weird starting problem

[Yoni_d]

Hi Guys

I have a weird starting problem.
Usually, the car starts without any problems on a first short starter. Sometimes it takes a little longer starter but it starts without any problem.
However, if for any reason it didnt start on the first starter (long or short) it will not start for 10-15 minutes unless I press the gas pedal all the way to the floor and hit the starter for about 10 seconds.

Now, this usually means that the engine is flooded...but how can it be?
I mean, the CO is normal, fuel pressure is normal so how can it get flooded?
Is it possible that too much fuel flowing to the engine while it is in idle? if so then I should see it in high CO readings right?

What can I do to solve this problem?

Thanks for your help!

[Mrmerlin]

check the fuel injectors for leaks try adding some techron to the fuel

[Yoni_d]

Everything in the injectors area is clean. no visible leaks.
Why do you think Techron might help?

[XLR8928]

Originally Posted by Yoni_d

Everything in the injectors area is clean. no visible leaks.
Why do you think Techron might help?

I think the Techron mrmerlin is referring to is the concentrated fuel system cleaner. I've used it myself... with good results.
-Kerry

[Landseer]

Related subject, are the inlet strainers removeable from the Bosch electronic injectors without damaging them? How?

[Yoni_d]

Yes, but how fuel system cleanup can solve flooded engine issue? or you think that it can be related to block injectors?

[Landseer]

Yoni, you have electronic injection, right?

And a hard start problem?

On a cold hard-start problem, as temperatures drop, the thermo-time switch could be the issue.
Its a common source.

The thermo-time switch is used to regulate the cold start injector and limit the amount of fuel on a start. If its bad, it acts like its flooded. The switch on my 4.7 84 cars is located on the passenger side of the front of the engine. It looks like a temp sensor. Its top faces the front of the car, and it screws in towards the back of the car. I've replaced them on two USA 4.7 cars.

Fixed the issue on both.

[Yoni_d]

Originally Posted by Landseer

Yoni, you have electronic injection, right?

And a hard start problem?

On a cold hard-start problem, as temperatures drop, the thermo-time switch could be the issue.
Its a common source.

The thermo-time switch is used to regulate the cold start injector and limit the amount of fuel on a start. If its bad, it acts like its flooded. The switch on my 4.7 84 cars is located on the passenger side of the front of the engine. It looks like a temp sensor. Its top faces the front of the car, and it screws in towards the back of the car. I've replaced them on two USA 4.7 cars.

Fixed the issue on both.

Well, I have mechanical injection...its a 80' model. is your solution still relevant?
How can I test the cold start injector to check if it is ok?

[Landseer]

I don't think so. Thought that the 80 EuroS was electronic fuel injection. Sorry.

(No experience with mechanical injection / there are control pressures and mechanical warm up regulator, apparently.)

[JhwShark]

Yani,

I am not that clear with the specifics (your descriptions) of the issue...but a euro CIS could have a Fuel Accumulator that is failing, not retaining pressure for second or warm starting.

I am not sure if the WUR (warm up regulator) is a cause??

Jon

[Yoni_d]

I thought about the Fuel Accumulator but I am not sure that it is the cause since when I start it with gas pedal pressed to the floor, it starts after 10 seconds and the engine feels flooded...I know that the Fuel Accumaltor is hard thing to test...
Could it really be the problem ??

[JK McDonald]

Hey Yoni, It sounds like your static fuel pressure is bleeding down after the car has been parked for a while. The CIS mechanical injection system should hold a fixed supply of static fuel pressure in preparation to restart the engine between a check valve screwed into the fuel pump and a parallel circuit that includes the fuel accumulator, a cold start injector and the 8 cylinder intake injectors. Your symptoms may indicate that one of these components is allowing the static pressure to slowly bleed off at engine shut down. Check the static fuel pressure after the car has sat for a while.

As a temporarily fix, you can jumper your fuel pump relay (pins 30 and 87) to provide power directly to the pump which will reestablish the needed pressure and easily allow you to restart your engine. The procedure you are currently using (holding the accelerator to the floor) will flood the engine every time.

One other comment - If the static pressure is bleeding off at the fuel pump - some of the early pumps integrated the check valve into the output port of the fuel pump. You may have to replace the fuel pump with a later year model that has a replaceable check valve. (I have seen where some owners with the early style fuel pump have added a new Bosch check valve (stacked in series) onto the built in check valve output port)

Good Luck, Michael

[Yoni_d]

Originally Posted by JK McDonald

Hey Yoni, It sounds like your static fuel pressure is bleeding down after the car has been parked for a while. The CIS mechanical injection system should hold a fixed supply of static fuel pressure in preparation to restart the engine between a check valve screwed into the fuel pump and a parallel circuit that includes the fuel accumulator, a cold start injector and the 8 cylinder intake injectors. Your symptoms may indicate that one of these components is allowing the static pressure to slowly bleed off at engine shut down. Check the static fuel pressure after the car has sat for a while.

As a temporarily fix, you can jumper your fuel pump relay (pins 30 and 87) to provide power directly to the pump which will reestablish the needed pressure and easily allow you to restart your engine. The procedure you are currently using will flood the engine every time.

One other comment - If the static pressure is bleeding off at the fuel pump - some of the early pumps integrated the check valve into the output port of the fuel pump. You may have to replace the fuel pump with a later year model that has a replaceable check valve. (I have seen where some owners with the early style fuel pump have added a new Bosch check valve (stacked in series) onto the built in check valve output port)

Good Luck, Michael

Hi Michael,

Thanks for your explanation!
But, if I understood correctly then if I am loosing static pressure, my FIRST start should be always very difficult. but in my case, the first start is usually good. if for example I try to start it at the first time and from some reason I stop the starter before it started and try again, then it is almost impossible to start.

Or, maybe the pressure issue is not stable...so some time it holds pressure and some times it doesnt and then I get this affect...strange...

[Yoni_d]

Forgot to ask...is it possible that the fuel pump pumping too much fuel when starting the engine? then it can explain the flooding issue...

[JhwShark]

The pump has a max flow rate and usually will not exceed it...bad/low/no pressure will cause a hard second/warm start. If so, it is most likely the accumulator or could be the check valve leaking. Cold start is usually indicated by other symptoms.

Look inside the right rear in-fender panel at the accumulator, if it has a gas smell and you can see seepage on it, it's leaking gas and pressure. Look (under the pump panel) at the check valve, either within the pump or external for any leaking/seepage.

Jon

[Yoni_d]

Thanks! will do!

[JK McDonald]

Hey Yoni, First use a gauge to test for the required static pressure. This will immediately indicate if this is your problem. A loss of static pressure is usually TIME related. The longer the car is parked (the increased loss of static pressure) and the more difficult it will be to start.....

There is a check list in the maintenance manual that gives the acceptable range of static pressure vs the length of time the vehicle sits. If I remember correctly your static pressure must not fall below the 14 - 15 psi mark or restart issues will occur.

Good Luck, Michael

[Mrmerlin]

if the fuel is dirty,
adding some Techron may clean the fuel components out.
This is the easiest thing to do..


If the accumulator is original replace it, ( in the RR wheel well)
also consider replacing the check valve in the fuel pump,
if it has a replaceable valve

[JK McDonald]

Hey Yoni - Don't forget that during the initial start your engine is cold and the cold start thermistor switch (in the front water jacket) is probably energizing your cold start injector as the starter turns. This solenoid style injector throws any remaining residual fuel pressure left in your system into the intake manifold (like a bucket with a hole in the bottom) and helps to start any engine as long as there is at least some residual pressure remaining. If your car does not start after the 1st cold engine attempt - all of the residual pressure may have been used up. Any additional attempt has no residual fuel available. Once the engine has warmed up - the cold start injector is no longer in the start mix.

After driving around a while - everything will be fine until you park the car. Then if you start it back up within a relatively short period of time, your residual pressure may not have bled down very much. But if you have shut down the car for too long, the residual pressure may now be too low for an easy start.

At this point the engine is probably too warm for the cold start circuit to activate and since the 8 primary intake injectors only open by pressure, they wont even begin firing until about 30 Psi is in the lines. The fuel pump has an air flow safety switch in the mixture control unit which doesn’t allow the fuel pump to run until air is being drawn into the intake from piston movement. Naturally - if the residual fuel pressure is too low - it takes 10 - 15 seconds of starter operation to bring the fuel pressure up high enough to begin opening the main 8 intake injectors.

All the above information is assuming that you have tested for a residual pressure issue. Please realize that we are all troubleshooting by guess and by golly using the information provided and there may very well be a different problem you need to chase down ... check Mrmerlin's input.

Hey Landseer - the thermo-switch (cold start thermister switch) may be a good call if the cold start injector is trying to over fuel every start process. Yoni - check to see if 12 volts is being applied to the cold start injector at every attempt to start your car.

Good Luck, Michael

[Landseer]

So it does have a thermo-time switch? I'd certainly replace it.