.
I used to use PB for other sites so know how it's done. I'll use Imgur if/when I've more photos to post.

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Re: Advice please!

#243 Post by Brian_H » Sat Aug 29, 2020 10:51 pm

Here you go uploaded directly here
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75083-e4344ab06227f78c300cfd40440b73f6.jpg
75083-e4344ab06227f78c300cfd40440b73f6.jpg (20.66 KiB) Viewed 393 times
As long as you keep the images fairly small (I think its around 2mb thats the limit) you can upload them directly here as Gillbertd has said, but you have to click the full editor and reply button to actually see the option to add attachments.

Pinger
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Re: Advice please!

#244 Post by Pinger » Sun Aug 30, 2020 10:26 am

Thanks Brian_H.
I remembered the 2mb limit and when I went to post them the first one was 1.6mb so below the limit but used the wrong facility.
I've just found the facility for adding attachments - I'll have a go at posting a photo of the other side of the mixer. Which won't work as it is 2.76mb (why it was rejected on MB forum as 'file too large' and I don't know how to 're-size'). No matter it only shows the slight radius of the ID. We've already established that it needs to be replaced.

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Re: Advice please!

#245 Post by LPGC » Sun Aug 30, 2020 1:52 pm

Looks like a type of hybrid mixer, part venturi part shield.
The gas entry point should probably be on the engine side of the venturi, or at least it will probably give a stronger signal that way.
Might also get a stronger signal if some metal is removed from the rear (in terms of airlfow) of the edge of the shield.
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Re: Advice please!

#246 Post by Pinger » Sun Aug 30, 2020 2:03 pm

It's looking like the Tinley Tech mixer is the only one suitably sized - but I won't get more info on it until Tuesday now it being a bank holiday weekend.
What I'm trying to figure out is if the gas enters the venturi via a single point or, if it is of the multi-hole type as pictured (hopefully!) below. The multi-hole type seems to be a better mixer. Is that correct. But I can't see if the TT one is that type and on account of the straight through holes on it, wonder if it's even possible. How are multi-hole ones manufactured - cast in one piece with a hollow internal core, in two parts and machined, other method?
Is a single point entry (if that's what the TT one is) acceptable over a multi-hole one?

Image

Here's the TT one.

Image

There's also this >> https://tinleytech.co.uk/shop/lpg-parts ... -diffuser/
But as the inlet is only 16mm (mine is 19mm) and it's described as being for engines with inlets larger than 60mm and, as 'requiring careful tuning'...
Image

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Re: Advice please!

#247 Post by LPGC » Sun Aug 30, 2020 3:04 pm

There are internal mixers designed to fit in rubber air ducting, as in Brian's pics and your middle pic.
There's the shield type again (something like your last pic) designed to fit in rubber ducting but these are sometimes effectively just an open ended pipe with just a plate shielding airflow from the end of the pipe, not much like a conventional mixer.
There's the plate/SU type designed to be bolted on to an SU or similar type carb (left in your top pic showing 2 mixers)
There's the male/female type mixers designed to fit between a throttle body (female end) and ducting (male end). Right in your top pic. What we consider a normal mixer (though the internal mixers are common too).
There's the Blos type, a bit like a carb with moving parts and more complicated than a normal mixer.
Not to mention Impco and similar type gas carbs which work a bit like Blos but have gas delivered under slight pressure.

TinleyTech's wording regards a shield type 'requiring careful tuning' may be due to knowing that shield types don't generally give very good signal.

Conventional mixers (those with interior holes / slots for gas to come out from) are usually made in 2 parts. The outer part has a recess machined around the middle inner circumference, the gas entry point feeds into this recess. The inner part is the sloped venturi with the holes/slots, it is an interference fit inside the outer part, when fitted gas feeds from the outer part recess to the holes/slots of the inner part. It will be easy for manufacturers to make the holes for the gas entry in the inner part/venturi, once they've cast / CNC'd the part they can just drill the holes / machine the slots as both the inside and outside of the venturi will be accessible.
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Re: Advice please!

#248 Post by Brian_H » Sun Aug 30, 2020 6:12 pm

Easiest way to make a photo smaller is to crop out the extra stuff thats unecessary, if that isn't an option or its still too big after that your looking for something to compress it. A free option for that is the office picture manager, which you can get from here > https://support.microsoft.com/en-us/off ... ca7b7c5730

Open your photos with that, click edit picture and then the compress option is the one to go with.

Or just post elsewhere and link it of course!

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Re: Advice please!

#249 Post by Pinger » Wed Sep 09, 2020 4:33 pm

I have the mixer from Tinley Tech as per previous posts. Out of the box it is ridiculously lean at out of idle but I'm experimenting with blocking the holes around its perimeter. With all the holes blocked I can get the actuator positions close in idle and out of idle. When I tried that, I manually re-set the default position for the actuator to 90 as at 154, in and out of idle were way below that.
Tried again with 8 of the 11 holes blocked and the in and out of idle positions were further apart and the default rose to 144. But, the bigger problem is the idle speed has risen to 1000 to 1200 rpm and I can't get it down though if I switch to petrol it immediately drops to where it should be.

When it is doing this the mixture is rich but the actuator isn't closing any further down though it isn't prevented from doing this and the TPS is in the second box despite the throttle being fully closed. This is a manual throttle with an IAV controlled electronically - which presumably is working (it is clean inside - I've previously checked) as when switching to petrol it idles fine. Something I observed earlier was as I slowly opened the throttle the mixture went lean and the actuator didn't do much to correct it until the second TPS box lit up - then the actuator leapt to the default position. I recall LPGC saying some AEB systems jump to default on changes in TPS boxes.
Why the high idle though? Any ideas?

Gilbertd
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Re: Advice please!

#250 Post by Gilbertd » Wed Sep 09, 2020 7:55 pm

High idle would suggest an air leak, although if it was that it would stay high on petrol. TPS staying in the second box suggests it isn't detecting a closed throttle so you may need to play around with the hysteresis setting in the software, that would also stop it from adjusting when you open the throttle as it thinks it is still closed. Odd that you are are having to block off some of the holes, might be worth a chat with Tinley Tech as they reckon it should be right for your motor.
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Re: Advice please!

#251 Post by Pinger » Wed Sep 09, 2020 8:23 pm

Gilbertd wrote:
Wed Sep 09, 2020 7:55 pm
High idle would suggest an air leak, although if it was that it would stay high on petrol. TPS staying in the second box suggests it isn't detecting a closed throttle so you may need to play around with the hysteresis setting in the software, that would also stop it from adjusting when you open the throttle as it thinks it is still closed.

Thanks Gilbertd.
Hysteresis IIRC is at 0.14. I'll need to give it some thought as to what direction it needs to go. I seem to recall at some point seeing some really low TPS values at idle - down to 0.48V when it's usually 0.6 something. O2 sensor is showing rich while this happens (red box, can't remember the actual voltage) and the actuator wasn't correcting it.
Gilbertd wrote:
Wed Sep 09, 2020 7:55 pm
Odd that you are are having to block off some of the holes, might be worth a chat with Tinley Tech as they reckon it should be right for your motor.
It was TT's suggestion that blocking off holes was an option. 11 x 10mm ID holes is quite a large area.

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Re: Advice please!

#252 Post by Pinger » Thu Sep 10, 2020 5:04 pm

TPS at idle sorted itself out - don't ask me how because I haven't a clue (I did find the equivalent of an 'idle stop screw' and backed it of until there was clearance but made no difference - throttle plate was as shut as it can be) but possibly a software glitch on my lap top software. It is very erratic in displaying O2 and actuator data (long after time allowed for O2 sensors to be read) but will show rpm and TPS during that wait.

Anyway, been driving it and it drives fine for the main part. Still a disparity between idle and out of idle settings and I'm still playing around with how many of the new mixers peripheral holes need to be blocked or unblocked.
Default has settled at 162 (though give-and-take driving at 50-70mph sees the actuator ar around 145 (the same as no load 3000rpm) but is is chronically lean above 4000rpm. The actuator is set to fully open when TPS is above 3.75V with the expectation of it subsequently closing. It doesn't. It stays wide open and the O2 reads its lowest possible voltage and the power is hobbled.

Is this the sign of an overly restrictive mixer (too many holes blocked) or an overly large mixer (too few holes blocked)? Kicking myself I forgot to switch over to petrol to see if lack of airflow was effecting power.

Recall, this is with the new R90E reducer which wont have had time to accumulate heavy ends and all solenoids and filter are clean so no blockages in LPG supply.

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Re: Advice please!

#253 Post by Pinger » Thu Sep 10, 2020 5:08 pm

Hopefully, here's a photo of the new mixer. To match the flow area of the old mixer, the new one needs to have ten and a half of its eleven holes open!
Today's running was with only three open and the remaining eight closed.
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Gilbertd
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Re: Advice please!

#254 Post by Gilbertd » Thu Sep 10, 2020 6:29 pm

I've never played with one of those mixers but the default sounds high still. Lean even with the actuator fully open says not enough gas so ordinarily I'd say to open up the bias on the vaporiser but we don't know if that will have an affect or if it is the mixer not sucking enough. To give you a clue, I checked the settings on mine before I left home last week and the default was at 108 with the average at idle being around 115. Checked it again a couple of days ago after cruising it at 75-80 mph for the best part of 2,000 miles (I'm currently at the in-laws in Latvia) and the default was at 107.
96 Saab 900XS, AEB Leo, sold
93 Range Rover 4.2LSE, Lovato LovEco, sold
97 Range Rover 4.0SE, multipoint, sold
98 Ex-Police Range Rover 4.0, AEB Leo, daily motor
96 Range Rover 4.6HSE Ascot, AEB Leo, my spare


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Pinger
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Re: Advice please!

#255 Post by Pinger » Thu Sep 10, 2020 7:00 pm

Gilbertd wrote:
Thu Sep 10, 2020 6:29 pm
I've never played with one of those mixers but the default sounds high still. Lean even with the actuator fully open says not enough gas so ordinarily I'd say to open up the bias on the vaporiser but we don't know if that will have an affect or if it is the mixer not sucking enough. To give you a clue, I checked the settings on mine before I left home last week and the default was at 108 with the average at idle being around 115. Checked it again a couple of days ago after cruising it at 75-80 mph for the best part of 2,000 miles (I'm currently at the in-laws in Latvia) and the default was at 107.
I think. the default ended up there after being pretty brutal with the throttle (ie when the actuator was fully open). It was at 144 when I left here and if I'd driven as I would normally drive I suspect it wouldn't have moved far from that. I was surprised driving at 60-70mph how close the actuator is to 3000rpm and no load.
I want (after working out the flow areas) to try again tomorrow with the holes unblocked. Before I got properly stuck in I wound in the bias (clockwise) so I can bring it back out to where it was with the other mixer. (With the three open holes today, the area is as a 36mm ID mixer).

Not really (or yet) much further on from where I was prior - with the exception of going on throttle from idle. It's not showing up on the screen but the engine is more responsive at that point - even with the bias screwed in.

It's looking like I'm not going to get the idle and out of idle settings as close as yours (if I have to run with the holes open). I've been re-reading the thread and LPGC commented that on some engines this may only be possible at the expense of top end power. I think I have such an engine! I did get them quite close with all the holes blocked but the area then is equivalent to a 31mm ID mixer. Maybe I should try that configuration on the road and see where the mixture is.

He also mentioned the possibility of locking the default and then setting the actuator around that knowing what the engine wants. Is that a valid path? It would at least curb my (almost inevitable) default drift.

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Re: Advice please!

#256 Post by LPGC » Fri Sep 11, 2020 12:53 pm

Calculating and comparing areas may allow you a half decent approximation of how many holes you need to cover etc but it's not really quite as simple as that.

Seems you've already seen that the default can shift in varying driving conditions and that this can cause any limitations you placed on stepper movement to have different effects to those you intend/anticipate. For example you may restrict idle closing steps to 10 below default to prevent a slight drop in rpm as mixture goes a bit too lean due to stepper overshoot and recovers as the stepper moves back towards open (you might do this to prevent a slight surge at idle) but if default position changes the same restriction may see the surging re-occur (if default decreases) or may see the engine hang rich at idle (if default increases). Locking the default position can overcome this... But on this type of (mixer) system no electronic measure is a good substitute for having a well matched mixer and reducer on which the stepper doesn't have to move much at all. There are disadvantages to locking the default too but on most installs where it seems a positive to limit stepper movement it's usually also a positive to lock the default as this prevents the limitations you set from moving along with the default. The default may move simply because you've nearly run out of gas (at low loads it may move up), it may move up or down a bit in different temperatures.
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Re: Advice please!

#257 Post by Pinger » Fri Sep 11, 2020 1:58 pm

Thanks LPGC. Locking the default is still some way away as still working on the basic set-up.

Drove it again today with the bias out as far as possible on Tinley's advice (only one turn on from removed (but I have it locked so it can't fall out)) and it's still chronically weak above 4000 rpm. Also, on petrol, it is flat above 4000 rpm suggesting restricted airflow (only 3 peripheral holes open - equates to a 34mm mixer) and very noisy at around 3000rpm and more - turbulent. Does turbulence not negatively impact on venturi efficiency?
But, no point in opening up the holes until more gas can get there.
Tinley suggest using both outlets on the R90E. I've asked them if I should consider refitting my old R90 in parallel (it may not be worn as previously thought- the rush of gas with the idle bleed closed could have been from the bias) and in either case whether to feed to the mixer inlet (only 10mm ID) or via a separate pipe immediately downstream from the mixer (butted up against it). A feed there from the second R90E outlet would be (relatively) easily achieved. Worth trying?

As for the closeness of idle and out of idle actuator settings I'm resigned to not getting them close. The transitions seem well catered for by the actuator (my AEB seems to go immediately to default as soon as the second TPS box is activated and that is almost instantaneous when opening the throttle from idle. The truck is predominately used on open road and there it is running very close to default. I understand idling will pull down the default. What constitutes idling (apart from the obvious) to the AEB Millenium? Currently, I have the ORFCO disabled and on over-run the actuator is around default (a bit below but default will settle lower when I quit poking it above 4000rpm). Does the AEB seeing closed TPS register that as something other than normal driving - or does it merely register the actuator position and add it to the calculation of default? Similarly, does ORFCO set low contribute to a lower default?

At least one thing in my favour though is that my truck draws its induction air from the very front via the inner wing. It is thus immune to temperature changes in the engine bay.

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Re: Advice please!

#258 Post by LPGC » Fri Sep 11, 2020 7:58 pm

Have we discussed ram air effect? If an air intake is facing forward, air pressure in the intake system from driving forward can see an increase in pressure at the mixer which causes the slight vacuum signal that the venturi is supposed to create to be much less than it would otherwise be, the effect can severely lean the mixture. Usually ram air is only a problem if the air intake is forward facing but if the air intake is anywhere where higher than atmospheric pressure is created whilst the vehicle is in motion it will effect mixture, it may be worth checking for this effect (by temporarily moving the point of entry of the air intake). Re-reading your post, you mentioned the stepper remains around default position on over run with ORFCO disabled and this likely means ram air isn't an effect on your install, but you didn't mention if the stepper remains in the same position at various speeds when you lift off (if you'd only tried it at low speeds it wouldn't disprove ram air).

Iirc there are slight differences between AEB175s wearing different labels (Millenium / Pegaso / etc) regards how the TPS boxes work and speed of stepper movement at various rpm / TPS combinations, in general the higher rpm the faster the stepper moves, I don't remember if the current TPS box has any bearing on speed of stepper movement but TPS box selection is directly related to throttle position (except on some where last box will only be selected above a certain rpm with above around 4v TPS voltage reading). If the TPS isn't enabled in settings the TPS box that's lit corresponds solely to rpm (e.g. anything below 1000rpm lighting the 1st box and anything above around 3000/4000 rpm lighting the last box, middle boxes for middling rpms).

If the mixer restricts airflow so drastically that you can easily tell seat of the pants in terms of power and the intake sounds so different it's probably too small. I expect you're right about turbulence but we have no way of metering turbulence etc, what I can say though is that on some installs if a male/female mixer is fitted on the throttle it can be far more restrictive to airflow than a mixer with same sized venturi spaced a little further from the throttle body (like a mixer fitted inside inlet ducting).
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Re: Advice please!

#259 Post by Pinger » Sat Sep 12, 2020 1:13 pm

LPGC wrote:
Fri Sep 11, 2020 7:58 pm
Have we discussed ram air effect? If an air intake is facing forward, air pressure in the intake system from driving forward can see an increase in pressure at the mixer which causes the slight vacuum signal that the venturi is supposed to create to be much less than it would otherwise be, the effect can severely lean the mixture. Usually ram air is only a problem if the air intake is forward facing but if the air intake is anywhere where higher than atmospheric pressure is created whilst the vehicle is in motion it will effect mixture, it may be worth checking for this effect (by temporarily moving the point of entry of the air intake). Re-reading your post, you mentioned the stepper remains around default position on over run with ORFCO disabled and this likely means ram air isn't an effect on your install, but you didn't mention if the stepper remains in the same position at various speeds when you lift off (if you'd only tried it at low speeds it wouldn't disprove ram air).
I don't think I have any ram effect. My Suburban shares its front end with the pick-ups and the intake is located in line with off-road (dust and water) requirements. On over-run and the actuator hanging at around default, that was at speeds in the 50-70 mph range.
It seems that it's suffering from a shortage of gas. When I tried the mixer with all holes opened at 3000 rpm and no load, the actuator was fully open and O2 voltage very low. I'm going to try using both reducer outlets (Y-piece before actuator) and see if that helps or at least points in a direction of travel to pursue. Tinley recommend using my old reducer in parallel. I can see this occurring.
Presumably there is a splitter (connector block?) to allow me to split the liquid LPG line into two feeds? And, if I'm not using ORFCO, does it matter overly the length of vapour pipe between reducer and actuator? (The hose from the current reducer is quite short. If I locate a second reducer at the other side of the engine bay, its hose will be longer. I do have the option of relocating the battery and having both reducers side by side). I understand the reducer has to be mounted vertical (on edge, like a plate in a dishwasher) and parallel to the vehicle centre line. Does it matter which way around, eg adjustment screws facing forward or back, hoses facing NS or OS?
LPGC wrote:
Fri Sep 11, 2020 7:58 pm
Iirc there are slight differences between AEB175s wearing different labels (Millenium / Pegaso / etc) regards how the TPS boxes work and speed of stepper movement at various rpm / TPS combinations, in general the higher rpm the faster the stepper moves, I don't remember if the current TPS box has any bearing on speed of stepper movement but TPS box selection is directly related to throttle position (except on some where last box will only be selected above a certain rpm with above around 4v TPS voltage reading). If the TPS isn't enabled in settings the TPS box that's lit corresponds solely to rpm (e.g. anything below 1000rpm lighting the 1st box and anything above around 3000/4000 rpm lighting the last box, middle boxes for middling rpms).
Now you mention it, it could have been tripping 1000 rpm that lit the second box.
I was working the throttle by hand (under bonnet) and bringing it in so so slowly and the actuator would open very slowly (while the O2 was showing lean) then at either a TPS voltage or, 1000 rpm - the actuator would then swiftly rise to default. In the car, the merest touch of the pedal does the same without any hesitation whatsoever. Driving it today, pick-up from off throttle was very smooth. Maybe though, because ORFCO is currently disabled - or maybe not as at the rpm I am picking up from, ORFCO would already have shifted to mere idling and whatever the O2 is asking for (with the plenum primed with gas/air).

I set the actuator to go fully open at a TPS of 3.75V (which is a fair way into the pedal travel and will invoke a down-shift) but it is so lean I end up jumping off the pedal.
LPGC wrote:
Fri Sep 11, 2020 7:58 pm
If the mixer restricts airflow so drastically that you can easily tell seat of the pants in terms of power and the intake sounds so different it's probably too small. I expect you're right about turbulence but we have no way of metering turbulence etc, what I can say though is that on some installs if a male/female mixer is fitted on the throttle it can be far more restrictive to airflow than a mixer with same sized venturi spaced a little further from the throttle body (like a mixer fitted inside inlet ducting).
Funny you mention that. In recent days it occurred to me that a male/female type could have been fitted directly onto my throttle body - but none were of a suitable size (92mm). I'm better with my internal mixer it seems.

While I'm waiting for my Y-piece to arrive - has anyone experience of trying both single and dual outlets on a reducer? Curious as to just how much a difference using both will make.

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Re: Advice please!

#260 Post by LPGC » Sat Sep 12, 2020 9:56 pm

Of course there are 'splitters' - simple T and Y connectors.

The idea behind installing the reducer facing sideways is so the diaphragm movement which should correspond to signal isn't affected by forward/backward acceleration/deceleration of the vehicle, so it doesn't matter which way (forward or backward) the adjustment screws face. Cornering forces are much lower than acceleration / deceleration forces... If you wanted both a bit of idle bypass and a bit more flow for a given signal then instead of dialling in a bit of idle bypass using the adjustment screw you could try fitting the reducer with it's outlet pointing face down so gravity would constantly pull down on the diaphragm a bit. I've never done this as part of a permanent install but I have experimented and seen richer mixtures, though mostly affected low load operation.

Length of hoses on this type of setup doesn't make a lot of difference under constant conditions but can slow response for changing conditions.

As soon as the TPS box that's highlighted moves to a new box the stepper moves very quickly to the default.

Yes I have used both outlets from an R90 reducer, I expect the same as TT in that you'll get a bit more flow from the reducer using both outlets, not double the flow but a bit more. At least in part for the same reason we'd expect the usual 19mm pipe to flow more than if you used 12mm or narrower pipe (narrower pipe is often used on small engines between reducer and mixer, albeit using a 19mm>12mm adaptor if using an R90 or similar spec vaporiser). But with more volume in pipes you get slower response.
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