SVT motor with 0psi fuel pressure reading

[hairball29]

Hi, folks

 

My 2005 SVT motor'd car runs well, except when it doesn't. When i first got it, it had jerky power delivery and a tendency to be hard to start. I traced it to a perished plug on the throttle body causing a vacuum leak. replacing that made it run much better and i thought all was well.

 

The last couple of days it's been hard to start again, sometime's when it's cold, sometimes when hot and not consistent. It will take about 4 goes to get it started but so far it does start eventually. Once running it's ok, but something's up.

 

I've notice on the live data on my scanner that the fuel pressure is 0psi at idle. My understanding is that this car runs a return-less system and that a fuel pressure sensor is important in that it reports to the PCM, so i'm wondering if this is a factor in my problem.

 

I also cannot hear a fuel pump running when the ignition is on. I can't believe it's not running else the car surely wouldn't start?

 

Does anyone know what their fuel pressure reading is at idle for comparison?

 

 

Thanks in advance.

Edited September 24, 2017 by hairball29

[Kitcat]

Cant answer, but my '03 Cat with the SVT went thru 3 fuel pumps in the first 1000 miles(It was 10 years old when I bought it). My mechanic finally converted it to a return fuel system and added a much bigger fuel pump which solved the problem. All done per suggestion of an occasional poster here, TurboTom, a SVT guru.

[hairball29]

Thanks, Kitcat, I'll keep that in mind.

 

Today I got under the car whilst my wife put on the ignition and I could hear the fuel pump run briefly. I also changed the fuel pressure switch and found pressure in the rail. The change made no difference so it seems that that 0psi reading is perhaps not related to my setup.

 

whilst i was in the mood, i changed the coil pack but i still get the odd slow-to-start problem. In fairness, the car has done only about 170 miles since 2012 so when I finally get plates, i'll take it on a longer drive, feed it some injector cleaner, and see what shakes out. Currently i'm only able to take it round the block. One unrelated thing I've noticed about these cars is that they really get a lot of attention! I should have expected it, but i'm new here

 

Thanks again

[1turbofocus]

If you have the stock SVT ECU I would recommend getting the SCT XCAL4 Flasher I sell and my Custom Tune , With the Flasher and logging I can help track down any issues with the sensors , see what there reading and either Tune any issues or help you track down issue

 

You get the XCAL4 , Full Custom Tune , Free Tune updates as you add more NA mods , shipped for 462.00 , there are not many people that know the SVT engine and ECU/PCM like I do

 

There is a log of scanners out there that dont read the SVT Black Oak ECU/PCM properly

 

Tom

[Kitcat]

To add some detail to my post: After replacing the 3rd fuel pump we discovered a low compression problem, so did a top end rebuild. And the nature of the damage (burned valves) suggested it was due to a too-lean A/F mix. So we added a much bigger fuel pump. When the car went onto the dyno, the A/F ratios still went waaay too lean over 4500 rpm. Without the dyno data we wouldn't have otherwise known. So that's when we took T Tom's advice and went to a return fuel system and that solved the too lean problem at higher RPMs. We also added a A/F ratio gauge on the dash and I keep an eye on it on the track-it has been rock sold for the last year.

BTW-we purchased/used T Tom's above-mentioned scanner/custom tune system wh/was very helpful, as was taping into his considerable knowledge of the SVT and its ECU.

And a final point: yes, when you drive a se7en, you are never alone:).

Edited September 25, 2017 by Kitcat

[breezy7]

Do you have access to an OBDII scanner? Behind the dash in the area of the steering column should be a OBDII connector. See if you have any codes displayed on the scanner. There are two more components in your fuel delivery system, the fuel pump control module located under the transmission tunnel arm rest. The PCM varies the operating cycle of the fuel pump through the control module based on the signal it gets from the fuel pressure sensor in the fuel rail. The inertia switch is involved too, it powers the fuel pump control module.

[hairball29]

Thanks, guys

 

That's all interesting information. Tom and I have been in contact. I'm waiting for the car back from the mechanic's to see what issues he finds.

 

As a note, i changed the fuel pressure sensor on the car at the weekend and nothing really changed in terms of PSI reading on my scanner, but when it failed to start this morning for a minute or so, it appears to have logged a code pertaining to fuel pressure sensor high output (that's from memory as i only saw it briefly at the mechanic's place) so perhaps the pump is not performing as well as it might, or perhaps something's up with the FPCM as Breezy points out.

 

Thanks again