92 W124 Power - IP timing possible ?
 

Hello,

92 W124 Low Power Issues.

I have gone over the all the simpmle and recomended and have hit a wall.
I have done
the turbo wastegate mod
the ALDA function and presence of boost at port
fuel suppy and fuel filters

condition: the car is smoky at all throttle posotions
it starts and idles and revs normally
the power loss was sudden

what else can I check and can the IP timing change irrespective of timing chain position .. that is to say if the timing chain did not stretch is there a condition that could exist with the mechanism of the IP drive sprocket itself or internal parts within the IP that could affect timing of the injection ?

Thank you

The IP has a Timer on the gear that drive it that advances the Timing but I don't know enough about it to say that is the issue.

Chris - I recall seeing some of your other posts regarding your dilemma but i don't remember all the details. You mention "the alda function and the presence of boost at port" Does this mean to say you've actually removed the ALDA and given it a test drive? I had something similar and I ultimately found a blocked line and non-functioning ALDA. the remove and drive test is definitive and actually about the easiest I guess. If you've already done that then sorry to waste your time reading this.

If it fells.down on power like no boost. You need to check or replace the vacuum transducers.

Thanks yes it is along these lines that I am leaning ... maybe someone has some specific experience with the gear advance mechanism to recommend
possible fault/remedies.

thanks... regarding the ALDA function I removed it and put shop air ( turned way down) to mimick boost and the plunger recedes properly.. I then reinstalled... and to clarify the "at port" comment that was to indicate that I have a single unobstructed line direct from intake to the ALDA... so in answer yes and no ... in that I did not do the drive test with removed but given that I have tested its function and the degree of smoke emiitted at all throttle positions (varies by throttle but smoky throughout and very smoky at full throttle/load )... I feel fairly certain that ALDA/ enrichment is providing full fuel... I am obviously overlooking something or have yet to learn something :) ... for reference and comparison of function my 91' W124 serves well ie degree of smoke etc...
the only other thing I can add is that the 92' in question was getting better fuel mileage and had more power at lesser throttle positions than the 91 until it suddenly lost power at which point I did the turbo gate mod etc....

Have you verfied that the EGR valve isn't stuck open?

OK, sounds like you are confident about the ALDA. I am not an expert by any means but since it's basically a free diagnosis to try and little effort, it might be worth removing again and driving just to be sure. Especially since the next round of diagnosis is likely to get a bit more involved and potentially expensive. But I agree it seems like you are getting fuel if you are smoking. Was just a thought. You've exceeded my knowledge about what to do. I'll be reading along to see where this goes. Good luck.

I went back and looked at your last thread. I saw that you got "boost building", but I saw no actual numbers. What do you get for boost on the road under load?

The RIV equipment for dynamic IP timing evaluation is expensive if still available. An option is to get one of those clamp-on inductive injection pulse sensors coupled with a timing light to determine whether the timer is operating to spec. Another option is to try a known good IP timer. The timer isn't difficult to replace. Removing the vacuum pump and chain tensioner gives you all the access you need. Maybe you can tell by inspection that it's bad but you have to remove it to see the workings on the hidden side.

However, if you have exhaust smoke as it is, you're either burning oil or getting too much fuel. I hesitate to suggest tweaking the full load stop if you're already heavy on fuel.

Sixto
87 300D

thanks and yes it does pay to cross check the easy and least expensive things for sure :)

I am getting a full 14 PSI but at exactly what RPM and when it starts to build I would have to test that again to report ... one thing I did do just as a precaution I opened the air/mass sensor flap and drilled a hole in the housing corresponding with the location of the now rotated-to-full-open flap location and inserted a heavy sheet metal screw to hold it permanently open and lo and behold it helped some... there is still an underlying issue but it helped noticeably and whats more and this in particular may be of help to others is that it now emits dramatically less smoke then it ever did and possibly less than the 91 which is still all factory. it was a very good and interesting discovery and really makes me wonder what the designers were thinking by placing spring loaded air restriction to a engine that needs lots of unobstructed air... it makes me want to do the flap securement to the 91 but it probably will make the computer go wild :) and the factory system is working well otherwise so I should probably leave well enough alone on that one... still tempting though...well the adventure continues :)
thanks

sixto thank you very much as I have long wondered how to go about checking the IP timing dynamically for a reasonable cost. It is also great to know that the IP timer can be changed through the vacuum pump access. I had just assumed that the engine would need to be pulled/timing cover removed etc... so this leads me to the next question... if using the inductive method then would I use the crank timing marks at the balancer pulley to determine wether it is firing at the proper time ?
and last but not least....
I have the timing light as you may imagine :) ... but where does one get a clamp-on inductive injection pulse sensor ? I have heard of these inductive pickups but always assumed ( there I go again) that they are very cost prohibitive.
thanks again

You're not so much checking IP timing as timing advance. The FSM has IP advance curves and specs.

Here's one - Ferret Instruments , V765-01 Diesel Injection Detector / Timing Adapter - 765

Here's another - http://buy.snapon.com/catalog/item.asp?search=true&item_ID=645205&PartNo=MT257&group_id=683096&supersede=&store=snapon-store&tool=all
Sixto
87 300D