Back on 4 cylinders,but...

[ga.spyder]

I think my fuel pressure,by the shop manual,is about where it should be.The shop manual says 36 +- not running,and about 30 running.Thats basically what I have.I was hoping it might just be the regulator On the bright side ,I have crossed a lot of stuff off the list.My injectors,and probably the computer are ok.Stan sent me something about the coolant sensor going bad ,and the symptoms being similar to what I am experiencing.The ignition is good.Compression is good.The jury is still out on the fuel pressure/regulator.There is a volume test in the shop manual,which I could do here,and I can test the coolant sensor.
If I had someone nearby to take the car to,it would be on the trailer as we speak.I am running out of ideas.

[Divers]

Craig,

Just take it one step at a time. If you are going to go after the sensors use the troubleshooting guide and go to the ECM connector for your readings.

Remember like I had to........everything that is not it...is just one more thing you have learned about the car. After my pain, I can identify every sensor, nut or bolt on the darn car. Consider it a learning experience and take a deep breath.

Robert

BTW - Put away the lighter and gasoline

[ga.spyder]

A glimmer of light at the end of a loooong,dark tunnel ?? I have been conversing with the only 2 experts that I know,Mark and Brad.It seems that the issue lies somewhere between the tank and the injectors.I went back out and at a suggestion from Mark,pinched the return with the car running.I could hear the rpms rise and smooth out.Hmmmm. So,being the Ga. boy that I am,I broke out my trusty vice grips and pinched the return line about half shut and headed out.The car went up and down the road ,happily hitting 5000 rpm in 1 thru 4,and even accelerating up a hill in 5th.I was trying to get it into crap mode...wouldnt do it! I am wondering if all along it has had a fuel starvation issue?There is enough pressure getting to the fuel rail,but can a regulator let so much out that the rail cant meet demand.Odd,but at least encouraging.The first time in weeks the car has run in anger!!!

[Divers]

If that's it, I would hope one of them has a moment to explain. Even if the regulator failed open I would thing with those skinny steel return lines you would get enough pressure from a good fuel pump to get by. I could see a restriction in the return causing major headaches......


Hmmmmm....learned something new today.

[ga.spyder]

I will keep you posted.I am very hopeful but not entirely convinced either.I am going to change the fuel filter and the pressure regulator and we will see.At least there is some joy in Mudville! There is enough fuel in the rail to keep the car running,just not well.Maybe it is stuck open and just not keeping enough in the rail at full demand?

[Divers]

I tend to trust the both of them....so interested in your outcome.

[ga.spyder]

As do I!! Robert ,thank you so much for your help.The posting and exchange of ideas via the Private Messages is just what I need to keep me motivated.Thanks for taking the time aid a distressed Fiat owner!!!!

[Curly]

I've been following this saga with interest; but knowing nothing about fuel injection, have been unable to offer any assistance. However, I certainly admire your tenacity and perseverance and look forward, as I'm sure you do, to a satisfactory outcome in the near future that doesn't involve an insurance claim.
If she were mine, I'd have retro-fitted twin carbs as soon as it looked like a fueling issue.

[ga.spyder]

Dont think the duals havent crossed my mind,Curly! I am a f.i. guy,but it has been trying me!

[ga.spyder]

Im gonna throw this update out there.Please hit me with any feedback
I drove the car this evening with the fuel pressure guage attached and under my wiper.W/o my redneck press reg(vice grips) the car runs like crap at about 32-34 psi.Rough idle,no power,and wont accelerate past 4K and it takes forever to get there!Clip on the vice grips and the car runs like a raped date.5k and beyond,great acceleration,smooth idle(high idle),etc...Big problem is all this comes at 60 psi on the guage.Obviously something isnt right! Nobody in Ga. would bat a eye at runnin' with vice grips ,but a blown hose is bound to happen,and it just isnt right.Any ideas.I think we have the found the problem ,but what are the steps to properly fix it?

[Divers]

So...

1. Higher pressure means that for the same injector pulse time, more gas goes in. So...infer that the ECM is not sending pulses to the injectors correctly....I believe something comes from the coil to tell the ECM when to fire and for how long the injectors.

Brad or someone else will have to chime in. I just barely have this injector stuff understood.

[So Cal Mark]

I'd still like to see a volume test, pressure isn't the issue it's the amount of fuel

[bradartigue]

I'd still like to see a volume test, pressure isn't the issue it's the amount of fuel

Now come on, pressure isn't relevant? The way these things are made you need adequate fuel pressure to deliver their rated volume. If pressure is low, the output volume is too low, which may force the ECU to leave the injector open longer but at some point (when pressure is too low) the ECU can't keep up with the demand to maintain 14.7:1.

[So Cal Mark]

I didn't say pressure is IRRELEVANT. Craig's pressure ISN"T the issue, and that's what I wrote. Geez, you want to start arguing about semantics? I'm just trying to help the poor guy solve this

[bradartigue]

I didn't say pressure is IRRELEVANT. Craig's pressure ISN"T the issue, and that's what I wrote. Geez, you want to start arguing about semantics? I'm just trying to help the poor guy solve this

Well, you didn't say anything except for him to ignore pressure. Sorry if I didn't read in between the lines.

I have to assume you missed the post where he said he crimps the return line (increasing pressure) and performance stabilizes? If a regulator is bad you'll never generate enough pressure to adequately push the right amount of fuel into the injectors. 30 psi in a 38 psi system is too low to deliver the 145cc/m or whatever FIAT injectors need.