1986 audi 4000 cs Q problem
#1
1986 audi 4000 cs Q problem
hey guys, im having fuel mixture problems i think.
so for starts ive replaced
.(IAC) idle air control valve
.cold star injector
.o2 sensor
.lower temp sender
. fuel filter
and its still running crappy
problems: when i start her up in the mornings and drive right away, she runs like a bat out of **** for about 30 secs, then after that she starts to stumble and bog down, if i press on the gas pedal at this point she misfires out of the intake POP POP and in order to keep going i have to clutch in and rev slow clutch out while high revs,
after about 2-mins of this she will idle fine and even out at 800-900 rpm, and she will run but with slow response and little power under load but in neutral or clutch in, i can press on the gas and slowly it will climb until 2k than it will climb really fast like i think it should .
my question is what could be the issue a relay? is there an obd 1 system on this car
vacuum lines?
so for starts ive replaced
.(IAC) idle air control valve
.cold star injector
.o2 sensor
.lower temp sender
. fuel filter
and its still running crappy
problems: when i start her up in the mornings and drive right away, she runs like a bat out of **** for about 30 secs, then after that she starts to stumble and bog down, if i press on the gas pedal at this point she misfires out of the intake POP POP and in order to keep going i have to clutch in and rev slow clutch out while high revs,
after about 2-mins of this she will idle fine and even out at 800-900 rpm, and she will run but with slow response and little power under load but in neutral or clutch in, i can press on the gas and slowly it will climb until 2k than it will climb really fast like i think it should .
my question is what could be the issue a relay? is there an obd 1 system on this car
vacuum lines?
#2
AudiWorld Senior Member
Join Date: Oct 2005
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hey guys, im having fuel mixture problems i think.
so for starts ive replaced
.(IAC) idle air control valve
.cold star injector
.o2 sensor
.lower temp sender
. fuel filter
and its still running crappy
problems: when i start her up in the mornings and drive right away, she runs like a bat out of **** for about 30 secs, then after that she starts to stumble and bog down, if i press on the gas pedal at this point she misfires out of the intake POP POP and in order to keep going i have to clutch in and rev slow clutch out while high revs,
after about 2-mins of this she will idle fine and even out at 800-900 rpm, and she will run but with slow response and little power under load but in neutral or clutch in, i can press on the gas and slowly it will climb until 2k than it will climb really fast like i think it should .
my question is what could be the issue a relay? is there an obd 1 system on this car
vacuum lines?
so for starts ive replaced
.(IAC) idle air control valve
.cold star injector
.o2 sensor
.lower temp sender
. fuel filter
and its still running crappy
problems: when i start her up in the mornings and drive right away, she runs like a bat out of **** for about 30 secs, then after that she starts to stumble and bog down, if i press on the gas pedal at this point she misfires out of the intake POP POP and in order to keep going i have to clutch in and rev slow clutch out while high revs,
after about 2-mins of this she will idle fine and even out at 800-900 rpm, and she will run but with slow response and little power under load but in neutral or clutch in, i can press on the gas and slowly it will climb until 2k than it will climb really fast like i think it should .
my question is what could be the issue a relay? is there an obd 1 system on this car
vacuum lines?
#3
AudiWorld Member
Check A/F mixture
Tendril,
Was it running good, then this poor running started all of a sudden?
Could be something as simple as a torn intake boot? Or a hose popped off attached to intake manifold or intake boot? Inspect intake boot closely, sometimes a tear isn't visible. I've patched tears with silicon to stop a severe vacuum leak.
You need Bentley manual if you don't already have it.
Advice: Troubleshoot first to find root cause, then replace what's broken. It can get expensive replacing parts that are not bad. Read everything you can on your car to gain an understanding, some links below to get you started.
First ignition system must be all working in order for fuel injection to do its thing, so make sure everything is solid there (plugs, wires (test them), dist cap, rotor, ignition timing).
Basic A/F mixture could be off, and/or vacuum leaks. At first start, there is warm-up enrichment which is masking the possible lean condition (vac leaks possibly or mixture is way off). Once it warms up a bit and goes closed-loop (oxygen sensor controlling mixture), the system can't adjust enough to run right.
You need to see where mixture is and whether system is operating in closed-loop. This is done with a test harness VW1315 (or make your own) and a digital V-Ohm meter that can read mAmp current draw from Differential Pressure Regulator [DPR] (gray thing on side of Fuel Distributor). The DPR can only adjust so far; if you are outside of the operating range of this system, mixture will be off (this could be your backfiring, too lean). There are many reasons this could happen (bad initial mixture adjustment, vacuum leaks many or a few, issues with fuel distributor, a torn intake boot).
Do some searching in the forums.
If this is all new to you, read up on it. Here is a post (8 pages) but good info to get you started, esp a few pages in about DPR and measuring mA current with links to other resources:
https://www.audiworld.com/forums/sho....php?t=2796735
If CIS-E is new to you, which it is to many since it's no longer used anymore, here's a good overview on it (VW training manual) which applies to Audi 4/5 cyl as well:
http://www.csupomona.edu/~bvnorum/ca...521-124-00.pdf
Good luck.
Was it running good, then this poor running started all of a sudden?
Could be something as simple as a torn intake boot? Or a hose popped off attached to intake manifold or intake boot? Inspect intake boot closely, sometimes a tear isn't visible. I've patched tears with silicon to stop a severe vacuum leak.
You need Bentley manual if you don't already have it.
Advice: Troubleshoot first to find root cause, then replace what's broken. It can get expensive replacing parts that are not bad. Read everything you can on your car to gain an understanding, some links below to get you started.
First ignition system must be all working in order for fuel injection to do its thing, so make sure everything is solid there (plugs, wires (test them), dist cap, rotor, ignition timing).
Basic A/F mixture could be off, and/or vacuum leaks. At first start, there is warm-up enrichment which is masking the possible lean condition (vac leaks possibly or mixture is way off). Once it warms up a bit and goes closed-loop (oxygen sensor controlling mixture), the system can't adjust enough to run right.
You need to see where mixture is and whether system is operating in closed-loop. This is done with a test harness VW1315 (or make your own) and a digital V-Ohm meter that can read mAmp current draw from Differential Pressure Regulator [DPR] (gray thing on side of Fuel Distributor). The DPR can only adjust so far; if you are outside of the operating range of this system, mixture will be off (this could be your backfiring, too lean). There are many reasons this could happen (bad initial mixture adjustment, vacuum leaks many or a few, issues with fuel distributor, a torn intake boot).
Do some searching in the forums.
If this is all new to you, read up on it. Here is a post (8 pages) but good info to get you started, esp a few pages in about DPR and measuring mA current with links to other resources:
https://www.audiworld.com/forums/sho....php?t=2796735
If CIS-E is new to you, which it is to many since it's no longer used anymore, here's a good overview on it (VW training manual) which applies to Audi 4/5 cyl as well:
http://www.csupomona.edu/~bvnorum/ca...521-124-00.pdf
Good luck.
Last edited by socalclimber; 02-14-2013 at 12:55 PM. Reason: edit
#7
https://plus.google.com/u/0/photos/i...25078373925266
this is pretty much me pressing down on the pedal half and full throttle
this is pretty much me pressing down on the pedal half and full throttle
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#8
this is hanging down by the horns G/Y and B wires
and also what is this and whats its purpose
another connector not connected unknown.
to socalclimber- i did read that thread good info but still a bit confused
as far as the bently man.
as of right now im kind of low on funds, but is on a to get list..i have two other car/ trucks that are getting most of my attention , they are datsuns 67' 520 p/u and a 69' 510 goon
im not sure where the fuel dist. plunger is?
and also what is this and whats its purpose
another connector not connected unknown.
to socalclimber- i did read that thread good info but still a bit confused
as far as the bently man.
as of right now im kind of low on funds, but is on a to get list..i have two other car/ trucks that are getting most of my attention , they are datsuns 67' 520 p/u and a 69' 510 goon
im not sure where the fuel dist. plunger is?
#9
AudiWorld Senior Member
Okay, the only one of those you need to worry about is the white connector. That's where you would test the fuel mixture if you have the ability. It's normally just sticking out like that, so it's normal.
The switch is the WOT sensor, and I'm not sure what the other connector is, but I have several of those left over from pulling the A/C system out of mine so it could be that.
As far as what to do with the mixture screw, I don't know how many turns would be a general ballpark. I would err on the side of rich personally, until you can either measure the mixture or read the plugs (which is what I've gotten in the habit of with my CIS basic car).
The fuel plunger is right under the fuel distributor. There are like three screws you have to take out and the distributor comes off. You'll see the plunger sticking out the bottom. Be careful not to drop it as a small scratch can ruin it. It's typical for those to get gummed up. It should move in and out easily.
-Rog
The switch is the WOT sensor, and I'm not sure what the other connector is, but I have several of those left over from pulling the A/C system out of mine so it could be that.
As far as what to do with the mixture screw, I don't know how many turns would be a general ballpark. I would err on the side of rich personally, until you can either measure the mixture or read the plugs (which is what I've gotten in the habit of with my CIS basic car).
The fuel plunger is right under the fuel distributor. There are like three screws you have to take out and the distributor comes off. You'll see the plunger sticking out the bottom. Be careful not to drop it as a small scratch can ruin it. It's typical for those to get gummed up. It should move in and out easily.
-Rog
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