Check Engine Light & Rev Counter drops out

[BigHorney]

Hi All,

I have a 1995 Isuzu Bighorn 3.1TD, Engine No. 4JG2

Check Engine light comes on intermittently when driving, even @ 100kmh and suffers an erratic Idle

With the Check Engine light the Rev Counter drops out altogether and the engine starts pulsing quite a lot (erratic Idle
) - so isn't happy about something, if I come to a stop it can stall due to the pulsing revs - erratic Idle

If I turn off the car and start it up again the Rev counter comes back and the Check Engine light dissappears - albiet only for a short time until it happens again.

Issue seems to have crept in since I had a slipping Alternator belt due to a broken Belt tensioner - I feel this could still be related to my issue and maybe needs even more tightening but maybe I'm wrong

Has had me baffled for some time.

[geeves]

is this the electronic or mechanical pump?

[BigHorney]

Not too sure on that one Jeeves, it's has a manual diesel pump located in the engine compartment if that's what you're referring too.

Or maybe you're referring to the cabling from Gearbox to Dashboard for speed/rev regulating.

This model is a 1995 3.1TD

I was trying to replicate the problem and was switching from 2WD to 4WD and then it happened whilst idling and rev counter drops out and the engine starts pulsing up & down by itself.

not sure if I have narrowed it down, I can only see a VSS Vehicle speed sensor underneath connected into the Gearbox, not sure what other gadgets are under there to check

[BigHorney]

Pretty much believe this is due to the slipping belts, but then again this has had me stumped so I don't have a clue really.

BTW I have since had the tensioner and belt fixed by mechanic so all is tight again, so that has ruled that out

Seems like the governor in the diesel pump may be the way to go so will find out what I can on that

[geeves]

My money is on the governor in the diesel pump. 95 could be manual or electronic. Have a look The manual has a cable on the front the electronic a box on the back and no throttle cable. Electronic pumps are known foe governor faults and this is the symptom

[BigHorney]

Thankyou for the reply geeves, much appreciate pointing me in the right direction as this is still happening and is very fustrating when Rev Counter drops out and Engine starts pulsing to the brink of cutting out at every set of traffic lights, so I must get to the bottom of it.

Will check out what I can find on the governor in the diesel pump or at least point my Mechanic in that direction.

Excuse my ignorance around Diesel pumps, but if the issue is with the governor which I reckon you are spot on with your diagnosis, would you happen to know what that would entail, a replacement pump (Ouch!) or a fix to the actuator/governor.

[geeves]

Its deep inside the pump so rebuild

[Myarmila24311]

Is this solved? Any update please... Same problem with my bighorn... hope not to point to that governor

[DonaldNZ]

if its electronic and if the alt belt Slipping, not charging, low voltage to ecu and pump might cause hickups,.

easy test is a voltmeter across the battery ~14v with the headlights on @ 2000 rpm, or take it for a drive with a fresh charged battery to see if any improvement., cheaper than a fresh pump

[Myarmila24311]

Yes, it is efi pump. The problem occur after wash the engine just with water only. Done spraying and cleaning every connector in engine, especially harness to efi pump. Seem ok but only last 3 days. Idle, power is ok. No smoke or less black smoke on hard acceleration. The hiccup is like ghost. Not permanently and not always. In common, it appear when on accelerate and yes, the alternator belt is a little lose. Meter in dash always show 13v to 14v. Will check that belt issue. Not seen and miss that. Very appreciate given an idea. Many thanks..