intermittent idle
Moderator: BCDelica
- after oil
- Posts: 1436
- Joined: Mon Feb 11, 2008 7:01 pm
- Member's Photo Album: http://www.delica.ca/Photos/
- Vehicle: 92 cham-reimo poptop L300. 78MB240D
- Location: on the road
- Location: occupied coast salish territory aka powell river
intermittent idle
when on WVO the rpms rise and lower while idling. is this a problem?
- konadog
- Posts: 1815
- Joined: Tue Feb 26, 2008 9:25 pm
- Vehicle: 1992 GLX L-300
- Location: Campbell River, BC
Re: intermittent idle
I'm no expert, but I'm pretty sure any motor should idle at a steady rpm. Fuel delivery issue, maybe... 


Happy Day!
- BCDelica
- Posts: 1808
- Joined: Tue Jul 18, 2006 4:12 pm
- Member's Photo Album: http://www.delica.ca/Photos/index.php?cat=10008
- Vehicle: WVO Powered Tuk Tuk
- Location: Central Van Isle
- Location: Somewhere with plenty of sun
Re: intermittent idle
First guess would be you do have a fuel restricten problem.
Second guess would be somethings up with your IP.
Second guess would be somethings up with your IP.

- after oil
- Posts: 1436
- Joined: Mon Feb 11, 2008 7:01 pm
- Member's Photo Album: http://www.delica.ca/Photos/
- Vehicle: 92 cham-reimo poptop L300. 78MB240D
- Location: on the road
- Location: occupied coast salish territory aka powell river
Re: intermittent idle
theres still some 5/16" line, ill change that to 3/8"
theres also 1/4" return but slavko says should be okay. ill change that to 5/16"
that should address all the fuel restriction problems
theres also 1/4" return but slavko says should be okay. ill change that to 5/16"
that should address all the fuel restriction problems
- mararmeisto
- Posts: 3276
- Joined: Wed Sep 19, 2007 10:00 am
- Vehicle: 2018 Ram EcoDiesel
- Location: Dartmouth, NS
Re: intermittent idle
Sounds like you've used two different-sized fuel lines along the supply side of the pump - bad idea, for it changes the flow rate when the piping gets smaller. Return side won't matter as much, because it just 'dumps' into the tank.after oil wrote:theres still some 5/16" line, ill change that to 3/8"
theres also 1/4" return but slavko says should be okay. ill change that to 5/16"
that should address all the fuel restriction problems
Other than that, does it do this surging when the engine is warm or just when cold? If only when cold, maybe your inline heater is not functioning properly.
Otherwise, it could be the injection pump.
JPL
I still miss my '94 Pajero!
I still miss my '94 Pajero!
- after oil
- Posts: 1436
- Joined: Mon Feb 11, 2008 7:01 pm
- Member's Photo Album: http://www.delica.ca/Photos/
- Vehicle: 92 cham-reimo poptop L300. 78MB240D
- Location: on the road
- Location: occupied coast salish territory aka powell river
Re: intermittent idle
thats right, the line into the filter is 3/8" and from the filter to the heat exchanger, 5/16" but 5/16" is the nipple on the heat exchanger and on the IPmararmeisto wrote: Sounds like you've used two different-sized fuel lines along the supply side of the pump - bad idea, for it changes the flow rate when the piping gets smaller. Return side won't matter as much, because it just 'dumps' into the tank.
Other than that, does it do this surging when the engine is warm or just when cold? If only when cold, maybe your inline heater is not functioning properly.
Otherwise, it could be the injection pump.
remember theres an assist pump 7 psi or close to that
it idles inconsistently when warm too
it better not be my IP... but it idles fine on petro-diesel
- mararmeisto
- Posts: 3276
- Joined: Wed Sep 19, 2007 10:00 am
- Vehicle: 2018 Ram EcoDiesel
- Location: Dartmouth, NS
Re: intermittent idle
Okay, no longer worried about the line size, but it still sounds like there is a problem on the WVO-side of your system. Did you check that other filter? Is it a paper one or a mechanical one (i.e. one you can clean)? I'd check that next.after oil wrote:thats right, the line into the filter is 3/8" and from the filter to the heat exchanger, 5/16" but 5/16" is the nipple on the heat exchanger and on the IPmararmeisto wrote: Sounds like you've used two different-sized fuel lines along the supply side of the pump - bad idea, for it changes the flow rate when the piping gets smaller. Return side won't matter as much, because it just 'dumps' into the tank.
Other than that, does it do this surging when the engine is warm or just when cold? If only when cold, maybe your inline heater is not functioning properly.
Otherwise, it could be the injection pump.
remember theres an assist pump 7 psi or close to that
it idles inconsistently when warm too
it better not be my IP... but it idles fine on petro-diesel
JPL
I still miss my '94 Pajero!
I still miss my '94 Pajero!
- after oil
- Posts: 1436
- Joined: Mon Feb 11, 2008 7:01 pm
- Member's Photo Album: http://www.delica.ca/Photos/
- Vehicle: 92 cham-reimo poptop L300. 78MB240D
- Location: on the road
- Location: occupied coast salish territory aka powell river
Re: intermittent idle
the main filter is a spin on hydraulic oil filter, brand new, the other is a glass sight filter, that can open up and be cleaned. the element inside is a metal screen i believe. i can see the odd bit of debris on theremararmeisto wrote: Okay, no longer worried about the line size, but it still sounds like there is a problem on the WVO-side of your system. Did you check that other filter? Is it a paper one or a mechanical one (i.e. one you can clean)? I'd check that next.
i still gotta post photos of that filter and there are still no photos of the control switch

- oceaneer77
- Posts: 54
- Joined: Fri Apr 25, 2008 5:26 pm
- Member's Photo Album: http://www.delica.ca/Photos/
- Vehicle: 91 exceed, 87 porshe 928, 67 datsun
Re: intermittent idle
If you have constant pressure (7+) psi at the ip inlet
then.. sounds like the viscosity of the fuel in your IP is to thick and is starving to fill the plungers.
can you heat the WVO any higher?
heavy fuel engines have the same symptoms when running bunker c and not hot enough.
oceaneer77
then.. sounds like the viscosity of the fuel in your IP is to thick and is starving to fill the plungers.
can you heat the WVO any higher?
heavy fuel engines have the same symptoms when running bunker c and not hot enough.
oceaneer77
- jessef
- Posts: 6459
- Joined: Tue Feb 26, 2008 1:27 pm
- Vehicle: JDM flavour of the month
- Location: Vancouver
- Location: Vancouver, BC
Re: intermittent idle
You can try running a small 12v inline fuel pump. 

- after oil
- Posts: 1436
- Joined: Mon Feb 11, 2008 7:01 pm
- Member's Photo Album: http://www.delica.ca/Photos/
- Vehicle: 92 cham-reimo poptop L300. 78MB240D
- Location: on the road
- Location: occupied coast salish territory aka powell river
Re: intermittent idle
two things possible regarding you thoughts oceaneer77oceaneer77 wrote:If you have constant pressure (7+) psi at the ip inlet
then.. sounds like the viscosity of the fuel in your IP is to thick and is starving to fill the plungers.
can you heat the WVO any higher?
heavy fuel engines have the same symptoms when running bunker c and not hot enough.
oceaneer77
could be the oil isnt heating enough because i presently have mostly water in the cooling system. i didnt want to leak coolant, but now im sure it wont leak (it never did) tomorrow i will put the correct ratio of coolant to water
number 2: my fuel is heated first by the engine coolant, then by a glow plug to 75c before entering the IP. the engine never gets warm enough for the thermocouple to tell the glow plug to shut off. maybe ill need a hotter thermostat for the cooling system, so i can run a little hotter...
got thatjfarsang wrote:You can try running a small 12v inline fuel pump.
- oceaneer77
- Posts: 54
- Joined: Fri Apr 25, 2008 5:26 pm
- Member's Photo Album: http://www.delica.ca/Photos/
- Vehicle: 91 exceed, 87 porshe 928, 67 datsun
Re: intermittent idle
Hi After oil
On #1 water and coolant will hold the same amount of BTUs just the coolant raises the boiling point so #1 is out in my books.
#2 seems to make the most sence.. if i had a viscosity meter we could check the WVO at 75C and compare to #2 diesel but the mere is on the ship and its on the way to panama now.
Can you try to thin the wvo sith some diesel and see what happens at 75C?
thanks
Oceaneer
On #1 water and coolant will hold the same amount of BTUs just the coolant raises the boiling point so #1 is out in my books.
#2 seems to make the most sence.. if i had a viscosity meter we could check the WVO at 75C and compare to #2 diesel but the mere is on the ship and its on the way to panama now.
Can you try to thin the wvo sith some diesel and see what happens at 75C?
thanks
Oceaneer
- after oil
- Posts: 1436
- Joined: Mon Feb 11, 2008 7:01 pm
- Member's Photo Album: http://www.delica.ca/Photos/
- Vehicle: 92 cham-reimo poptop L300. 78MB240D
- Location: on the road
- Location: occupied coast salish territory aka powell river
Re: intermittent idle
sorry about waiting so long to post results....
i replaced some of the 5/16" line with 3/8", but its still 5/16" from the wvo filter to the heat exchanger and IP
i was in at ccauto to get ip timing and valve clearance set in advance of my trip to mexico.
yesterday i was all over town on WVO and the idle seems steady at around 750 in D and 1000 in P
i replaced some of the 5/16" line with 3/8", but its still 5/16" from the wvo filter to the heat exchanger and IP
i was in at ccauto to get ip timing and valve clearance set in advance of my trip to mexico.
yesterday i was all over town on WVO and the idle seems steady at around 750 in D and 1000 in P
- jrman
- Posts: 506
- Joined: Thu Aug 16, 2007 12:29 pm
- Member's Photo Album: http://www.delica.ca/Photos/
- Vehicle: 1991 MMC Delica Exceed - Scoobus
intermittent idle
I'm almost having the same issue.
Just had IP fully rebuilt.
Idle set at 750 in D, comes slighting in P or N - maybe 800.
But occasionally I'll go to park and it comes up to 1000. Back to drive, and she's at 750. Doesn't do it every time - and appears to be only after driving for a while. But once it starts doing this - nothing will change till I shut the engine off. Fire it up right away - and it idles normally (ie, 750 in D / 800 or slightly less in P or N).
Funny behaviour!
BTW - didn't do this prior to IP rebuild - solid at 750, ever slightly higher in P or N.
I believe its related to the throttle position sensor (black unit with wire sticking out on top of IP - two flat head screws holding it in place)....but just guessing.
Mardy has 6 mo warranty so may have to go back to check it out, but will tamper with the TPS first and see if that changes things at all.
Just had IP fully rebuilt.
Idle set at 750 in D, comes slighting in P or N - maybe 800.
But occasionally I'll go to park and it comes up to 1000. Back to drive, and she's at 750. Doesn't do it every time - and appears to be only after driving for a while. But once it starts doing this - nothing will change till I shut the engine off. Fire it up right away - and it idles normally (ie, 750 in D / 800 or slightly less in P or N).
Funny behaviour!
BTW - didn't do this prior to IP rebuild - solid at 750, ever slightly higher in P or N.
I believe its related to the throttle position sensor (black unit with wire sticking out on top of IP - two flat head screws holding it in place)....but just guessing.
Mardy has 6 mo warranty so may have to go back to check it out, but will tamper with the TPS first and see if that changes things at all.
Sean in North Van
1991 Delica Exceed - Scoobus
1991 Delica Exceed - Scoobus
-
- Posts: 81
- Joined: Fri May 23, 2008 5:20 pm
- Member's Photo Album: http://www.delica.ca/Photos/
- Vehicle: toyota surf TD
Re: intermittent idle
nope, the flow stays the same but pressure changes...mararmeisto wrote: Sounds like you've used two different-sized fuel lines along the supply side of the pump - bad idea, for it changes the flow rate
basic hydraulics