ok
it's a 1700 cc FI engine (enginecode W) mounted in a type 3 with an automatic transaxle (the donor type 4 was also automatic).
the donorcar drove ok
after the transplant, we hunted down a couple of vacuum leaks. and cleaned the trigger contacts.
the vacuum can was taken from the type 3, because the type 4 one was faulty, but the dizzy itself is stock.
the timing is set a the red "I" at 3500 rpm with the hose to the vacuum can off.
it idles great - a drives ok at low speeds.
i'm having trouble accelerating - cant get the RPM over 3000ish while driving - if i try the car just judders along.
in neutral there's no problem rev'ing the car.
any suggestions ?
engine can't accelerate - troubleshooting
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ploug
- Posts: 20
- Joined: Mon Apr 14, 2008 2:26 am
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david58
- Moderator
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- Joined: Sun Oct 23, 2005 6:14 pm
It probably is fine. I didn't know you cleaned the trigger contacts, adjusted the timing, and corrected a few vacuum leaks. The problem is most likely in what you did. I would replace the points and condenser, double check the timing, and recheck for vacuume leaks.ploug wrote:before i cleaned the trigger contacts, adjusted the timing, and corrected a few vacuum leaks.
the car drove fine at high speed (130 km/h) but couldn't idle corectly. and had problems in the low rpm's
so i assumed the fuel pressure was good enough.
well, one more thing for the "to do list"
Hot, humid air is less dense than cooler, drier air. This can allow a golf ball to fly through the air with greater ease, as there won't be as much resistance on the ball.
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raygreenwood
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- Joined: Wed Jan 22, 2003 12:01 am
If things were better before you cleaned the contacts then in many cases teh contacts have issues. You need to pull the three pin plug and clean the pins. As AMP/Bosch research found....just plugging and unplugging D-jet connectors can lead to up to a 50% connectivity loss.
The female connectors frequently are to loose on that plug causing connectivity loss and high resistance.
You must check the reistance of both trigger sets after cleaning. Neither should be over about 1.2-1.4 ohms. There should be not more than about .2 ohms difference between the two triggers.
Ideal is about .9 one side and .8 to 1.0 on teh other. As close to even as possible is best. Also check the gap between the rubbing bvlocks of the two trigger sets. I think about .943 is new. About .950-.955 max. Do a seacrh...I have posted this before. Ray
The female connectors frequently are to loose on that plug causing connectivity loss and high resistance.
You must check the reistance of both trigger sets after cleaning. Neither should be over about 1.2-1.4 ohms. There should be not more than about .2 ohms difference between the two triggers.
Ideal is about .9 one side and .8 to 1.0 on teh other. As close to even as possible is best. Also check the gap between the rubbing bvlocks of the two trigger sets. I think about .943 is new. About .950-.955 max. Do a seacrh...I have posted this before. Ray
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SureFit Travis
- Posts: 168
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raygreenwood
- Posts: 11906
- Joined: Wed Jan 22, 2003 12:01 am
The ECU or brain from the type 3 should not be swapped to a type 4 engine. They are not the same. This is not saying that some type 3 cans cannot be used...just that you must find one similar in charateristics to the type 4 unit.
The vacuum can can make a great deal of difference as well. There were a lot of them for both type 3 and 4. Even though the other one was faulty....and you did not mention how it was faulty....swap it back in to see if it changes how you run. It may also be that the type 3 can is bad in some way.
How did the donor car drive with this transmission? Ray
The vacuum can can make a great deal of difference as well. There were a lot of them for both type 3 and 4. Even though the other one was faulty....and you did not mention how it was faulty....swap it back in to see if it changes how you run. It may also be that the type 3 can is bad in some way.
How did the donor car drive with this transmission? Ray
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ploug
- Posts: 20
- Joined: Mon Apr 14, 2008 2:26 am
the ECU are from the donor car, so no problem there
the vacuum can on the type 4 didn't work - it had a big leak, i sucked (no pond intended ) and it didn't operate the little arm = no advancing
the 412 with engine in place - ran well, it had cold start issues and a high idle
these things are now corrected. (vacuum leaks, and incorrect ignition timing)
so the plan are
swop the vacuum can back again
check and clean the connections on the trigger contacts
recheck timing
anything else ?
the vacuum can on the type 4 didn't work - it had a big leak, i sucked (no pond intended ) and it didn't operate the little arm = no advancing
the 412 with engine in place - ran well, it had cold start issues and a high idle
these things are now corrected. (vacuum leaks, and incorrect ignition timing)
so the plan are
swop the vacuum can back again
check and clean the connections on the trigger contacts
recheck timing
anything else ?
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raygreenwood
- Posts: 11906
- Joined: Wed Jan 22, 2003 12:01 am
It sounds like the vacuum advance. Also, make sure the copper ground braid between the breaker plates within the dizzy is not loose or frayed. It has an effect similar to this.
Also, check the vacuum modulator on the transmission for leaks. I am not sure if the radjustment is different for that modulator in type 4 versus type 3. It might be as itstands to reason that the two engines will have different vacuum signatures.
If the tranny came from type 3 and the engine from type 4....this could be part of the problems. Ray
Also, check the vacuum modulator on the transmission for leaks. I am not sure if the radjustment is different for that modulator in type 4 versus type 3. It might be as itstands to reason that the two engines will have different vacuum signatures.
If the tranny came from type 3 and the engine from type 4....this could be part of the problems. Ray
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ploug
- Posts: 20
- Joined: Mon Apr 14, 2008 2:26 am
sorry for the late feed back 
but i turned out to be a combination of things.
the trigger contacts where faulty - note to self: don't just clean - meassure 
the throttle valve switch had som deep grooves - now cleaned up, where nicely done by a friend who has the right tools to clean electric circuts
again thank you all, for your help - couldn't have done it, with out this forum
but i turned out to be a combination of things.
the trigger contacts where faulty - note to self: don't just clean
- meassure the throttle valve switch had som deep grooves - now cleaned up, where nicely done by a friend who has the right tools to clean electric circuts
again thank you all, for your help - couldn't have done it, with out this forum
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Piledriver
- Moderator
- Posts: 22687
- Joined: Sat Feb 16, 2002 12:01 am
Ray, weren't you working on a hall effect switch mod or something to replace the mechanical points with something reliable?raygreenwood wrote:If things were better before you cleaned the contacts then in many cases teh contacts have issues. You need to pull the three pin plug and clean the pins. As AMP/Bosch research found....just plugging and unplugging D-jet connectors can lead to up to a 50% connectivity loss.
The female connectors frequently are to loose on that plug causing connectivity loss and high resistance.
You must check the reistance of both trigger sets after cleaning. Neither should be over about 1.2-1.4 ohms. There should be not more than about .2 ohms difference between the two triggers.
Ideal is about .9 one side and .8 to 1.0 on teh other. As close to even as possible is best. Also check the gap between the rubbing bvlocks of the two trigger sets. I think about .943 is new. About .950-.955 max. Do a seacrh...I have posted this before. Ray
(Also something about full sequential injection?)
I know the issue is fixed, but something that gets overlooked is the mechanical advance is supposed to get a drop of oil every oil change... And they sometimes rust up otherwise.
Addendum to Newtons first law:
zero vehicles on jackstands, square gets a fresh 090 and 1911, cabby gets a blower.
EZ3.6 Vanagon after that.(mounted, needs everything finished) then Creamsicle.
zero vehicles on jackstands, square gets a fresh 090 and 1911, cabby gets a blower.
EZ3.6 Vanagon after that.(mounted, needs everything finished) then Creamsicle.
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raygreenwood
- Posts: 11906
- Joined: Wed Jan 22, 2003 12:01 am
Yes, hopefully this year I will have my engine back in my 412 and be able to test run this.
It is actually a mechanical spring contact switch just like the stock one...but is much more reliable. Here is what it entails:
(1) trigger point arms cut from small (3/16") square section torlon stock. Small light and stiff. Each trigger arm is .75" long with a fulcrum point in the dead center on a 1/16" steel pin.
The cam follower for each trigger arm is a torlon roller cut from rod stock. There is a strip of chromolly up the back and front of each (u-shaped) as a stiffener and the springs bear upon it.
(3) The fixed contact points are made of a slice of the same chromolly and anchored by a 1/16th pin
(4) The contacts themselves are made of gold plated silver rod (had a friend of mine make me about 20 of them. They are 1/8" in diameter
(5) The signal is carried by high temp silver plated copper wire...soldered to each contact and running down the back of each trigger arm. Very clean. I ahven't figured a way to crimp these on yet instead of soldering but I will.
(6) There are eight trigger arms in all. Four actual trigger arms and four interupter arms. You find two arms at approximately every 90 point...although there are still only two actual triggering cam points 180 degrees apart.
(7) each pair of triggers has a "hood" that stretches over them made of pourable cast silicone...that is high temp and super pliable. It effectively keeps all oil and grease from the contacts.
(8) The springs are made of simple bent spring steel. (bought it at Elliots hardware in Dallas a couple of years ago $6 ). They have a single bend and are mounted on teh plate between two pins and go into a stot cut in each arm. They are slightly stiffer than the stock triggers
This plate must be installed from the top of the distributor because it wraps all around the cam and shaft...but its position can be adjusted through the original side plate opening....even while running.
The whole mess is roughly 17-19 mm thick. Just fits in the D-jet dizzy.
It uses essentially eight cams that are very flat and thin made of teflon or Peek 1/16th" plate. I originally thought that torlon would be killer...but at about $900 for a 6" x 6' x 1/4" thick plate....
...maybe too killer. I made four plates of each (PEEK and teflon)..just to see. It would be roughly $100 worth of PEEK for all four cams ...or $20 worth of teflon for all four cams. The PEK and Torlon are much stiffer, but all are so low in friction and so high in temp range....that no lube in this system will be reuired especially with a torlon cam folower on a teflon or PEEK cam.
A refresher: D-jet has only two injection driver channels. In order to energise one...the field from the other has have built and then collapsed. So...if one trigger is malfuntioning, you get no injections at all....as the other trigger will not enable until its opposite has cycled.
In operation.....each D-jet channel has a window of injection opportunity. As far as the ECU is concerned...this is not degree related...it is time related. If you look at the cam in the dizzy...it opens each set of points and keeps them open for very close to 180* of trigger cam/dizzy shaft rotation.
The most important part about that...is what the actual surface length is of that cam lobe. So...the trigger point cam follower/rubbing block...travels a specific length or circumference of that cam lobe.
That length of lobe relates to length of time....as multiplied by the speed of rotation......with me so far?
So...what I have done is using the same two injection channels I am firing all four injectors at one time at each of the two injection points....instead of in pairs.
Reminder.....it takes two complete 360 degree crank revolutions to bring all four cylinders through all four strokes. During that...being that the dizzy runs at 1/2 speed....it takes a full 360* turn to hit four firing points now (instead of two)
But....each injector has an interuptor cam (its actually distributed between the four interuptor cams at multiple points)...that only lets each injector fire at a specific 90* point.
This Stack of cams is mounted essentially a modified steel shaft collar split clamp on the dizzy shaft. In this way I can set up the start point of #1 injector to fire at the instant the intake valve on #1 begins to lift. With proper spacing...the other three fire at essentially 90* spacing (but 180 degree time intervals).
The eight cams were indexed together, properly spaced and pinned together.
The 8 cams are a total of .75" thick with 1/32" spacers between each.\
The whole gist is that the interupptor cams work by breaking the injector ground when they are not allowed to fire
What used to be pairs of injector grounds grounding at the block centerline was broken into four seperate injector grounds and pigtailed to the dizzy.
I noted the time factor and cam lobe length earlier. These cams are larger in diameter...so in effect....with the lobe face father from the vertex point....each degree of arc/rotation...happens in a slower time frame. This is how I was able to get two channels to effectively act like four.
The system still thinks its firing the same two channels (and it is)...at the same approximate injection window length. Its just that its been spread out and by interuption......its really only firing one injector at a time.
The risk is this.....In reality.....I am using roughly half of each original injection window of two channels...splitting it into four.
The same two injection channels are firing one after another. The worry is that they will have to cycle slightly faster...which may cut off some of teh potential open window time.
If teh ECU can then not cycle fast enough...I will make up teh difference in percentage of fuel lost (whcih will be linear across any rpm range)...with higher fuel pressure.
It works. I just need to see if its tunable.
I have not yet finished the centrifugal advance mechanism that would advance the injection point by twisting the trigger plate (just like points)...to advance the point of injection ..starting at about 1200-1500 rpm and ending at about 2200-2500 (specualtion at this point)....because after that it may not matter.
It really is very simple...its just hard to explain. Ray
It is actually a mechanical spring contact switch just like the stock one...but is much more reliable. Here is what it entails:
(1) trigger point arms cut from small (3/16") square section torlon stock. Small light and stiff. Each trigger arm is .75" long with a fulcrum point in the dead center on a 1/16" steel pin.
The cam follower for each trigger arm is a torlon roller cut from rod stock. There is a strip of chromolly up the back and front of each (u-shaped) as a stiffener and the springs bear upon it.
(3) The fixed contact points are made of a slice of the same chromolly and anchored by a 1/16th pin
(4) The contacts themselves are made of gold plated silver rod (had a friend of mine make me about 20 of them. They are 1/8" in diameter
(5) The signal is carried by high temp silver plated copper wire...soldered to each contact and running down the back of each trigger arm. Very clean. I ahven't figured a way to crimp these on yet instead of soldering but I will.
(6) There are eight trigger arms in all. Four actual trigger arms and four interupter arms. You find two arms at approximately every 90 point...although there are still only two actual triggering cam points 180 degrees apart.
(7) each pair of triggers has a "hood" that stretches over them made of pourable cast silicone...that is high temp and super pliable. It effectively keeps all oil and grease from the contacts.
(8) The springs are made of simple bent spring steel. (bought it at Elliots hardware in Dallas a couple of years ago $6
). They have a single bend and are mounted on teh plate between two pins and go into a stot cut in each arm. They are slightly stiffer than the stock triggersThis plate must be installed from the top of the distributor because it wraps all around the cam and shaft...but its position can be adjusted through the original side plate opening....even while running.
The whole mess is roughly 17-19 mm thick. Just fits in the D-jet dizzy.
It uses essentially eight cams that are very flat and thin made of teflon or Peek 1/16th" plate. I originally thought that torlon would be killer...but at about $900 for a 6" x 6' x 1/4" thick plate....
...maybe too killer. I made four plates of each (PEEK and teflon)..just to see. It would be roughly $100 worth of PEEK for all four cams ...or $20 worth of teflon for all four cams. The PEK and Torlon are much stiffer, but all are so low in friction and so high in temp range....that no lube in this system will be reuired especially with a torlon cam folower on a teflon or PEEK cam.A refresher: D-jet has only two injection driver channels. In order to energise one...the field from the other has have built and then collapsed. So...if one trigger is malfuntioning, you get no injections at all....as the other trigger will not enable until its opposite has cycled.
In operation.....each D-jet channel has a window of injection opportunity. As far as the ECU is concerned...this is not degree related...it is time related. If you look at the cam in the dizzy...it opens each set of points and keeps them open for very close to 180* of trigger cam/dizzy shaft rotation.
The most important part about that...is what the actual surface length is of that cam lobe. So...the trigger point cam follower/rubbing block...travels a specific length or circumference of that cam lobe.
That length of lobe relates to length of time....as multiplied by the speed of rotation......with me so far?
So...what I have done is using the same two injection channels I am firing all four injectors at one time at each of the two injection points....instead of in pairs.
Reminder.....it takes two complete 360 degree crank revolutions to bring all four cylinders through all four strokes. During that...being that the dizzy runs at 1/2 speed....it takes a full 360* turn to hit four firing points now (instead of two)
But....each injector has an interuptor cam (its actually distributed between the four interuptor cams at multiple points)...that only lets each injector fire at a specific 90* point.
This Stack of cams is mounted essentially a modified steel shaft collar split clamp on the dizzy shaft. In this way I can set up the start point of #1 injector to fire at the instant the intake valve on #1 begins to lift. With proper spacing...the other three fire at essentially 90* spacing (but 180 degree time intervals).
The eight cams were indexed together, properly spaced and pinned together.
The 8 cams are a total of .75" thick with 1/32" spacers between each.\
The whole gist is that the interupptor cams work by breaking the injector ground when they are not allowed to fire
What used to be pairs of injector grounds grounding at the block centerline was broken into four seperate injector grounds and pigtailed to the dizzy.
I noted the time factor and cam lobe length earlier. These cams are larger in diameter...so in effect....with the lobe face father from the vertex point....each degree of arc/rotation...happens in a slower time frame. This is how I was able to get two channels to effectively act like four.
The system still thinks its firing the same two channels (and it is)...at the same approximate injection window length. Its just that its been spread out and by interuption......its really only firing one injector at a time.
The risk is this.....In reality.....I am using roughly half of each original injection window of two channels...splitting it into four.
The same two injection channels are firing one after another. The worry is that they will have to cycle slightly faster...which may cut off some of teh potential open window time.
If teh ECU can then not cycle fast enough...I will make up teh difference in percentage of fuel lost (whcih will be linear across any rpm range)...with higher fuel pressure.
It works. I just need to see if its tunable.
I have not yet finished the centrifugal advance mechanism that would advance the injection point by twisting the trigger plate (just like points)...to advance the point of injection ..starting at about 1200-1500 rpm and ending at about 2200-2500 (specualtion at this point)....because after that it may not matter.
It really is very simple...its just hard to explain. Ray