Outer Limits 4x4 Board

Have a 1988 TD42 GQ SWB, 268000km, has developed an engine miss when accelerating through the gears. It is not consistent, meaning it doesnt happen every time it is accelerating. It is almost like an electrical cutout as power picks up immediately after the missfire. To eliminate any possible electrical fault with the wiring or relays to the pump solenoid, I have run a wire directly from the battery to the pump solenoid, but it has not affected the problem.
Have also changed the fuel filter, and blown out the thimble filter in the banjo connection at the pump, and have blown out the lines from the pump back to the tank. Have also added some fuel conditioner to the tank, and checked all pipe connections in the engine bay for possible air leaks but all to no avail.
Any suggestions gratefully recieved.

get the timing checked have you checked the filter in the tank? its on the bottom of the sender i had algae in mine made it blat under revs pull the carpet up in the cargo area in the back pull the sender out get a torch and have a look inside tank if theres black shit in the bottom you will have to drain the tank hope this helps

Thanks Adam,
I will try cleaning the pick up filter, although I thought blowing right back into the tank from the fuel filter line with a workshop compressor would give me at least a temporary fix. I certainly had not considered the timing so that may also be worthwhile. Thanks for the tips.
Ian

Check your plug leads, sounds like a lead breaking down.

Joel

PGS 4WD wrote:Check your plug leads, sounds like a lead breaking down.

Joel

Plug Leads? Isn't it a TD42 ... ie a Diesel? Or is it a TB42 .. ie a petrol?

Had the same problem myself just yesterday. Diesel conditioner didn't seem to help much. Took injectors out + found some crap on cyl No 3 injector. Buggered if I know how it got through the filters. Mechanic mate of mine says he has seen overheated motors deform the injector which effects the jet profile. Hasn't overheated while I've had it but who knows what the previous owner got upto. Lucky it wasn't that. Didn't feel like paying out for new injectors.
Hope it helps.

the best thing i did was to piss off the factory type fuel filter and replaced with a cav type with the glass bowl on bottom so you can see whats going on cheers Adam....

Thanks for the input lads, Muddy Troll,As you have had exactly the same problem, I will be pulling those injectors out for a squint tomorrow. Also my engine hasa not been overheated during my ownership.
Adam, i have also replaced the original fuel filter with a CAV,great minds think alike!
Thanks again for the input lads.
Ian

Talking to a couple of mates since my last post. Subject of water in the fuel came up. I know you said you changed fuel filter but you may be picking it up from your tank. Standard fuel filters have a water bleed off line on the bottom of them. See if you get any water out of it now that it is new. If not then that ain't your problem, but if yes, check and drain your tank before you refuel and check the seal on the fuel cap to make sure there is no water ingress from there.
I have a wagon and although it has that flash looking flap over the fuel cap, it still allows a heap of water to run inside and around the fuel cap when I wash the Troll. Wouldn't take much to get in there if the cap was dodgy.
Also gets in when refuelling in the rain if not under cover and from condensation when the fuel tank exchanges air while refuelling.
Good luck

Sounds like water in the juice to me, seen simialr sounding thing in mates defender.

Mine used to do exactly the same.

All I've done is replaced the Safari snorkel head with a larger Airflow one, put a new fuel filter on, cleaned out the water trap, and started using FuelX Diesel Guard which vapourises water and has a cetane booster.
The hesitatons have pretty much dissappeared.

Simo63 wrote:

PGS 4WD wrote:Check your plug leads, sounds like a lead breaking down.

Joel

Plug Leads? Isn't it a TD42 ... ie a Diesel? Or is it a TB42 .. ie a petrol?

Sorry, I stop browsing and start reading.

I've seen them start on 6 then miss for a couple of seconds and then run on 6 again, I put it down to glow plug timer as they normally stay powered for a bit after start. Id' be thinking missfire under load on a diesel could be injector, pump or head gasket leakage. If you can simulate it on a dyno then crack one injector pipe at a time to locate the faulty cylinder, swap the injector with another and repeat to eliminate the injector or cylinder.

Joel

is it worst uphill?
could be the pump getting a little worn and running out of fuel, not being able to pick up enough.
a small hi volume low pressure (3 or so psi) pump from the tank to the fuel pump can solve this and save you the cost of a pump rebuild if this is the problem.

cheers, andrew

There is a small broze gauze filter on the pump inlet of the later pumps GU, not sure if it's there on the GQ but it blocks and causes power loss, not necessarily a missfire.
Joel

Thanks for the continuing input, i am still chasing the cause but i am time p[oor so have not tried everything yet To answer some queries, it will happen down hill or uphill, it can be at almost any revs, most noticable of course under load but feels just like an electrical problem on a petrol version, It is unreliably unreliable, if that makes sence!. At times it will pull hard and clean well up into the revs and other times hesitate at various spots on the way up. Still playing but I will be away until afetr the week end now so bonnet down for the moment Cheers Ian

It sounds like all the basics are done. If it misses at idle, undo each injector line and see if engine revs don't drop. That is your weak cylinder. It could be fuel or mechanically related. Thats where further diagnosis comes in.

It may just be an injector problem.




Andy

Another thought it only takes a very small bit of shit to get stuck in a delivery valve in the pump head. It will cause a miss,, then be good then play up again.. These are a precision valve... Or yes a injector problem..
just my 2 cents worth as ive learnt about delivery valves the hard way