Poor idle ONLY when driving

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Jun 22, 2017 | 08:15 AM

#21

JasBass

Thread Starter

Racer

Joined: Jun 2017

Posts: 343

Likes: 18

From: Newport News VA

Quote:

Originally Posted by aklim

Fuel leaks out from the small tear in the diaphragm and goes into the manifold and you get a rich condition. If the ECM can adjust, you don't see it. If not, well....

Yessir. Thanks for all the help man, much appreciated. I'll post an update when everything gets installed.

Jul 3, 2017 | 08:15 PM

#22

JasBass

Thread Starter

Racer

Joined: Jun 2017

Posts: 343

Likes: 18

From: Newport News VA

Well... New FPR diaphragm installed along with new Delco fuel pump and pressure/idle issues persist. Reads 35psi at idle and as it revs, drops down to 30psi and wants to choke out on idle. Don't smell gas in the vac line going to the FPR. After running, Pressure begins to drop quick, about 15 psi in a minute and by 5 minutes pressure is on 10, settles down on about 4-5 at 20 mins. All those readings are with the new regulator and pump. It has a brand new set of rebuilt Bosch D3 32lb injectors from FIC, so I hate to think one of them is leaking. At this point, i'm fresh out of ideas and need some help. I hate to take it down to the local speed shop to get sorted out, but figure one more shake before that happens. Thoughts?

Jul 4, 2017 | 03:50 PM

#23

VikingTrad3r

Oil Producer

Joined: Apr 2014

Posts: 9,372

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Quote:

Originally Posted by JasBass

was the sock replaced? and when is the last time the fuel filter was replaced.

you could blow the lines out towards the fuel filter after its been removed in case you have a blockage.

what happens to fuel pressure after you turn key band pump primes but you do not start.

Jul 4, 2017 | 06:08 PM

#24

JasBass

Thread Starter

Racer

Joined: Jun 2017

Posts: 343

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From: Newport News VA

Quote:

Originally Posted by VikingTrad3r

Has a brand new Delco sock on it that came with the pump. I installed it with a new stainless sending unit since the other steel one was beginning to rust pretty bad. Fuel filter is only a month old with about 20 miles on it (cant get the car sorted enough to actually get some miles on it...). I rented a fuel pressure gauge from O'reilly's but it broke mid test, I think the gauge had some trash in the line that clogged it. It worked and then dropped to zero with the engine still running. Exchanging it for another kit tonight and will do the pinch test tomorrow to isolate the drain down. I hate to think it was a bad FPR diaphragm that I installed, but that seems to be common to get bad diaphragms. Engine will fire decent the first time, but has a long long crank sometimes and will finally stumble on. I have a feeling its a bad FPR diaphragm, we'll see tomorrow. It's not a bad idea to blow out the old lines and replace the rubber ones. Poor thing is an abused barn rescue lol

Jul 17, 2017 | 08:49 PM

#25

JasBass

Thread Starter

Racer

Joined: Jun 2017

Posts: 343

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From: Newport News VA

Fuel pressure issues are resolved. Bought a new FP gauge and between installing a new pump and FPR diaphragm, pressure will hold at 35 on idle, 44 idle with vac line removed. Pressures will rise appropriately on rev and hold steady on constant throttle. Still have some pressure bleed down when I key off, but at least the car runs well and won't stall out under minimal loads.
Thank you all for the time in reading this as well as all the tips you've offered. It is much appreciated

Jul 17, 2017 | 10:52 PM

#26

A Peter C4

Burning Brakes

Joined: Jun 2016

Posts: 761

Likes: 66

From: Fitzwilliam New Hampshire

Why did you install such a high poundage set of injectors ? Sounds like the new injectors are to rich for your engine.

Last edited by A Peter C4; Jul 17, 2017 at 10:55 PM.

Jul 17, 2017 | 11:02 PM

#27

aklim

Team Owner

Joined: Jul 2004

Posts: 28,472

Likes: 3,290

From: Hartford WI

Quote:

Originally Posted by A Peter C4

Why did you install such a high poundage set of injectors ? Sounds like the new injectors are to rich for your engine.

I think he was trying to compensate for the mods but I would think 24pph would have cut it although, if he has it adjusted in his EPROM, would it matter much?

Jul 18, 2017 | 07:10 AM

#28

JasBass

Thread Starter

Racer

Joined: Jun 2017

Posts: 343

Likes: 18

From: Newport News VA

Quote:

Originally Posted by A Peter C4

Why did you install such a high poundage set of injectors ? Sounds like the new injectors are to rich for your engine.

Just like the the above reply, the engine is a 383 build. It's a mild 383 at the moment but I plan on new heads and intake in the near future. It has the PCM flashed for the current configuration and runs clean. Who knows what else I'll throw at it in the future. Just wanted the peace of mind that I had plenty of injector as I progress