Starting problem - something has choked?

[Bali]

Hi,

I have some starting problem:
When I start the engine it starts working for a second and then stops.
I checked the spark-plugs and they were oily, and I could not smell any gas even when I tried to start it for a longer time.
The fuel pump seems to be working (I can here it).
Maybe something somewhere has choked.

Is it a good start to check it after the fuel filter?
It is a 2.0 IE with electric AC.

Thanks,
Bali

[Bali]

I have checked it after the fuel filter - the gas flows quite intensely.
Then I checked the back stream of the gas (tank connection in the trunk) - it is OK.

So the engine starts for a moment then stops...
Maybe the injector section has been blocked somewhere?

I have changed the spark-plugs and the air filter (there were paint chips as bbb said in an other topic...).

Maybe I have a similar problem as Paul (Pbarick167) in the Fuel Pump topic...
Any suggestion?
Thanks

Bali

[Bali]

Sorry for coming up with this again, but maybe somebody has some advice.

Now I am able to start the engine if I do the following steps (it was adviced by a car service):
- disconnect the electric connection at injectors
- give direct 12V for a second (repeat this a few times)
- reconnect the connections
- start the engine - it runs.

The next day it will not start again, I have to do the steps again.
Is it possible that I have bad gasoline in the tank, and it is choking /dubbing the injectors every time?
Should I clear the tank, get cleard the injectors?

And one more question - how many volts should I measure on the injectors during starting the motor and when its runing (if I disconect only one at once)?
I measure about 0.5 during starting and 0.5-1V when the engine is running (it is decreasing with the rev).

Thanks

Bali

[Gregory Smith]

Bali,

You could damage your injector coils putting 12V to them, they run on .5 V normally.

The injector grounds are switched in the ECU, and it get's it's injector timing signal from your ignition coil. Look there for a loose or corroded connector. Also check for loose or corroded grounds at the cam towers or cam towr end caps.

It's running breifly on the cold start injector, so you know you have good fuel and spark, you just need the injectors to fire!

[Bali]

Thanks Gregory,

I do not want to damage them! I was adviced to do this, and it looks like the engine will start if I do this.
When I did it on only two injectors I could start the engine and I could feel that only two cylinders was working, then three and after some minutes all of them...
I will check the connections again.

One more thing: recently I feel that the car is quite weak at low rev. From about 3000 its OK.

Bali

[Maigret]

This problem can be caused by a broken ballast resistor to the coil. Where a ballast system is used the resistor is bypassed while cranking giving extra voltage to coil. This drops back when key in normal run position.

If resistor circuit is broken the engine will fire but not continue to run once the key is released.

[Bali]

Hi Maigret,

Can you help me with more imformation about you wrote?
How and where should I check it?

That's true after starting the engine it starts running for a few seconds than stops, but if I do not relase the key it can work longer...


Thanks in advance,

Bali

[Will]

The two times I've had similar L-jet problems, the first turned out to be a clogged filter (which it appears you've ruled out) and the second was as simple as low system voltage. The starter will turn over with only 10v, possibly due to the fact it's such a little motor. The probem is, the Bosch ECU requires a minimum of 10.5v fire the injectors. Ooops!
Now I change to fresh battery first before even going about diagnosing an L-jet problem. Simple, but it took a lot of expletive language to reveal the problem!

[Bali]

Fortunately I can try it with a brand new battery so I will check it too during the weekend.
It would be interesting if it solves the problem.
I have this for a long while and I tried a lot to work it out (according to my possibilities and abilities).

Thanks

[Will]

It seems to usually be the stipid little stuff that goes wrong. While it's true that items like the aux air valves and such do go bad over time, My US spec beta FI suffered from things like poor grounds and terminals that had rotted off the ends of wires. In particular, there's a large hand-shaped ground connected up by the headlights that the spade connector "fingers" rot off on. That thing is an endless nuisance, but not related to the fuel system. I've never seen an L-jet ECU go bad on any car, although I have welded on at least have a dozen cars with an electric welder with no ill effects. On at least one of thes, I didn't even disconnect the battery!

There are lots of good references to help you troubleshoot the L-jet online, you might want to take a look over at the Mirafiori.com site. However, none of these will help unless you've established the very basics;

a) good supply voltage

b) good ground, both engine to chassis and the ECU/coil grounds (these are at the triangular cover plate at the tail of one of the cam boxes on a FI Beta.

c) Dual relay feeding power to fuel pump and ECU

d) Good fuel supply, both flow and pressure. Note that these are two different entities.

e) Good fuel- "bad gas" syndrome is painfully common here, as many enthusiasts run the car a few times a year and it might have five year old petrol in the tank by the time they refill it.

Once your are good with this checklist, THEN and only then, can you diagnose the rest of the system. Also note that when the system goes to closed loop, the 02 sensor grounded will force the car rich, and if you want to force it lean you can do so by grabbing the 02 sensor lead and touching the + battery terminal with the other hand. This should feed the ECU about 2v.

Good luck.

[dbirrell]

It almost sounds as like the fuel pressure regulator has gone bad. Seems as thought the injectors are clogged since giving it the atomic shot of voltage helps. I had an old SAAB 99 that every so often needed the injectors pulled and aimed into coffee cans while lifting the air flow plate all the way up. This give them a shot of full duration fuel pressure to clan them up a bit.
It is possible that the fuel pump relay is bad or the MAS is not turning it on. You can remove the air bellows between the filter box and the air flow sensor and lift the plate slightly with the key in the run position. You should hear the pump running as this simulates the engine drawing air through the MAS. The injectors should not squirt until the signal is sent to the ECU from the dizzy.
Another thing to check in the multi-ground in the trunk. The fuel pump gets the ground on the tail light mounting stud. I think.
Most problems with the system can be put squarely on bad grounds.

Dan
81 Zagato tucked away for the winter

[Will]

Ummmm......my 82 Zagato had a Bosch L-jetronic- no MAF sensor and no air bellows or plate that lifts- those are all components of a K-Jetronic or CIS, and they don't use pintle-type injectors so I don't follow the above- unless you meant THROTTLE plate, and that moves the TPS but the TPS has no bearing on the fuel pump as far as I know. So I am totally confused by the above? Maybe 'cause it's 4AM here, I dunno.

[dbirrell]

Some improper terminology used in my last post. There is a vane inside what I call the mass airflow sensor that is hinged at the top and swings forward being pulled by the low pressure once the throttle is opened. When it first starts to move, a contact closes to allow the fuel pump to run. This appears to be a safety feature to assure the fuel pump does not run if the engine has died. There is a start circuit to get the fuel pump running as long as the starter is engaged. My 81 will have a short stumble between start mode and run mode as the power feeding the fuel pump is switched in the double relay.
This is why I said to open the vane slightly with the key on and you can hear the pump running.
There is also a potentiometer inside that changes resistance when the vane is moved toward full open to signal the ECU that more fuel is needed.

[Bali]

Hi,

I had no chance to check the whole system - its quite cold here and it is dark after 5pm nowadays. Winter is coming...
And my MOT expired (is it the correct expression?) and I had to apply a new rear bumper with licene plate lights (I had an accidente in summer).

But some parts are already checked in the past.
For example the power supply to the fuel pump from the doble relay, fuel pressure, tempreture sensor and switch, some grounds and connections etc.
In the air flow sensor there is the plate, which when I lift by hand and the ignition is on the fuel pump starts to opertate. Yes, as I know this is a safety solution, during starting the engine the fuel pump gets the energy in a different way, after the engine is running the plate moves, and from here goes a sign to the doble relay.
I have tried to move this plate by hand during starting the engine to assure that the fuel pump gets the energy all the time - but the result was the same: the engine dies after a few second.

The fuel pressure was checked in a service, but I don't know whether it was checked after the fuel pressure regulator or not. I hope it was checked after, which can mean that the pressure regulator is good...

I will write if I have chance to check the other things - for example with a new battery! (This can be a propable winner because the starter motor also carry itself badly because it is quite often deny to operate and I only can here the fuel pump when starting, and if I understand well that Will wrote it can be due to old and weak battery.)

Thanks,

[Will]

IMO moving the "vane" in the AFM (it's actually a big chunky wedge) in order to force the fuel pump when the engine is running is not a real good idea, or at least not optimal (it lets you know the switch is working, but you can't run the engine like that). The reason is, you are also moving the wiper arm across the resistor network (there are 11 or so contacts), telling the ECU to increase the injector pulse width. This will probably stall the motor, or at least make it run real rich.

The way I've forced the fuel pump is to jump it out at the dual relay.
All you need to do is feed + voltage to the appropriate pin on the relay. The dual relay has two sides. The ignition relay has 5 pins, the FI harness relay has 7 or 8 (7 I think on the Zagato). Anyway, on the side with the LEAST number of pins, find the connector furthest from the indexing notch (If you pop out the relay, it says "88d" on this pin. You can simply tie into the wire there that feeds the fuel pump. You can also do it at the pump, but the dual relay is a handy location- you can also add an anti-theft that lifts or grounds this pin. Not that anyone in their right mine would steal a Zagato, mind you! ;)

You'll find the wiring diagram I made up for the L-jet harness back when I was monkeying around with those Zagato FI systems here:

http://www.savetheledges.org/test/AVS/images/tech/BoschFI.jpg

I'm in the process of moving my webspace, so if you don't get it, try later.

Ciao.

[Bali]

Hi,

During the weekend I could check some area. I have charged the battery (I will check it with a new one later), gave extra power supply to fuel pump, changed the resistor - not much success.
At the end I tried the old way: "The Atomic Shot" :wink:
And it worked. The engine started to run BUT no idle! Formerly I had no problem with it.
And as I wrote it before the engine is quite weak below 3000 rpm...

I have checked some grounds too, but Will, I am not quite sure about you wrote: "b) good ground, both engine to chassis and the ECU/coil grounds (these are at the triangular cover plate at the tail of one of the cam boxes on a FI Beta."
Because English is not my mother language - if you may have pictures about the sections to be checked... :oops:

Thanks,

[Gregory Smith]

Bali,

Have you searched for a large vacuum leak? This could explain why your engine won't run on the normal injectors and has a weak idle.

A common area is the bottom of the large hose between the AFM and the throttle, cracks can form there.

[Bali]

Hi Greg,

Yes, once I have tride to check it. I found a big one here (red square):
http://www.lancisti.org/forum/modules.php?set_albumName=album25&id=Air_1&op=modload&name=gallery&file=index&include=view_photo.php

I did not find other hole... there was some little cracks on it but I think that aren't holes.

It is possible that I caused the injury in this hose because when I was trying to start the engine and I have pulled down the accelerator pedal during starting sometimes it "backfired" or I do not know the correct expression. There was a boom and the hose was removed from the AFM...

[Bali]

Hi,

Firts thanks everybody for the help.

The idle problem has been solved - there was a vacuum leak at that large hose.
I have fixed it. I think there aren't more holes, but the engine still not run.
BUT! Somewhere in Lancisti I have red that knocking the injectors can help, so I have tried it and it works!
So in the future I will rather knocking than use the "Atomic Shot". :)

Today at first I gave electric shots to 2 injectors, then I started the engine
2 cylinders were working.
Then I knocked the third - 3 cylinders were working, then knocked the fourth injector - 4 cylinders were working.
For me it means that all the 4 injectors are blocked.
What do you think will that be enough if I get cleaned the tank, put a new fuel filter and give a shot of injector cleaner?

[Gregory Smith]

Good news Bali!

I would just use some injector cleaner and see how it goes. The injectors might be "sticky" from lack of use, and improve quickly. Using injector cleaner might loosen dirt in the system that then makes the problem worse, however.

If it continues to be a problem, consider removing the injectors with the rail as an assembly and taking it to an injector cleaning service for a good ultrasonic cleaning. If you have trouble finding an injector cleaning service, look for places that service diesels too.

[Bali]

Hi to all,

Thanks for your help - at the end I have became more or less familiar with EFI :D
I am not a mechanic but I am interested in cars - especially the Beta, so I can say that it was interesting the check every part of the system (as I could, of course).

So the problem are the 4 injectors. I have used a bottle of cleaner and now I can start the engine - but if not, I just knocking them carefully.
It is OK for me now, maybe I will continue to work on it when it will be warm outside :wink: