Too rich run / no idle after starting

Hello together,

so after the problem with the injection is solved...I got another one...although the two injector banks firing alternating now, the Bronco runs mach too rich and also get's not into idle when not helping with the gas pedal. When holding at about 1,000 rpm the engine runs rough and, as I've said, very rich.

Doing a KOEO test shows a trouble code 95.

I don't have any of the emission control solenoids or EGR installed anymore. Maybe I have to simulate them with a resistor?

As having the problem with the EFI, I have had also turned the idle screw in and out...so I have no reference for it.


I use all new sensors: MAP, TPS, Idle valve, water and air temp.

The fuel pump relay was also changed with a Bosch-type, while re-wiring the whole engine harness.

I also have a new fuel pump in stock...so changing should be no problem...

I think I have set the timing near 10 degree TBDC, but maybe my timing mark isn't correct...as I also have no reference...here is an image of mine...

Rene' I do hope you are aware that Ford timing scales read both directions from 0.


You need to be on the 10° BTC end with the timing jumper unpluged.

Hi Bill,

Yes, I know. The thing is that I don't know if my timing mark...lets say "sheet" is bend or correctly adjusted...

But in my understanding this could be about the raw run...but why adds the ecu so much fuel?

And what is about the error code 95?
If I would have a idle run without pressing the pedal all the time, I would check the fuel pressure...

i would not expect the truck to be using peripheral circuits immediately after start up. the ecu should be operating on a base program until it reaches a certain temp, then the ecu goes into a more efficient mode of operation. you are able to keep the engine running with the pedal? if so then it seems to be getting enough fuel but is it possibly too much? obviously as it is rich. after running it for a few seconds this way have you re inspected the plugs? if they are sooty then they are burning fuel at least if inefficiently. if any are wet then I would be concerned with a stuck /dirty injector.

Hi,

Injectors all checked in the past...they are ok. Nothing suspicious. All refurbished original Bosch.

In know what you mean with the rich run at start-up...but I don't have a real start-up...

As I have turned the idle screw in and out in the past it won't be at any reference...

My MAP sensor is directly connected to the throttle body with a Y-distributor.

As I also have a new TPS, maybe it isn't set correctly to zero...

Rene', MAP sensor should be directly to the intake vacuum tap on top of the plenum, taps on the throttle body are ported canister purge ports and have no vacuum at closed or low throttle and less than full manifold vacuum running at higher throttle.

TPS, on 1987 up Ford truck EFI systems, ECU reads initial voltage at start and uses that as closed throttle.

Code 95, 1989 ECU picks up a voltage signal at pin#8. 1986 Bronco wiring lacks this circuit. It is simply a wire from pin #87 of the fuel pump relay to the ECU pin #8.

If after moving the MAP sensor line it still is super rich, try pulling the hose off the power brake booster check valve. If it is now too lean, squeeze it with a clamp until it will keep running.

Timing marks:

Hi Bill,

Ok..
Pin 8 is not connected...as I use the 1989 ECU, this seems to be the problem with that error code...how do I have to connect pin 8?
As I have a complete new wiring I'm free to route this wire wherever I want...

Regarding the map...is was wrong...it seems to be I'm getting blind...my MAP vacuum line goes directly to the plenum...as you've said, the vacuum of the throttle body is going to the canister...

About the timing: my problem is not the scale on the harmonic balancer...my problem can be a bow bracket...a blue one on my photo...where the word "TIME" is stamped in...

My main problem is that the bronco will not stay in idle...only by pressing the pedal...so other, advanced checks are very hard to do...

Ok...that's interesting...after pulling the vacuum line of the power breaks, ist starts and runs in rough idle...but still very rich, as I smell...
With connected it won't start at all without pressing the pedal...

obviously, it is wanting more air. with an added vacuum leak, it runs rough but at what rpm. is it struggling or running at 1500? I'm thinking it may be running well enough to check timing at least and see if you need to bring it in a little better.
by "throttle body ports connected to canister" do you mean the charcoal canister or vacuum canister?

Ok, so I will check timing again with vacuum  leak. So it seems that's a problem with the idle air screw as mentioned before...

Yes, I mean the charcoal canister.

Ok, I have re-checked the timing...it's about 10 degrees BTDC. I also have recorded the fuel pump at ignition key stage one.

engine running with disconnected power break vacuum hose

fuel pump at turning ignition key stage 1

So with vacuum hose of the power breaks connected it won't start...see here...

Yes...another video...

So, whee should I start to search the error...and how should I connect pin #8, the FPM?

Ok, that's interesting...when pushing the pedal to the floor while starting the engine, it starts...SPOUT disconnected...I think I have read that the injection signal should be interrupted, if throttles are wide open while starting...so it shouldn't start at all...only wipe out the gasoline of the cylinders...or do I have a misunderstanding reading this...

So, if I put the idle screw to the max, it will start...rough...but it starts...all with SPOUT disconnected...


So maybe there is something bent? The counterplate of the idle screw?

TPS problem?
No error from the ECU...

MAP problem?

I don't know where to start...

if it starts and stays running hen that gives you an opportunity to do a couple run tests timing with and without the spout disconnected. measure the return signal from the tps. this can be done without the engine running but key on and adjust the idle screw to the point where the tps return signal is between .5 and 1 volt. I usually set them close to .9v. after that I'm wondering if you are getting proper reading from map sensor. either of these can skew afr/ vac responses.

Ok, I will check the TPS.

About the MAP signal: I think I have to do a KOER test to see if the EEC will give me some errors? Or should this error come up after short idle and stored in the memory?

Have I said that all sensors are new? Also TPS and MAP?

I have forgotten to ask:
May my rich run maybe caused of the missing emission controls? I have removed everything...EGR and all solenoids...maybe, as I've asked before, I need to place some resistors on the regarding pins of the EEC to simulate these components...

Hi again...asking Google brought me to this:

I will try this....

with all emissions removed or disconnected it is very likely that the ecu is "taking roll call and no one is answering back" I am not sure which or if any are required at startup only but if the ecu registers egr as open it will read as a vacuum leak. it may be very necessary for you to fill in the blanks. when opting to delete any item I will usually have them all plugged into the harness and make alterations one at a time testing the results each time. your case may be a good teaching example of "only change one thing at a time"

Very good point Matt
I wouldn't have attempted to do such a build without a proven article.
Sometimes we forget the simple "basic rules" of automotive principles and dive into the electronics.

On another note I was at a shop sitting in the waiting room. A customer approached the service counter to book in their car to be fixed. They disclosed all their info and before they left they made it a point to say that they googled the problem and they knew what was wrong. The service writer immediately said " why don't you get Google to fix it then"!