Calling all Suzuki Vitara Experts

Sorry... I should of filled you in.

Compression is down only a little bit and not much diff between cylinders, manifold vacuum's is also a bit low, squeezing the fuel return line (to up fuel pressure) doesn't help either... its a bit of a curly one???

Ok will check it out and let you know

Thank You :-)

No - no engine check light on
Can't get codes

No - no serious 4WDing but your fuel/air starvation is right on the money.
ie there is no difference power wise from 1/2 throttle to full throttle

Check fuel pump for pressure and flow.
Drive around the block with fuel filler cap off. Is the fuel tank venting.
When was the last service, has spark plugs been changed recently. Could also be a plug breaking down under load, even a faulty new one. Maybe a lead or two also.

Tail pipe emissions? Is there any? What colour? At what revs?

As you can see I start simple then work up, but without actually looking at the vehicle, it's hard to diagnose.

Alan

Hi Alan,

Thank you for your time on this, I appreciate how hard it is without seeing the vehicle and running the diagnostics yourself :-)

The last service was 2 months ago spark plugs were changed and have been checked and a faulty one changed since.

Tail pipe emissions are black not sure at what revs will have to check and get back to you.

If you've done the tests, or items I suggested to check are known to be ok, I keep giving you ideas.

Catalytic converter was replaced. Why, because in the fear it was collapsed and blocked. What about main muffler, could also/instead be collapsed.

Check air filter box, look in box and up all inlet & outlets. No obstructions such as mechanics rags. Look at air intake no shopping bags or the like blocking it. Make sure the hoses are not being sucked in with the engine running.

Check the timing, is it out due to belt skipping a cog. Is it time to change the belt.

Fill the tank with fresh fuel, put 98 ron into her. Put a bottle of fuel system cleaner in.

Now we're into spending money. Injectors, are they running correctly, good spray pattern etc. ECU, is it telling the injectors the right thing, check the codes make doubley sure there's no faults recorded. Could be the ECU itself thats at fault.

You menioned a mechanic has suggest it's a head problem, what made him say that. On what facts did he base his prognosis on. He maybe right.

Unfortunately I'm done at this stage. If I think of anything else, I post it here.
If you do find the fault soon, and I hope you do, please post the results. I bet it's something simple, it always is!

Alan

I'm leaning towards a stuck open injector. This would explain the rough running, black exhaust fumes, and (I'm guessing) crap fuel economy. Other possibilities, bad spark lead (usually the longest one), bad distributor/ignion timing (failure of mechanical/vacuum advance mechanism), or failure of coil pack/leads (ECU controlled ignition if fitted)

Going on previous information, the block seems OK (compression test low but all equal consistant with old engine), head seems to be working (valves not leaking), no abnormal noises reported, timing belt seems reasonable (slipped would cause bad running, but not black exhaust). All the expensive bits seem OK.

GET THE CODES READ or tell us precisely if there are no codes to be read. I cannot believe it would run as badly as it seems to be and not throw some codes.

Also worth checking all the little vacuum hoses are plugged in too.

The Vitara is fuel injected, however the symptoms are very similar to your description

Bilbo, that was going to be my question too. The Maruti engined Suze here had a fuel and oi recirculation system. It wasn't meant to be, but the fuel pump leaked petrol to the sump, and filled it to overflow the mix back through the recirculating line to the tank. The result was a mix of fuel and sump oil in the fuel tank and also the sump!

The diaphragm was leaking both ways, the fuel was going down inside the engine from the distributer drive shaft cavity. The mix, as I said overflowed back again.