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Today's topics:
* 1990 Nissan Sentra 1.6L 4speed - followup on stumble during acceleration - 5
messages, 4 authors
http://groups.google.com/group/alt.autos.nissan/t/f9821d0c76287d5e?hl=en
* Nissan, Toyota and Ford investigate Dana-sourced parts - 1 messages, 1
author
http://groups.google.com/group/alt.autos.nissan/t/3dd92db98419a458?hl=en
==============================================================================
TOPIC: 1990 Nissan Sentra 1.6L 4speed - followup on stumble during
acceleration
http://groups.google.com/group/alt.autos.nissan/t/f9821d0c76287d5e?hl=en
==============================================================================
== 1 of 5 ==
Date: Sat, Feb 20 2010 8:40 pm
From: robbie
On Feb 20, 5:32 pm, al <abuo...@msn.com> wrote:
> On Feb 20, 4:19 pm, robbie <robbie.h.wil...@gmail.com> wrote:
>
>
>
> > Had a problem with a stumble on acceleration, especially at WOT-
>
> > the car seemed like it was losing power, stumbling, low rpms, the car
> > just seemed like it wasn't getting fuel.
>
> > THEN, if you let off and gently accelerate the power is back,
> > everything is fine. This is repeatable ad infinitum
> > and is less apparent (sometimes doesnt happen) when the engine is cold
> > but always present at normal operating temps.
>
> > it has good fuel pressure, all 4 injectors work, the fuel pressure
> > regulator works properly,
> > the ECU shows 55 - no faults- same as it always does when i crawl
> > under the dash and check for error codes!
>
> > it was recommended to check/replace the engine temp sensor and/or O2
> > sensor.
> > For whatever reason, I want to blame the TPS so I tested it according
> > to the Haynes manual-
> > I followed the test procedure, and the manual claims it should read .5
> > -1volt at closed throttle, and 4-5volts at WOT-
> > well according to my meter MY TPS reads the opposite- at the closed
> > throttle it reads 4.3? volts and at WOT it
> > reads 1.1 volts. Have I found the likely culprit? Does the Haynes
> > manual have it wrong?
>
> > Thanks to all who take the time to read!
> > robbie
>
> The problem is clearly being caused by something that depends on
> engine vacuum. When vacuum is low, the problem appears and then
> disappears when vacuum is high. I'd check the EGR system. Too much
> EGR will lean out the mixture on acceleration and cause stumbling and
> hesitation. You can test this hypothesis by blocking the vacuum line
> to the EGR valve thus disabling the EGR system. If the problem
> disappears, you know it's the EGR system. Another characteristic of
> EGR system trouble, is that the stumbling/hesitation will not happen
> when the engine is cold and warming up but rather begins abruptly at a
> very specific coolant temperature during warmup. That occurs because
> the vacuum for the EGR system is supplied through a themostatically
> controlled vacuum switching valve which only opens above a specific
> coolant temperature. Good luck. Al
Thanks for the advice. I will test this out using your theory and plug
the egr valve and giving it a test drive.
== 2 of 5 ==
Date: Sun, Feb 21 2010 12:59 am
From: Peter Hill
On Sat, 20 Feb 2010 20:40:48 -0800 (PST), robbie
<robbie.h.wilson@gmail.com> wrote:
>On Feb 20, 5:32 pm, al <abuo...@msn.com> wrote:
>> On Feb 20, 4:19 pm, robbie <robbie.h.wil...@gmail.com> wrote:
>>
>>
>>
>> > Had a problem with a stumble on acceleration, especially at WOT-
>>
>> > the car seemed like it was losing power, stumbling, low rpms, the car
>> > just seemed like it wasn't getting fuel.
>>
>> > THEN, if you let off and gently accelerate the power is back,
>> > everything is fine. This is repeatable ad infinitum
>> > and is less apparent (sometimes doesnt happen) when the engine is cold
>> > but always present at normal operating temps.
>>
>> > it has good fuel pressure, all 4 injectors work, the fuel pressure
>> > regulator works properly,
>> > the ECU shows 55 - no faults- same as it always does when i crawl
>> > under the dash and check for error codes!
>>
>> > it was recommended to check/replace the engine temp sensor and/or O2
>> > sensor.
>> > For whatever reason, I want to blame the TPS so I tested it according
>> > to the Haynes manual-
>> > I followed the test procedure, and the manual claims it should read .5
>> > -1volt at closed throttle, and 4-5volts at WOT-
>> > well according to my meter MY TPS reads the opposite- at the closed
>> > throttle it reads 4.3? volts and at WOT it
>> > reads 1.1 volts. Have I found the likely culprit? Does the Haynes
>> > manual have it wrong?
You are testing at wrong place. You are testing between feed voltage
(constant 5V) and output. Test is between output and ground.
Sounds like a fuel starvation problem. Really needs a fuel pressure
test under load. T a pressure gauge in after filter, on a long hose.
Route the hose under back of bonnet and place pressure gauge so it can
be seen from drivers seat.
When I had this problem, I went though the whole fuel system.
Everything pointed to a faulty connection but I couldn't find it. Then
it packed up completely. Power at relay, no power at pump. Then I
found the alarm, dry joint and quite well toasted. Some dork had put a
5A fuel pump circuit though a 2A relay circuit and connectors on the
alarm. Soldered alarm and wired up external relay.
>> > Thanks to all who take the time to read!
>> > robbie
>>
>> The problem is clearly being caused by something that depends on
>> engine vacuum. When vacuum is low, the problem appears and then
>> disappears when vacuum is high. I'd check the EGR system. Too much
>> EGR will lean out the mixture on acceleration and cause stumbling and
>> hesitation. You can test this hypothesis by blocking the vacuum line
>> to the EGR valve thus disabling the EGR system. If the problem
>> disappears, you know it's the EGR system. Another characteristic of
>> EGR system trouble, is that the stumbling/hesitation will not happen
>> when the engine is cold and warming up but rather begins abruptly at a
>> very specific coolant temperature during warmup. That occurs because
>> the vacuum for the EGR system is supplied through a themostatically
>> controlled vacuum switching valve which only opens above a specific
>> coolant temperature. Good luck. Al
>Thanks for the advice. I will test this out using your theory and plug
>the egr valve and giving it a test drive.
--
Peter Hill
Spamtrap reply domain as per NNTP-Posting-Host in header
Can of worms - what every fisherman wants.
Can of worms - what every PC owner gets!
== 3 of 5 ==
Date: Sun, Feb 21 2010 8:40 am
From: robbie
Darned Haynes manual! those pictures are never accurate! I will
retest. Thanks.
On Feb 21, 12:59 am, Peter Hill <peter.usen...@nospam.demon.co.uk>
wrote:
> On Sat, 20 Feb 2010 20:40:48 -0800 (PST), robbie
>
>
>
> <robbie.h.wil...@gmail.com> wrote:
> >On Feb 20, 5:32 pm, al <abuo...@msn.com> wrote:
> >> On Feb 20, 4:19 pm, robbie <robbie.h.wil...@gmail.com> wrote:
>
> >> > Had a problem with a stumble on acceleration, especially at WOT-
>
> >> > the car seemed like it was losing power, stumbling, low rpms, the car
> >> > just seemed like it wasn't getting fuel.
>
> >> > THEN, if you let off and gently accelerate the power is back,
> >> > everything is fine. This is repeatable ad infinitum
> >> > and is less apparent (sometimes doesnt happen) when the engine is cold
> >> > but always present at normal operating temps.
>
> >> > it has good fuel pressure, all 4 injectors work, the fuel pressure
> >> > regulator works properly,
> >> > the ECU shows 55 - no faults- same as it always does when i crawl
> >> > under the dash and check for error codes!
>
> >> > it was recommended to check/replace the engine temp sensor and/or O2
> >> > sensor.
> >> > For whatever reason, I want to blame the TPS so I tested it according
> >> > to the Haynes manual-
> >> > I followed the test procedure, and the manual claims it should read 5
> >> > -1volt at closed throttle, and 4-5volts at WOT-
> >> > well according to my meter MY TPS reads the opposite- at the closed
> >> > throttle it reads 4.3? volts and at WOT it
> >> > reads 1.1 volts. Have I found the likely culprit? Does the Haynes
> >> > manual have it wrong?
>
> You are testing at wrong place. You are testing between feed voltage
> (constant 5V) and output. Test is between output and ground.
>
> Sounds like a fuel starvation problem. Really needs a fuel pressure
> test under load. T a pressure gauge in after filter, on a long hose.
> Route the hose under back of bonnet and place pressure gauge so it can
> be seen from drivers seat.
>
> When I had this problem, I went though the whole fuel system.
> Everything pointed to a faulty connection but I couldn't find it. Then
> it packed up completely. Power at relay, no power at pump. Then I
> found the alarm, dry joint and quite well toasted. Some dork had put a
> 5A fuel pump circuit though a 2A relay circuit and connectors on the
> alarm. Soldered alarm and wired up external relay.
>
>
>
> >> > Thanks to all who take the time to read!
> >> > robbie
>
> >> The problem is clearly being caused by something that depends on
> >> engine vacuum. When vacuum is low, the problem appears and then
> >> disappears when vacuum is high. I'd check the EGR system. Too much
> >> EGR will lean out the mixture on acceleration and cause stumbling and
> >> hesitation. You can test this hypothesis by blocking the vacuum line
> >> to the EGR valve thus disabling the EGR system. If the problem
> >> disappears, you know it's the EGR system. Another characteristic of
> >> EGR system trouble, is that the stumbling/hesitation will not happen
> >> when the engine is cold and warming up but rather begins abruptly at a
> >> very specific coolant temperature during warmup. That occurs because
> >> the vacuum for the EGR system is supplied through a themostatically
> >> controlled vacuum switching valve which only opens above a specific
> >> coolant temperature. Good luck. Al
> >Thanks for the advice. I will test this out using your theory and plug
> >the egr valve and giving it a test drive.
>
> --
> Peter Hill
> Spamtrap reply domain as per NNTP-Posting-Host in header
> Can of worms - what every fisherman wants.
> Can of worms - what every PC owner gets!
== 4 of 5 ==
Date: Sun, Feb 21 2010 9:37 am
From: Andrew Chaplin
robbie <robbie.h.wilson@gmail.com> wrote in
news:e4725107-bf52-4534-a2f5-6e3335900cf9@g28g2000yqh.googlegroups.com:
> Darned Haynes manual! those pictures are never accurate! I will
> retest. Thanks.
If you haven't checked already, inspect any air hoses leading to the
throttle body carefully. If they are cracked and open up when your engine
flexes the motor mounts as you accelerate, then it may be screwing up the
air mixture.
--
Andrew Chaplin
SIT MIHI GLADIUS SICUT SANCTO MARTINO
(If you're going to e-mail me, you'll have to get "yourfinger." out.)
== 5 of 5 ==
Date: Sun, Feb 21 2010 3:22 pm
From: Jim Yanik
Andrew Chaplin <ab.chaplin@yourfinger.rogers.com> wrote in
news:Xns9D26805F941AAbluegriffin@216.196.109.144:
> robbie <robbie.h.wilson@gmail.com> wrote in
> news:e4725107-bf52-4534-a2f5-6e3335900cf9@g28g2000yqh.googlegroups.com:
>
>> Darned Haynes manual! those pictures are never accurate! I will
>> retest. Thanks.
>
> If you haven't checked already, inspect any air hoses leading to the
> throttle body carefully. If they are cracked and open up when your
> engine flexes the motor mounts as you accelerate, then it may be
> screwing up the air mixture.
Heh,they just talked about this on Motorweek yesterday...about the air duct
from the MAF to the throttle body cracking and opening under motor torque.
--
Jim Yanik
jyanik
at
localnet
dot com
==============================================================================
TOPIC: Nissan, Toyota and Ford investigate Dana-sourced parts
http://groups.google.com/group/alt.autos.nissan/t/3dd92db98419a458?hl=en
==============================================================================
== 1 of 1 ==
Date: Sun, Feb 21 2010 11:09 pm
From: sjmmail2000-247@yahoo.co.uk
Toyota Canada and Nissan Canada have jointly identified just over 2,100 trucks and SUVs related to the Dana propeller shaft cracks that will need to be serviced. Ford says it used similar components, but believes it has nothing to worry about. According to Toronto Star, Nissan, Toyota and Ford have all found themselves opening investigations into [...]
Read More: http://feeds.leftlanenews.com/click.phdo?i=b9f7280202bc8446a990fc9bf13ee1f1
-----------------------------------
Nissan NewsHub: Latest auto news sourced from websites, portals and blogs
http://www.carshops247.co.uk/news/Nissan.html
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