| Author | Message | ||
| Steve Magnusson (91tr)
Member Username: 91tr Post Number: 983 Registered: 1-2001 |
Understood -- pressurizing the intake tract downstream of the throttle plate to check for air leaks from the intake tract to the outside world (I mistakenly thought you were talking about testing the aux air valve itself). | ||
| Stephen Simpson (Steph)
New member Username: Steph Post Number: 10 Registered: 8-2002 |
if shop air is added to the return side of the aux. air valve hose and throtttle opened you can use soap water to look for bubbles forming at different points of the eng. to simulate a air leak | ||
| Steve Magnusson (91tr)
Member Username: 91tr Post Number: 982 Registered: 1-2001 |
Stephen -- What do you mean by "added air to the aux. air valve to see if we could find a leak"? The aux air valve is a simple on/off device -- open cold (which bypasses some extra air in parallel around the throttle plate) and closed warm (so air only passes thru the throttle plate). When they fail, it's a case of the internal flap not moving correctly rather than an external air leak in the housing. When warm, if you physically collapse closed one of the air lines going to or from the aux air valve (like with some vice-grips) you can force the "closed" condition (which would simulate a working aux air valve). With regard to the throttle plates just check that the stop on the end of throttle plate shaft is returning against its set screw at idle and that the motion is smooth. If you really want to see them you need to remove the top ribbed intake plenums (with the "testarossa") and look down into the throttle body. | ||
| Stephen Simpson (Steph)
New member Username: Steph Post Number: 9 Registered: 8-2002 |
Steve after another trying day, we removed the fuel distributor to check the plunger for freedom of movement,(FINE) added air to the aux. air valve to see if we could find a leak. (FINE). We swaped the brain boxes (FINE) all to no avail...when the car is cold it will idle then to 3-4000 and back to idle ....BUT NOW ONCE THE CAR IS WARM IT STAYS AT ABOUT 3000RPM..maby it is a throttle plate and if so how do we ck. and the fix.. | ||
| Steve Magnusson (91tr)
Member Username: 91tr Post Number: 981 Registered: 1-2001 |
Stephen -- I have a hard time convincing myself that and air leak to the outside world downstream of the airflow sensor plate can cause the airflow sensor plate to move more downward (but wouldn't be my first error). An internal air leak around the throttle plate would have that effect (pulling the air sensor plate downward), but if it was something mechanical in the throttle plate stuff, and if it had a problem, I'd think it would be a more constant problem rather than the intermittant problem you described (but I still think you could verify the throttle plate stuff seems relatively healthy with no regrets). Next step? -- (Assuming you've got a US TR with KE-Jetronic) the control plunger is held in a force balance between the regulated supply pressure and the air flowing around the air flow sensor plate; consequently, measuring what the regulated supply pressure is doing is probably the next step (after the quick look at the throttle plates  ). | ||
| Henryk (Henryk)
Junior Member Username: Henryk Post Number: 195 Registered: 8-2001 |
Steve Mag: The book is by Probst. I will order both. Thanks for your suggestion. | ||
| Henryk (Henryk)
Junior Member Username: Henryk Post Number: 194 Registered: 8-2001 |
Steve Magnusson: The link is the one you posted. I just scrolled down a bit, and there was the offer for both books. | ||
| Stephen Simpson (Steph)
New member Username: Steph Post Number: 8 Registered: 8-2002 |
could it be an air leak? if so which way is the best to go about finding it> | ||
| Steve Magnusson (91tr)
Member Username: 91tr Post Number: 974 Registered: 1-2001 |
Henry -- Can you post a link? If you mean the Probst book, I bought it as well, and would recommend it for the serious DIYer (the Aird book is plenty for for those just trying to deal with the usual service-speak.) Stephen -- "air flow sensor plate" -- now that's I term I understand. Now the question becomes: is it the problem? or is it just responding to some other problem? | ||
| Stephen Simpson (Steph)
New member Username: Steph Post Number: 7 Registered: 8-2002 |
after running the eng today I noticed the left hand air flow sensor plate would burp/backfire and when it did, that is when the idle would jump to 3-4000 rpms the back to idle and repeat ( I opened the book and finaly got the right terms) | ||
| Henryk (Henryk)
Junior Member Username: Henryk Post Number: 191 Registered: 8-2001 |
Steve: Amozon also has the fuel management book available......would you recommend one buy it also, or just the fuel injection manual? | ||
| Steve Magnusson (91tr)
Member Username: 91tr Post Number: 972 Registered: 1-2001 |
Stephen -- The throttle plates are what get moved (rotated) when the accelerator pedal is pushed. If you follow the mechanical linkages you should be able to find the ends of the throttle plate shafts (which is all that can be seen because the throttle plates themselves are inside the body). If you'd like a very reasonably priced Bosch injection text for K-Jetronic and KE-Jetronic, I can recommend: http://www.amazon.com/exec/obidos/tg/detail/-/1557883653/qid=1030061786/sr=8-1/ref=sr_8_1/002-7920206-1159255?s=books&n=507846 It has some good introductory chapters, covering the general stuff, and chapters on K-Jetronic and the KE vs K differences (it's not like you need to read the whole thing). Even if you don't DIY, IMO it can be very helpful to get some familiarity with these systems. | ||
| Stephen Simpson (Steph)
New member Username: Steph Post Number: 6 Registered: 8-2002 |
help | ||
| Steve Magnusson (91tr)
Member Username: 91tr Post Number: 967 Registered: 1-2001 |
I think we might be mis-communicating term-wise -- for me, the air metering plates in the mixture control units are "drawn" down by the airflow (and if you've got 1 opening 1/4" more than the other that is bad). The throttle plates are strictly mechanical devices (like in a carburettor and can't be seen from the outside on a running TR) , and it's the physical position of the throttle plates that determines how-much-air-comes-in (assuming the aux air vavles are closed) -- then how-much-air-comes-in determines how far the air metering plates are drawn down. Are we using the same terms? | ||
| Stephen Simpson (Steph)
New member Username: Steph Post Number: 5 Registered: 8-2002 |
i was tols that the throttle plates need the approiate pressure supplied by the boost pumps to draw the plates constant. made sense at the time just couldnt figure out why 1 (the Left ) plate was opening !/4 and the other was not also it seems to be Backfiring / burping from the left throttle plate | ||
| Steve Magnusson (91tr)
Member Username: 91tr Post Number: 965 Registered: 1-2001 |
"boost pumps"? -- you lost me. | ||
| Stephen Simpson (Steph)
New member Username: Steph Post Number: 4 Registered: 8-2002 |
Steve, both throttle plates are returing well but I did notice that when looking at the eng. while running the left side throttle plate is drawing in only on that side which coinsides with the rpm rise and fall we did jump the boost pumps and tested the throttle plates for the same "pressure feeling" and that appears fine,Now someone told to swap the boost pumps side to side to see if the problem follows...God turbine engines are so much more simple. | ||
| Steve Magnusson (91tr)
Member Username: 91tr Post Number: 964 Registered: 1-2001 |
What about the other basics -- both throttle plates returning well to their stops? -- tamper-proof caps still on the adjustment screws (and working)? | ||
| Stephen Simpson (Steph)
New member Username: Steph Post Number: 3 Registered: 8-2002 |
I blocked the aux air lines, still Ideling at 3-4000 rpms also replaced the vacume lines to and from the aux air valves still nothing... | ||
| Steve Magnusson (91tr)
Member Username: 91tr Post Number: 954 Registered: 1-2001 |
Stephen -- the first thing I'd try is manually blocking the aux air valve lines (3500 RPM is a heck of an air leak!). | ||
| Edward Gault (Irfgt)
Intermediate Member Username: Irfgt Post Number: 1835 Registered: 2-2001 |
You are getting some extra air into the intake manifold from somewhere. | ||
| Stephen Simpson (Steph)
New member Username: Steph Post Number: 1 Registered: 8-2002 |
The eng will Idle for 30 Sec then raise RPM's to 3500 and Flux up an down 1000 Rpm's |