[THE_DICTATOR]

I am down on power and using a shit load of fuel. Just serviced with hpr5 oil, new air filter, new plugs. New 215/75/15 tyres with to much air in them. On Saturday I couldn't get over 95kph in 5th and only just in 4th. Did 300km on Sunday and put in a heap of injector cleaner. Could do 120kph but only down hill in 4th. Couldn't hold 100kph in 5th. Fuel light came on at 270km.

I suspect fuel pump or filter. I use jerry cans a lot. Or maybe a blocked cat.

Car has done 52000km and is in otherwise as new cond.

No error codes and seems to run well just down on herbs

How do I diagnose fuel issues without just randomly replacing bits?

[Gwagensteve]

Hasn't "accidentally" had any leaded fuel (i.e avgas) through it has it?

[30ONA]

If the problem started after the service maybe check over what you worked on. Air box closed properly, plug leads/cool packs all clipped on properly, plugs correct type and tight in the seat. Could be the cat as you suggest though. Wack it and listen for rattles or drop it out and look.

[alien]

Is the acceleration linear or does it only bog down at a certain RPM?

My guesses are fuel pump and bad injectors...

If it were coil packs / leads you'd have an obvious misfire.

When my fuel pump died though, i could idle and rev up to about 2500rpm before it'd bog down badly and not want to accelerate. it was a really obvious "cut out" in the power.

I recently had reco injectors done and that's helped a lot of the hesitation at low RPM in mine, though i still feel like mine bogs down under 2,000rpm. Almost like it's down a cylinder then after 2k it suddenly revs freely.

Joys of old cars =)

[MrRocky]

Timing belt skipped a tooth

[shep]

Gwagensteve wrote:

Hasn't "accidentally" had any leaded fuel (i.e avgas) through it has it?

Has had about 180L of low lead avgas through it but none for around 15000km.

Started using a lot of fuel around 3000km ago, didn't notice it at the time as things gradually got worse.

Had given the cat a good belt and no noises but it's not possible to do a visual inspection as it is welded in.

Not keen on just replacing things in the hope of fixing it plus fuel filters are very expensive.

MrRocky wrote:

Timing belt skipped a tooth

Doesn't have a timing belt

[shep]

Should also mention that we have truly shit fuel in the territory and I am sure that a lot of places sell opal as 95 because they are the same colour and the 95 often smells very odd.

Opal is prob the worst fuel ever made and is a massive con on taxpayers

[Gwagensteve]

Lead plugs cats.

[britvit]

Try disconnecting the exhaust at the flange then gaffa tape a blow gun in it, shouldn't be much back pressure. If there is, smash that cat like you're a Donald.

[striker99]

shep wrote:

Should also mention that we have truly shit fuel in the territory and I am sure that a lot of places sell opal as 95 because they are the same colour and the 95 often smells very odd.

Opal is prob the worst fuel ever made and is a massive con on taxpayers

I found if I had to use 91 fuel my jimny would really struggle to maintain 100km/H, as soon as it had a few fills of 95 it would be better again.

[alien]

^^ that could be related to timing, but surely the computer can adjust for fuel? Mine runs fine on 91... though i put 95 or 98 in most of the time "just cos". I used to have to run 98 because it'd ping on anything lower - turns out timing was far too advanced... since fixing that, power is the same if not better and i can now run cheap 91 if i have to.

[Gwagensteve]

Not sure if the M series motor is knock sensed. If it's not, it won't matter what fuel you put in it. If it is (and the computer is programmed to search for the most possible timing) then sure, 95 or 98 will be better.
AFAIK, suzuki make no claim for increased performance on 95 or 98, so it's unlikely to make any difference.

As an aside, we have a couple of Renault Kangoos at work. They mandate 95 octane. The numpties at work can't read the big letters on the fuel cap so regularly put 91 in them. They are just awful to drive on 91. Borderline dangerous duet how much timing the computer pulls out. They just won't pull.

Anyway, this is all off topic - the only relevant issues I can see in sheps case would be fuel pickup screen, fuel filter, lead blocking the cat as first ports of call.

[shep]

Suzuki have a sticker on the fuel filler flap stating that 95 must used. Trouble is that it isn't alway available.

No screen on fuel pump as far as I know as the pump is in the middle of the filter.

[striker99]

shep wrote:

Suzuki have a sticker on the fuel filler flap stating that 95 must used. Trouble is that it isn't alway available.

No screen on fuel pump as far as I know as the pump is in the middle of the filter.

My m13vvt had the same warning on the fuel cap for only 95.

[Gwagensteve]

so what was in it when it started driving bad?

[THE_DICTATOR]

Started playing up about 3000km ago. Was a gradual worsening rather then sudden. Hasn't had avgas in it for about 15000km

[shep]

Which bit is the cat? I thought it was after the second section but looks like it might be in the manifold

[Gwagensteve]

You have two. One is in the manifold. This is generally a very "open" cat which heats up very quickly to bring emissions into spec on cold start. The second cat is a regular cat same as that found in any regular car.

[steak_knife]

Normally the 2nd (down stream) O2 sen will pick up on a blocked cat. (but Sheps not normal)

Egr could be stuck open.

Injectors partially stuck open, they have very small hole.

[shep]

Egr tested ok with scan tool. Both O2 sensors are in a happy zone.

Have a fuel pressure test kit on the way but will prob take 2or3 weeks to get here.. will dose it right up with injector cleaner tomorrow as I am driving 400km in it.

What happens if egr gets blocked off? It made a big difference to my family car in a good way, but it is a common rail turbo diesel.

[shep]

If the egr works the same way as on the TD motors it will pretty much be open all the time due to the temps here

[watermouse]

Im not sure of how the egr works on the m series but the one on my old j20a (and on my current diesel Colorado) the EGR poppet valve is only pushed by the egr actuator, not pulled to closed. If it gets stuck open the position circuit cannot tell and assumes the valve spring is pushing against it to close. The pin on the actuator just lifts clear of the stuck valve

Blanking the EGR on the J20a improved throttle response slightly. (more so with the Colorado)
Someone else may know if the EGR on the M is flow sensed in which case you may have problems blanking it.

[shep]

I weighed the car tonight and maybe it's just to heavy. Loaded up with my fossicking gear, 20L jerry can, full tank, 40L engle full of stuff
Plus heaps of other shit it weighs 1400 on a gov weigh bridge. Just did 200km highway at 90-100kph and 50km in low range crawling around
In escarpment country and used 38L fuel.

[henno]

That's one fat jimny. My shorty GV with two people on board, a toobox of junk, a belly full of fuel and a box trailer attached was still less than that.

[shep]

Yeah I will clean it out tomorrow and see how it goes.
Is full of stuff, including 4x20L buckets of hopefully dirt full of gold.

If weight is the issue it's getting traded in on a new wrangler.

[vet 180]

shep wrote:

Yeah I will clean it out tomorrow and see how it goes.
Is full of stuff, including 4x20L buckets of hopefully dirt full of gold.

If weight is the issue it's getting traded in on a new wrangler.

That is one heavy Jim. If I load mine full of gear and people I guess it would weigh close to 1400 and I can hold 140, but it's far more comfortable at 120.

[THE_DICTATOR]

Got it down to 1250kg by cleaning it also removed the roof rack for no improvement. Exhaust isn't blocked.

Have ordered a fuel pressure test kit that will hopefully be here during the week.

I suspect that the motor might be dusted as there was a fair bit of dirt in the intake but will do a leak down and compression test before getting out the flamethrower.

If the motor is stuffed I don't think I could be bothered with a motor swap so will prob trade it in on a jeep.

[THE_DICTATOR]

Oh and intake is very clean so pretty sure there are no egr issues

[Gwagensteve]

Cruising speed has almost nothing to do with weight. Whilst it slightly increases rolling resistance, it also increases inertia.
Salt racers ADD weight (lots of it) to improve stability.

That's bad news if the motor is dusted. Visible dirt in the intake is a pretty bad sign.

It would explain the symptoms though. It wasn't something that had occurred to me as dusting a 50K motor isn't common, but then neither is your use.

[shep]

Will compression and leak down test tonight. Anyone know the specs for VVT M13 motor?