Another D jetronic problem
- rickycox
- Posts: 24
- Joined: Sat Oct 17, 2009 4:31 am
Another D jetronic problem
Ok another D jetronic FI problem... car is a 72 412 automatic.
Firstly I have checked all electrics, replaced all vacumn hoses, the car has been running ok til this problem occurred as shown below in a video.
Once the car is driving it's fine with no problems. I'm thinking it's the TVS ( Ray is sorting me photos of how to adjust ) but thought I would post here to see what everyone thought....
It's the fact it's an automatic makes it hard to pull away from standstill / idle
Anyway here's the video
http://www.flickr.com/photos/29228608@N02/
Firstly I have checked all electrics, replaced all vacumn hoses, the car has been running ok til this problem occurred as shown below in a video.
Once the car is driving it's fine with no problems. I'm thinking it's the TVS ( Ray is sorting me photos of how to adjust ) but thought I would post here to see what everyone thought....
It's the fact it's an automatic makes it hard to pull away from standstill / idle
Anyway here's the video
http://www.flickr.com/photos/29228608@N02/
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Re: Another D jetronic problem
you have 2 problems,, first the fire is bad on one spark plug,, plus your mps,, leaking,, make a pressure test for one night,,albert
- rickycox
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- Joined: Sat Oct 17, 2009 4:31 am
Re: Another D jetronic problem
Double checked the MPS today and 100% holds it's vacumn....
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- raygreenwood
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Re: Another D jetronic problem
Ok...couple of things. You are running a bit rich at idle I would bet.
Albert is correct that you could be having an ignition issue. Either way it is choking on fuel off the line. What is your idle timing like?
Fuel pressure?
How well is your advance working and does the vacuum advance unit hold vacuum?
Does the MPS still have its screw in the back....is the epoxy still around this screw or has it been removed (not a big deal just wondering about full load stop adjustment).
The peculiar thing about the automatic with D-jet is that the loading of the torque converter requires the throttle dashpot to be there to keep a sharp drop in idle after closing the throttle from happening. If that throttle dashpot does not work properly....the owner or mechanic will erronesouly make the fuel mixture too rich.
Originally from your description I was thinking it was the tvS...might still be...but this papears to be a more basic fueling issue. Ray
Albert is correct that you could be having an ignition issue. Either way it is choking on fuel off the line. What is your idle timing like?
Fuel pressure?
How well is your advance working and does the vacuum advance unit hold vacuum?
Does the MPS still have its screw in the back....is the epoxy still around this screw or has it been removed (not a big deal just wondering about full load stop adjustment).
The peculiar thing about the automatic with D-jet is that the loading of the torque converter requires the throttle dashpot to be there to keep a sharp drop in idle after closing the throttle from happening. If that throttle dashpot does not work properly....the owner or mechanic will erronesouly make the fuel mixture too rich.
Originally from your description I was thinking it was the tvS...might still be...but this papears to be a more basic fueling issue. Ray
- rickycox
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- Joined: Sat Oct 17, 2009 4:31 am
Re: Another D jetronic problem
I'll check the ECU setting, the plugs do indicate it's running rich.
There is some wear in the throttle linkage also which on an automatic is making it hard to set up. I have set the gap correctly for the anti stall ( dashpot ) and it appears to work and function properly.
There is some wear in the throttle linkage also which on an automatic is making it hard to set up. I have set the gap correctly for the anti stall ( dashpot ) and it appears to work and function properly.
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- rickycox
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Re: Another D jetronic problem
Forgot to mention that I have 17 clicks from close to fully open on the TVS...is that correct as I thought read on here somewhere it was 22 ?
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- raygreenwood
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Re: Another D jetronic problem
The ECU knob is for idle only. It should be out of the picture when the TVS comes off the stop when the throttle opens.
Check your fuel pressure first...always. Also....what about the large aluminum screw in the back of the MPS. Is it there? is it still glued in place?
If its still glued in place, that does not mean that it could not stand to be adjusted. But if the glue/epoxy is missing....it could be that it has simply turned outward with vibration and is giving you too much fuel off the line.
This could also be bad grounds at the case centerline or dirty trigger points.
Your valves sound a little loud. How is your valve adjustment? D-jet is very sensitive to valve adjustmnet. Ray
Check your fuel pressure first...always. Also....what about the large aluminum screw in the back of the MPS. Is it there? is it still glued in place?
If its still glued in place, that does not mean that it could not stand to be adjusted. But if the glue/epoxy is missing....it could be that it has simply turned outward with vibration and is giving you too much fuel off the line.
This could also be bad grounds at the case centerline or dirty trigger points.
Your valves sound a little loud. How is your valve adjustment? D-jet is very sensitive to valve adjustmnet. Ray
- raygreenwood
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Re: Another D jetronic problem
rickycox wrote:Forgot to mention that I have 17 clicks from close to fully open on the TVS...is that correct as I thought read on here somewhere it was 22 ?
What is the part # on it? 17 sounds a little short either way. Most are 20 clicks. It may be adjustment as we originally thought. Ray
- rickycox
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- Joined: Sat Oct 17, 2009 4:31 am
Re: Another D jetronic problem
I'll check the MPS in the morning, the valves are a good 6 thou, checked only yesterday before the video clip...
I'll get the part number of the TVS in the morning also
But the plugs do look rich, not wet but dark.....
I'll get the part number of the TVS in the morning also
But the plugs do look rich, not wet but dark.....
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Re: Another D jetronic problem
wow,,i look back again your ,,vdo,, i see the finger push 1 inch, on the trotle val. ,body,,for to geeve the gas ,,this thing is not normal,, if the t,v,body is correct you geeve only 1/4 inch. for to geeve more ,,rpm,, or more gas,, look in the porsche 1.7 d,jet bosh book on internet for adjustment,,plus you can open the black plastic cover and clean the contact inside with spécial électronic contack cleaner,, good luck,,
- raygreenwood
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Re: Another D jetronic problem
albert wrote:wow,,i look back again your ,,vdo,, i see the finger push 1 inch, on the trotle val. ,body,,for to geeve the gas ,,this thing is not normal,, if the t,v,body is correct you geeve only 1/4 inch. for to geeve more ,,rpm,, or more gas,, look in the porsche 1.7 d,jet bosh book on internet for adjustment,,plus you can open the black plastic cover and clean the contact inside with spécial électronic contack cleaner,, good luck,,
yes...albert is correct. Something is odd. Ray
- raygreenwood
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Re: Another D jetronic problem
rickycox wrote:I'll check the MPS in the morning, the valves are a good 6 thou, checked only yesterday before the video clip...
I'll get the part number of the TVS in the morning also
But the plugs do look rich, not wet but dark.....
By a good .006"...do you mean exactly .006....or just more than enough. D-jet valves need to be exact. Excessive clearance is bad. Ray
- rickycox
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- Joined: Sat Oct 17, 2009 4:31 am
Re: Another D jetronic problem
Firstly thanks Albert and Ray for your continued help and advice... rearly appreciated... certainly the " friendliest " forum
Ok then update ---------
I've stripped, cleaned and adjusted the TVS, it was rather greasy inside so sorted that and adjusted it to 2 clicks, it was at around 3-4....
As I found it...
..and adjusted to 2 clicks...
also I do have 17 clicks, and if you count the bars they also = 17... a serial / item number can be seen in this photo..
I've checked the MPS and the screw is still resined over as per factory...
So all that done and its still sluggish off the line !!! although it does rev better from idle...
I had the automatic gearbox rebuilt last winter, would the oil level in the box effect the drive from idle as the car moves from stationary ? Or the vacumn hose to the gearbox ????? I've haven't changed that yet !
Once it is moving it drives great, changes gear at the right time etc, its ONLY from idle in " drive " or " reverse " which made me think it might be something to do with gearbox / torque converter... but maybe I'm totally barking up the wrong tree lol
Ok then update ---------
I've stripped, cleaned and adjusted the TVS, it was rather greasy inside so sorted that and adjusted it to 2 clicks, it was at around 3-4....
As I found it...
..and adjusted to 2 clicks...
also I do have 17 clicks, and if you count the bars they also = 17... a serial / item number can be seen in this photo..
I've checked the MPS and the screw is still resined over as per factory...
So all that done and its still sluggish off the line !!! although it does rev better from idle...
I had the automatic gearbox rebuilt last winter, would the oil level in the box effect the drive from idle as the car moves from stationary ? Or the vacumn hose to the gearbox ????? I've haven't changed that yet !
Once it is moving it drives great, changes gear at the right time etc, its ONLY from idle in " drive " or " reverse " which made me think it might be something to do with gearbox / torque converter... but maybe I'm totally barking up the wrong tree lol
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Re: Another D jetronic problem
wow,,nice pict,, but,,look in the center of the black cover,,the hole in the center is over-size,, if you have a big loose in the certer ,, first that geeve a bad air suction,, plus if the shaft play wend you pull on the gas cable,, the contact inside are not in connection with the slider,, many persons change the return spring for one more strong and this thing press on the schaft and use the center on the black cover ,, if you have a big play ,,up and down,, restore the chaft,, Ray can geeve you long description for the restauration,,or you can look in the old forum for the restauration,, by Ray,,,,albert
- raygreenwood
- Posts: 11895
- Joined: Wed Jan 22, 2003 12:01 am
Re: Another D jetronic problem
Yes, what Albert is getting at is that there are two kinds of play possible in the TVS. one is axial...meaning running in teh same direction as the throttle shaft. These TVS's did not have seals around the shaft so the TVS must fit as tight as possible onto the cast bracket and in the recess so as to leak as little vacuum as possible. The vacuum leakage though is usually not the issue until they get really bad.
Its the axial play...meaning its similar to having the hold down screws loose...and you can have up and down chatter where the wiper arms do not contacts a section of the circuit traces (possibly why you only get 17 clicks).
The other chatter is radially...which affects where the forked contact on teh upper ledge seats or floats at light throttle.
Like I said, I hope to have a few pictures posted for tuning over the next few days.
So...you had your transmission rebuilt? Yes, low fluid can give odd start up running and shifting. But also...just like on any automatic and after they reach a certain # of miles...the modulator valve should be adjusted. Ideally you should get a gauge and some hoses and do the full running test.
But...in a pinch....you can insert the allen key into the nipple of the modulator valve...mark exactly where the arm is on the allen key....and move it encrementally....first in one direction then in another.....testing the drivability over a set course with several driving styles. It you find that a small change makes a dofference...good deal. Just make sure that you cool it down and then drive it again to make sure this change does not affect you negatively on a cold engine and transmission. Every adjustmnet is a compromise. Ray
Its the axial play...meaning its similar to having the hold down screws loose...and you can have up and down chatter where the wiper arms do not contacts a section of the circuit traces (possibly why you only get 17 clicks).
The other chatter is radially...which affects where the forked contact on teh upper ledge seats or floats at light throttle.
Like I said, I hope to have a few pictures posted for tuning over the next few days.
So...you had your transmission rebuilt? Yes, low fluid can give odd start up running and shifting. But also...just like on any automatic and after they reach a certain # of miles...the modulator valve should be adjusted. Ideally you should get a gauge and some hoses and do the full running test.
But...in a pinch....you can insert the allen key into the nipple of the modulator valve...mark exactly where the arm is on the allen key....and move it encrementally....first in one direction then in another.....testing the drivability over a set course with several driving styles. It you find that a small change makes a dofference...good deal. Just make sure that you cool it down and then drive it again to make sure this change does not affect you negatively on a cold engine and transmission. Every adjustmnet is a compromise. Ray