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Old 04-04-2004, 11:49 AM   #1
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Default Fuel pressure

As work continues on the resurection of the Bonnie, it has developed a problem where the car must be cranked excessively to start and intermittently idles like crap with the trans in drive and the brake fully depressed. This morning I bought a fuel pressure gague and tested. Here are my findings:

Initial hook up showed 0 PSI. When ignition was turned on the pressure increased to about 8 PSI. Cranking several times, it climbed slowly to 38 PSI and started. The pressure remained steady at 38 PSI through idle increasing to 42 as the engine RPMs were increased quiclky. After turning the ignition off, the pressure went down to 0 within 2 seconds.

The book states that operating pressure is 40-47 PSI

I'm thinking pressure regulator. I wanted to know if this would be the general concensus and if there is any other suspects I should look at.

Thanks

EDIT: When the idle is poor, a light tap of the EGR valve restores the smooth idle. Seems like I have two problems??
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Old 04-04-2004, 01:23 PM   #2
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Or maybe just one problem with the EGR?
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Old 04-04-2004, 02:01 PM   #3
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I'm not sure about your model year but it shouldn't be much different than mine.

I just recently installed a gauge and adjustable regulator.
I checked the stock regulator pressure before I swapped it.
At idle it was 42 psi. If I remove the vacuum line from the regulator, the pressure increaded to 52 psi.
When I turn off the car, the pressure stays up around 40 psi for quite a while and only drops after sitting for a long time.

It was recommende to up the pressure 2 psi for street and 4 psi for race.
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Old 04-04-2004, 02:15 PM   #4
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I just finished replacing the regulator. The pressure remains constant after shutting the engine off now. Around 36 PSI. At idle, it'* at 32 at WOT it'* 42 and with the vacuum line disconnected it'* 42 PSI. The car starts much better now and idles well but that seems a little too low still. I'm going to leave the gauge on for the rest of the day and monitor the pressure to check for bad injectors although the plugs I removed yesterday didn't show any signs.

The engins still idles rough though when it is "lurched" forward or backward. Slapping the EGR valve cures this but the auto parts store didn't have a replacement valve. Is this typically a dealer only part?
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Old 04-04-2004, 04:49 PM   #5
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Those EGRs can be cleaned, too. Sometimes a cleaning/lubrication will do the job instead of replacing the part.
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Old 04-05-2004, 05:58 PM   #6
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Could it be torque converter lockup ?
Could it be TV cable adjustment ?

If your pressure is up now it was the regulator, thats why it started hard. If that happens, you can turn key for a few seconds to cycle pump before starting. The old reg. was leaking off pressure so you didnt have instant pressure at the injectors.

Is there any signs of dirt in regulator ?

what do you mean by learch ? hesitation ?
hesitation can be MAF, MAF is expensive so dont replace anything your not getting code for.

Did you get your breaks bled ?
I like to know how people make out. And what was the cure.
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Old 04-05-2004, 07:27 PM   #7
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Quote:
Originally Posted by Steve LS
Could it be torque converter lockup ?
Could it be TV cable adjustment ?

If your pressure is up now it was the regulator, thats why it started hard. If that happens, you can turn key for a few seconds to cycle pump before starting. The old reg. was leaking off pressure so you didnt have instant pressure at the injectors.

Is there any signs of dirt in regulator ?

what do you mean by learch ? hesitation ?
hesitation can be MAF, MAF is expensive so dont replace anything your not getting code for.

Did you get your breaks bled ?
I like to know how people make out. And what was the cure.
I couldn't find any signs of dirt but the new regulator certainly did the trick. The pressure gauge stays right up there after shut down.
"Lurched" is when you quickly hit the gas and release. "Lunge forward" like you want to pop a wheelie.
It'* ironic that you mention the MAF. I registered the car today and logged about 70 miles. The SES light came on for several miles but eventually turned off. The codes I pulled were 34, 39 and 63. MAF, EGR and something else. The strange thing is that I have not been able to duplicate the poor idle since the SES light turned off.
As far as the brakes are concerned, yes and no is the answer. I'll post a full report on todays activities soon. In a nutshell, they work OK but I had to pull a fuse to make it that way.
Stay tuned!
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Old 04-05-2004, 10:02 PM   #8
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Unhook your battery for a few minutes to clear the codes. Then see what codes you have next time after you light comes on.

Did you bleed them brakes good like I suggested ? I did see later that you mentioned ABS I missed it the first time. They say thats harder to bleed if you start from fresh. That may include after placing new lines. I have ABS on LSS but have yet to tackle and brake work involving ABS. I hate ABS and traction control. No useful value for good driver.
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Old 04-05-2004, 10:50 PM   #9
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Quote:
Originally Posted by Steve LS
No useful value for good driver.
Agree 100%.
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