A Cars forum. AutoBanter

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

Go Back   Home » AutoBanter forum » Auto makers » VW water cooled
Site Map Home Register Authors List Search Today's Posts Mark Forums Read Web Partners

Loss of power 91 jetta 8valve



 
 
Thread Tools Display Modes
  #11  
Old May 28th 05, 05:15 AM
dave AKA vwdoc1
external usenet poster
 
Posts: n/a
Default

how did you set the ignition timing?
did you check the ign advance which should check the knock sensor operation
too?
did you check the fuel pressure regulator since it may be allowing fuel into
the intake manifold?
Did you check the air flow box?
Are you sure you have the firing order correct on the distributor?
You also need to check the TDC mark on the flywheel with the position of the
#1 piston!

Time to check the wiring and sensors going to the ECM at the ECM's plug!

good luck,
dave
(One out of many daves)


Ads
  #12  
Old May 29th 05, 04:29 AM
Bernd Felsche
external usenet poster
 
Posts: n/a
Default

"dave AKA vwdoc1" > writes:
>"dubljay" > wrote:
>>I have a 1991 Jetta gl, 1.8L 8valve, with about 184k miles.


>> I thought perhaps that it was a air flow problem, as the previous
>> owner had installed an aftermarket Neuspeed P-Flo air intake.
>> Replaced it with a stock air intake from a salvage yard, no help.
>> Checked Digfiant computer (according to shop manual) no indication of
>> computer problem.


Maybe the previous owner also had some work done on the camshaft or
head.

Make sure that the cam sprocket is the right way around. If timing
appears to correctly set up according to Bentley, yet has poor power
until you get to almost 5000 rpm, then the sprocket is probably
reversed so the wrong marks line up resulting in cam timing being
retarded by some 30 degrees.

Check the sprocket orientation to make sure it's not on back to
front -- or inside-out -- whichever way you think of it.

Another "quick" check is to check the cam lobe positions. At TDC on
cylinder 1, a straight-edge placed diagonally across the lobes
should be parallel to the top of the head.

>> The crazy part is that the car passed California smog standards
>> despite all these problems.


Digifant has a habit of doing that!

>and how is your cat. conv.?
>Maybe it is partially clogged?


>How did you check the ECM? Ohm meter at it's plug to check the sensors out?

--
/"\ Bernd Felsche - Innovative Reckoning, Perth, Western Australia
\ / ASCII ribbon campaign | I'm a .signature virus!
X against HTML mail | Copy me into your ~/.signature
/ \ and postings | to help me spread!
  #13  
Old June 6th 05, 01:56 PM
One out of many daves
external usenet poster
 
Posts: n/a
Default

You will need to make sure the ECM/ECU numbers are exactly alike. Just post
the numbers you find on yours here too.

I doubt if it is the ECM but it might be. I think I have replaced one
Digifant II ECM where the vehicle did not start at all. I am not sure why
this one went bad, but all has been well for years.
Did you test all sensors/switches at the ECM harness plug? Very important
to check those grounding wires!!!!

Are you sure you have an exhaust that is not clogged? Check the vacuum with
a gauge during different engine loads (idling, part throttle, full throttle
and deceleration). Post results!

Are you sure you checked the ignition very carefully while checking the
spark advance? That will tell you if the knock sensor is working correctly.
If it is not working correctly then you will have a loss of power while
accelerating.

Not sure if your CA equipped Jetta has an EGR valve. Maybe that is a test
pipe you are looking at. If it has a rubber cover over it's tip you can
remove it to see if the exhaust comes out of it slowly or almost like a
tailpipe. (Another test for restrictive exhaust)

Time to think about taking this Jetta over to a good VW shop so you don't
spend unnecessary $$$. ;-)

JMHO
dave
(One out of many daves)

"dubljay" > wrote in message
snip
> OK I am pretty sure that it is not an ignition problem. I know that
> the fuel pumps (both) are good, as is the relay, and the pressure
> regulator. I've tested a few sensors using an ohm meter and the
> Bently, and come up negative. I think the ECU is dead. I have doubts
> that it is even the original ECU. So I think the problem lies within
> the ECU. There is an '87 jetta GL with Digifant 1 in it, will that
> ECU work or do I have to get one out of a '91? Also I can't seem to
> find an EGR valve anywhere, and the part of the EGR that is supposed
> to be plugged into the cad. converter is no there... the hole is just
> plugged, no sensor or wires coming from it. Could this be part of the
> problem?



  #14  
Old June 6th 05, 11:35 PM
dubljay
external usenet poster
 
Posts: n/a
Default

"One out of many daves" wrote:
> You will need to make sure the ECM/ECU numbers are exactly
> alike. Just post
> the numbers you find on yours here too.
>
> I doubt if it is the ECM but it might be. I think I have
> replaced one
> Digifant II ECM where the vehicle did not start at all. I am
> not sure why
> this one went bad, but all has been well for years.
> Did you test all sensors/switches at the ECM harness plug?
> Very important
> to check those grounding wires!!!!
>
> Are you sure you have an exhaust that is not clogged? Check
> the vacuum with
> a gauge during different engine loads (idling, part throttle,
> full throttle
> and deceleration). Post results!
>
> Are you sure you checked the ignition very carefully while
> checking the
> spark advance? That will tell you if the knock sensor is
> working correctly.
> If it is not working correctly then you will have a loss of
> power while
> accelerating.
>
> Not sure if your CA equipped Jetta has an EGR valve. Maybe
> that is a test
> pipe you are looking at. If it has a rubber cover over it's
> tip you can
> remove it to see if the exhaust comes out of it slowly or
> almost like a
> tailpipe. (Another test for restrictive exhaust)
>
> Time to think about taking this Jetta over to a good VW shop
> so you don't
> spend unnecessary $$$. ;-)
>
> JMHO
> dave
> (One out of many daves)
>
> "dubljay" > wrote in message
> snip
> > OK I am pretty sure that it is not an ignition problem. I

> know that
> > the fuel pumps (both) are good, as is the relay, and the

> pressure
> > regulator. I've tested a few sensors using an ohm meter and

> the
> > Bently, and come up negative. I think the ECU is dead. I

> have doubts
> > that it is even the original ECU. So I think the problem

> lies within
> > the ECU. There is an '87 jetta GL with Digifant 1 in it,

> will that
> > ECU work or do I have to get one out of a '91? Also I can't

> seem to
> > find an EGR valve anywhere, and the part of the EGR that is

> supposed
> > to be plugged into the cad. converter is no there... the

> hole is just
> > plugged, no sensor or wires coming from it. Could this be

> part of the
> > problem?


Acutally I have given up. I was right they have replaced the engine,
and in doing so they have cliped wires and connectors off leaving me
no way to tell what is what. Anyone want a 91 jetta parts car? I
would take it to a shop however there isn’t a mechanic within 100
miles that i would trust to work on a VW.

--
Posted using the http://www.autoforumz.com interface, at author's request
Articles individually checked for conformance to usenet standards
Topic URL: http://www.autoforumz.com/Volkswagen...ict120690.html
Visit Topic URL to contact author (reg. req'd). Report abuse: http://www.autoforumz.com/eform.php?p=600139
  #15  
Old June 7th 05, 03:14 AM
dave AKA vwdoc1
external usenet poster
 
Posts: n/a
Default

Get a Bentley, a Multimeter and some time.
Do it yourself....................You can!! ;-)
You will gain a lot of knowledge about your Jetta and a lot of satisfaction
when you find and repair the problem(s).
--
later,
dave
(One out of many daves)


"dubljay" > wrote in message
news:1_600139_5bcae8a9628e412ee38d86720169e5f6@aut oforumz.com...
> "One out of many daves" wrote:


snip snip

> Acutally I have given up. I was right they have replaced the engine,
> and in doing so they have cliped wires and connectors off leaving me
> no way to tell what is what. Anyone want a 91 jetta parts car? I
> would take it to a shop however there isn't a mechanic within 100
> miles that i would trust to work on a VW.



  #16  
Old June 8th 05, 06:35 AM
dubljay
external usenet poster
 
Posts: n/a
Default

"dave AKA vwdoc11" wrote:
> Get a Bentley, a Multimeter and some time.
> Do it yourself....................You can!! ;-)
> You will gain a lot of knowledge about your Jetta and a lot of
> satisfaction
> when you find and repair the problem(s).
> --
> later,
> dave
> (One out of many daves)
>
>
> "dubljay" > wrote in message
> news:1_600139_5bcae8a9628e412ee38d86720169e5f6@aut oforumz.com...
> > "One out of many daves" wrote:

>
> snip snip
>
> > Acutally I have given up. I was right they have replaced

> the engine,
> > and in doing so they have cliped wires and connectors off

> leaving me
> > no way to tell what is what. Anyone want a 91 jetta parts

> car? I
> > would take it to a shop however there isn't a mechanic

> within 100
> > miles that i would trust to work on a VW.


I’ve got a bently, and a multimeter... however a good portion of the
wires are not even the correct color so I really dont know how i can
trace or test them.

--
Posted using the http://www.autoforumz.com interface, at author's request
Articles individually checked for conformance to usenet standards
Topic URL: http://www.autoforumz.com/Volkswagen...ict120690.html
Visit Topic URL to contact author (reg. req'd). Report abuse: http://www.autoforumz.com/eform.php?p=601583
  #17  
Old June 10th 05, 03:55 AM
dave AKA vwdoc1
external usenet poster
 
Posts: n/a
Default


"dubljay" > wrote in message
news:1_601583_cf117989302ab2c91e8cb185f4cf830d@aut oforumz.com...
> SNIP
> I've got a bently, and a multimeter... however a good portion of the
> wires are not even the correct color so I really dont know how i can
> trace or test them.
>


Yeah I am not sure about those California cars. :-(

I usually have to test the resistance of wiring from the ECM to where ever
it goes to. I don't always trust those wiring diagrams too.
I sometimes make mine own just in case the books are wrong. I had to do
this for my 91 Passat auto transmission's valve body.

Oh and I have seen a bad AirFlow box causing a lack of power with one
Digifant II vehicle. Or a dirty filter (fuel or air).

good luck,
dave
(One out of many daves)


  #18  
Old June 15th 05, 07:35 PM
stevejf
external usenet poster
 
Posts: n/a
Default

"dave AKA vwdoc11" wrote:
> "dubljay" > wrote in message
> news:1_601583_cf117989302ab2c91e8cb185f4cf830d@aut oforumz.com...
> > SNIP
> > I've got a bently, and a multimeter... however a good

> portion of the
> > wires are not even the correct color so I really dont know

> how i can
> > trace or test them.
> >

>
> Yeah I am not sure about those California cars. :-(
>
> I usually have to test the resistance of wiring from the ECM
> to where ever
> it goes to. I don't always trust those wiring diagrams too.
> I sometimes make mine own just in case the books are wrong. I
> had to do
> this for my 91 Passat auto transmission's valve body.
>
> Oh and I have seen a bad AirFlow box causing a lack of power
> with one
> Digifant II vehicle. Or a dirty filter (fuel or air).
>
> good luck,
> dave
> (One out of many daves)


I have a 91 jetta, manual, same engine (RV), same problem. I also
suspect my motor has been replaced, because the title says its a
rebuild and that it’s exempt from odometer readings. (although I dont
see any clipped wires around the engine)

I have tried the basics, just like Dubljay. when I got this car it ran
fine. there were a few rare times where it would stall out and
wouldnt start, but then this problem developed over last winter. now,
it starts right up, and runs forever at idle (until i stall it), but
there is significant loss of power, it acts like there is a clogged
fuel filter on acceleration, (during which sometimes initially it
floods and dies immediately at a slight touch of the gas),. it will
accelerate fine for a few seconds,, but then power will fade almost
completely, and then usually the car will start bucking, or power
comes back in the higher RPM range, or the car stalls, and wont start.
one characteristic of this problem is the surging of the throttle. I
know the car is going to lose its power when when I take it out of
gear to shift and the engine maintains a high RPM, or the throttle
surges at idle sometimes maintaining an idle of 1800 rpm’s or so, or
just surging from 900-1400 rpm’s up and down, then dipping down to
400-800 either stalling, or almost stalling.

The car has always seemed to run too rich. when I first got the car, I
failed emissions tests so I replaced the Oxygen sensor about 2 years
ago which helped thin the fuel mixture, and it passed ( I didnt drive
it much even when it ran)

When this problem started:
First I replaced the fuel filter (lifetime my ass) I have a fairly new
air filter too I replaced a while back (K & N), and i replaced the
checker auto spark plug wires with Bosch wires. that didnt help so I
took this into VW mechanics shop where they tested the fuel pump, put
on new spark plugs, checked a valve and some sensors, but they
couldn’t figure out what was wrong, so after around $200 of labor, so
I had them stop. at this point the car would only do a dead stall, it
didnt do any bucking or jerking, it would just unpredictabley lose
power slowly and stall, So I could still drive it around I would wait
until it was cooled off then it would *usually* start again. then my
radiator fan switch went out, and I thought it would be a good idea to
change the cap and rotor when I changed out that heat sensing switch
on the radiator. The old cap was not bosch, and and it was worn, so i
put on a genuine bosch cap and rotor. If you can believe it, this is
when the bucking and surging started ! I expected the new cap to help
get back some power, and maybe help with the stalling, but instead it
made things worse, now I had even more power loss, except when it hit
the high rpm’s it would give me back the power I once had, (still not
to the engine’s potential, I never had that), then I would need to
shift, and it would repeat all over again. this effect of power
kicking in at high rpm’s slowly wore off, and all the while the car
would sometimes crap out and not start. So during that time I had a
friend do a timing check at his acura shop, he said the timing was
fine, and gave me two suggestions: Air flow sensor, or a clogged cat.
so I went to the foreign wrecking yard and the owner helped me try
several parts, my airflow sensor tested ok to me, but thats what we
tried first ( got one off a 91 fox). same resistance readings, and no
change in the condition. Next we tried the Ignition control module
on top of the ECU housing, no change. then we tried the selenoid by
the intake manifold, which i think is the EGR valve, because one hose
went into the intake manifold, I cant remember where the other hose
connected to (crankcase?), Still no change, so we put in a brand new
in-tank fuel pump, I had a little better throttle response after, but
the same sputtering occurred. then the junk yard owner suggested I
try taking off the gas cap and running it, well I did have the wrong
cap on, one that didnt allow air to get in, (my sister had driven the
car, and she had changed the old cap for some reason) now with the
gas cap off, the car didnt sputter or stall, (it sometimes has to run
for a while before it begins sputtering, but I drove for a few miles,
and everything was good) much to my disbelief, and I drove home from
the junkyard thinking the guy was pure genius. I found my old gas cap,
that seems to be a breather cap, and put it back on, (though not
tightly). most days the car still didnt have the power it originally
did, but somedays it would get back to its old peppy self. that great
solution lasted for less than 2 weeks, and now it is as bad as ever

I am so grateful for your site where I found the same problem on the
same engine.
I do take off the gas cap when it starts sputtering but that doesnt
help now. So after reading your suggestions yesterday, at a muffler
shop I had my tailpipe cut off at the catalytic converter to test for
clogs, they couldnt find anything wrong with air flow there, and they
tried to diagnose the problem but couldnt find anything. I dont have
a bentley manual, just a cheap one. I would appreciate any suggested
solutions to this problem, I dont think it is timing or engine
related, I was looking to replace the distributor next, until I read
here that that hadn’t helped dubljay. I am guessing that it is some
other electrical problem, or and issue with the fuel lines and/or the
accumulator/regulator for those fuel lines. but right now I dont have
the money to get a manual on top of the part(s) I need.

Thank you for your time and ideas,

Steve.

--
Posted using the http://www.autoforumz.com interface, at author's request
Articles individually checked for conformance to usenet standards
Topic URL: http://www.autoforumz.com/Volkswagen...ict120690.html
Visit Topic URL to contact author (reg. req'd). Report abuse: http://www.autoforumz.com/eform.php?p=607150
  #19  
Old July 28th 05, 11:36 PM
dubljay
external usenet poster
 
Posts: n/a
Default

"" wrote:
> "dubljay" > wrote in message
> news:1_601583_cf117989302ab2c91e8cb185f4cf830d@aut oforumz.com...
> > SNIP
> > I've got a bently, and a multimeter... however a good

> portion of the
> > wires are not even the correct color so I really dont know

> how i can
> > trace or test them.
> >

>
> Yeah I am not sure about those California cars. :-(
>
> I usually have to test the resistance of wiring from the ECM
> to where ever
> it goes to. I don't always trust those wiring diagrams too.
> I sometimes make mine own just in case the books are wrong. I
> had to do
> this for my 91 Passat auto transmission's valve body.
>
> Oh and I have seen a bad AirFlow box causing a lack of power
> with one
> Digifant II vehicle. Or a dirty filter (fuel or air).
>
> good luck,
> dave
> (One out of many daves)


Ok its been a while. I got the power back... hehe I’m gonna have to
be careful when driving it now, I don’t need speeding tickets.

My currnet problem now is that it surges badly, not just at idle
either. I can feel the engine surge while under load, when i down
shift, and when it idles. When idling it surges so bad that it causes
the check engine light to flicker on and off. a few times the surging
was bad enough while normal driving that the knock sensor kicked in
and dropped the rpms and power way down.

On the throtle body there is that adjustment screw that is supposed to
be pluged (the one you are not supposed to adjust) well the previous
owners have the plug removed and i think that the screw has been
adjusted. any thougts?

also its mid summer here, hot as hell out and the temp gague doesnt
really get up to normal while driving, it hovers around the colder
side, unless idling for long periods. is the gague screwed, the
themostate, or the sensor bad? I was under the impression that VW’s
generally run hot.

--
Posted using the http://www.autoforumz.com interface, at author's request
Articles individually checked for conformance to usenet standards
Topic URL: http://www.autoforumz.com/Volkswagen...ict120690.html
Visit Topic URL to contact author (reg. req'd). Report abuse: http://www.autoforumz.com/eform.php?p=638200
 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
rec.autos.makers.chrysler FAQ, Part 4/6 Dr. David Zatz Chrysler 0 April 22nd 05 05:32 AM
No power loss light on 1987 caravan 2.5 dmitchell Chrysler 5 February 22nd 05 01:07 AM
rec.autos.makers.chrysler FAQ, Part 1/6 Dr. David Zatz Chrysler 3 February 18th 05 06:34 AM
rec.autos.makers.chrysler FAQ, Part 1/6 Dr. David Zatz Chrysler 10 December 2nd 04 06:19 AM
Loss of Power Whilst Towing Caravan Stuart Thomson Audi 6 June 1st 04 09:46 PM


All times are GMT +1. The time now is 03:01 AM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 AutoBanter.
The comments are property of their posters.