[L.Ol.II]

Yo dude, sorry to hear about your tuning woes. Sounds to me like you have something electrical going on, most likely power or ground. If you don't have one I would recommend getting your hands on a factory wiring diagram, link below will get you one. I would be interested to see what your 12v and 5v reference are doing from various ground points as the motor heats up. Back probing the terminal would be the way to go into the connectors so that you can leave everything plugged in as the motor is running. As the temp increases so does resistance in an electrical circuit. Sensors that are going bad can cause some issues once they get some heat into them. Terminal fretting could also cause some funky things, you typically see it more in your airbag system since those modules are all monitored for resistance but it can still cause issues with engine management. A simple unplug and plug back in will usually resolve the issue, do not use dielectric grease. Do this to your pcm connectors and take apart and clean the ground closest to the pcm. Properly grounding your car will do wonders for performance. Another slight possibility would be pin fitment but this typically causes a hard fault. Fluke has a couple good articles that cover automotive electrical diagnostics that might be helpful..

Hope this helps, Lars

Automotive Industry Electrical Resources & Solutions

Learn how to identify voltage drops and avoid replacing parts that are not bad, spot and solve bad grounds before they destroy the electronic control unit (ECU), and remain safe when working with high-voltage hybrid vehicles.

www.fluke.com

2004 Ford Focus Wiring Diagram Manual Original

www.faxonautoliterature.com

 

[1turbofocus]

Not much is more annoying than waiting weeks upon weeks for tune updates or even a revised baseline tune while the car sits in the garage, fully assembled and not drivable lol.

Why are you waiting weeks upon weeks for an update to your Tune , 90% of the time I get my Customers Tunes back to them with in 24 Hrs , Thats insane waiting weeks

Tom

 

[euro-bred]

Just can't figure it out and I'm really really thinking it's tuning related. After replacing the MAF, changing the oil, and improving the engine and battery to chassis grounds, I now have a halfway decent cold start idle. A/F bounces between 13.5 to 15.5 but the average is stoich. Better than making my oil smell like gas. It's still really cold out but not arctic cold. It takes about 10 minutes to get the engine hot. My low speed fan is 196f and high speed is 206f. Once the engine temp reaches 205f, it goes completely lean. I'm thinking either the bosch wideband sensor is malfunctioning, it is located too close to the turbine housing and overheating, or once it switches to closed loop it gets starved of fuel. I'm at a stopping point and have to decide which route I'm going to go next.

 

[euro-bred]

I just did a little research on when it's supposed to switch to closed loop and apparently it does it within a minute after starting. I thought it was only temperature based at 205f or something. I'm not sure what triggers it to switch from open loop to closed loop, but at idle it seems to do alright. Not perfect, but a good starting point. The fact that it goes lean when the engine is nice and hot is now making me think that the wideband sensor is faulty. I have an extra one so I will put it on and let it get hot and see what happens.

I think the ultra rich problem I was having was due to a bad tune dumping fuel and saturated my oil. The fumes from the oil was making the O2 sensor think it was rich and when the car got hot, it showed lean. Now that I changed the oil, it's near stoich but still goes lean when hot. It even seems to drive smoothly, but obviously it's too risky to push it hard. I'll update when I swap the wideband sensor tonight.

 

[euro-bred]

I might have gotten it! Out of grasps of desperation I removed the 5 downpipe bolts, cleaned the mating surface thinking there might be a leak that could be causing the lean condition. I re-torqued them in sequence and started the car up. It immediately went to full lean and stayed there. I drove the car to see how it reacted under load and it didn't budge from max lean. The weird thing was that it drove very smoothly.

At this point it could only mean one thing since the afr keeps going lean. My wideband sensor. I changed it out after the car cooled off then I wrapped the harness in heat wrap. The old one was solid black with carbon. Fired up the car and at stayed stoich! Took it out for another drive and the afr responded well with load. It went max rich with anything more than half throttle but the afr would bounce back to ~14.7. I was able to safely play with boost a little and it pulls really hard! No knocking and smooth across the board.

I got back home after about 15 miles of driving and let it idle for a few minutes and the afr stayed where I needed to. Obviously it needs more tuning but now that I can monitor the air/fuel ratio I can start the real datalogging.

Here is the wideband sensor. You can see how dirty it was. No wonder it failed. I should have changed it weeks ago.

 

[Blokhead]

Isn't there a procedure to calibrate it?

 

[euro-bred]

There is something about calibration in the instructions but I can't make any sense of it. It's working with the new sensor though.

 

[Blokhead]

Hmmmm, my NTK AFX you just take it out of the exhaust and power it for a minute, hit the right button, and its done.

 

[euro-bred]

The tune is looking good so far. I did a wide open throttle pull earlier and the boost is exhilarating to say the least! Right now it's very rich over half throttle, so that will be addressed with the next tune. I felt safe enough to push it in second gear as well and I was surprised that the tires broke grip and spun at 50 mph. He is still going to add in some timing, so it's only going to get more fun.

I was talking to Raffi at fswerks and the plan is that my next tank of gas I will fill up with 93 octane and we will finish tuning with that and turn up the boost a little. This summer I will get some dyno time in and find out my power curves with the 2.5 intake manifold and probably tune with that for more power. The pistons are not a limiting factor but I want to stay under 400 hp just to be on the safe side. I think 14 to 15 lbs of boost should put me close to 350. Right now I'm at 12 lbs with the 2.3 intake manifold with tumble flaps. I'm probably close to, but not over, 300 hp.

 

[euro-bred]

Oh no... Bad news. Apparently my fuel pump is losing pressure at wide open throttle, which means my pump is at the end of its life. It drops down to 10 psi which can't keep up with the demand.

I guess I will try this: How to cut a fuel pump access panel/door.

I need to check the lines first and the filter is a year old. Being that the pump is original and has over 220k miles, it's likely that it's at the end of its life. Sucksssss. So close!

 

[euro-bred]

Decided against cutting the hole to access the fuel pump for now. I might still do it but I want the tank out first. Speaking of which, I did that today! What a pain that is... And it's a 1/4 full of 91 octane. I don't want 91 anymore so I might drain it and put 5 gal of 93 in after I put it all back together. Anyway, next I have to clean up the top of the tank and remove the pump then shove in the new one.

 

[euro-bred]

Got the new pump in and reinstalled the tank. I was short on time so I didn't cut a batch for the fuel pump on the inside of the car. I got all the 91 octane out of the tank and tomorrow I'm going to put 93 in it and tune with that. Crossing my fingers that fuel pressure will be more consistent!

 

[euro-bred]

Alright, I got it all put back together, filled it with 93 octane, then did a datalog. At WOT, 3rd gear, 2000-4500 rpm it has around 34 psi of fuel pressure. After 4500 it drops down to about 24 psi and as predicted the air fuel ratio starts to go lean.

Shouldn't I have more fuel pressure than that after 4500 rpm? When I let off the throttle, it spikes up to 70 psi, so I know the pump is doing its job. The fuel filter has around 5,000 miles, but I don't know what else it could be. I guess I'll change it out for a new one. I don't know what else to do. This whole thing has been a headache.

 

[1turbofocus]

Have him raise the fuel psi in the Tune , The PSI is controlled by the PCM

Tom

 

[euro-bred]

I will definitely mention that to him, Tom. Thank you very much.