CIS problem or electrical, car wont start.
 

Hi
My car has not started i 2 weeks! Even when I brought her new Fuchs with SO3 to replace her cookie cutters did she start !!! :)

I have sparks so I´m guessing fuel problems...

I have Probst fuel injection book so I am going through the trouble shooting..
I have measured:
Fuel delivery, 1450ml in 30 seconds.
Fuel control pressure delivery, 125 ml in 30 seconds.

Today I made myself an pressure gauge and measured:
System pressure: 0.6 bar
cold control pressure: 1.2 bar

That is odd!!
In Probst book the pressure gauge had its valve on the FD side but when I read a post here (cant remember who) is said valve on WUR side.
What should it be?

Also when you jump the fuel pump. Does it circulate fuel in the system?
Because when I jump it the pump is very quiet and when I disconnected the return hose for the delivery test it "sounded" a lot more. Its almost as it is trying to pump fuel but cant, also when jumped it draws 16 amps!

Magnus,
I can help you with some of this. The gauge should go between the connection @ the top center of the FD and the top of the WUR. Your cold cp seems OK, but your fuel pressure should be 4.7 to5.2 bar. Your residual fuel pressure after 10 min should be at least 1.3 bar, and after 30 at least 1.1. Your fuel pump should draw usually around 5 or 6 amps, w/ a max of 8. The tests should be done w/o the engine running.

To answer my own question about pressure gauge: the valve pust be on the WUR side, how else could you meassure system pressure? It helps to think sometimes......

I will go back to the car and get correct values.

I can get back to you in a few hours to verify cold cp.

New values:
System pressure: 4.8 bar
cold control pressure: 1.4 bar

Safe,

I have a CIS car, and the cold start injector was not working. The engine would kick when you initially hit the starter, but then the engine would not fire at all - just crank and crank.

The cold start injector is controlled by starter voltage and a thermotime switch.

It is in the back of the CIS unit, and probably really hard to get to, but it might be worthwhile to unbolt it and see if it is spraying fuel.

Rex

Your values are OK. Now check the residual pressures I mentioned earlier. Could be your fuel accumulator or fuel pump check valve. A search will give you lots of info on this.

Check the cold start valve as Rex Walter suggests. Even if all else is OK, the car will be difficult if not impossible to start if it's not working properly,

ianc

I will go and try to check the cold start valve.

Problem is I cant see it or get to it.

Does someone have a good close up picture of the back and what kind of fastener that is used?

It's true you need a third elbow to get at the damned thing with the engine in the car. Mirrors re helpful.

I believe it's secured by a couple 6 mm allen heads,

ianc

A small breakthrough maybe.

When checking cold start valve I had it disconnected to see if it got any power while cranking.

I had ignition on and jumped the starter from the 14pin connector and the engine fired for a second and died. Wow !
I connected the cold start valve again and jumped the starter and the engine fired as long as I cranked it and then died with a backfire.
The I remembered that I didn't have the fuel pump relay connected so I installed that and cranked again, but from the key. As dead as before.....
I then tried without the relay but with a wire from 30 to 87a so the fuel pump would pump on ignition. Still dead!

Any theories?

Fuel accumulator, fuel pump check valve, vacuum leaks, blown or open popoff valve, blown airbox, leaks around injector seals, stuck or out of adjustment sensor plate or plunger, boot over sensor plate.

Paul: But those thing dont explain why it starts when I jump the starter from the engine bay and not when I try to start it from the ignition.

The car has never ever backfired before.

When I jumped it it is like it started but when the starter lost power the fuel pump stoped.

Check around behind the fuel dist/ throttle area. There is another connection near the cold sv. It is green. It isdesigned to turn off the pump in case the car tips over. See if you have one of these. If so, make sure it is connected and receiving power.

You may have a starter wire/ switch problem separate from the run problem.

Check the round black connections under the dash/ steering wheel.

That switch seam to work. When I removed the connection the FP relay lost power.
I also think that this is not my older start problem.

Forgot to check connections under the dash.

I found this in another thread:
http://forums.pelicanparts.com/uploa...1122481907.jpg

I set up a test on a bench:
I put 12v on 86 and 87a and ground to 85.
When I then put 12 v on 87 (starter) then 30 gets 12v. But when I remove 87 I lose power to 30.

What is responsible for powering the fuel pump when the engine runs?

Are you doing this w/ a relay in place? Have you tried another relay? Checked fuse box wires and connections for contact and corrosion?

Were you able to start the car by raising the sensor plate?

I have tried another relay, did nothing.

I sprung a fuel leak in the enging bay so I decided to take a brake letting it dry up.
Im also giving up for the day, it´s late over here now.

I finaly understand how the relay work now!

When the Air plate switch breakes it breakes power to the relay and it goes back to its "Normaly Closed" position and supply the pump by 30-87a.
So the relays only function is to kill the pump when the engine isn´t turning over.

I think that is the only difference between the red and black relays.

The red relay has a diode in it while the black ones don't. What the diode does I don't know. You can use the black relay for the fuel pump and it will work fine.

The reason the car ran when you cranked it is because it was running off the fuel supplied by the cold start valve alone. The CSV supplies continuous fuel while cranking until the bimetal in the thermotime switch shuts it off. It's like 3 or 4 seconds, depending on ambient temp. Sounds like the injectors are not receiving fuel when the key is in the run position.

Turn on ignit and raise the sensor plate. Does the fuel pump run?

ianc

First time I didnt have the electrical connection to the CSV connected.

Yes, it runs.


/Magnus

OK, so you are getting fuel to the injectors when the fuel pump is running?

The fact that the car runs off the CSV means it is not an ignition issue. You said your system and cold control pressures were in spec, right?

Is there some issue preventing the sensor plate from lifting when you're cranking? Sticky sensor plate? Massive vacuum leak that's pulling air from downstream of the sensor plate and preventing it from lifting and thus metering fuel?

Or am I just not understanding something you've said?

ianc

I got the car running now. It was getting to much fuel and soaked (is it called that in English??).

I made a switch for the fuel pump instead of the relay so I could operate it from the engine bay. Then with the fuel pump off I cranked it (from the engine bay) and I got some life in it. Then when it started to fire I hit the fuel pump and the engine came to life.
Lots of smoke!!! I let it run for a while, turned it of, replaced fuel pump relay and now with the engine warm it started up the normal way.
Then I took it for a spin. It had high idle, 1500-2000 rpm, or maybe sticky idle for it can come down (to 900-1000) if I let it sit or use the clutch (in gear and foot on the breaks).

Ianc:
Pressures are in spec I think (see earlier in thread), I actually don't have the specs, but from other threads it seems ok.
The sensor plate seems to move freely. I could not detect anything when I moved the plate by hand (without fuel pressure).

Safe,

Excellent progress. If your idle continues to stay high, there are a few discussions that I can point you to for diagnosis of similar problems. Most problems involve vaccum leaks, but it is also possible that the distributor advance weights may be dirty and are not returning to the idle position. Good luck, and great to hear that you can now drive it.

**************
It was getting to much fuel and soaked (is it called that in English??).
*********

English slang for too much fuel is flooded, and wet plugs will get fouled.

Rex

I´m now letting the car cool down to see if it will start the normal way when cold.
And later this evening I´m going see "Batman Begins" as a little treat, I hope its good :)

I think the high idle is related to my start problem.

Your high idle may be due to vacuum leaks, the decel valve, the AAR, distributor sticking, or even a too lean mixture, or the idle speed screw turned up too high.

Sometimes when you put the clutch in and the idle speed goes down, that's because your mixtureis too rich. It may have been richened by someone to make up for a lean condition like a vacuum leak.

If you rotate your rotor by hand, does it spring back quickly by itself?

BTW I think you'll like Batman Begins. Great special effects.

I will test for vacuum leaks later. Which are the most likely places for a leak?

I don't think its to lean or to rich, not normally, that would have shown in the exhausts levels, wouldn't it? But something is probably making it lean or rich on an intermittent scale.

The rotor springs back. I´m not really familiar with the distributer.
You can rotate it a little and it springs back and you can pull it up a bit and it rotates and springs back but a little different.

I posted a new post asking for specifications on fuel pressures warm and cold. As the control pressure is responsible for the plunger back pressure when running.

I´m amazed but what you can learn from problems ;)

I´m really no mechanic, I have never worked on cars in the past so I´m learning a lot as time goes. The first time I did something other than brakes was this winter when I made my first engine drop to seal oil leaks and as it turned out replace cam chains.

Magnus, I can't remember, you did get the car going, correct? If you can get to run for a few minutes, turn it off and check your residual pressures. They should be at least 1.3 bar after 10 min and 1.1 bar after 30. You can also get the engine started usually by lifting the sensor plate. If your residual pressures are too low, you probable need a new fuel accumulator or fuel pump check valve, as I mentioned previously. As a general rule, if the engine starts, it is not the cold start valve. Search air or vacuum leaks. Many members use an open but unlit propane torch and hold it close to various areas of the enging. If the revs change, there is a leak (except if held near the intake). Common areas are the rubber intake runner connections from the airbox, the airbox itself, the decel valve, the CSV o-rings, the fuel inj o-rings, the popoff valve,the AAR, the AAV, and all vacuum hoses.

I got it going yes. Waiting for it to cool down again...

I checked residual pressure yesterday. I had 2 bar right after I turned of the fuel pump and 1 bar after 38 minutes. Didn't get any messuremets in between.
But I have never had any hot start problems only cold start.

You might also want to check your thermotime switch. It's on the chain/ tensioner cover on the driver's side. Disconnect the wires and put a ltest light on the 2 connectors. Try to start the engine and see how long the light goes and stays on. It should be a few seconds, and then go out. This switch controls how long the CSV injects.

Thats a good idea, I'll on that.
The car started cold in less than 1 second today.

BTW: Batman Begins, was really good! Way better than I expected. Only problem is that Katie is way to cute to be believable as a DA.

Safe..just to clear up the function of the Fuel pump relay and the safety switch. I think you are wrong or perhaps I'm not understanding exactly what you stated. It is my understanding that the fuel pump relay is energized when the safety switch completes the circuit to ground. When the air sensor plate is at rest the safety switch is open [no ground connection]. When you crank the engine the cold start valve squirts fuel and while the engine cranks it draws air. This raises the air sensor plate and closes the safety switch, completing the circuit and energizing the fuel pump relay. The relay then allows the fuel pump to operate. In the event of an accident the motor would stall and the air sensor plate would come to the rest position. The safety switch would open and break the ground connection and prevent the fuel pump from flooding the engine with fuel. If you are having problems with a new relay operating I would check the functioning of the safety switch and the harness that connects to it. If it all checks out then you have a huge air leak that is preventing the air sensor plate from lifting during startup and closing the switch.

Engine does not have to fire. Just cranking it over will raise the sensor plate enough to energize the relay.

ianc

yes, thats true. Sorry for a bit of mis info! Let me edit that so we keep it pure!

Nope, I am pretty sure its the other way around. Sensor plate at rest = closed circuit and ground to the relay.
The relay is normaly closed 30 to 87a.

I always get confused by saying a relay is open or closed.

I don't think the diagram that you posted on the previous page is correct Magnus. I think that the connections to 87 and 87a are shown backwards on it. I'm almost 100% certain that the circuit 30-87a is completed even if there is no control current energizing the relay (85-86). When the relay is energized (current through 85-86), then the circuit 30-87 is active instead.

If what I believe is correct, then the starter connection (cranking only) would be on 87a. That way, the fuel pump (30) would always get power when cranking. When the engine fires and the ignition switch moves to the run position, power comes from 87 instead. 87 would only be active if you have current through 85-86, and in order for that to happen, the safety switch must be grounded while the sensor plate is lifted by airflow.

Make sense?

ianc

Here's the diagram again:

http://forums.pelicanparts.com/uploa...1122678865.jpg

Well, when I say closed I meen that its connected.

30 and 87a is only connected when the relay is NOT energized.

30 and 87 is connected when relay IS energized.

So the fuel pump gets power from the starter trough 87 when you turn the key.
That raises the sensorplate breaking grund, 85, to relay.
The relay then goes back to its normal condition, connecting 30 to 87a.
Now the fuel pump gets power from the ignition switch.
That is why you can jump 30 to 87a and the pump run when the ignition is on.
If the engine stalls the sensor plate comes to rest, getting ground to relay and that pulls the relay to 30-87 turning off the pump.


Its seams backwards , i know :)
I had to hook upp the relay on an bench with a power supply and a multi-meter.
The Haynes manual also has some good electrical diagrams.

Alright, I'll buy that; it seems to make sense. I was forgetting that both 87 and 87a have power when cranking. If 87a didn't have power when cranking, as soon as the plate lifted, the fuel pump would cut out.

This arrangement depends on there being current through 85-86 to cut off the fuel pump in an accident though. I'd rather have a fail-safe situation where if 85-86 wasn't energized (eg. relay shaken loose in crash, sensor plate jarred so it doesn't come fully to rest, wire cut etc.) the pump wouldn't run.

Such a design would count on the relay being energized during running though, which would probably be less reliable overall. Choices...

ianc