Low power under load and exhaust blowing ...

Hi all,
I need to call on your collective wisdom, I have spent some time searching for existing treads but not found anything similar...  hopefully someone can help.
So,  I'd had the Jimny (1.3 16v) for a week, all working fine,  nice and tidy truck.
I'm on the motorway sitting between 60-70mph for about an hour, all good.  Come up behind a lorry,  put my foot down to overtake,  and then I get an exhaust blowing noise, and not much in the way of throttle response...
The problem has remained constant since then;
Revs fine out of gear.
1st is fine.
2nd a little exhaust noise and reduction in power.
3rd,  ok on the level, more noise, less power.
4h,  lots of noise, very little power.
5th - no chance unless you are going downhill.
Underload (uphill) is by far the worst. Local hills I would normally be in 4h going up happily at 50mph are struggling in 3rd,  need to drop do 2nd, 30mph max.  Load % reading on the OBD will not go past 40% in 3rd.

No EML.
Connected OBD - no fault codes.
Removed middle and rear exhaust (checking for blocked cat)- no change.
Changed exhaust manifold gasket - no change.
Changed spark plugs - no change.
Checked for inlet manifold gasket leaks (ran engine and sprayed brake cleaner) - no increase in revs.
Checked the MAS - doesn't appear to be one.

Next on my list was egr - but OBD reader reports this as all ok (reading through a previous thread it suggested if that's the case leave if alone), also,  why would this stick open when the engine was up to temperature?

Any help or advise would be welcome...  








 

If I am doing 60-70 on a motorway and put my foot down I don't get much acceleration either, that is in a 2011. I don't however, get an exhaust blowing noise.

It looks like you might have a leak, but it only occurs at higher temperatures and higher load/revs.

When you mention about uphill was 50mph in fourth in this car or another car? I am in fourth in my Jimny with the foot flat to the boards when I would in top gear in another car.

Robin

Hi Robin,
Unfortunately the comparisons are with this Jimny, and it is way way down on what it was (and it didn't have that much to start with !).

Just changed the coil packs - no change.

Going to be EGR this evening me thinks...

Not the

This increase in noise that sounds like a blowing exhaust, still present?

That's a big step change that should be possible to find if it is a blowing exhaust. If not what can make blowing sound and not be the exhaust?

Maybe worth doing a compression test just in case it's leaking.

 

Sounds like when mine had a blocked cat or two.
Depending on market and year there is two cats, one in the manifold that often disintegrates and these pieces go into the next cat. Got two jimnys in my parking lot now, one with no cats, one with an aftermarket cat. Same with a friends jimny i met In Denmark 3 weeks ago.

Cheers guys, didn't know about the 2 cats thing... I'll strip of the manifold and see what happens....
Will report back !

Ok., so we have a winner !

Removed the exhaust manifold and ran it up the road, and the power is back to normal (normal for a 1.3...).

Thanks Yakusa for the comment.

Not sure where your based, but if you have a Wetherspoons pub near you let me know and I'll have a beer sent to your table (other beverages are allowed).

off to order me a new exhaust !

Norway so no such service here due to the strict and strange laws on alcohol.
Grateful for the thought and when in Britain I'll catch you up on that if we meet
I removed the broken cat element inside my manifold and replaced the cat no2 with a "halfords" generic aftermarket cat. Cost was just 75£ -ish.
Now i get a check engine light once every 2-3 months or so but with a bluetooth OBD2 adapter I clear faults on ECU on the go with the phone.
MOT so far is no problems.

So the issue has been fixed.

In a single blast down the motorway something in the exhaust manifold, or possibly the pre-cat, got lose and damaged both he main cat and the rear silencer !

Whole new exhaust from the head to the tail pipe and the Jimny is back in the game.

Thanks for the help guys.