Pnm35 Power Loss And Louder Exhaust

[Stag-do]

Hi all, I'm new to this forum but have looked aroud the site a fair bit.

I've had my arx for 2 years now and love the car. Basic mods- BC Gold coilovers, whiteline swaybars, and undercar braces.I've run into my first major issue and have essentially been raped by the mechanic. I could do with some advice from those in the know amongst you.

Basically I noticed a loss of power. Low speed response is ok-ish, but on accelerating there is a definite sluggish response and a much more audible exhaust sound. Sounds like it should be powering (given the noise) but only a lazy acceleration. Really not so bad at low speed, but still noticeable.

The only event I can recall was rolling over a raised manhole. I heard something knock under the car but all seemed well.

Anyway no engine lights are on. The mechanic did the full computer scans etc but essentially felt all the sensors etc were ok . They said something was wrong with the cams, but it wasn't electronic.

They ultimately took engine apart and found the cam chain was stretched. They replaced the timing chains.Also replaced airflow meter.After 3 weeks I picked up the car today.

It's absolutely no different! Perhaps a little worse.

Below is what they put on the invoice:

NO CODES COMES FOR ENGINE.

BUT FEW COMES ON FOR THE TRANSMISSION.

P1754 INPUT CLUTCH SOLENOID FNCTN P1759 FRONT BRAKE SOLENOID FNCT

P1764 DIRECT CLUTCH SOLENOID FNCT

P1769 HIGH AND LOW REVERSE SOLENIOD FNCT

TEST DRIVE VEHICLE AND INDENTIFY FAULT TO AIR MASS SENSOR

Could I have damaged a catalyst?

Anyway any help would be appreciated .Thanks in advance.

[scotty nm35]

You likely got raped. Timing chains rarely stretch, unless there is no oil getting to them, and they would make an almighty racket if that was the case.

Either they messed up the cam timing, which is very likely, or there is an exhaust blockage. Nothing much else would change the note.

Edit, just realised it was sluggish before the chains were changed. Are you sure there were no engine codes? Does the engine light come on when you turn the ignition on?

[conan7772]

Sorry to hear that mate, and I might be down the same path as you.

I have the same problem, it's intermittent.

Doesn't seem to do it in 1st or 2nd, hammering off the mark but does it in third gear with my foot down.

It's a loud droning burble under the car, not at the engine or at the ass, no power.

My mechanic has checked and all diagnostics are normal.

I had him check the AFM as this could be the problem but it reads fine.

Have you had your cat checked for blockage ?

However I have leaking stem seals and oily /fouled plugs so I'm putting my money on bad spark.

Got told today it's engine out to fix stem seals...

[R31 POWER]

Turbo to manifold gasket leaking?

[Stag-do]

Thanks for the replies.

Defintely no engine lights come on. The only codes seem to be from transmission.

Yeah Alex ,the sound is from under the car not front r rear.

I haven't had the cats checked for blockages. I do have a pair of Berk hfc's in the shed....

[scotty nm35]

The engine light should come on when you turn the key on, then extinguish when it's started. is yours?

Sounds like the transmission might be in limp mode, and the throttle is restricted because of it. Have you taken it to a trans specialist yet?

What did they mean by the AFM is the cause? (Mass air sensor)

[conan7772]

I had stalling issues too, so had AFM checked - no irrattic readings though. Had throttle and closed throttle relearn carried out.

Idle was too low, still is but a bit better.

Wouldn't a warning light come on with transmission playing up ?

[Hertz Donut]

Please tell me the mechanic did the simple checks first before pulling the engine apart, like was the exhaust damaged when you went over the manhole? Extra noise makes me think maybe a damaged muffler, possibly a broken baffle or even a cracked manifold.

The trans codes are interesting though. Maybe there's two separate issues caused by hitting the manhole - exhaust damage for the extra noise and trans damage for sluggishness.

Edited September 10, 2015 by Hertz Donut

[iamhe77]

You should check those cats both externally and internally ASAP (change them out regardless if you have a set of Berks there).

They may have a leak or some kind of damage (hole, collapsed core etc)

Don't rely on "trustworthy" mechanics unless they have proven that they know M35 Stagea's... or at the very least are well versed in 350z and/or V35 skyline

Those transmission codes do not sound good. Can you get under the car to look for visible damage to the transmission/transmission lines?

[Stag-do]

With the key on, all the lights turn on, then go off with ignition.

I'll have a good look under the car this weekend, not that I really have a clue. Will look for any obvious damage anywhere and try to remove the cats.

Taking it back in on Monday to work out some "fair and just" resolution and ask some questions about the trans codes they mentioned. I haven't taken to trans specialist as only got the car back yesterday.

Can the car throw error codes without engine lights going on?

Thanks again all.

[scotty nm35]

The trans doesn't throw a light, it just goes into limp mode which is stuck in 4th with our box.

It could have been an old code, but if you are saying it's down on power, something is definitely still wrong with it. See if the codes popped back up when they cleared them, if so the trans is buggered.

[tomo123]

My PM35 is stuck in limp mode and the same P1759 Code came up aswell as P1757. After about 10 seconds of driving the car will kick itself into 4th and stay there until you turn it off.

[scotty nm35]

Good chance this is a common issue, and possibly the reason your car was sold at auction cheap in Japan. I'm just glad my TCU is inside the car.

[Stag-do]

I will definitely try to pin down the trans issue as things seem to be pointing in that direction unfortunately.

From other's description of what limp mode is, mine seems not to be in it.

The car operates in all gears etc and will reach motorway speeds etc, just without the gusto that it should.

cheers for your suggestions, awesome!

[nickrussel]

I don't understand modern mechanics reliance on checking for fault codes, when there are codes it should be easier to track down, that's all, it doesn't negate the need for mechanical diagnostics. ECM's are not true computers, they're chipsets that confirm basic inputs. If all the inputs make sense, there will be no code. Unless something is drastically wrong, the sensors will compensate before they throw a code; that's their job.

In 15 years of tinkering with OBDI and OBDII cars, I've only ever had a code when there's been a wiring fault. I've had plenty of faulty sensors, but none have ever thrown a code (the above video is a perfect example of my point). The beauty about sensors is that they're all working together to come to the same conclusion, how much fuel and when, which makes fault finding a piece of piss; once you've sussed out the full symptoms.

The questions you need to ask of the car:

How does the fault manifest?

When does the fault occur in relation to engine temp?

What are the atmospheric conditions?

What part of the rev range is affected?

Does load affect the symptom?

What speed and driving conditions?

What age is the engine?

Is there a smell?

Is there smoke from the exhaust and what colour, (ask the same questions, when, what RPM, what load etc)?

How does the engine perform at idle throughout?

How does the engine free rev?

How is the fuel consumption?

From there you look at what sensors the engine has, and then you can work it out pretty quickly.

An excellent (Nissan) mechanic once told me, "it's a car mate, they're all the same". And he's spot on, all cars are basically the same, with small nuances here and there. Sure the above video is an example of a model common fault, but it shouldn't take a genius to work back from the fault to the problem.

A shit mechanic a friend went to said "I've checked ALL the sensors and everything is fine, I just can't figure out what's wrong with it". For 3 months he search every sensor to work out why the engine would rev to 5000rpm with the throttle closed. I told my friend time and time again, "It's not the sensors, the sensors will compensate, they don't know there's a problem, all they do is make the command to add more fuel". It took this mechanic 3 months of wasting my friends time, and it took me 30 minutes to find the vacuum leak. I have never worked on a daewoo or a holden, but it doesn't matter, engines are all the same.

From what you've described, and going along the same lines as the others, I'd first address the gearbox issues. The exhaust tone change could be one of two things, exhaust fault, or engine load, I'd be leaning towards engine load if you have a gearbox fault. Exhausts are pretty simple, unless there was some serious damage it's unlikely to cause an instant blockage. A couple of quick easy tests though; hit the pipe with a wooden/copper mallet (lump of wood is also fine) to check for rattles, hit the mufflers, if they echo, they're stuffed. Then try free revving the engine. If it doesn't pick up freely I'd look at your cats, as suggested. If it's a chugging sound, I'd suggest the manifolds could be damaged, and check that by listening inside the engine bay for a loud clanging/clicking/tapping noise down by the exhausts. Holes, cracks etc, have a distinctive sound of air rushing (similar to what you'd hear at the tail pipe, but different volumes and resonance at different points).

There's also potential for it to be related to cam/crank position or airflow; however, it does sound to be a mechanic symptom rather than electrical (engine working hard than it should to push air, or the gearbox). The free revving will give you a clue here, but only once you've ruled out the gearbox.

Also don't settle with a little better/almost gone (common attitude I've heard time after time), it just means something has masked the actual fault, you will end up causing damage, if it's not back to normal, keep searching.

[conan7772]

Sorry to hear that mate, and I might be down the same path as you.

I have the same problem, it's intermittent.

Doesn't seem to do it in 1st or 2nd, hammering off the mark but does it in third gear with my foot down.

It's a loud droning burble under the car, not at the engine or at the ass, no power.

My mechanic has checked and all diagnostics are normal.

I had him check the AFM as this could be the problem but it reads fine.

Have you had your cat checked for blockage ?

However I have leaking stem seals and oily /fouled plugs so I'm putting my money on bad spark.

Got told today it's engine out to fix stem seals...

Ha, Craig was right, the burble and loss of power was the factory BOV.

Chuck on a Turbosmart Kompact, away you go..

[Stag-do]

Thought I'd update this thread.

My car is still getting fixed. I'm told the seals related to the solenoids are leaking, and are unable to maintain adequate pressure. I'm wondering if this is anything to do with the cam actuators. The engine has overheated before (due to the low-speed fan not working) and this may have contributed to premature seal failure. They do not think the trans is a problem.

Parts are coming ex-Japan, and mechanic is not charging for labour.

Just a question: would a stretched cam chain produce the same symptoms as these failed solenoids/seals?

BTW, nickrussel's post above should be enshrined!

Will keep you posted

[scotty nm35]

With codes like that popping up, I can't see how they would think the trans isn't a problem, but anyway, the cam actuation can be easily seen on the Consult3 unit, you can set a desired degree advance and see if it goes there and remains stable. If the solenoids are leaking for the cams they could be dropping out, but that would throw a code.

The cams have nothing much to do with the gearbox faults. So you either have a few issues to fix, or they are working on the wrong end. If the car was in limp mode due to the gearbox, it may stop the cams actuating as a part of it's limp mode.

[Stag-do]

Finally got my car back. That's 1 good thing. And I know I'll never go back to that mechanic again and that's another good thing.

Outcome was failed oil seals on the cam pulleys, which were replaced, in addition to the cam chain which was replaced. Likely factor was overheated engine, which has occured in the past due to failed low-speed fans.

He also mentioned , as a side, that they suspected some problem with the cats due to ?blockage. They opened them up, removed the catalyst honeycomb, and welded it back up!

The car certainly drives as it should again, but with obvious new exhaust tones, as can be imagined. Luckily I have a new set I've been waiting to put on.

Thanks again for your advice, I managed to sound like I knew what I was talking about when discussing with the mechanic.