[philcrombie]

Having got half way through my quest to check and/or fix the boost on my '96 aero, I have a couple of questions ask... firstly I 'll tell you where I'm at..

1) The car boosts to the top of the yellow section on the boost gauge - no further - i.e. never into the yellow/orange section.
2) Checked the wastegate R pin (OK)
3) Checked Wastegate rod (can move it by hand - so seems OK)
4) Changed plugs (old were 1.3mm - new are 0.9mm)
5) Changed fuel to Optimax and did a calibration run. - Although I only took the fuse 5 out for about 1 minute (enough?)
6) Checked for vaccum leaks - all hoses in good nic - still potential for a leak somewhere I suppose.
7) APC solenoid is 3.1ohms on pins 1-2 and 2-3 (2 being the middle)

As a result of the above, the car now pulls better low down and is much smoother but top boost is the same as stated.

next Steps:
1) Calibrated boost gauge is on order - looking for 1.1bar on full boost - this is really the key test.

Question:
I want to test the APC solenoid - and the information I have is to disconnect the hose marked 'W' and go for a drive (assuming I dont need to nip the end of W?). If I get lots more boost then it suggests that the solenoid is sticking. If not then it's probably something else....
I'm also a little concerned about boosting too far!
I've read the thread below this for info. - along with about 30 other similar threads, but still keen to hear experience of others..

PS - to me the car goes rapidly, but I believe that base boost only is still pretty quick.

 

[DaveS]

Probably not relevant but when you checked the vacuum hoses, did you check the ones under the dash?

Don't know about a '96 but on an '89 there are TEN separate joins in the hose, under the dash. (pressure cut-offs, guage etc etc).

 

[whitesaab]

I think I'm right in saying that the fuel cut off switch will be activated before you develop terminal amounts of boost.
It's easy to tell when it's happened - it feels like someones just slung an anchor out of the boot .
Then it doesn't.
Then it does.
& so on.

 

[philcrombie]

ok - just back from a test run....

new checks were done:

1) The APC Solenoid buzzes away quite happily when the ignition is on (not necessarily the engine)

2) Pulled the APC fuse and drove to see where base boost is - couldnt get the boost above 1/3 into the yellow.

3) Reconnected the APC fuse and pulled the lead going to the APC solenoid. Behaviour was identical - couldnt get past 1/3 into the yellow.

4) replugged Solenoid and after repulling and replacing the APC fuse (for a reset) - tried the calibration run, but the boost still goes to the join between the yellow and orange/yellow hatched area. hmmm

Currents thoughts are to check further for leaks as suggested (thanks DaveS) and try pulling the W hose to the Soleniod - but I dont think that will tell me much????
I should be able to try out the 'accurate' boost gauge tomorrow.

 

[wrighar]

Faero,

pulling fuse 5 will not do nothing for a reset, pulling fuse 21 may, but disconnecting the battery for 20 mins certainly will.

Boost should make it into solid red, but not if you've ben overboosting and the ecu has adapted down (just reset mine tonight as it was only making 12-13psi)

clamping/pulling W will do little other that showing that the turbo will generate masses of boost and hitting overboost.

Best to check all hoses and the dump valve for leaks and do a battery pull for reset, and ensure you have decent high octane fuel.

Andrew

 

[philcrombie]

hmm - interesting. All the bits of information I have gathered on the Adaptation run say that you just need to pull fuse 5 for a few minutes, refit and floor it a few times between 2 and 3.5k rpm (manual)
I will quite happily disconnect the battery for an hour or so just to be sure that everything is reset though - I reckon that may be tonight's job along with a more thorough check of the hoses.

The only other thing I have is a new ITG air filter to replace the rather dirty looking standard item (although its not so dirty that it would affect the boost)
Im running Shell Optimax due to popular opinion - and it does run much better...

 

[johncc]

I'm sort of partway along a similar path on a 2.3FPT with similar symptoms. I have yet to really spend decent time on it, but I'm following your progress with interest! I may have a spare BPC valve to try, which should be interesting.

Did you see the whole load of stuff here?

A few possible other reasons for low boost, but I reckon start with the obvious like leaky hoses

My boost is intermittent rather than consitantly low, which may suggest a different problem, not sure... does your car ever misfire? Faulty DI could cause boost to be restricted, I understand.

Good luck though and keep posting your progress!

 

[philcrombie]

my boost is very consistant and the engine is very smooth (to my ears). If you listen very carefully at tickover you can just make out the odd 'blip' but inside the car the revs sit solidly at tickover - no sign of any 'upset' If it were a DI Cassette fail I would assume that the symptoms would be quite obvious - although it would be nice to try out a good cassette though just elimintate the possibility.
On poorer fuel, and flooring the car in 5th, you would very easily get a solid shudder/power drop towards the peak of my boost(I think this was boost being cut on pre-ignition?). I cant get the car to do this on Optimax - but again I wonder whether poorer fuel might also expose a dying DI? (car has done 90k miles). My current hope is that the boost has been well backed off due to poor fuel and that I just havent done the Adaptation run properly... will report back.

 

[ben hall]

If your DI cassette is on the way out you will probably experience intermittent misfires (which you might not notice) and when it dies properly it will misfire all the time. If you have a friend with a known good DI cassette it's a very quick job to swap it into your car and see if there's any difference.
Same with the APC solenoid off the top of the radiator. Yours may seem to be working, but if you can try a known good one then it will be immediately obvious if that's the problem.

I may be ignorant, but does a '96 Aero with Trionic actually need to be recalibrated/reset? I thought that since the ignition systom essentially tunes itself constsntly there's no need for letting it re-adapt to different fules..??

Good luck,
Ben.

 

[philcrombie]

yep - in a perfect world I would swap over the BPC solenoid and then the DI cassette - but I have a few other bits and pieces the check first anyway. With a few more bits of information, I could be persuaded to buy a new DI cassette as I will be keeping the car for 2-3years anyway - and it is quite likely to 'go' during this period, but I'd rather not start that sort of random approach!

As for the APC adaptation run - it seems to be a standard issue event right through the model range. If the car has been running on low octane fuel, the boost will be less. Change to Optimax(eg) and over a long period, the APC should relearn to boost higher - but this could be a long time!. The quick fix is to reset the APC which then starts from scratch and quickly learns to match the fuel - or at least in theory it does.

 

[DaveS]

Just another thought. Am I right in thinking that the system dumps boost when the brakes are used?

As faero seems to be on base boost, could the brake/ECU interface be jammed on? (presumably it's just a switch).

I don't know how to test for this, though - would clamping hose "w" do it or does this bypass the APC ECU?

 

[wrighar]

for base boost, you could accelerate hard in 3rd/4th and left foot brake slightly to see if the boost dips slightly. this would show if you were at base boost before braking or not.

Boost is limited to base when braking or when on cruise (if not a TCS car, TCS will do full boost with cruise on - Maybe the later non tcs T5's would too?).

 

[philcrombie]

ahh - good point but I'm not on base boost. I disconnected the electrical connection to the BPC Solenoid last night and drove the car and couldn't get above 1/3 into the yellow - car like a slug etc. The same occurred when I drove w/o fuse 5 - so I know where base boost is sitting.
That's what makes me think the BPC solenoid and the wastegate gubbins are actually OK?? I'm well above base boost - but not far enough into full boost.
(PS - I boost up to the top of the yellow section with the BPC Solenoid connected)

no sign of my 'calibrated' boost gauge arriving yet... humph

 

[philcrombie]

thanks scaero - nice neat way of double checking my base boost assumptions. Just need to dodge speed cameras and bemused drivers as I drive strangley down the A3... oh the fun of Adaptation runs in central London...

 

[DaveS]

OK, fair enough. What would the effect be of a faulty knock sensor? That's part of the APC system, too.

Easy enough to test, just unplug it and go for a run (errr, bear in mind I've got an '89 without Trionic, though - might be worth hanging on a day to see if anyone comes in and rubbishes the idea!)

 

[wrighar]

Dave,

On Trionic based cars, and possibly DI/APC ones, the knock sensor is not a sensor, but the Resistor plugs measuring ionisation within the cylinders using the DI module.

You can't unplug it...

Andrew

 

[DaveS]

Ah, right, thanks. On my '89 with DI/APC it's a separate sensor.

There's a lot to be said for the old clockwork-driven cars

 

[philcrombie]

PROGRESS MADE!!!!

Started to have a look around at the pipework - focussing on the BPC solenoid. Then had a good look at the very thin pipe coming out of the round black thing on the pipe coming up from the air inlet (just along from the air filter).
As I took it off, it started to crumble in my hands. Further up its path is a little white T connection - just before it is a supporting clip and as I tried to release the pipe, it crumbled more. (the pipe goes on to the inlet manifold and boost gauge)
So - sacrificing the horizontal bit of the windscreen washer below the bonnet and going for test drive gave me the correct boost reading!!

I had also disconnected the battery for 30 minutes to reset the APC so thanks to Scaero for pointing out that fuse 5 doesn't reset the APC effectively...i had thought my previous adaptation run was pretty uneventful!
On this new run, everytime I floored the accelerator through the rev range, the dump valve would blow off at a greater and greater frequency until it settled down (assumed to be normal Adaptation behavior?)

Conclusion:
Boost now goes about 1/4 into the red! Hurrah!
i must have been getting very close to this anyway - just that the gauge wasnt reading due to the leak in the vaccum hose. What amazed me was the consistancy of the reading given that it was an air leak.
The boost adaptation run was the icing on the cake (so to speak) and has definitely given me a bit more urge although I cant tell 'cause I changed two things at once - I'll never learn!

Anyway cheers to all and I now plan to remove the heatplate so I'll open a new topic as i have a couple of questions.

 

[philcrombie]

Sorry - meant to ask - anyone know a good source of replacement silicon hose? Dont think washer hose will hack it for long!

 

[wrighar]

Faero,

Good news. You obviously don't have tcs, coz if you did it would have gone to a valve on the ns wing.

The dump vavle is working ok then and not leaking (another common problem that causes low vacuum readings showing on overrun/idle).

Silicon hose can be got from many places such as:-

Most performance motor factors,
Elsparts,
Demon tweeks etc.

You just need to be careful to get the correct internal diameter 3mm, lots are 4mm and feel loose.

Andrew


Erm, edited for god awful spelling....