Hyster H70FT:
No start, then sorta running

Hey guys,

New here, I recently acquired a Hyster H70FT, with the complete cab and fingertip controls, a fairly decent machine. Its a 2006 and it has the GM Vortec 2.4L LPG engine in it.

Serial Number: L177B09417D

I'm experiencing a no-start condition, and I haven't worked much on these types of units, I'm more of a diesel guy.

I would like to walk you through the steps that I have taken so far, and how the lift is responding to everything.

The original problem. Long cranking time then briefly starts, sputters a bit and immediate decrease in RPM, then stalls.

I haven't used this lift in sometime now, so I figured I would start with the basics.

I performed a quick spark test, and #2-4 had a strong spark, while #1 did have spark, was much weaker compared to the others ( much dimmer light on the tester )

I figured it should be able to run off of 3 cylinders at the very least, so I continued on.

I disconnected the injector rail fuel inlet hose to see if there were anything coming out of it.

When I key on, a large amount of vapor was heard coming out of that hose, scared me a bit to be honest. I've done a similar test to an old Clark unit and there wasn't nearly the large amount of flow present.

So my first question, why is there vapor gases going into the injector rail when I key on, shouldn't this be vacuum activated like the much older LPG setups?

Anyways, I reconnected the hose and carried on. At least I know the lockout valve is working. The next valve after the lockout, I believe is a GFI Regulator/converter/vaporizer, has LPG in/out and two coolant hoses on it and has a small orange hose leading to the intake manifold.

I took this small orange hose off the intake manifold and I connected a hand operated vacuum pump to it. I applied maximum vacuum to this hose, approximately 25Hg and tried to start the unit.

It started, but was running pretty rough, and slowly dies down as if it was starving for fuel.

If I give it throttle while starting, I am able to rev up the engine, but then as soon as it reaches idle, it stalls.

After a few more attempts of this, the engine started to run longer and longer, I then swapped over the orange hose from the tool back onto the intake manifold and the engine was still running, which is odd because if I were to release the vacuum of the tool, the engine would stall, but that one time, i was able to swap the hose back onto the manifold.

So far my record, is having it run for about 5 minutes.

Alright so now I know it's getting fuel, and at least 3 cylinders are getting strong spark, now what about the injectors, are they working?

I started poking around at the connectors with some back-probes, to find all of the supply wires on the injectors to have similar resistances, about 14 ohms if I remember correctly. Power is present at these wires as well while cranking. I then tested the second wire, ground I'm assuming, and also assuming it could possibly be triggered by the ECM, to find some abnormal readings. The #4 injector had something around 100 ohms of resistance, while the first three injectors were in the Kohms, and one even in the Megaohms.

I thought this was weird, so I decided to check out the harness leading to the ecm, and even pulled the connectors off the ECM to check for any abnormalities.

Everything looked good, and pretty normal. ( will circle back to this later, unless you guys think this is normal )

So at this point, I'm thinking back to the fueling that I saw earlier. I have a hunch, possibly, the engine is being over-fueled, and since I didn't get the engine started until I applied vacuum to the hose between intake manifold and the GFI valve, that my next step would be to attempt to disassemble and inspect the GFI regular/converter/vaporizer. I'm expecting to find either a broken diaphragm or some sludge build up.

What do you guys think? This is as far as I have gotten so far.

I'm new with LPG systems, and also new to the brand.

If anyone knows how to retrieve fault codes without software, that would also be a great place to start.

I know where I'm heading next, but I would love to get some of your opinions.

Hope to hear from you soon!

Bye for now
  • Posted 28 May 2021 15:16
  • Modified 30 May 2021 02:02 by poster
  • Discussion started by Jeff_Donald
  • Alberta, Canada
Showing items 1 - 4 of 4 results.

Should you find higher pressures as you suspect, I would replace the LPG convertor. As posted before, change the filters just to be safe. There have been issues with the wire harness on the 2.4 GM engines. Makes sure there are no power issues with the coil supply. We have had a number of wires breaking in this location. With your experience, I am sure you have already checked the plugs. There has also been cam lobs that have worn down over time. You can get a GM engine idot light that should plug into a four prong plug either at the engine fuse box or under the floor board on the left side. Hard to reset password without the correct program. Good Luck
  • Posted 15 Jun 2021 00:54
  • Reply by Fishmech
  • Virginia, United States
The hard to do we do right away. The impossible just takes a little longer.
Also check the Fuel Filter, it is in-line with the hose that feeds Propane to the engine from the LP Tank.

It looks like it's made out of Aluminum and is about the size of a small bottle of Anacin.

You need to disconnect the hose from the LP Tank and bleed off what propane is remaining in the hose.
The filter is located inside of the part that I described.

You'll need to replace it if it's very dirty, or broken/falling apart.
  • Posted 2 Jun 2021 11:57
  • Reply by LaGrange
  • Missouri, United States
Strong in mind, Strong in Health.
The fuel pressure was a steady 12 PSI while cranking. So it is safe to say that it is getting the proper amount of fuel.

So my guess is that I'm either looking at an injector issue, being either the injectors themselves or the ECM or timing.

Other than that, I could always grab an oscilloscope and see if the cam and crank sensors are matching. Would be a good tool to have regardless.

This is where I'm at. Let me know if you guys have any ideas, or if you have encountered something like this before.

  • Posted 31 May 2021 16:00
  • Reply by Jeff_Donald
  • Alberta, Canada
Learn or be lost
There's an update:

The valve I was referring to is an Impco A7-242.

I did end up removing the outer cover on it for a quick inspection and everything seemed normal inside, I managed to do so while it was still installed on the lift.

I did manage to get the machine running much longer with very poor throttle response, I had to again apply vacuum to the MAP referencing hose ( orange hose on the valve ) and once it is running I disconnected the MAP sensor. This prevented it from stalling.

I have pulled up some specifications of this valve and the output pressure is supposed to be between 11.6-12.3 PSI, so my next step is to tap a gauge at the injector rail and check my pressure, I have a suspicion that my result will be much greater than the specification.

Does anyone know if a rebuild kit for this valve would solve an excessive pressure condition?

I will let you know of my result, I'm hoping this is the issue, since if not I will then be stuck on any further troubleshooting steps.

Also, I learned that you can pull fault codes from the small dash display, turns out that the factory password of 55555 is not accepted, so It must of been changed, since this was a leased unit many many years ago.

Thanks for tuning in, I will keep you posted on my pressure reading.
  • Posted 31 May 2021 02:43
  • Reply by Jeff_Donald
  • Alberta, Canada
Learn or be lost

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