Mazda B2500 Low power

[Captaincademan Senior Member Find all posts View Profile Close Captaincademan]

I have been trying to troubleshoot this problem for a few weeks now, and cant seem to fix it. I am at the point I believe of overhauling the IP, unless someone has any bright ideas.

Engine starts and runs smooth as silk. No misses or hesitations. It is just very, very low on power.

So far I have (in order):

• Blown compressed air down fuel pickup line into tank to clear screen
• Replaced fuel filter
• Replaced all fuel hoses with quality fuel hose and checked clamps for tightness
• removed air filter to check for blockages
• checked turbo air output
• checked for fuel leaks
• checked boost compensator feed hose was clear
• Replaced facet pump (cheap little $20 one off ebay - works fine)
• flushed injector pump with ATF - run about a litre through the IP with engine running
• checked compression - all cylinders even and at least 400 PSI - as per factory spec's
• cleaned mesh screen under inlet banjo
• replaced injectors - old ones weren't coked or anything, but getting low on options now so I figured after 200,000km probably due for overhaul. cheaper to replace them.
• removed waste gate actuator pressure line in case it was opening early - no change
• checked timing control valve is earthed across the right terminal

I am about to have a crack at measuring the outputs form the power train control module, but am not really expecting anything untoward there. The only thing i can think is that the voltage outputs to the TCV arent correct or perhaps a faulty lever position sensor.

If the PCM is ok, I think I need to pull the pump down and inspect for wear and blockages etc. I have never had a problem with bug in my fuel (yet) so I hope thats not the case. although it would be an easy fix. there was no sign of it under the TCV or inside the inlet banjo.

Is there something I have missed? can anyone think of another cause of a serious drop in power?

thanks ahead of time.

[Captaincademan Senior Member Find all posts View Profile Close Captaincademan]

Re: Mazda B2500 Low power

update.

Over the last hour or two I pulled the air intake components off to get a clear look at the turbo.

The compressor intake vanes are clean, smoothly rolling, no dings or bent vanes.

I found the waste gate lever was very stiff after I took off the actuator. After about 10 mins of working the lever back and forth with my fingers and some WD40 under the lever tab, I managed to free it up so it moved full travel smoothly with no catching or binding.

At this point I thought I found the problem. I put it all back together and went for a little drive.

now the waste gate chatters above 3000 rpm and with the low power condition, I almost couldn't make it up the driveway.

I am beginning to consider it may be a bung turbo (or at least the waste gate) now, but I dont really know to be honest. I doubt I could buy a waste gate on its own as it looks rather integrated into the turbine housing but I will see whats out there.

anyone else run into this before?

[smithw Senior Member Find all posts View Profile Close smithw]

Re: Mazda B2500 Low power

Blocked exhaust maybe? Unbolt it and go for a drive. Also pull the timing cover off and check the cam belt hasn't jumped a tooth, pretty unlikey but if front seal on the injector pump is leaking it can dump fuel on the belt. My Pug did just that and it jumped a tooth on the injector pump. Also if the front seal is chewed out from the bio it can cause an air leak around the seal.
Also check that it is getting full throttle, I have seen a cracked gas pedal cause the same symptoms.

[Johnnojack Senior Member Find all posts View Profile Close Johnnojack]

Re: Mazda B2500 Low power

Not familiar with your type of IP but an iP which doesn't deliver enough fuel can make a turbo look crook, turbo needs exhaust to make boost and exhaust needs fuel, low fuel no boost.
Don't touch turbo until fuel delivery is sorted.

[Captaincademan Senior Member Find all posts View Profile Close Captaincademan]

Re: Mazda B2500 Low power

It's a rotary pump very similar to what's on the 1hz.

The chattery waste gate gate has to be fixed now anyway. I have just got one frozen nut to undo and then I can get the turbo off and check it out. There is some slop in the cartridge shaft but I'm not sure how much is acceptable so I need to research that a bit more. I would think the play should be almost zero.

I certainly agree that there is fuel delivery issues that need to be resolved.

Smithy- I will check what you suggest this morning but I'll be disappointed if that's the case because I replaced the front seal along with the timing belt a few months ago when the old seal let go. The timing case was dry. It all ended up in the sump and caused a runaway. I was in heavy traffic in Brisbane at the time so my slamming on the breaks in the middle of an intersection wasn't appreciated!!!

This is my first turbo so I'm pretty unfamiliar with their sounds. If a waste gate was stuck partially open would you hear it? Would it cause a constant whistle?

What would you suggest next Johhno on the fuel side of things? Overhaul the pump?

[3DB Senior Member Find all posts View Profile Close 3DB]

Re: Mazda B2500 Low power

It might be worth buying or borrowing a boost gauge to see how much you are making. You can get cheap mechanical ones on eBay that work fine for this purpose, though the cheapest ones are a few weeks away from China.

As JJ says, if you're not making enough exhaust, you won't make any boost either.

I would think that you wouldn't hear a wastegate opening early - I've certainly not herd it unless the car was fitted with a blowoff valve.

And if you disconnect the boost hose to the pneumatic actuator, it should never open.

I was interested to read about you getting the actuator to move with WD40 and some jiggling. I've never been able to get one to move without (in my case) 13 PSI being applied to the actuator. Just my experience, but this could be a factor - if it moves by hand the actuator bay be buggered. Can you sort of lock it out in the closed position and take it for a run with the hose disconnected and see what happens.

One other thing that came to mind: the smoke screw. Sounds like there is no reason why this should have moved and perhaps the tamper seal is still intact, which means it probably can't move. If you're going to pull the pump anyway, you could try having a fiddle with that. It worked wonders for me in the low power stakes, but then mine had low power from the day I bought it. This may be a complete furphy - I have no idea how your IP works and it sounds like it is fitted with a bit of electronic control like the 5L Hilux engine and the later model Rodeo / Jackaroo after mine.

Best of luck.

[Johnnojack Senior Member Find all posts View Profile Close Johnnojack]

Re: Mazda B2500 Low power

It does sound like the waste gate is faulty, as DB says normally you can't move them by hand. If the waste gate is open at no boost then there will be no boost. If you have a vacuum gauge from an old engine tuning kit you could use that as they have a pressure side to the gauge. A picture of the Ip would be useful, is it like a 1HZ pump but with a flat box on top? With a wiring loom going on to it?

[3DB Senior Member Find all posts View Profile Close 3DB]

Re: Mazda B2500 Low power

Does sound that way. As you say, JJ, even if it was sitting open just a fraction there would no boost at all made by the turbo - all the exhaust gases would be bypassing the impeller.

I drove my Rodeo round the block once with the turbo-to-intake pipe disconnected just to see what would happen. So the turbo was spooling up from the exhaust but just sending the air to the atmosphere and the engine was operating just like an NA engine. It was soooooo gutless. Basically un-driveable over 1500 rpm.

So maybe this is another test to help confirm the theory - do the same as I did and see if it makes any difference.

[Captaincademan Senior Member Find all posts View Profile Close Captaincademan]

Re: Mazda B2500 Low power

Hi Gents,

thanks for the replies.

The actuator is very stiff, it takes a lot to move it. I disconnected the actuator in order to check the waste gate travel, thats when I was moving it by hand and freeing it up. I dont have a pressure gauge that reads low enough to see how many PSI it takes to force the actuator to move in order to check it, but the book reckons it needs 50 PSI or so. I forget the actual number but its around that. I think the waste gate might have been stuck open a tad.

I pulled the turbo off yesterday and got a good look at it. The exhaust side was surprisingly clean as was the exhaust manifold, so I am very happy with that.

There is sideways play in the cartridge shaft which is noticeable.

I have ordered a new one off fleabay. Genuine Jap IHI turbo's are super expensive, so I went for the knock off turbo for around $400. Not sure how long it will last but if it bolts back on a works I am happy.

My feeling is the waste gate was stuck open and playing up.

Will keep the old turbo to use as a compressed air supply for my fireplace when I build it eventually. I will have the only turbo charged fireplace around!!

[Captaincademan Senior Member Find all posts View Profile Close Captaincademan]

Re: Mazda B2500 Low power

Johnno,

the pump looks like this -

https://www.google.com.au/search?q=w...YXoDm8iq-v4QM:

pretty simple pump. electrical sensors for lever position, timing control valve and ofcourse fuel shut off.

[3DB Senior Member Find all posts View Profile Close 3DB]

Re: Mazda B2500 Low power

When you put the new turbo on, can I suggest a custom exhaust system like this?

[Captaincademan Senior Member Find all posts View Profile Close Captaincademan]

Re: Mazda B2500 Low power

I reckon he would need to use a pretty full on windscreen additive to keep that sucker clear!!

[Captaincademan Senior Member Find all posts View Profile Close Captaincademan]

Re: Mazda B2500 Low power

Update.

Fixed. Thankgod.

New turbo i think pushes pushes a lot more air than the old one. Initially little improvement on changing it. I then did a 'delete cat' mod which improved things a fair bit more. Final kicker was turning up the fuel in the low boost range by adjusting the boost compensator spring tension by a half turn down. My goodness now that really made it go. I didn't want to adjust the fuel screw as I don't have an EGT gauge fitted. Difference is phenomenal. Goes like a bullet.

Synopsis: I think the pump is showing signs of wear. I will probably be up for a re build sometime soon as I really shouldn't have had to touch the boost compensator. Turbo was worn and the catalytic converter half clogged.

Spent about $1000 turning it from an undriveable pile of poop to something that is a joy now.

Thanks for for all of your input. Looks like it was a fuelling issue at heart but there were lots of bits that needed maintenance too.

Time for a beer ����

[Dr Mark Senior Member Find all posts View Profile Close Dr Mark]

Re: Mazda B2500 Low power

This is your lucky day. I have a BT50 and it had the exact same problem that you described.

Take it to an exhaust place and get them to remove the catalytic converter. It doesn't have any electronics on it so it won't cause any problems.

I got it done and hey presto - back to what it used to be before I started running BD in it. Actually it's even better...

[Captaincademan Senior Member Find all posts View Profile Close Captaincademan]

Re: Mazda B2500 Low power

Hey Mark,

Thanks but all ready done! Lump hammer and length of 1 inch pipe did the trick nicely. No need to spend coin. It took all of 30 mins. Not sure how much they charged but I hope you weren't ripped off!

2 weeks in car is going great. Better than ever. Biggest improvement was more fuel during boost.