Audi 4000s fuel problem - wont start

I was wondering of anyone could help me with a problem that suddenly developed with my AUDI,
The car is a 1987 Audi 4000s 1.8L Here is the deal, the car will start for second or two, but will not
rev up, then it dies.
Fuel pump and filters are new.
Strong fuel pressure to the Fuel injector unit.
The injector unit is sending fuel to the cold start valve, but not to the cylinders, thus the car will start but will not continue to run. The pressure to the cold start valve is strong, but not a drop to the fuel injectors.
I replaced the external fuel regulator with a spare one and checked for vacuum leaks etc.
I am not sure where to look from here, internally on the Fuel Injection Unit, or to a relay or other control.
As I stated the problem happened overnight.
Any help would be appreciated. I have not used a internet group before, do I hope I am doing this right...........:)
Thanks,
Richy Jackson
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
snipped-for-privacy@aol.com wrote:

This can be due to vacuum leaks (you checked but check again) or deposits on the rod above the plate.
Open air cleaner and reach up into the intake just above. The plate should move but with a little pressure. Don't force it.
Other ideas: Differential fuel pressure sensor (just in front of fuel distributor.
Blown engine management fuse (in the side of the relay box.
Failing engine temp sensor. In the T44s it is called the MFTS and it is located by the upper radiator hose inlet to the engine.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Like TonyJ said..............it might be a Failing engine coolant temp sensor (CTS)
Or a fuse in the fuse box. It is positioned to look like a spare fuse and many times I will find it missing on a vehicle that is not running right if running at all. 8^o Examine all of the fuses for any broken ones and stick a fuse in all sockets with terminals.
Or it could be the ground wire for the fuel pressure regulator is broken and it should be located at the cold start valve.
Or it could be a defective fuel distributor.
Or it could be a massive air leak at the large intake manifold boots. Maybe a light engine backfire into the intake system along with the gas pedal being depressed might have caused a hose/pipe to pop off creating a large vacuum leak.
Or it could be the ign switch not allowing power to the systems when it is in the ON position. Telltale signs would be those red idiot lights not being ON with the ign ON or while cranking over the engine.
good luck and let us know what happens! later, dave AKA vwdoc1
wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Hello Audi 4000 fuel help still needed
Been busy at work, not much time to work on the Audi until last week.
Still having problems getting this car to run, was wondering if there are any other ideas out there?
I still can not get the fuel injector unit to shoot fuel into the injectors. It still fires fuel to the cold start valve, enough juice to run 3-5 seconds.
I checked all fuses, put new ones in the blank spaces.
I checked the fuel injector air-door, it opened fine.
I replaced the entire fuel injector unit with a used one I had from a parts lot I bought.
I changed the fuel regulator as well, the one on the injector unit, I believe this is the "Differential fuel pressure sensor (just in front of fuel distributor." ,that you mentioned As far as the "Failing engine temp senso" " the MFTS ", is this the same as the temperature sending switch? . Could this really keep the fuel injector unit from firing? Can I bypass this to test it? There is no massive air leak at the large intake manifold The ignition switch is fine, it is new, it is getting power to the fuel pump and other systems
Any help would be appreciated!!
Richy Jackson

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Do you have a repair manual? Even a Haynes (cough cough) could help some.
Remove intake boot off of fuel distributor so you can manually lift up the plate. Remove injector(s) out of the cylinder head and aim into a container so you can examine spray pattern. Remove fuel pump and jump correct wires to run fuel pump continually. Turn ign on but do not start car.
Pull up on fuel distributor plate to check fuel injector spray pattern. Tell us what happens? If it sprays out that is good and you might just need to adjust something or change a sensor. If nothing sprays out then I suspect either a bad fuel distributor, bad Fuel Pressure Regulator, bad wiring, missing fuse, clogged injectors, no fuel pressure or ????
The ground wire for the FPR usually breaks at the cold start valve.
No the temperature sensor for the gauge is different than the one for the fuel injection. ;-)
later, dave (One out of many daves)

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Hey Dave,
Thanks for the reply,
Yup, I have a good old Haynes manual; read it a couple times...!! I will get a shop manual..
I did take off the hoses to the fuel injectors and cranked the engine, nothing comes out, except for the line to the Cold Star Valve that gives a nice spray to the intake...
I tested this with both my original, and a replacement fuel injector unit, in both cases, plenty of fuel to cold start valve, nothing to fuel injectors. I already pulled the plate up as you suggest. still nothing from the fuel injector hoses
Replaced both fuel regulators, car has new fuel pump and filters, plenty of fuel pressure to injector unit...
The ground to the cold start valve is fine
As I have tried a replacement injector unit, it does the same thing, I am thinking it I electrical, fuses are good.
I read the voltage of the fuel regulator that is on the fuel distributor unit or, it shows 8 v, there is an electrical connection on the other side.
Something is keeping the Fuel distributor unit from shooting fuel to the injectors, any other thoughts?
Tell me again about the temp sensor for the fuel distributor, where is it located & would it stop the fuel injector unit from firing?
This car ran fine until a couple months ago, I changed brake lines & complete exhaust & then it stopped running...
Any help would be cool..
Richy Jackson
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
hmmm Not to get too picky or exact, but did you perform the tests like I instructed? :-) Cranking the engine brings other things that could cause problems such as the ign switch which could, if faulty, lose power to key components like the FPR, fuel pump, ign system, etc! Even the power could drop below 10 volts while you are cranking over the engine.
It sounds like you disconnected the lines to the injectors instead of removing the injectors. It sounds like you did not jump the fuel pump relay.
Now if you are getting correct power to the fuel system and ign system, and you have fuel pressure at the fuel distributor, and you pull up on the fuel distributor plate while the fuel pump is running and you get no fuel out of the injectors................................then it sounds like either the FPR or the Fuel Distributor might be the cause of your problem. But I am just guessing here since I am not sure if power gets lost to the FPR while you are cranking over the engine.
Bentley is the better manual and you can find them on Ebay sometimes.
later, dave (One out of many daves)

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Thanks Dave
Sorry, I was not disrepecting your instructions.....I had run the tests the way I stated a couple days ago before I read yourinstructions...:)
I will dig in & get the Bently manual
If I could bother you with one more Q... tell me about how to jump the fuel punp relay, did you mean the pump itself, I did this acouple timnes when I tested, how do I jump the FPR?
Thanks
RJ
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
snipped-for-privacy@aol.com wrote:

fuse in the top of the fuel pump relay to 'jump' the pump to running. This is a manual override. Some models may not have the fuse slot on the top of the relay so if this is the case you could use a jumper wire in the slots of the relay if you pull it out. Careful, as you know sparks / fuel are dangerous.
One other thought is that some people have traced a no start condition on the T44s to a sticking decel valve located in the passenger finder and hidden behind the fuel distributor. when the stick they create a vacuum leak. I don't know if you even have one on the 4000 and I think that lifting the air plate would have overridden this issue but thought it was worth suggesting.
Good luck. Dave's the authority.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
please do jump in TonyJ! Always a free-for-all conversation! ;-)
I don't think I have ever tried the fuse in the fuel pump relay, although my old '83 Audi 4000S does not have that type of relay. I have seen that type of relay before, but I did not have to install that fuse/jumper.
I'll have to remember about the 'sticking decel valve' just in case I encounter a problem.
thanks, dave (One out of many daves)
snip

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
The temp sensor (in a coolant manifold) is an input to a box located behind the glove compartment. An output of that box provides current to the gray box on the side of the mixture control unit (differential pressure regulator). More current = richer mixture. Open circuit = very lean mixture. The proper / quick check is to measure the current through the differential pressure regulator but that is difficult to do without the test jig and a solid electrical theory in mind.. I believe the normal current is in the 100ma range. It's in the books but they make it harder to find as time passes.
Doubt that the control box would actually fail unless there has been a major electrical event. Once I found / replaced an open transistor in the box and we drove it for years, but I'd purchased that car due to it's having an electrical fire due to the radiator cooling fan.. Oh those days of $1200 Audi 4000s.
I'd be crawling around under the glove box, looking for where the mice have been unless you have a Fluke 77 and feel like cutting wires.
mark lemon Woodward Iowa

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Try replacing the temperature control switch which could be sending a false reading to your ECU hence no fuel in cylinders.
"TonyJ" wrote: > snipped-for-privacy@aol.com wrote: > > I was wondering of anyone could help me with a problem that > suddenly > > developed with my AUDI, > > > > The car is a 1987 Audi 4000s 1.8L > > Here is the deal, the car will start for second or two, but > will not > > rev up, then it dies. > > > > Fuel pump and filters are new. > > > > Strong fuel pressure to the Fuel injector unit. > > > > The injector unit is sending fuel to the cold start valve, > but not to > > the cylinders, thus the car will start but will not continue > to run. > > The pressure to the cold start valve is strong, but not a > drop to the > > fuel injectors. > > > > I replaced the external fuel regulator with a spare one and > checked for > > vacuum leaks etc. > > > > I am not sure where to look from here, internally on the > Fuel Injection > > Unit, or to a relay or other control. > > > > As I stated the problem happened overnight. > > > > Any help would be appreciated. > > I have not used a internet group before, do I hope I am > doing this > > right...........:) > > > > > > > > > > > > Thanks, > > > > > > > > Richy Jackson > > > If the air plate just above the air filter is stuck the > injectors will not fire. > This can be due to vacuum leaks (you checked but check > again) or deposits on > the rod above the plate. > > Open air cleaner and reach up into the intake just above. The > plate should move > but with a little pressure. Don't force it. > > Other ideas: > Differential fuel pressure sensor (just in front of fuel > distributor. > > Blown engine management fuse (in the side of the relay box. > > Failing engine temp sensor. In the T44s it is called the MFTS > and it is located > by the upper radiator hose inlet to the engine.
--
Posted at author's request, using http://www.AutoBoardz.com interface
Articles individually verified to usenet standards. Visit URL to contact
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Related Threads

    Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.