signs of a failing fuel pump

[schierholz]

*EDIT PLEASE REFER TO MY LAST POST HERE

Hey
I have my A6 with a A1 intake/plenum (not my idea person before swapped apparently just the block)
My symptoms
Code 43 (fuel supply)
And the Re occurring map sensor code

O2 sensor is just over 6k old (denso)
New fuel filter within this past week
Replaced firewall mounted canister, black box (one the map sensor sits in) (used J. Y parts)
New intake gasket

The car takes two trys to start... but idles normal. Driving and power are all fine (sometimes the check light will come on during movement) and tonight for sure the car out of no where died at a stoplight, restart was fine and the check light stayed off for the rest of the trip
All vacuum lines are good and secure

[EsperHamid]

timing? as for map sensor, maybe you got the vacuum line in the wrong location

[schierholz]

I am now at the point of throwing parts at the car and depressed the car is not very fun anymore with cel's posing up. Heck the car won't even start with a first try of autostart or key in the morning (I had my friend watch my tail pipe with the map sensor CEL shinning bright and he didn't see any smoke)

I have a H23 intake I was going to use but I don't have the plenum to use it.
I havery stripped and cleaned both the idle control peices off it
I have Cleaned my intake and installed a new intake gasket
I have checked over the vacuum lines 3 or 4 times (all of them)
I have tightened my lose throttle cable
I have specific adjusted my idle
I have replaced my fuel filter
I have replaced the fuel charcoal canister (one from a 92 wagon it's a little bigger but it had the A6 as my block is)
I replaced the black idle control box (from the same car)
New oil 400 miles


The symptoms are a code 43 (fuel supply) .... and the not so often but still Map sensor problem. When the car has no CEL or just the 43 it runs and drives fine no power loss nothing.

When I get the map sensor (this is the one that drives me up a wall) nice backfires, if you just try and tap the gas your car dies double tapping the gas allows you to drive really inoying

Spark plugs are coming out black

I've never had such a problem with my white cb
Sometimes even at idle it will just die for no reason what so ever

My only intake mods are
Short ram intake (took a civic intake and cut it short)

I have never had the problem before but I am running the ecu from my white accord which I would imagine is looking for actual A6 action. Should I swap the A4 ecu back in?


I am really trying to figure out if the engine is worth the money of a new timming belt !

I know there is only so much anyone can help on a Web fourm but anything is welcome at the moment

[dj_ender]

I would try the PT3 and see if the problems persist.

[schierholz]

Alright i am still running into my check engine light problem.

still coming up as a code 43

I would blame this on my intake but I did not have the light when I got the car

I replaced the ECU with a A4 which took away it asking for a map sensor code.
I cleaned and replaced my IAC
I have a Duralast Fuel filter
I have checked and keep checking all my vacuum lines, coolant lines
I have tweaked my idle screw in and out to retain 750 rpm at idle
I keep all my fluids topped off
I did a month ago now do a complete clean on my A4 intake with new gasket
I run cheveron gas (highest quality around my area) through my system and ( don't normally) but have drained out my tank twice in the past month
I have checked my spark plugs and wires
I have pulled my 3/4 k old O2 sensor and gave atleast a wipe down and visual inspection
I run 5/30 oil (if that matters)

Performance of the engine is un affected with the light on or off

The symptom is that I can start the car ( which seems a little late * meaning when i use auto start sometime 90% of the time it can start and 10% it cant but a flick of the ignition starts right up but this is only for the first start*) also first start idle starts at 1k
I can sit and rev it and drive it around but when i go a CONSTANT speed it will throw the code.

Where can I go from here any more ideas completely welcome

[Losiracer2]

try swapping in a different main relay.

[RyanD]

The 2 tries to start in my case was caused by a failed check valve in my fuel pump whjch would cause the fuel in the line to bleed back to the tank.

When you start the car next put it through 2 priming cycles before you crank. If it starts right away then its the check valve.

Fuel pumps usually work or they dont. However, they do tend to get noisy before they quit.

Also for your code. Try replacing the fuel regulator

[JDMDriver]

Spark plugs are coming out black

This is what's making me think it is a combustion issue not a fuel pump or fuel supply issue.

If it is intermittent fuel supply issue then the burn should be fine. However this to me is not a fuel supply issue. As air is not a problem (since you have changed your air sensor and I am sure you would have checked your air filter and any restrictions) then I would think it is an electrical problem.

Combustion = air, fuel and electricity

Sometimes even at idle it will just die for no reason what so ever

This further supports my thinking it is an electrical problem as mechanical failure is usually not instantaneous. But electrical problems are since electricity is either on or off and a disruption in the flow results in total cut out.

I have had an engine "cut out" problem on me in the past and it was due to a faulty ignitor. Perhaps this is a coil problem also which can give the other symptoms you have mentioned like back firing and starting problems.

Suggestion
-----------

Replace your distributor with a JY distributor or a friends working distributor. You must know it is working to make sure you are not diagnosing with a faulty part, it would throw a monkey wrench in the works.

Believe me I have experienced inadvertently being given a dud part and came full circle (with much angst, frustration, time, money and effort) only to find out my method was right but the stupid replacement part was faulty and had me chasing ghosts, shadows, phantoms and banging my mind trying to find another fault having wrongly ruled out the part itself that WAS the fault (incorrectly placing my faith the new part or supposedly tested second had part from the JY was working) .

[RyanD]

^i have a question

black spark plugs indicate a rich burn condition

now, wouldn't a bad fuel pressure regulator cause it to run richer then it should which would also explain the code 43?

[schierholz]

I think I have a new problem I am not very happy with. The first start up was fine 1k as always I got through my neighborhood streets fine, hit the strait away I have its about a 45/50 mph area upon driving the car out of the blue it just decided to lose a lot of engine power and tapping the gas was my only solution to get to where I was going, idle was fine at the lights and initial take off from a stop was fine ..... these problems mostly appear during constant speed increments.... but the check engine light did not show with this problem but once it came on it ran fine no power loss or anything

I will try a new distributor tomorrow I have a working one on hand I may be going to check the fuel regulator next

[RyanD]

reset the ecu by pulling the neg cable and post up what happens. i think i know what the problem is

[JDMDriver]

^i have a question

black spark plugs indicate a rich burn condition

now, wouldn't a bad fuel pressure regulator cause it to run richer then it should which would also explain the code 43?

It could be the cause but a failing distributor (with its many parts) in my opinion has more probability of failure than a fuel pressure regulator.

As parts are so cheap in the JY and the parts themselves so easily accessible in the engine bay with not much work to it, I think grabbing both and doing a diagnostic replace and check is really not a big deal.

[schierholz]

I have reset the Ecu plenty of times and there is no change. as I think I said it run's the same with the light on or off. I may try cleaning my O2 sensor once again and giving a diffren't distributor a try because now i'm just down to the injectors, the fuel regulator, the distributor and the fuel pump itself I have gone through and replaced or cleaned everything on the intake to get rid of that and my timming is just 2 degrees off mark.

You may be onto something with the distributor going. it seems to take about 5 to 7 cranks for the engine to start and It only starts at 1,000 rpm gets to maybe 1.3 then goes back down.

( I know don't compare apples to apples) but I know my last cb started at 1.5k and as it warmed up the Rpm dropped down ( I figure this is more normal for the car)