LOW Iddling PROBLEM: one day in TEXAS to fix it...

[lost2]

Hi guys (and girls..),

We made it to Houston, Texas, starting from Montreal on tuesday. After 4277 km, our beauty is doing fine except for a small problem with too low idling, and not starting as easily as before.

Here are the basic symptoms:
*Even after driving a long stretch, when I start the engine, I have to hold the key for about 3-4 secs to get her running. She used to start in half a second (especially when the engine was warm). I also have to push a bit on the gas pedal to see her start. Once started it idles fine most of the time (but sometime it goes slowly from 850 rev to 1000 rev, than back to normal).
*Once it's running (in park or driving), if I give a good shot on the pedal, she runs fine but then returning to iddle she goes too low (under 750 rev., even as low as 250 rev.) Sometimes it comes back to normal (around 850 rev.), but sometimes the engine chokes. It seems that the higher I let the engine revolute, and then let it slow down, the more it goes down in rev.
*Once accelerating or once driving it on the highway, everything seems fine, there are no apparent lost of power. The problem only occurs when I let the engine goes back to idle.
*These symptoms appeared the first time after a 4 hours drive at night in HEAVY RAIN. When I got to our camping site, I stopped the engine after a few minutes, then tried to start the engine to move the vehicle a bit forward, and had to do as mentioned earlier (hold the key and give some help with fuel pedal).


What has been done in the past weeks/month:
*fuel filter changed with a full flush of sea foam
*reinstalled 2 three-way 3/8" brass valves to connect the extra fuel tank (it used to be wvo), one for fuel supply lines, and one for the return lines.
*the idling adjustment screw is NOT the problem
*While trying to figure what was wrong with idle, I have noticed that the wire that connects to the “kick down thing” on top of the IP was thorn and cut, so I reconnected that wire, put it seems not related to my actual problem.

Now, today I’ll check the air filter (I have an extra at hand). I’ll also take the time to do an oil change. We leave during the night for Laredo, and then we’ll be in Mexican territory!

I hope you won’t tell me my IP is giving up, and that I should rather look at a very simple thing that never crossed my mind…
air in fuel line? I suspect I would have some lost of power…
not enough fuel coming to the injectors? An injector blocked by crap? I suspect I would have some lost of power…
Any bright full thoughts or just any idea would be appreciated.

Thanks,

Davy

[jessef]

Hi Davy

How is it when driving casually around the city and sitting at stop lights?

If you're getting good power at 1/2 to full throttle but it still dies at low throttle, check your extra fuel tank, tee and line connections for any leaks.

Different vehicle but similar setup I had the same problems as you. It turned out to be the injection pump was stuffed.

Workaround unless you have done it already is to install an inline fuel pump near the main tank. This will take the strain off the IP when at low throttle and not pulling enough fuel.

Either you're not getting enough air or fuel but because you need to press the throttle while starting points to ip not pulling enough fuel.

[lost2]

Thanks Jesse for this quick answer. Very much appreciated!

How is it when driving casually around the city and sitting at stop lights?

As you suspect, when I drive around in the city or stop at lights, it tends to die at low throttle.

If you're getting good power at 1/2 to full throttle but it still dies at low throttle, check your extra fuel tank, tee and line connections for any leaks.

That's it: it is even perfect from 1/4 to full throttle, but dies at low. I have already check for leaks, and didn't found any (I mean I visually checked for fuel leaks around the lines). I am not using the secondary tank. It is for emergency purpose.

It turned out to be the injection pump was stuffed. Workaround unless you have done it already is to install an inline fuel pump near the main tank. This will take the strain off the IP when at low throttle and not pulling enough fuel.
Either you're not getting enough air or fuel but because you need to press the throttle while starting points to ip not pulling enough fuel.

Inline fuel pump sounds great. Can I place it after the three-way supply line valve, so that it would pump fuel at either tank?
What brand or spec this inline pump should have?
And finally, where do I electrically plug it so that it works when it has to?

By the way I have constant internet access today, and a camera to take pictures if needed to. I forgot to say the truck is a L300, 1990 3d56t, auto trans. 4wd.

I will go in a store this afternoon trying to get everything I need.

Cheers,

Davy

[jessef]

Just go to lordco or auto / marine parts store and ask for an inline fuel pump with maximum 7-8 psi. Any more is not good.

Also ask to see if the inline pump similar to this one: http://www.fuel-pumps.net/fra11.html

You want to get a fuel pump that allows flow even if it dies (no power/mechanical malfunction) otherwise if something happens to the pump, you're dead in the water.

The walbro pumps are the best because they have replacement filters that are good for dirty diesel in CA.

And you want to mount the pump as close to the fuel tank as possible, best position is above the tank. If you have two tanks, get two pumps.

Having the pump up at the valves is a recipe for air/fuel mix issues.

Good luck !

[lost2]

I understand what you say about pumps closer to tanks. The supply lines are exiting on top of each tank, so i figure this is the best, and lowest place to install them. And having pumps that permit flow even if they are out is a good advice too.

Do you have a suggestion on how to make these work. I can't plug them directly on 12v and let them turn until they are burned... Or do they have a special device like an integrated pressure switch that activate them when there is a demand for fuel (i doubt it...)? Is there a relay where I can connect them?

[lost2]

I went to Auto Zone and found that inline 12v fuel pump.

Will try to fond where to wire it now. Let you know of the results.

Davy

[R.Costa]

Hey lost, If you go through Oklahoma and you have any problems, or just want to hang out, I am in Ada, Oklahoma which is in southeast Oklahoma. I will be willing to lend a hand and some tools.

[jessef]

if you haven't already, pickup a voltmeter. this will allow you to diagnose electrical problems down the road.

Wire the 12V+ wire of the fuel pump to a switched source (when the ignition is in the 'on' position - pump is on, when the ignition is in any other position - pump is off).

Use either a relay or a good fuse.

[lost2]

Everything is wired and working. Problem seems to be partially resolve, as it still does once in a while the symptom previously enumerated, but at a lesser degree.

We cross the Mex border within 2-3 hours and a let you know later if things evolves...

Thanx again for your advice Jesse,

Davy

[jessef]

If you noticed a change after fitting the pump then the problem lies within your fuel system.

Did you bring a spare injection pump and injectors with you?

Contact After Oil (Ari) on this forum. He may have contacts in Mex as to where you can get it serviced.

I pm'd you Felix's mail (used to be on this forum flexboi). They are doing a SA trip and are in Mex now and I'm sure they brought a spare down with them (wise on cross country trips).

If you can, have your IP and injectors done before you go into Mexico. It may be cheaper to buy them here from a vendor (look in the Vendor's section) and ship them to you compared to having it rebuilt down there.

Good luck!

[lost2]

Hi again Jesse,

We did cross the border yesterday because wew found the problem wasn't totally fixed while driving and wanted to clear the border area before night time.

The car runs ok, even in the Sierra Madre Oriental, but it does some black smole while accelarating hard.

I remembered reading about black and white smokes, one being too much fuel mixture and the other too much air, but can't remember which is which. My internet accesses are limited, so I won't do any more search on th e site now, but as long as we can get to the yucatan peninsula, we will than be there for 2 weeks and I will have time to try fixing the problem.

A friend suggested the problem could be a extra air suplly (i.e. air getting in somehoow after the filter) so that adding a inline pump would have helped by augmenting the fuel/air ratio. Does gthat make any sense?

I hope things won't get worse, but still feel confident.

Thanks for your help, I will try to reach the fellow delica's owner in MEX as soon as I get more time (or sooner if things turn bad...)

Davy

[jessef]

Glad the pump helped. Good vibes for a safe trip.

[Firesong]

A quick maybe to this.
Would turning up the pressure of the IP by a 1/8 or quarter turn
help the scenario out as a quick fix?

Only a temporary fix till you get home after the vacation.

FS

[PinkPig]

A few other thoughts...
other than dirty injectors / failing pump here are so things to rule out that are cheap and quick to do:

I had air in fuel problems once - I fitted a length of clear fuel pipe from the filter to the pump which allows you to see if the fuel is clear or bubbly/foamy going into the pump. Turned out to be the filter mount itself had a small air leak in one of the unions.

Check or even remove the air filter briefly and see what happens - heavy rain may have got the air filter wet and then dust/dirt gets stuck to it restricting the air flow (making the mix richer and causing the black smoke)

Check all the turbo piping for air leaks including the small pipe that runs from the turbo side of the engine to the fuel pump (across the top front on mine)

bit leftfield ..Check the auto gearbox fluid level and colour - could it be gearbox/torque converter drag?

And lastly, it might be the fuel pump timing slightly out. Not sure how that would have happened by itself, but if something is worn, then maybe.

Good Luck!

[jessef]

All good point FS and pinkpig.

They have already ventured into Mex and if the inline pump holds up, they should have no major issues down the road.

Pinkpig, you mentioned the timing.

At the driveshaft end of the injection pump is a vane style fuel-supply pump that's used to bring fuel from the tank. If it's worn and pulls a lower psi, the timing becomes retarded, affecting their performance. By putting an inline fuel pump before the IP, it pushes fuel and 'helps' the vane pump essentially advancing the timing back to the original timing it was set at. This is most likely why their original problem got better after the pump install.