odd one - started happening today ... nothing different, just decided to stop playing nicely!

Although I have recently rebuilt the engine, I don't think this is at all related as it did something kinda simlar beforehand .. although nowhere near as bad as it is at the moment (IMG:style_emoticons/default/smile.gif)

in a nutshell, whenever the engine revs past 2000 rpm it splutters and jerks quite badly - it's as if I have completely removed my foot from the accelerator/ If I put my foot down, there's nothing at all ... it's as if the ignition is off. However ... it doesn't die, it will idle quite happily.
It's not an ignition problem as the rev counter stays active.
It may be a full cut of some type, but I haven't got a scope onto the injectors yet so I don't know.
If I keep the revs below 2000, it's fine.
It also only seems to do it when the motor has warmed up - for a couple of minutes after starting it cold, it's happy. Soon as the gauge starts to move though it starts playing up again.
It does it in every gear as well as in neutral.
If I floor it, it will cut out well past 2000 and coast back down - if I put the pedal down whilst it's coasting there's no response.

odd.

I know it's a long shot ... but ... any ideas? (IMG:style_emoticons/default/smile.gif)

cheers,
slapper

Do you have a ballast resistor on your ignition?? If so, change that and try again.

no ballast resistor ... bugger!

I'm hoping to get a scope onto various bits this weekend - so long as it plays nice and fails when I want it to, I should have some more info about what's cutting out. Went for a couple of 10 min errands on the weekened and it ran fine! Happily, it's playing up today so at least I know it hasn't just gone away!

Sometimes the cutout is quite short, sometimes a good second and a half or so, but it's a real NO SPARK type feel. Do you know where the tacho feed is in these engines? It feels like an ignition breakdown, but the tacho keeps showing revs, so if it is spark, it's happening after the tacho pickup.

I also suspect it's a loose connection somewhere given its intermittent nature.

On a happier note ... the rebuild seems to be fine ... still waiting for it to leak oil everywhere and it's still refusing to do any more than dribble a tiny bit out the back of the head where that crescent shaped seal lives at the end of the cam!

Here's some stuff I added in a delica forum in response to other questions:

1989 petrol 2.4 8valve EFI (4G64).

- Electronic dizzy
- No backfires
- last filled up a week ago and have been driving since
- Engine was completely rebuilt 2000 km ago

The day it started I had plugged a crack in the exhaust with some muffler putty until I can get it welded. To assist drying, I let it idle for 15 minutes or so - temp gauge got to 2/3 whereas it normally sits below 1/2. So, the fact that I let it get that hot is unusual. I have a sneaking feeling this is related as it was doing something similar before the rebuild - and it also started after I'd let it idle for a while and register a high temperature.

The similar thing it was doing then was the same cutout/lurching - but it seemed to happen when cruising at very light throttle rather than whenever it hits 2000 rpm. I had a feeling this also was heat related as it seemed to start after a similar extended idle (after repairing a hole in the muffler) and accompanying engine heat up. I didn't chase it then as I tore the engine down and rebuilt it for other reasons and it hasn't shown itself again until now.

The cutouts are intermittent and don't seem to start happening until the engine's warmed up - for the first minute or so when cold, it doesn't seem to do it. Having said that, it doesn't always do it either. I stopped, disconnected the ECU temp sensor and the problem seemed to go away. I reconnected the sensor and it came back - so I disconnected it and this time it stayed.





hmmmmm,
Slapper

My van did started playing up when the coolant temp sensor went, its the larger one of the two and cost me a few bucks to replace. I disconected it and it also worked fine after. Mine would hold revs at 2000rpm.

Try replacing the 2 terminal sensor and see how you go.

Does yours have an engine check light? You could try testing to see if you have as fault code.

So, disconnecting the sensor stopped yours from playing up? I hoped that, if it was dodgey, disconnecting it would force a limp mode that would at least not exhibit the same problem. I concluded that, since it still played funny buggers with the 2 wire temp sensor disconnected, the sensor was probably not the problem.

hmmm .... don't know about the check engine light. there's not one showing on the dash when the ignition's on - but there is a (!) symbol on the dash (that's not illuminating). Do you know if there's a way of forcing it on? (so I can check that the bulb's good).

Do you know what tha "suck out the fault code" procedure for this engine?

cheers,
slapper

Yeah disconecting it cure it, replacing it fixed it perminantly but my symptoms were a bit different. Also check the O2 sensor if yours has one.

The code check is done usually by earthing out the number 1, pin on the connector under the dash nr the fuse box.

I'll check tomorrow what pin it is...

i HAVE 91 STARWAGON WITH EXACTLY THE SAME PROBLEM, I HAVE REPLACED THE OXYGEN SENSOR WHICH IS WHAT CAME UP ON THE MISUBISHI COMPUTER CODE BUT DIDNT FIX THE PROBLEM, HAVE ALSO REPLACED IAT SENSOR, NO CHANGE, DOES ANYONE HAVE ANY IDEA AS NO ONE CAN SEEM TO TELL ME WHAT IS CAUSING THIS PROBLEM WITH THANKS

Okay ... got around to checking spark last night.
it's fine (IMG:style_emoticons/default/sad.gif)
just connected timing light to plug leads.
when the engine cut out, timing light continued flashing.

Interestingly, it seemed to stop doing it when the temp gauge reached half way.

So I'm looking fuel next. Either

• fuel pump (there's just the in-tank one so far as I know)
• pressure regulator
• fuel filter

Does anyone know whether this engine is batch fire or sequential on the injectors?
If batch fire, then I'll suspect them as well ... if sequential, I guess it's unlikely they'd all die at once.

onwards,
Slapper

that connector has two pins populated in mine ...
is it a earth pin 1 and run a current damped LED between the other and ground?
I've had a wander around the 'net, but can't find a clear indication what to do (IMG:style_emoticons/default/smile.gif)

I don't suppose you also have alisting of the codes?
Same story, not sure I can find any info that's definitley for the pre-OBD engines.

cheers

If you suspect the injectors not firing. Try listening with a stethoscope or a long skinny screwdriver. grab the handle in a fist and put it flush against your ear. The pointed end on the middle of each injector and listen for a distinct click. Believe these are sequential but it doesn't make much difference.

If you know anyone with access to Alldata, they have the codes.

on pre OBD-II it's usually a jumper wire (paper clip) , ground one pin or connect 2 pins together. It will flash the check engine light on the dash in a code pattern. long flash for the 10's, short flash for the 1's.

like

long, long, short, short, short, ..... would be code 23

or

long, short, short..... would be code 12

used the screwdriver trick - injectors stop firing .. so it's a fuel cut by the looks.
I am now suspecting this ...
 l300_thing.JPG ( 83.37K ) Number of downloads: 14

 l300_isc_connection.JPG ( 146.13K ) Number of downloads: 14


When I disconnected it, the cutout stopped.
It came back when I plugged it in - so I'm 99% sure it's the culprit, whether from a dodgey connection or a failure in the module itself.

Unfortunately, I have no idea what it is! In all the pictures I can find in my Gregory's of that area, it's not attached.

hmmmm ....
any ideas what it is, and/or how to test it?

cheers,
Slapper

aha!!!
it's the idle speed control by the looks of things.
or maybe even the idle position sensor ... or something ...

still don't know how to test it either (IMG:style_emoticons/default/smile.gif)

I'll try find some info on it, thats what was involved with my issues too the Idle control....

try a "known good unit", a friend that has one you can swap out real quick or something, always quicker/surer than testing, especially when it's intermittent. But testing works if you have a meter and pinout info

sort of weird that it would disable the injectors, maybe it's tied into the circuit and it's conflicting with the 5v supply or something, strange.

Quick update ...

After disconnecting the connector indicated earlier, the problems at 2000+ rpm have gone away.
A couple of days later, the original (pre engine rebuild) problem of lurching when cruising came back - disconnecting the other connector to the ISC assembly fixed that.

As far as I can tell, the first disconnection I made is the ISC motor position sensor and the second disconnection was to the motor itself.
So - diagnosis would seem to be faulty ISC assembly (not surprising really!)

I've trying for the last couple of weekends to find time to pull the ISC assembly out so I can:
1) attempt to fix it - long shot but I know enopugh about electronics and mechanicals and being a cheapskate to maybe pull this off (IMG:style_emoticons/default/smile.gif)
2) identify it so I can replace it

cheers,
Slapper

I have a copy of how you test the throttle position sensor and idle position switch if its any use, yours is pre 91 so is different to mine as i was gonna say you could try mine.

The trouble seams to be the TPS or IPS for sure. Its getting confused about where the throttle position is in relation to load and how many RPM your doing.

that would be good ...

I pulled it down tonight - I'm guessing you must have the stepper motor version as I think that's what they went to after mine ...

on analysis, mine is:

• Two wires to control a motor - which seem to be fine.
• Three wires to what looks like a hall effect sensor that senses how far the idle-up piston has moved.
• One wire that gets earthed when the idle-up piston presses against the throttle wheel.

The connector I originally disconnected was indeed the piston position sensor.
That second connector has the motor power and piston end pressure switch in it.

There was some gunk inside that might have affected the "I'm pressing the throttle wheel now" switch, but I can't be sure - it seems okay after I've cleaned everything though.
There is some adjustability in how close the piston sits to the hall-effect sensor at rest, but I have no idea where I should put it, so I've left it untouched. Well, when I say untouched ... I may have moved it a little bit before I worked out what was going on (IMG:style_emoticons/default/smile.gif)

I've cleaned everything and stuck it back together so we'll see what happens. A check procedure would be good though.

cheers,
slap

Sounds like your on the right track yeah.

Hows this?

That's mainly the TPS - although it does got the "idle position switch" at the bottom of the page - I don't suppose there's anything else on the next page about the ISC motor and sensor?

bugger (IMG:style_emoticons/default/smile.gif)