# 83 gti, starts and idles great. no fuel under Acceleration??



## TWIZTD R32 (Feb 21, 2009)

Realised I posted this in the not technical section so I am copying and posting here also. 

Been trying to figure this.out for awhile but .....just..... can't ....figure it out. 

I had my 83 gti, body rotted so I bought a 82 rabbit diesel . Swapped. Everything from the gti into the.rabbit. in the swap I did timing belt ,cam gear , water pump, head gasket, port polish , valve job ,TT. Valve.springs , poly motor mounts . 

Got it all done drove it all day tuning it , went through 1 tank of gas . Car was running great . Filled up parked it and it's run like crap ever since. 

Here is a video of me driving it .the.day it ran . 

https://www.youtube.com/watch?v=0hV2b_-5rO8&feature=youtube_gdata_player 


Now it starts right up every time and idles fine bit the second I give it gas it runs lean . I installed a wideband air fuel gage the next day and that's how I determined that it's super lean . I can adjust fuel mixture at idle but it doesn't mater how rich I set it , as soon I I accelerate it goes lean... Off the gauge lean . 

Here is a video of me starting the.car and of the a/f gauge . 

https://www.youtube.com/watch?v=VeicoxkD1aw&feature=youtube_gdata_player 


I have changed the fuel filter, checked for leaks, I bought a CIS fuel pressure tester , car runs at 75psi even when it is running lean . I ran the pump and lifted the plate to check the spray Pattern and they look good but I did find that during the pressure tests that the injectors did leak a little . They would drip . , though like I said they spray fine . 

What I did find is that if I pinch the line from the intake manifold to the valve cover the car will die right out . Also if I unscrew the oil filer cap the car will die. I don't remember this being an issue when the motor was in the other car. 

Here is a video of me pinching the line and removing the cap. I only pinch it about half way so that it doesn't die 


https://www.youtube.com/watch?v=pYP5GgDCQKw&feature=youtube_gdata_player 


Here is another video of it running and me playing with the line 

https://www.youtube.com/watch?v=IGFhlnMLH_4&feature=youtube_gdata_player 



Any help would be great. It's just so frustrating that it starts and idles so well but I can't drive it. 

Thank you 
Shawn


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## TWIZTD R32 (Feb 21, 2009)




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## DjBij099 (Jul 21, 2003)

I'll try and help, but bare with me a little. My first real stab at trying to help with the system. When you say it's at 75psi, is that system pressure or control pressure warm? As far as I remember, the system pressure should be about 75psi and control pressure warm in a range between 48-57psi.


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## WaterWheels (Aug 14, 2005)

System pressure, which you tested, is not real important in this case. In your case I would have checked control pressure as that is what effects the fuel delivery. System pressure can be maybe as low as 50psi and the engine will still run better then the videos show. I have my doubts as to if the vacuum/intake air lines are all installed correctly, but will have to take your word on that part. What really stands out to me while watching the videos is the way the engine runs and sounds. It really sounds to be a tooth off on the engine timing which will cause the engine to act just as it does when you do what you are doing. It will run rich at idle and lean out when you open the throttle. It will want to die with just about any change made to air flow, pinching the hose or opening the oil fill cap. And it will sound more or less like your engine does when it is running. Might be something else, hard to say from here with nothing to go on, but I would re-check the engine timing to be 100% sure it is correct.


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## TWIZTD R32 (Feb 21, 2009)

DjBij099 said:


> I'll try and help, but bare with me a little. My first real stab at trying to help with the system. When you say it's at 75psi, is that system pressure or control pressure warm? As far as I remember, the system pressure should be about 75psi and control pressure warm in a range between 48-57psi.


 That is correct . 75psi system pressure . 

My control pressures were just low . Cold was 10psi and hot was 40psi I believe but it was also 30deg out . My injectors were dripping also during the control tests so I figure I need new injectors but spray pattern seems good so I don't think they are causing lean issue's .?? 



Thanks for any help, I'm at a loss at the moment . If I had money I'd just start replacing stuff but I don't. Everything was running in the old car and ran great. Dyno'd 90wheel & 120wtq with a 13-13.2 air fuel. Only thing different is the head cause we found mine was cracked between valves . Did all the valve work and I eliminated the charcoal can and expansion tanks when I swapped it.


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## TWIZTD R32 (Feb 21, 2009)

WaterWheels said:


> System pressure, which you tested, is not real important in this case. In your case I would have checked control pressure as that is what effects the fuel delivery. System pressure can be maybe as low as 50psi and the engine will still run better then the videos show. I have my doubts as to if the vacuum/intake air lines are all installed correctly, but will have to take your word on that part. What really stands out to me while watching the videos is the way the engine runs and sounds. It really sounds to be a tooth off on the engine timing which will cause the engine to act just as it does when you do what you are doing. It will run rich at idle and lean out when you open the throttle. It will want to die with just about any change made to air flow, pinching the hose or opening the oil fill cap. And it will sound more or less like your engine does when it is running. Might be something else, hard to say from here with nothing to go on, but I would re-check the engine timing to be 100% sure it is correct.


 My control pressure was low . Posted in post above . Wur/CPR has been apart and cleaned . 


The was running well but I haven't rechecked the belt again. Maybe it jumped a tooth? I will double check that. 

I'm not totally sure on the vacuum lines. I eliminated the charcoal can and expansion tank when I did the swap. I can take some good pictures of all the lines . 


Thank you for the help


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## TWIZTD R32 (Feb 21, 2009)

Forgot I had posted the test results in my build thread on another forum . 




System pressure = 75psi perfect 
Cold control pressure = 9psi should be 22-25 
Warm control pressure = 48psi should be 55 

Was about 30deg out 


On the sound of the motor I should mention it does have a webcam 272 cam , .13 shaved off head , mk2 4:2 exhaust manifold , what's left of a TT down pipe and a 2.5 straight pipe . All of which were on the motor when it was running right in the other car. I did have to change the head in the swap but the old one was also shaved to similar spec. New one got p&p and valve job with TT springs. 












I don't know how many times I have looked at this picture in the last few days trying to see if I missed something . But maybe I eliminated the charcoal can wrong . 

When I get home from work I'll edit the picture to show how it's all hooked up . Easier then trying to type it.


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## DjBij099 (Jul 21, 2003)

TWIZTD R32 said:


> My control pressure was low . Posted in post above . Wur/CPR has been apart and cleaned .
> 
> 
> The was running well but I haven't rechecked the belt again. Maybe it jumped a tooth? I will double check that.
> ...


 Here's a little help for the vacuum connections. Just click on the one that's yours and it'll show a picture of the routing for the hoses :thumbup: 

http://www.cabby-info.com/engine.htm#Vacuum


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## TWIZTD R32 (Feb 21, 2009)

DjBij099 said:


> Here's a little help for the vacuum connections. Just click on the one that's yours and it'll show a picture of the routing for the hoses :thumbup:
> 
> http://www.cabby-info.com/engine.htm#Vacuum


 Thanks his one is similar and looks right but I don't have a second line on the distributor . There is no port there just the one . 

I do think I have the can bypassed wrong


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## TWIZTD R32 (Feb 21, 2009)

TWIZTD R32 said:


> I don't know how many times I have looked at this picture in the last few days trying to see if I missed something . But maybe I eliminated the charcoal can wrong .
> 
> When I get home from work I'll edit the picture to show how it's all hooked up . Easier then trying to type it.


 Hooked my phone to my ****tie work comp and made this magnificent rendering . 











I was thinking instead of capping the line to can I should have T'd that line into the the one from the gas tank to the "on/off valve" . But I just remembered why I didn't. The "on/off" is plugged into the intake . Yes/no?


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## TWIZTD R32 (Feb 21, 2009)

WaterWheels said:


> System pressure, which you tested, is not real important in this case. In your case I would have checked control pressure as that is what effects the fuel delivery. System pressure can be maybe as low as 50psi and the engine will still run better then the videos show. I have my doubts as to if the vacuum/intake air lines are all installed correctly, but will have to take your word on that part. What really stands out to me while watching the videos is the way the engine runs and sounds. It really sounds to be a tooth off on the engine timing which will cause the engine to act just as it does when you do what you are doing. It will run rich at idle and lean out when you open the throttle. It will want to die with just about any change made to air flow, pinching the hose or opening the oil fill cap. And it will sound more or less like your engine does when it is running. Might be something else, hard to say from here with nothing to go on, but I would re-check the engine timing to be 100% sure it is correct.



Belt didn't jump but the timing was half a tooth high . I believe that's do to the shaved head. I went and moved it a tooth which put it a half a tooth the other way and tried that. It ran much better , reset the ignition timing to the 6deg mark and it's running good. I took it for a spin down the street and it runs well but has no balls . When I get more time I'll work on the adjustable cam gear .but it was dark. It still stalled if I pinch ed that line or opened the.oil fill cap though. 

I picked up a vacuum pressure tester and hooked it up . What should it be running for vacuum at idle ??


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## WaterWheels (Aug 14, 2005)

Yes, having the cylinder head surface machined will affect the timing mark for the camshaft. That is one of the “real” reasons for an adjustable camshaft gear. You also can’t expect the engine to function exactly as it would in its factory configuration. More than the factory 6 degrees of static ignition advance would help it work better, I would say 10-12, a higher idle (slightly) would make it smoother at idle. But before doing too much of anything I believe the vacuum and vent hoses need to be sorted out. I don’t know exactly what you have for an ignition but there could be issues in that area also which could help, like advancement curve and total.

The drawing you made notes on shows some problems in my opinion, or I just don’t understand your changes. In the drawing at the valve cover there is an arrow stating “to air box”. If I recall on the video you have the hose from the air box running up to somewhere by the throttle body (couldn’t see where it was connected). Maybe it bends down and connects to the valve cover but I can’t tell. You show the gas tank vent being connected to the on/off valve, remove it from there and leave it free to atmospheric air so the tank can vent properly. The vacuum switch in-line with the ignition distributor can be removed in many cases but not knowing the exact ignition system I’ll not say to do it. For that camshaft I would change the vacuum source for the ignition from venture to manifold and the same for the air shrouding air, get it from the manifold vacuum.

The vacuum gauge reading for a warm motor is too low. Could be a few things, like not enough ignition timing, but I would expect more in the 17-18 inches area. What happens when you “blip” the throttle? Is the reading steady?


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## TWIZTD R32 (Feb 21, 2009)

WaterWheels said:


> Yes, having the cylinder head surface machined will affect the timing mark for the camshaft. That is one of the “real” reasons for an adjustable camshaft gear. You also can’t expect the engine to function exactly as it would in its factory configuration. More than the factory 6 degrees of static ignition advance would help it work better, I would say 10-12, a higher idle (slightly) would make it smoother at idle. But before doing too much of anything I believe the vacuum and vent hoses need to be sorted out. I don’t know exactly what you have for an ignition ( not sure what you mean. Just the factory stuff I think)but there could be issues in that area also which could help, like advancement curve and total.
> 
> The drawing you made notes on shows some problems in my opinion, or I just don’t understand your changes. In the drawing at the valve cover there is an arrow stating “to air box”. If I recall on the video you have the hose from the air box running up to somewhere by the throttle body (couldn’t see where it was connected). Maybe it bends down and connects to the valve cover but I can’t tell.
> Yea, the hose from the air box goes to the valve cover
> ...




Thank you for the.help


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## WaterWheels (Aug 14, 2005)

> (not sure what you mean. Just the factory stuff I think)


I can see the ignition distributor but can’t tell if it is the dual vacuum port type, if it is points, if it is the correct one for that engine or if it has been modified in any way. If the car was brand new we would all know just what is installed in it, but seeing as it is not there could be any number of changes or modifications. I just can’t see clogging things up confusing anyone by posting suggestions that are not relevant.



> Yea, the hose from the air box goes to the valve cover


OK, good. 



> So I'll take it off and just cap the line on the on/off valve ??


Don’t just cap things off and leave unnecessary stuff sitting around in the way, delete it or keep it, in this case I would delete everything no longer in use.
> I would leave the Aux Air valve as it currently is (in drawing)
> I would run a single line from the ignition distributor vacuum advance to a manifold vacuum source.
> Leave the thick hose from the air filter box to the valve cover and either cap the small nipple at the valve cover or use a cover/adapter with a single nipple for the large hose.
> I would delete the intake manifold to valve cover hose and use that manifold nipple as stated below.
> Leave the brake booster hose as it is with all nipples on the valve capped off if not in use.
> Vent the fuel tank as discussed above.
Again, this is what “I” would do but you have to make the call.



> could you explain what you mean. Vacuum for the ignition is coming from the TB now , right? What is "shrouded air" ?? Where on the manifold would I tap into ?.


There are two forms of “vacuum” used on engines, manifold and venturi. Manifold vacuum is just that, low pressure which is drawn from the intake manifold or its extensions. The other is venturi which comes from just before the throttle blades and at idle is almost 0 (zero). Once the throttle is opend, venturi vacuum is the same as manifold vacuum. Auto makers started using the venturi ports for emission concerns but for a modified or performance engine it really should not be used. You want the ignition distributor to see manifold vacuum all the time and not just when the throttle is opened. One source if no port is present on the manifold or throttle body (after the blades) is the one way valve in the line running to the brake booster. Often there are one or two un-used nipples on them and if not you can get one from a car which has 2 or three.

Air shrouding was used again for emissions with a side benefit of maybe a smoother idle. An air passage was machined which allows air to enter behind the fuel injectors and as it passed the injector tip it cooled the injector and caused better atomization of the air/fuel. I have found that there seems to be two methods to draw the air past the injectors. One type draws air before the throttle blades and the other after (manifold air if you will). In either case the air entering the engine past the injectors has already been measured by the sensor plate and fuel added. I find the method of using manifold air works best for some reason and if it were my motor I would switch it over (I would delete the hose from the valve cover to the intake and run a hose from that intake port to the one on the cylinder head).



> The vacuum is steady , when I blip the throttle vacuum raises . I think it was 25-30 maybe but I don't remember . I can redo it tomorrow.


That’s odd unless you are not stating the entire sequence of events. Did you watch the gauge the entire time? For the reading to increase to 25 or there a bouts when the throttle closes again during the “blip” is fine, but if when you do it the reading goes up right away, that would indicate things are not right. On a healthy well-tuned engine the reading should be steady minus any camshaft roughness. The exact reading depends on the engine, factory engines will see 19-20 in most cases and slightly modified may be lower like 17-18 leaving the highly modified engines to get even lower. When the throttle is opened sharply and left to close again the reading should drop to almost 0 (zero) and then jump back up to that 25 or so reading you stated before settling back to the normal idle reading.


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## TWIZTD R32 (Feb 21, 2009)

Didn't get a chance to work on the car but snapped a couple pictures to help show the setup. Unfortunately I didn't gettoto post them before your last response. 

























Distributor













Line from the distributor to the on/off valve with the line from the back of the throttle body T'd in. When checking vacuum leaks I accidentally broke the plastic T that was there and the parts store was closed. That's why it looks like this .





























The on off valve 

Top line to the distributor, bottom line to the gas tank and side plugged into the intake boot .












The 4 way T plugged into the bottom of the intake boot . The 2 ports capped and the port that 90's on the bottom that you cant see goes to the Head. 












In line valve , not in use.


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## TWIZTD R32 (Feb 21, 2009)

QUOTE=WaterWheels;80023591]I can see the ignition distributor but can’t tell if it is the dual vacuum port type, if it is points, if it is the correct one for that engine or if it has been modified in any way. If the car was brand new we would all know just what is installed in it, but seeing as it is not there could be any number of changes or modifications. I just can’t see clogging things up confusing anyone by posting suggestions that are not relevant.



> posted picture above , I believe single .


OK, good. 


Don’t just cap things off and leave unnecessary stuff sitting around in the way, delete it or keep it, in this case I would delete everything no longer in use.
> I would leave the Aux Air valve as it currently is (in drawing)


> yes it is still hooked up


> I would run a single line from the ignition distributor vacuum advance to a manifold vacuum source.


> so remove the on/off valve all together? Does the port on the back of the TB work for vacuum?


> Leave the thick hose from the air filter box to the valve cover and either cap the small nipple at the valve cover or use a cover/adapter with a single nipple for the large hose.
> I would delete the intake manifold to valve cover hose and use that manifold nipple as stated below.
> Leave the brake booster hose as it is with all nipples on the valve capped off if not in use.


> I'm not running that yellow piece with the 4 ports . Would that matter ?


> Vent the fuel tank as discussed above.
Again, this is what “I” would do but you have to make the call.


There are two forms of “vacuum” used on engines, manifold and venturi. Manifold vacuum is just that, low pressure which is drawn from the intake manifold or its extensions. The other is venturi which comes from just before the throttle blades and at idle is almost 0 (zero). Once the throttle is opend, venturi vacuum is the same as manifold vacuum. Auto makers started using the venturi ports for emission concerns but for a modified or performance engine it really should not be used. You want the ignition distributor to see manifold vacuum all the time and not just when the throttle is opened. One source if no port is present on the manifold or throttle body (after the blades) is the one way valve in the line running to the brake booster. Often there are one or two un-used nipples on them and if not you can get one from a car which has 2 or three.


> mine had 4 unused ports but there was no valve in it. It was open straight through so I removed it .



Air shrouding was used again for emissions with a side benefit of maybe a smoother idle. An air passage was machined which allows air to enter behind the fuel injectors and as it passed the injector tip it cooled the injector and caused better atomization of the air/fuel. I have found that there seems to be two methods to draw the air past the injectors. One type draws air before the throttle blades and the other after (manifold air if you will). In either case the air entering the engine past the injectors has already been measured by the sensor plate and fuel added. I find the method of using manifold air works best for some reason and if it were my motor I would switch it over (I would delete the hose from the valve cover to the intake and run a hose from that intake port to the one on the cylinder head).


That’s odd unless you are not stating the entire sequence of events. Did you watch the gauge the entire time? For the reading to increase to 25 or there a bouts when the throttle closes again during the “blip” is fine, but if when you do it the reading goes up right away, that would indicate things are not right. On a healthy well-tuned engine the reading should be steady minus any camshaft roughness. The exact reading depends on the engine, factory engines will see 19-20 in most cases and slightly modified may be lower like 17-18 leaving the highly modified engines to get even lower. When the throttle is opened sharply and left to close again the reading should drop to almost 0 (zero) and then jump back up to that 25 or so reading you stated before settling back to the normal idle reading.[/QUOTE]




> I will re do the test and record it . I had the gauge connected to the post on the throttle body that is capped. You can see it in pictures above. Maybe it's on the wrong side of the valve ?



Thank you for explaining the manifold and shrouded air. Makes sense.


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## WaterWheels (Aug 14, 2005)

posted picture above , I believe single 

Yes, it looks to have only one connection for vacuum. It also looks very "weathered", do you have a vacuum pump with gauge? I have found the vacuum diaphrams of old ignition distributors to be bad very often. If you have a pump, pump up a few psi and see if it holds, or if you even can build some vacuum. The ignition distributor itself might need some work as I have discovered missing or broken springs in them often, dried up grease so they don't work smooth, broken or missing parts like E-clips or the plastic advance stops, etc. Even the pin for the advance pops off sometimes and one never knows unless you look inside.

so remove the on/off valve all together? Does the port on the back of the TB work for vacuum? 

As I stated, *I* would and believe you should but you have to make the call. What is it doing? You want the fuel tank vented "always" and not just when the switch opens to allow venting. You seem to have put together a slightly modified fun kind of car, saw the exhaust for one, why keep crap that does not fit or work with that kind of set up?

I would, do is more correct, believe that the rear is venturi vacuum. The only way to tell for sure is with your vacuum gauge unless someone knows for sure. At idle, so long as the throttle blades close correctly, there should be little or no vacuum if it is venturi. Try it on both the front and rear nipples and you will know for sure what you have and where.

I'm not running that yellow piece with the 4 ports . Would that matter ?

Get one. It can be dangerous or cause problems if you do not have a working check valve in-line to the brake booster. Its there for a reason and the reason is rather important so either find a working one or buy a new one and add it.


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## TWIZTD R32 (Feb 21, 2009)

Made the recommended changes and I like it. Seems to run much better, I was actually able to adjust the idle with the idle air screw. Before it was totally closed and still idled very high. Vacuum is at 15 and I have timing somewhere over 6 . I don't have a digital timing light so I just guest at what was 10-12 . Unfortunately I still have the same lean issue. 

You were correct about the vacuum , when you blip the throttle it goes to 0 then 23 then back to 15 at idle. 


I do not have a pump with a gauge to check the distributor. Is there any other way to check it. I did notice that the car ran differently when I had the distributor unplugged and the line plugged , to do the timing . Is that normal? 

The line on the back of the TB had 0 vacuum so I ran it to the front one and T'd my vacuum gauge there. 


I took a couple videos, just need to upload them to YouTube.


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## TWIZTD R32 (Feb 21, 2009)

This is after the initial tune and getting it running with the lines rerouted .








This is after tuning it a little better 








This is a little drive down the street


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## WaterWheels (Aug 14, 2005)

> Vacuum is at 15 and I have timing somewhere over 6 . I don't have a digital timing light so I just guest at what was 10-12.


I would expect the vacuum to be more like 17 or there abouts, so in my opinion it is still a little low. This could be related to the timing and you could try nudging it up some. It does not sound to be too far advanced right now and if you do start to hear some pinging just dial it back until it stops. You don‘t need a „digital“ timing light, double the distance from TDC mark to the notch and make your own mark, that would be 12°. This is also not a stock motor and set-up so you could need maybe 14°, just can‘t tell you an exact figure it always varies. 



> I do not have a pump with a gauge to check the distributor. Is there any other way to check it. I did notice that the car ran differently when I had the distributor unplugged and the line plugged , to do the timing . Is that normal?


Normal but for your setup I would not set the timing with the hose removed and plugged. As long as you keep the idle down around 1000-1200 things will work well. If you have to use a higher idle then you are going to have to do some distributor work. Warm up the engine, get a stable idle and adjust the ignition timing with the vacuum line attached. 



> Unfortunately I still have the same lean issue


Was toying with the idea that you have a bad control pressure regulator but you posted the readings and both were low and not high. So the idea of it being plugged up and causing way to high control pressure is out I guess. I don‘t see a frequency valve and you don‘t say anything about O2 sensor or such so I assume it is basic CIS (though it should have come with CIS w/Lambda). Does not leave too much simple stuff for it to act as it does. So I have to ask, how is the exhaust system? Cracked exhaust manifold or leak between the engine and the sensor for the air/fuel gauge?


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