GU Running Rough

[bov17]

Hi Guys,

Names Mitch - just picked up a 98 GU 2.8 for next to nothing (body and interior is mint) so was worth the buy!

Knew when I got it that it does have an engine issue going on, starts and runs (roughly) and drives (hard to rev) and has excessive exhaust smoke with very strong diesel smell on idle and less so but still excessive i would think when driving.

Slow revs upto about 2.5k and then seems to become a little more normal but has next to no power to go up hills.

The apparently looked ats are:

Head (new head gasket)
Injectors (checked okay)


My brother (mechanic) seems to think (without a proper look at it) that it could be glow plug relay or glow plugs not working properly / staying on / getting hot enough which would account for the excess fuel?

I've been searching around on the interwebz for a few nights now see lots of people seem to change the glow plugs to 4.2 plugs and just wire in a switch. Thats all well and good except I am lazy and will most likely to forget to flick the switch on and off etc every time i start the car.

Thoughts, Recommendations and Advise are extremely welcome!

Thanks heaps,

Sorry should mention it has 250k on the clock one owner car.

I am far from a mechanic but am thankfully can read instructions lol

[mudski]

Compression test would be on my list of things to do....Just to rule it out..

[SiberianPatrol]

I picked up a 99 GU 2.8 a few months back and didn't have the rough idle or running, but I did have the loss of power up hills, etc. After compression and injector pump tests, turns out I have low compression in the #4 cylinder and had very very low injector pump pressure.

Chose not to do anything about the compression but went ahead and did the IP rebuild, rebuilt injectors, and replaced the turbo (all needed). Runs great now :)


1999 GU RD28Ti; mechanical injector pump, 5kBt Webasto circulation heater, 33" Yokohama Geolander I/T, SaaS boost & EGT gauges, 2" Ironman suspension...more to come

[SiberianPatrol]

BTW, I changed my injector pump to a mechanical so all the tuning is done manually now and nothing major is controlled by the ECU :)


1999 GU RD28Ti; mechanical injector pump, 5kBt Webasto circulation heater, 33" Yokohama Geolander I/T, SaaS boost & EGT gauges, 2" Ironman suspension...more to come

[bov17]

thanks for the info - brother will be doing compression test tomorrow. will have to get him to check the injector pump etc too. It has lots of fuel going to it heaps of smoke out the back.

I wonder would it do that if perhaps an intercooler pipe was buggered?

[tuckertrucker]

Usually if the pipe is farked you will loose your boost and the engine will pretty much be naturally aspirated again. And if you've turned up the pump to compensate for the boost, then the engine will be getting too much fuel, not enough air and running rich.

Running rich will make the engine gutless under load, hard to rev and will idle high/ rough. So depending on how buggered the pipe is, that could be the problem. But you'd have to be loosing pretty much all of your boost for the engine to run rich. But if its just got a little cracks, or a small split then I'd be replacing it, but looking else where for the problem.

Cheers, Dylan.

[tuckertrucker]

Usually if the pipe is farked you will loose your boost and the engine will pretty much be naturally aspirated again. And if you've turned up the pump to compensate for the boost, then the engine will be getting too much fuel, not enough air and running rich.

Running rich will make the engine gutless under load, hard to rev and will idle high/ rough. So depending on how buggered the pipe is, that could be the problem. But you'd have to be loosing pretty much all of your boost for the engine to run rich. But if its just got a little cracks, or a small split then I'd be replacing it, but looking else where for the problem.

Cheers, Dylan.

Actually, ignore my post completely. We're talking diesels here and diesels have a varying fuel/ air ratio. More fuel means more revs in a diesel. So on that note I doubt its your intercooler line. Id be looking at low injector pressure or dead compression test.

Sorry mate.

[bov17]

Looks like still the factory nissan glow plugs. So I've ordered some new ones today as they were rather rusted

On saying that all appear to operate but perhaps a bit worn out and not glowing well without 12v being pumped through them.

Have also ordered new air flow meter as it's rather dodgy looking and rough.

Will see how she runs with all new glow plugs going to her. Does anyone know the correct voltages on a 98 gurd28 for the glow plugs. R they the same as the gq and have two relays?