engine pictures Options

[mipstien]

im confused as to why you folks won't answer my questions. they are questions about WHY not how to.
i would like to know why my car idles perfect with the valve off whether hot or cold.
also want to know why putting the vacuum hose on the front of the distributor it runs smoother than on the back where it was intended to go?
i have read every single thing on the rennlist site. but im still confused which is why im asking questions. im not sure why everyone wants to send me to another web page every time i ask something its kinda frustrating when a straight answer is easier than pointing me down the road and having me walk there. i understand if you teach a man to fish, but i learned to fish. i have an actual question because the other sites, including searching on here for hours, has turned up no answer's to my questions.
(IMG:style_emoticons/default/skull.gif)

and i cleaned the thing, the previous owner cleaned it. a lot of trial and error has already happened.

Don't get your panties in a bunch (IMG:style_emoticons/default/biggrin.gif)
Your AAR is stuck. It needs to come out and soak overnight in PB blater, or it's not getting voltage. Thats the first one.

Idle's better with the line on the front- it's advancing the distributor. Some cars have a line on both sides of the distributor, some only on the front. That is basic for any old car. So more learning to fish is in order. (IMG:style_emoticons/default/biggrin.gif)

i understand advance and retard, what i don't understand is why plugging the one everyone says to use and using the one everyone says to plug is causing faster idle with the AAR on.
if the AAR is stuck then why would it run like crap when warmed up and that hose plugged?
you still didn't answer my questions.
if i have normal idle with the line OPEN and engine WARM then what ELSE could be causing my problem?

[Tom]

Did you look at the engine bay pictures on the originality and history section on this forum? If and when you do, pay attention to the vacuum advance can on the distributors in those pics. Now look at yours. Something seems wrong there!
Also, I'm surprised someone hasn't mentioned this before - trying to diagnose a running problem over the Internet is difficult at best. AND when your engine is new to you, you should always go back to basics. Tune up, valve adj., and timing at the very least.
Hope this helps,
Tom

[underthetire]

If you have normal idle with the aar open and pulling vacuum, ad it idles higher with the front of the vac can plugged in, you need to re-check your timing, ECU knob, head temp sensor. Also check that your MPS is working and holds vacuum, and the throttle position switch is set right. You also need to check that all the sensors are compatible with the ECU you have. Seems like you want a quick answer to me. Ain't gonna happen without seeing it in person. Pelican articles, banders site, and the chilton all have vacuum diagrams in them. All the distributors have a line on the front, not all on the back. It also makes a huge difference what line goes where on the throttle body. One is switched the other is not.

Make a list of everything you check, like this..
Fuel pressure xx
compression xx
Timing xx
Valve clearance XX
Etc.....

[mipstien]

i have a head temp sensor on its way and that was a lot more help than you know
im not asking for quick and easy. i was asking outa curiosity. rather idc if it makes my car run i just want to understand.

[mipstien]

i have been reading a little more on
http://members.rennlist.com/pbanders/manif...sure_sensor.htm
(mps) and looked at mine and it has been 'played with' basically the seal on it is broke and someone has been turning the screw. can this cause a stall in power at around XXXX rpms or bad idle? if its been adjusted wrong should i look into purchasing another one or should i just try to readjust it assuming that it is electronically sound?

i know i need to make sure that the whole thing is mechanically and electronically working testing ohms and pressure being held.

one last question about the MPS. if the 'glue' seal that it has is broke on the screw adjuster would that cause it not to hold a vacuum and basically need that screw filled in. i didn't see that on the rennlist sight.

(IMG:http://www.914world.com/bbs2/uploads_offsite/members.rennlist.com-11576-1274666649.1.jpg)

if that is broke does it not keep vacuum basically?
and is this the answer to my question....

Q: I've heard that all I have to do to get my car to run right is to remove the epoxy, unscrew the plug (whoops, I stripped/lost/broke it when I did this), and use a screwdriver to adjust that center screw until I think it's running smooth? What do you think?
A: Some of the old D-Jet references suggested a procedure like this to fix part-load mixture issues. The problem with this procedure is that it doesn't comprehend that the full-load stop (the "plug") is a critical adjustment in this system. Removing the plug and either not replacing it or screwing it in randomly will likely result in either a rich or lean full-load mixture, and possible premature failure of the diaphragm due to mechanical stress. Also, depending on the vacuum level in the MPS, turning the inner screw usually turns the outer screw at the same time, due to friction on the threads. This causes the part-load mixture to remain unchanged, but changes the full-load mixture. I strongly suggest that you do not adjust the MPS without using an LCR55 to first characterize the secondary inductance vs. vacuum characteristic. Otherwise, you will lose your reference point for all three adjustments and probably won't be able to get back to them by random adjustments.

[mipstien]

weirdest thing just happened.
earlier we regaped the spark plugs and the distributor and it was running the same way (AAR valve off) and running like a champ
went out there to see if it had vacuum off the MPS and started it up and ran really high rpm. its warm but not hot by any means maybe 3 hours of sitting. i actually plugged up the hose where the AAR should be and it idled PERFECT.
im just thinking and posting my results so i have something to look back on if i forget/change something. and if anyone has any input.

[mipstien]

so im starting to talk to myself.
anyways
after a lot of searching on rennlist site i can't quite grasp what the air temp sensor/intake temp sensor affects. mine is apparently unplugged. it can cause the engine to run rich but what other symptoms could it cause?
this is a question and for my curiosity if someone has a link to 'all about the air temp sensor' then post it.

[detoxcowboy]

weirdest thing just happened.
earlier we regaped the spark plugs and the distributor and it was running the same way (AAR valve off) and running like a champ
went out there to see if it had vacuum off the MPS and started it up and ran really high rpm. its warm but not hot by any means maybe 3 hours of sitting. i actually plugged up the hose where the AAR should be and it idled PERFECT.
im just thinking and posting my results so i have something to look back on if i forget/change something. and if anyone has any input.

You AAR has been stuck open..

[mipstien]

weirdest thing just happened.
earlier we regaped the spark plugs and the distributor and it was running the same way (AAR valve off) and running like a champ
went out there to see if it had vacuum off the MPS and started it up and ran really high rpm. its warm but not hot by any means maybe 3 hours of sitting. i actually plugged up the hose where the AAR should be and it idled PERFECT.
im just thinking and posting my results so i have something to look back on if i forget/change something. and if anyone has any input.

You AAR has been stuck open..

the aar isn't on the car right now, hasn't been for a few days. ran like a champ with it off for a few days then yesterday just started running like it should with it off.
are you saying that it caused it to act up even after the aar was removed? if so when i put it back on this evening it should run like its supposed to?

[detoxcowboy]

so im starting to talk to myself.
anyways
after a lot of searching on rennlist site i can't quite grasp what the air temp sensor/intake temp sensor affects. mine is apparently unplugged. it can cause the engine to run rich but what other symptoms could it cause?
this is a question and for my curiosity if someone has a link to 'all about the air temp sensor' then post it.

It has very little efect on the enitre djet system, unpluged can make it runner slightly richer, actually have read that unplugging it was an old mechanics trick to richen the mixture when needed..

here is a cut and paste from THE ECU rennilist Doc.. ( alot of info there you probably just missed it)

http://members.rennlist.com/pbanders/DJetParts.htm

Intake Air Temperature Sensor

Function: Senses intake air temperature and sends signal to the ECU to provide mixture compensation.
Normal Value(s): 300 ohms @ 68 deg. F, about 100 ohms @ 122 deg. F.
Failure Modes
Open: Makes the mixture somewhat richer. Check with an ohmmeter.
Shorted: Makes the mixture somewhat leaner. Check with an ohmmeter.

THIOS IS THE IMPORTANT PART.. NOTICE SMALL EFFECT ECT..
Notes: The output of this sensor is used by the ECU to adjust the mixture for the intake air temperature. This is a secondary adjustment and has a small effect on the mixture. The sensor corrects for the decrease in air density with increasing temperature by leaning out the mixture. Disconnecting this sensor has the effect of richening the mixture, a common mechanic's trick.


THAK GOD for CUTTING AND PASTEING CUASE i TYPE LIKE _____!

[mipstien]

so im starting to talk to myself.
anyways
after a lot of searching on rennlist site i can't quite grasp what the air temp sensor/intake temp sensor affects. mine is apparently unplugged. it can cause the engine to run rich but what other symptoms could it cause?
this is a question and for my curiosity if someone has a link to 'all about the air temp sensor' then post it.

It has very little efect on the enitre djet system, unpluged can make it runner slightly richer, actually have read that unplugging it was an old mechanics trick to richen the mixture when needed..

here is a cut and paste from THE ECU rennilist Doc.. ( alot of info there you probably just missed it)

http://members.rennlist.com/pbanders/DJetParts.htm

Intake Air Temperature Sensor

Function: Senses intake air temperature and sends signal to the ECU to provide mixture compensation.
Normal Value(s): 300 ohms @ 68 deg. F, about 100 ohms @ 122 deg. F.
Failure Modes
Open: Makes the mixture somewhat richer. Check with an ohmmeter.
Shorted: Makes the mixture somewhat leaner. Check with an ohmmeter.
Notes: The output of this sensor is used by the ECU to adjust the mixture for the intake air temperature. This is a secondary adjustment and has a small effect on the mixture. The sensor corrects for the decrease in air density with increasing temperature by leaning out the mixture. Disconnecting this sensor has the effect of richening the mixture, a common mechanic's trick.


THAK GOD for CUTTING AND PASTEING CUASE i TYPE LIKE _____!

i guess i coudln't find that its a small part in that huge wall of text on that page. but i did a google search over his whole site and none of that showed up (IMG:style_emoticons/default/sad.gif)

[mipstien]

is the wire that goes that thing red or white? anyone have any idea what the stock wire color is?

[detoxcowboy]

i have been reading a little more on
http://members.rennlist.com/pbanders/manif...sure_sensor.htm
(mps) and looked at mine and it has been 'played with' basically the seal on it is broke and someone has been turning the screw. can this cause a stall in power at around XXXX rpms or bad idle? if its been adjusted wrong should i look into purchasing another one or should i just try to readjust it assuming that it is electronically sound?

i know i need to make sure that the whole thing is mechanically and electronically working testing ohms and pressure being held.

one last question about the MPS. if the 'glue' seal that it has is broke on the screw adjuster would that cause it not to hold a vacuum and basically need that screw filled in. i didn't see that on the rennlist sight.

(IMG:http://www.914world.com/bbs2/uploads_offsite/members.rennlist.com-11576-1274666649.1.jpg)

if that is broke does it not keep vacuum basically?


If the mps has been tampered with it can cause all types of drivabilty porblems, including lost idle, power loss at certain power bands, ect. ect. the plug is just a cover. my plug was missing for a year , then i tamperewd with the screws and ooooops!! Screwed myself into a hole.. Luckily my mechanic diod not laugh at me and had an NOS unit, they are expensive and NLA.. BUt there is another solution..

Jeff Bolwsby can recalibrate and replug the mps, he is a memebr here, well known for his 914 knowledge and has a website below...

Basically the MPS is one of the most important sensors on the car, if not the most important..

http://members.rennlist.com/914_wiring_harnesses/
and is this the answer to my question....

Q: I've heard that all I have to do to get my car to run right is to remove the epoxy, unscrew the plug (whoops, I stripped/lost/broke it when I did this), and use a screwdriver to adjust that center screw until I think it's running smooth? What do you think?
A: Some of the old D-Jet references suggested a procedure like this to fix part-load mixture issues. The problem with this procedure is that it doesn't comprehend that the full-load stop (the "plug") is a critical adjustment in this system. Removing the plug and either not replacing it or screwing it in randomly will likely result in either a rich or lean full-load mixture, and possible premature failure of the diaphragm due to mechanical stress. Also, depending on the vacuum level in the MPS, turning the inner screw usually turns the outer screw at the same time, due to friction on the threads. This causes the part-load mixture to remain unchanged, but changes the full-load mixture. I strongly suggest that you do not adjust the MPS without using an LCR55 to first characterize the secondary inductance vs. vacuum characteristic. Otherwise, you will lose your reference point for all three adjustments and probably won't be able to get back to them by random adjustments.

[SirAndy]

if so when i put it back on this evening it should run like its supposed to?

No ...

Randomly removing and adding components will not help you to diagnose your problem.

You need to start with the basics and methodically work through each of the components.

- Adjust valves
- Grab your timing light and time the engine.
- Take your multimeter and trace each and every wire in the engine harness. If in question, cut back the plastic sheeting and look for brittle or broken wires.
- Check your relay board. Check all relays. Check all connectors.
- Check your spark plus, plug wires and distributor.
- Check all your vacuum hoses.
- Report back here.


Right now, you are going in circles ...
(IMG:style_emoticons/default/shades.gif) Andy

[detoxcowboy]

if so when i put it back on this evening it should run like its supposed to?

No ...

Randomly removing and adding components will not help you to diagnose your problem.

You need to start with the basics and methodically work through each of the components.

- Adjust valves
- Grab your timing light and time the engine.
- Take your multimeter and trace each and every wire in the engine harness. If in question, cut back the plastic sheeting and look for brittle or broken wires.
- Check your relay board. Check all relays. Check all connectors.
- Check your spark plus, plug wires and distributor.
- Check all your vacuum hoses.
- Report back here.


Right now, you are going in circles ...
(IMG:style_emoticons/default/shades.gif) Andy

(IMG:style_emoticons/default/agree.gif) method to the madness, or your chaisng your tail whacking moles. I am not discouraging or chatising you, I have been there and have been my own worst enemy.. You have alot of heart,, and you will get this. alot of people say screw it and get carbs then have carb issues.. once you get it you will see its simplicity and still chase aghost once in a while but know where to look here after.. I like the Djet.. before whacking moles I feared it..

[mipstien]

I'm only asking questions I n theory. I want to understand its how I learn. I know the steps I have read them many many times now but most of you have done a lot of this stuff. I want your opinions not "well you need to stop asking questions and go do thiks blah blah blah." I have a lot more time at work to sit at the computer and theorize about what if situations I just would like opinions and input because that is how I understand things.
If you know qn engineer then you would understand how I learn things please accept that I do not expect nor want an easy answer. I just what group discussion.

[mipstien]

i know you said im chasing my tail but as of today the car is running great. battery was dead so i had to charge it. started it up and about 2 minutes into running i was able to plug the AAR valve hose and it ran like it was supposed to at just under 1k rpm but this is without messing with the air idle screw and the ECU idle control. now to get ready to do a valve job and the rest of the tune up.
thanks for the input and such!!
ryan

[mipstien]

did some more testing and playing around yesterday and found that there was a leak in the MPS vacuum. that leak is/was causing it to idle really rough. when i plug the leak it runs good or rather like it should. when i open the leak back up or unplug the vacuum line it runs horrible again. for one the mps has been tampered with and there is a hole drilled through it. for two and for good news. i have another one comming in a few days so i can hopefully swap the two out and have better luck with the new one.
couldn't see the leak because of the cloth covered hoses... blah

[type47]

.... when i plug the leak it runs good or rather like it should. when i open the leak back up or unplug the vacuum line it runs horrible again.

Where are you able to plug and un-plug? Are you removing the MPS from the system? If you are unplugging the hose and leaving it OPEN to the atmosphere, the MPS might not have a problem. To test the MPS, you put a vacuum on the port of the MPS (5-10 lbs) and observe leakage. There is also an electrical test of an MPS.

[mipstien]

The mps isn't bad but it has been tampered with and it is stilll working and we played with it a little and got it to do different stuff. But its. Still set wrong.