Question for the zetec gurus

[He49]

Hey everyone!

I’m having some running issues with my zetec. Seems to not want to stay running for more than a minute or so and if I give it any throttle it will die. However, if I unplug the throttle position sensor it runs great no issues. I checked it thru the AIM computer that I have and it shows working fine from 0-90 degrees.

I’m not sure what the heck I got going on. Anyone have any insight before I burn this thing to the ground?

[BeerBudgetRacing]

Have you checked fuel pressure?

[He49]

Have you checked fuel pressure?

Yeah, showing about 29lbs. I wonder if my ecu is fried.

[BeerBudgetRacing]

Yeah, showing about 29lbs. I wonder if my ecu is fried.

That isn't enough.

[John LaRue]

Tap in with a manual pressure gauge. If you are using the schrader valve for fuel testing a standard fuel pressure gauge will fit right up. Don’t count out a messed up ECU.

[He49]

Cool sounds good. What is a normal fuel pressure?

[BeerBudgetRacing]

Cool sounds good. What is a normal fuel pressure?

60 psi
Like john said - at the fuel rail. A fuel pressure gauge from an auto parts store has a screw on adapter for the schrader value on the end of the rail. Screw it on, power up the pump.

[He49]

Cool I will try it tomorrow. We got one in the shop here.

[He49]

We’ll the fuel pressure seems to be the culprit. I jury rigged an old one I found in the shop and she runs great.

Need to find out where to buy a diaphragm for the one I got here now.

[BeerBudgetRacing]

We’ll the fuel pressure seems to be the culprit. I jury rigged an old one I found in the shop and she runs great.

Need to find out where to buy a diaphragm for the one I got here now.

I'm not sure it's worth the time to R&R and have it not work....
https://www.primusracingparts.com/Wa...ps_p_1014.html

I've been told you can find for $60 on ebay but I never bothered.

[He49]

Oh cool that sounds good. I think my fuel pressure regulator might be junk too. Have to see where I can find a diaphragm for one of those here.

[DaveW]

A failed diaphragm will raise fuel pressure, not lower it. Fuel behind the diaphragm will fool it into thinking the fuel pressure is low and make it keep raising the actual pressure. So, IMO, it's not the diaphragm causing low pressure. Might be a fuel pump issue or the regulator could be assembled incorrectly - I had that issue once.

[He49]

Fuel pump was toast. I got a new one from summit racing for $80 bucks and car runs better than ever. Why I haven't been checking the fuel pressure I don't know.

Thanks everyone for the help!

[problemchild]

Not directly related to this situation, but everyone running the Zetec engine should be aware, that if the fuel pressure regulator fails, and FP is above a certain threshhold, the ECU reads and displays FP as zero. The engine will continue to start and run, but will run poorly. The assumption will be that the FP sending unit is NFG, but it is the FP regulator that is NFG. Sorry that I cannot recall that threshold value. Perhaps someone else recalls the value (85-90 psi ?).

[ejsprint30]

When I replaced my diaphragm, I made sure to reset pressure at running battery voltage.

[DaveW]

Not directly related to this situation, but everyone running the Zetec engine should be aware, that if the fuel pressure regulator fails, and FP is above a certain threshhold, the ECU reads and displays FP as zero. The engine will continue to start and run, but will run poorly. The assumption will be that the FP sending unit is NFG, but it is the FP regulator that is NFG. Sorry that I cannot recall that threshold value. Perhaps someone else recalls the value (85-90 psi ?).

Related question - did this FP issue occur with a Pectel T2, or with a PE3 ECU? It seems to me that these 2 ECU's might act differently in this situation.

[problemchild]

Related question - did this FP issue occur with a Pectel T2, or with a PE3 ECU? It seems to me that these 2 ECU's might act differently in this situation.

it was the original Pectel ECU.
Non of my technical advisors remembered this, and it turned out to be a very expensive lesson.
I expect the oil pressure (same model sensor) is also configured this way.