Hi,
The FSM says to plug one of the top two ports and apply a 'pressure' with an arrow to the guy's mouth which leads me to believe they want a vacuum ie suck on the top port with the other plugged? It's hard to figure out.
If I plug one of the top ports and suck on the other I get a leak sound coming from the valve. Then when I suck or blow (please dont go there) on the bottom port the diaphragm goes up and down. Is my BPT faulty?
Please help,Thanks
Is my BPT faulty?
vaccum should not go to the port on the other side unless there is pressure applied to the bottom of it. When there is no pressure on the bottom it will vent the vaccum through the middle [foam area] of the BPT. This is why your still hearing the noise.
The picture in the service manual is good for one thing, give it to your kid to enter the next big coloring contest...lol
Start your car and find a constant vaccum sorce at idle. t into that line and hook one side of your BPT to it and hook a vaccum gauge to the other side. There should be no vaccum on the gauge, then use a pump [or blow into a hose] hooked to the bottom of the BPT,vaccum should now show on the gauge. If that all comes out good your BPT is fine.
The picture in the service manual is good for one thing, give it to your kid to enter the next big coloring contest...lol
Start your car and find a constant vaccum sorce at idle. t into that line and hook one side of your BPT to it and hook a vaccum gauge to the other side. There should be no vaccum on the gauge, then use a pump [or blow into a hose] hooked to the bottom of the BPT,vaccum should now show on the gauge. If that all comes out good your BPT is fine.
Thanks a lot. When I hooked one side to a constant vacuum source and the other side to a vacuum gauge I got -5 inHg vacuum. Then when I put a pressure on the bottom (blew into it) I got about -20 inHg. Since I have -5 without any pressure on the bottom that leads me to believe the thing is faulty, correct??
Just for a reference, here is how to test it ( I didn't understand fully at first).
1) disconnect the upper egr vacuum line and plug it.
2) add a hose on the outlet that went from the top of the bpt to the top of the egr.-stick a vauum gauge on that hose
3) with motor warm, rev the engine, you should get a vacuum which would otherwise pull the egr diaphragm up.
if you have a leaky bpt, there will be a vacuum with the engine idling.
I hope that makes sense!
1) disconnect the upper egr vacuum line and plug it.
2) add a hose on the outlet that went from the top of the bpt to the top of the egr.-stick a vauum gauge on that hose
3) with motor warm, rev the engine, you should get a vacuum which would otherwise pull the egr diaphragm up.
if you have a leaky bpt, there will be a vacuum with the engine idling.
I hope that makes sense!
that does and that is exactly correct. It takes as little as 5Hg of vaccum to apply the EGR. So there should be 0 vaccum at idle.
Further note though: You should not have vaccum to the bpt from the solonoid at idle either[once the car is warmed up] If you do, either your TPS is out of adjustment or you solonoid is stuck open.
Further note though: You should not have vaccum to the bpt from the solonoid at idle either[once the car is warmed up] If you do, either your TPS is out of adjustment or you solonoid is stuck open.
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rogermills
- Posts: 19
- Joined: Thu Oct 07, 2004 5:55 am
- Car: 1994 Nissan 240SX convertible
Re: (NISTECH)
NISTECH, this is the first reference to 'solenoid' that was made in this posting.NISTECH wrote:that does and that is exactly correct. It takes as little as 5Hg of vaccum to apply the EGR. So there should be 0 vaccum at idle.
Further note though: You should not have vaccum to the bpt from the solonoid at idle either[once the car is warmed up] If you do, either your TPS is out of adjustment or you solonoid is stuck open.
What and where is this solenoid, and the TPS .?
The BPT has three 'vacuum' connections, one to the EGR valve, and a second right next to it on top, and the third (with an elbow) at the bottom. I hope this solenoid is connected at the second connector at the top. (The bottom connector is PRESSURE, not VACUUM, right??)
I will research TPS BPT = Backpressure Control Transducer, right??
Barry sends
Modified by rogermills at 1:35 PM 4/30/2005
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rogermills
- Posts: 19
- Joined: Thu Oct 07, 2004 5:55 am
- Car: 1994 Nissan 240SX convertible
Re: (NateDogg)
NateDogg, since NISTECH agrees with you, I am now wondering if I did something invalid. Instead of your 1) and 2) I 'teed' a vacuum gauge in-line with the BCT and EGR. I did get good results, but should I have done the two steps as you did?? Just for the heck of it, I am going to put another vacuum gauge in-line at the other BCT vacuum outlet so I can see two gauges. I don't know what I am going to prove, or what I should expect to observe at idle and at 2000 rpm.NateDogg wrote:Just for a reference, here is how to test it ( I didn't understand fully at first).
1) disconnect the upper egr vacuum line and plug it.
2) add a hose on the outlet that went from the top of the bpt to the top of the egr.-stick a vauum gauge on that hose
3) with motor warm, rev the engine, you should get a vacuum which would otherwise pull the egr diaphragm up.
if you have a leaky bpt, there will be a vacuum with the engine idling.
I hope that makes sense!
Questions: why is it necessary to plug the EGR valve after removing the hose from the BCT. I thought we were only measuring the vacuum at the BCT outlet, and that the EGR valve would not play into the effects. If you NateDogg DID NOT plug the EGR valve, would his reading be invalid?? Are my readings invalid??
Barry sends
Re: (NateDogg)
Wait i re read it again and it appears you unplugged the line from the BPT?,left the other end of it plugged into the egr?, And plugged the end that was connected to the BPT???
If that statement is correct, there was no need to plug the line as the egr does not have any vaccum at this point.
Here is a quickly thrown together picture, used paint to do it so I labeled everything incase its not identifiable.
If that statement is correct, there was no need to plug the line as the egr does not have any vaccum at this point.
Here is a quickly thrown together picture, used paint to do it so I labeled everything incase its not identifiable.
Re: (NateDogg)
There is no hose on the bottom of the egr, that picture is as if you are looking straight down from the top.NateDogg wrote:Alright I think I need a beer I'm gettin a little brain baked tryijn to understand this thread.
In the diagram is the hose from the bottom of the EGR to the BPT plugged or is that on the top?
The hose in the picture coming off the egr in the picture,does not need to be plugged as there is no vaccum there. That hose is suppose to be plugged into the BPT where the vaccum gauge is since that is where the egr gets its vaccum from. This picture indicates how to test if the BPT is functioning properly. In this picture you should see no vaccum on the gauge at idle and a quick burst of vaccum under snap throttle, it will almost never hold vaccum on the gauge when the car is sitting still as the exhuast wont build enough back pressure
Does it make sence now?
Yah I pinched it but nothing happened to the idle speed so I guess that confirms I don't have a vacuum leak.
Here's the scenario: Start up the car in the morning so it's pretty cold (Canada eh?) . I slowly ease into it in first till 3000 rpm and then shift to 2nd. I then apply about 20% throttle or so and the engine completely bogs out, and requires another second to recover.
This also happens in other gears but it's not as noticeable.
When the engine is warm it doesn't occur nearly as often, although this car has less low-end power then my dad's 240sx. This could be due to the 2.5" exhaust and tightly shimmed valves.
I also have a Walbro 190lph fuel pump, JWT ECU, Aurora wires and newer spark plugs. I am thinking the stock S13 fuel pump wiring is not keeping enough current to power the pump. The plugs looks REALLY clean. White insulator and blackish ring around the outside. THe electrode is pretty grey looking.
Either that or my MAFS, knock sensor etc.. is going out. Since this happens mostly when the engine is cold does that trigger any ideas?
Here's the scenario: Start up the car in the morning so it's pretty cold (Canada eh?) . I slowly ease into it in first till 3000 rpm and then shift to 2nd. I then apply about 20% throttle or so and the engine completely bogs out, and requires another second to recover.
This also happens in other gears but it's not as noticeable.
When the engine is warm it doesn't occur nearly as often, although this car has less low-end power then my dad's 240sx. This could be due to the 2.5" exhaust and tightly shimmed valves.
I also have a Walbro 190lph fuel pump, JWT ECU, Aurora wires and newer spark plugs. I am thinking the stock S13 fuel pump wiring is not keeping enough current to power the pump. The plugs looks REALLY clean. White insulator and blackish ring around the outside. THe electrode is pretty grey looking.
Either that or my MAFS, knock sensor etc.. is going out. Since this happens mostly when the engine is cold does that trigger any ideas?
Is there a way to clean the CAS or is that a work/no work item? I think Chris ("car problems" thread) and I may have a partially functioning CAS since the pickup on the inducting timing light sometimes skips a beat or two.
BTW I check the MAF ground and it read .067V. I read conflicting information about the ground - should it be less than .02V or less than .2V? .02 sounds right! If so, should I just cut the ground and extend it to the intake manifold or splice into it (ie does the ground go to the ECU?) and should I use shielded wire and where should it go?
Modified by NateDogg at 4:55 PM 5/2/2005
BTW I check the MAF ground and it read .067V. I read conflicting information about the ground - should it be less than .02V or less than .2V? .02 sounds right! If so, should I just cut the ground and extend it to the intake manifold or splice into it (ie does the ground go to the ECU?) and should I use shielded wire and where should it go?
Modified by NateDogg at 4:55 PM 5/2/2005
A misfire will make it skip a beat that does not indicat ethe CAS is failing it could be any number of things, wires, cap, rotor, plug...anything in the ignition system could cause it to skip a beat. your CAS either works or it doesnt, you can however go in and see if anything is on the pickup wheel,you do that by removing the cap and rotor then remove the metal plate to inspect it. I dont think there is anything on it tough as your car runs fine when it gets hot.Electrical components tend to fail on the hot side not cold. your problem is when its still in warm up process. If you can try to wire up a volt meter to the gnd on the MAF and watch it while driving and under the condition it losses power, see what the voltage is on that wire,if its more then .2v you need to run another ground.
Well I ran another ground wire for the MAF. Now I have .00V on the ground wire. I took the car out for a drive. After we came out of XXX the engine was still at operating temp but still stumbled when I shifted into 2nd. Then after another 10 minutes of driving to get the engine really warm it didn't hesitate or stumble anymore.
The stumble only noticeably occurs after an rpm drop like when shifting from 1st to 2nd in these cars. The 1st gear is pretty short soyou gotta wind it up and then 2nd gear is quite a bit longer so it drops about 2200rpm between shifts and that's when the hesitation occurs.
I don't think it could be a spark problem. The plugs are clean, the cap and rotor basically new, although they ARE from Italy *oops*. The plug wires check out fine and I have a 70kV coil that fires the plugs with .058" gap.
Could that rotor be arcing or does it sound like a sensor of some kind acting up when the temperature is not quite hot enough? I didnt think it could be the ignition system because that doesnt seem to be a heat related problem and it revs all the way out without breaking up, even when its cold out.
The stumble only noticeably occurs after an rpm drop like when shifting from 1st to 2nd in these cars. The 1st gear is pretty short soyou gotta wind it up and then 2nd gear is quite a bit longer so it drops about 2200rpm between shifts and that's when the hesitation occurs.
I don't think it could be a spark problem. The plugs are clean, the cap and rotor basically new, although they ARE from Italy *oops*. The plug wires check out fine and I have a 70kV coil that fires the plugs with .058" gap.
Could that rotor be arcing or does it sound like a sensor of some kind acting up when the temperature is not quite hot enough? I didnt think it could be the ignition system because that doesnt seem to be a heat related problem and it revs all the way out without breaking up, even when its cold out.
I dont think it is that cap and rotor by your description of your problem ,but the lower RPM when it occurs is kinda a key thing here. I would still loose that cap and rotor if I was you.
Do a couple experiments here, First drive it through the range it has the problem with hose going to the egr disconnected. Jsut disconnect it before you go driving it and see if that has any effect on the problem.
If you get no results with that. The next time you drive it and you know it will do it have the TPS disconnected. see if that has any effect on it.
Do a couple experiments here, First drive it through the range it has the problem with hose going to the egr disconnected. Jsut disconnect it before you go driving it and see if that has any effect on the problem.
If you get no results with that. The next time you drive it and you know it will do it have the TPS disconnected. see if that has any effect on it.
I have completely by-passed and plugged the BPT before and that had no effect on anything.
I also disconnected the TPS and that made the hesitation way worse.
Interesting find though...When the engine was cold this morning I put a volt meter on the MAFS. Was reading 1.1V and happy but then it started going all wonky like .6V .8V .2V..then back to 1.1V for a few seconds...I hope this is it man I'm running out of things to check. I also did notice a Code 12 the last time I pulled the codes but I've had the MAFS on and off so much I thought it was just because I forgot to put the connector on.
I kept reading the voltages and once the engine got to operating temp the MAFS seemed more stable. Should I be able to clean the MAFS or is this thing shot? I mean I just sprayed it a couple weeks ago with contact cleaner, maybe that was a dumb idea.
The MAFS makes sense though because when I shift the MAFS has to adjust to the changing airflow rates and this one doesn't do that worth a $#!T. Maybe it's been de-sensitized by all the oil from the K&N and the semi-annual spraying with contact cleaner.
I also disconnected the TPS and that made the hesitation way worse.
Interesting find though...When the engine was cold this morning I put a volt meter on the MAFS. Was reading 1.1V and happy but then it started going all wonky like .6V .8V .2V..then back to 1.1V for a few seconds...I hope this is it man I'm running out of things to check. I also did notice a Code 12 the last time I pulled the codes but I've had the MAFS on and off so much I thought it was just because I forgot to put the connector on.
I kept reading the voltages and once the engine got to operating temp the MAFS seemed more stable. Should I be able to clean the MAFS or is this thing shot? I mean I just sprayed it a couple weeks ago with contact cleaner, maybe that was a dumb idea.
The MAFS makes sense though because when I shift the MAFS has to adjust to the changing airflow rates and this one doesn't do that worth a $#!T. Maybe it's been de-sensitized by all the oil from the K&N and the semi-annual spraying with contact cleaner.
the important thing you said in your last post was"you have had the maf on and off so many times" Did you happen to monitier the ground voltage when it was warming up? If not do that now. The ground could be weak at different temps, the problem is most definitly with the maf signal being sent to the ECM but you need to determine if the problem is the maf it self or a poor connection, like the terminals spread open in the connector causing a poor connection when cold but when they get a bit warmer they make better contact. Check the wiring/terminal integrity before you just through another MAF in it.
the ground voltage is 0.00V all the time now that I've added a ground.
I was checking the TPS resistance and I got 10k ohms closed with pins 1+2 and 2k ohms with the throttle depressed. This is the opposite of what should be, however when I tested pins 2+3 I got the correct readings. Is the FSM wrong?
I was checking the TPS resistance and I got 10k ohms closed with pins 1+2 and 2k ohms with the throttle depressed. This is the opposite of what should be, however when I tested pins 2+3 I got the correct readings. Is the FSM wrong?
My old man works at a garage and he is going to bring home a Consult diagnostics computer so we can monitor all the sensors while the engine is running. I have a feeling it's a bad ground or connection somewhere.
On another note, when I have the key to "ON" to check the codes and I remove the key, the dash lights like parking brake, check engine, ABS, etc stay on. I have to start the car and then remove the key to get the lights to shut off. Could these two problems be related? What would I check?
Thanks again.
On another note, when I have the key to "ON" to check the codes and I remove the key, the dash lights like parking brake, check engine, ABS, etc stay on. I have to start the car and then remove the key to get the lights to shut off. Could these two problems be related? What would I check?
Thanks again.
Well, the Snap-On tool is a useless POS, especially without the proper connector.
So, I probed the ECU wiring harness with some T-pins i bought at a fabric supply store. All the sensors turn out OK and whithin spec.
The only sensor I have a problem with checking is the knock sensor. The circuit is fine but I dont know the readin or voltage it is supposed to output for normal operation.
I'm beginning to think I have an injector or two which are not squirting enough fuel. They check out fine for resistance (11 ohms) across the board but the O2 sensor is reading .25V at idle, which seems pretty low. That combined with the very white plugs I am thinking about the fuel injectors.
Also, I just put in some Chevron Techron fuel system cleaner about a week ago. Could this cause a fouled injector?
Here are the symptoms:- cold engine won't rev up slowly, just bogs. Major hesitation.- warm engine will rev up a bit better. I think this is the O2 sensor helping out the injectors by adding fuel, since the O2 is not used in open loop.
Another fellow I talked to had the same problem with the pause between shifts and he fixed it with an injector.
I pulled the injector harnesses off 1 at a time while the engine was running, but it was difficult to tell any difference from injector to injector, as far as rpm drop.
I feel like ordering the PLMS consult software just to do a power balance test.
Could I be on to something?
So, I probed the ECU wiring harness with some T-pins i bought at a fabric supply store. All the sensors turn out OK and whithin spec.
The only sensor I have a problem with checking is the knock sensor. The circuit is fine but I dont know the readin or voltage it is supposed to output for normal operation.
I'm beginning to think I have an injector or two which are not squirting enough fuel. They check out fine for resistance (11 ohms) across the board but the O2 sensor is reading .25V at idle, which seems pretty low. That combined with the very white plugs I am thinking about the fuel injectors.
Also, I just put in some Chevron Techron fuel system cleaner about a week ago. Could this cause a fouled injector?
Here are the symptoms:- cold engine won't rev up slowly, just bogs. Major hesitation.- warm engine will rev up a bit better. I think this is the O2 sensor helping out the injectors by adding fuel, since the O2 is not used in open loop.
Another fellow I talked to had the same problem with the pause between shifts and he fixed it with an injector.
I pulled the injector harnesses off 1 at a time while the engine was running, but it was difficult to tell any difference from injector to injector, as far as rpm drop.
I feel like ordering the PLMS consult software just to do a power balance test.
Could I be on to something?
the techron wont hurt the system, techron additive is one of the leading fuel additives on the market. The .25v reading at idle is not all that bad as Nissan's in general tend to "clamp" at idle and it is usually on the lean side. It sounds more as if you have a MAF not registering properly or hard idle contacts not coming off at the right point.
What is "PLMS consult software" and what do you use it in? laptop? hand held aftermarket scan tool? I know what a consult unit is as I have 3 of them at my disposal.
What is "PLMS consult software" and what do you use it in? laptop? hand held aftermarket scan tool? I know what a consult unit is as I have 3 of them at my disposal.