The Joy of EX

[jcasey007]

You know what it's like, hours and hours under and in the EX in freezing weather trying to fix that elusive fault (Jan knows all about that !) and then it all comes together....

I've just done a sprint up to Edinburgh this afternoon (380 miles) and not a thing has gone wrong with her, no backfires followed by gaffer taping the airbox up (again), no tasty suspension clunks thinking the steering rack will seize at any moment, I even averaged 20 to the (UK) gallon!

I'm starting to think she will go on for ever, just replace each part as it wears out... reminds me of the bloke who had the same hammer for 40 years having replaced the head and handle when ever each wore out.....

OK so there is still lots to do on her, just let me enjoy the road trip this week and then I'll rebuild the rear axle next weekend

So off the Aberdeen tomorrow, back to Edinburgh the following day with Leeds on Thursday... keep your fingers crossed it all goes as smoothly

 

[janolsson]

Don't rub it in.
I'm glad its all good
I've only done about 5 miles since June hmmph

 

[jcasey007]

So I made it back safe last night, 1150 miles round trip

The weather in Sotland and Northumbria was quite wild with bad snow, high winds and floods all in one trip. Very sad to hear about the school coach crash and fatality, as it happens I travelled the same road 8 hours before and the snow was bad then and was still a challenge in the EX.

I also had fun in the floods with water over the top of the diffs coupled with high tides and high winds.

As with all trips not all went as smooth as I had liked, I had 2 inlet backfire/backdrafts. Interestingly it only occures when I'm coming out of a slow corner (not all the time), the engine is spinning about 1500 rpm and I lightly feed in the throttle,

I can feel it bogging down, if I ease off and reapply the throttle she clears and accelerates. If I kickdown it clears and again it is fine.

I've also watched the real-time o2 sensor I've installed when it is doing this and it neither goes lean or rich.

So at the moment I'm thinking either the TPS (as it happens just above closed) or the stepper motor on the gas system.

Any other idea's or things to check.

Apart from this ball ache she is running fine, The airbox is now a mass of gaffer tape so I want to sort it before getting a new airbox

cheers

Jim

 

[janolsson]

I also had fun in the floods with water over the top of the diffs coupled with high tides and high winds.
Jim

So you'll be changing the diff fluids then. Recommended if immersed in water. Personally i'd be inclined to just syphon a little out to check for water ingress but i'm on a tight budget.
regards

 

[colingel]

Have you tried for help on the LPG Forum?

 

[jcasey007]

No colingel, when I first got the EX I posted a couple of questions on the LPG forum and was basically told to junk the system I have and get a sequential system.

So I made it my mission to understand the gas electronics and to do the gas mechanics myself. I have taken it into two different gas specialists in the pask but both times I found that I was giving them advice on my system.

On the current fault I can replicate the problem when I want to, and my gut tells me it is the TPS. So that is where I will start.

cheers

Jim

 

[wetdog]

source a chap on here called boots, he once had a single point lpg ex and was knowledgable on tuning them and getting the best from them.

mick.

 

[colingel]

Was just a thought.Have noticed that they can be a bit abrupt your face either fits or it doesent

 

[jcasey007]

It's a faulty component as opposed to a tune up that is causing the occasional backfire.

It's been running great since I fitted a new vaporisor for months now and has just started doing it in the last 2 weeks. I thought it was plug gaps but they are still at 30 thou.

I'm thinking it has to be one of the systems that is shared between the gas and petrol systems so that narrows it down to TPS and crank position sensor as I have a judder on petrol when I'm cruising with the throttle in the same position.

cheers

jim

 

[janolsson]

Just a thought but what plugs are you running?
I read somewhere that the standard plugs as opposed to platinums run better with gas. I believe usa automotive sell autolite.

 

[jcasey007]

I've run both platinums and standard with the same effect (both run fine) at present I am using standard with the gaps reduced to 30 thou

 

[jseabolt]

Have you tried for help on the LPG Forum?

Where is this LPG forum? I thought about doing a conversion on my 5.0 liter Explorer

Since LPG is cheaper here in East Tennessee (low octane petrol is currently $2.69 for a US gallon (4.54 liters) versus $1.69 for LPG).

But do you end up using more LPG than gasoline? Or can the system be set up to use the same amount of fuel but loose power? It wouldn't bother me to loose some power.

I've got a 500 gallon LPG tank I use to heat my garage with if I could get a fitting for the tank to fill my Explorer directly.

There are no automotive LPG filling stations around here. All LPG dealers are closed on weekends anyway. So that's why I'd go with a dual fuel system rather than a dedicated LPG.

What I'd like to do is find a tank that will fit in place of the spare tire. Suposably there are some available in New Zealand but I haven't found a source here in the US.

I'd like to use a BLOS mixer which should fit perfectly in the intake hose being it's roughly the same size.

I'm not sure where to place the vaporizier since the engine takes up allot of room under the hood. Maybe do away with the air cleaner and use a K&N.

Anyone got any photos of such a conversion on an Explorer?

 

[colingel]

Hi

Check out www.lpgforum.co.uk

Lots of good information

 

[jseabolt]

Hi

Check out www.lpgforum.co.uk

Lots of good information

The forum owner has yet to give me access to sign. I signed up weeks ago.

 

[jcasey007]

The LPG forum is I think run as a lead generation engine for a few LPG installers so as you are in the US maybe they don't give you access as they can't sell you anything.

Sorry to be cynical but when ever I posted questions about my regmatic, single point closed loop system all I got was it's old and crap and needs to be replaced with a bright and shiney multi-point system.

6 months of web searching and translating a load of italian documents I now know how the electronics and mechanical bits work together and my LPG installation is running like clockwork. So no replacement needed!:

 

[janolsson]

my LPG installation is running like clockwork.

Running like clockwork eh, ticking. Bombs also tick LOL

 

[jcasey007]

yes thankyou Jan

I get about 1 bomb going off every 8 weeks at the moment but I found that the standard air filter box is part of the problem as (I think) excess LPG builds up in it when you open the throttle wide (from a standing start) and then quickly shut it.

you know the manouver at the lights when the lights have changed and you are going, but the guy in front isn't.

You saw the big hole in the top of my air box, caused by a backfire, when I was running like this I didn't have any problems. I fitted the replacement chris gave me and within a week, I had a backfire.

So I've now fitted a 'performance' cone filter to the MAF and have had no problems with backfires since (4 weeks and rising)

My theory is that the single point systems (Leoardo and Regmatic etc) have a 5 second update cycle, meaning that the stepper motor that controls the gas flow only changes every 5 seconds. That is why a rapid open and close of the throttle can result in the stepper motor delivering a lot of gas to the intake when the throttle is closed and demand is low. Hence they gas backs up in the air hose, MAF and Airbox.

I have some forced recuperation time over the next 2 weeks following an operation next monday, I'm thinking of designing a faster processor to replace the regmatic controller with a faster control cycle.

cheers

 

[janolsson]

That sounds a reasonable diagnosis.
Now to design your own chip you're starting to talk voodoo. I don't really trust it if it can't be fixed with a hammer.
Good luck with that, who knows could be a product you could sell if all works well.

 

[jcasey007]

I also own and love a big hammer but my day job was designing real-time control systems. The regmatic systems use a very old processor which is why it takes 5 seconds to read 5 inputs and calculate what the value to send to the stepper motor.

With a modern PIC processor I can run it with a cycle time of a quarter of a second or less and can monitor some of the other sensors not currently used (i.e. the MAF or engine coolant temp or air temp)

I'm in on monday to have an operation on my shoulder (I heroically fell over in the ice!) which will immobilise me for 3 weeks at least so no hammer work for a while so I need somthing to work on.

 

[janolsson]

I also own and love a big hammer but my day job was designing real-time control systems. The regmatic systems use a very old processor which is why it takes 5 seconds to read 5 inputs and calculate what the value to send to the stepper motor.

With a modern PIC processor I can run it with a cycle time of a quarter of a second or less and can monitor some of the other sensors not currently used (i.e. the MAF or engine coolant temp or air temp)

I'm in on monday to have an operation on my shoulder (I heroically fell over in the ice!) which will immobilise me for 3 weeks at least so no hammer work for a while so I need somthing to work on.

Now we're talking!
That means you will be able to adjust the mixture more accurately to improve power, economy and therefore reliability. You are gonna have fun trying to understand what mixtures you will need or is the idea to go for a perfect stoichimetric (spelling?) mix at any condition?
Is the stoic the same for gas as petrol? You got some more reading to do me thinks