Engine 1989 LX - Engine Trouble Noise & Rich - Help Appreciated

Romanoski2

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Jan 2, 2019
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Hi Everyone,

Just recently purchased a 89 LX from a guy who did not know much about it and has sat for ~5 years.

My Father and I drained old gas (orange color) and changed the fuel pump. It now has 35-40psi fuel pressure, will turn over, start but run poorly.

We are having two main problems, engine noise (roller rocker arm? Distributor?) and running really rich. Do not think they are related... The car is running so rich our eyes and nose kill after having it run, also the tail pipes are coated with carbon & plugs were very black. Think this was a problem from day one for the guy who we bought the car before, then he just parked it, let sit...

Some details about mods on the car.

Walbro 255LPH fuel pump
Pro-m Mass Air Meter - PFT - 77 - similar to now Pro M 80. says its calibrated for 24lb injectors
EGR block off plate
24LB Fuel Injectors
Comp Cams roller rocker arms (we recently adjusted, couple were loose) - turned motor over until exhaust value started to move, then cranked the motor until the intake almost was returned to the home position, then adjusted the exhaust rocker. Making sure push rod to have zero lash, then turned the nut half turn, lastly tightened the Polly lock.
Ford B303 Cam
Ford shorty headers
Saleen plug wires
New spark plugs
Timing at 10 degree BTC
TPS 1.032V
Idle Air Control should be good, reset it.

Stock A9L computer

KOEO pulling codes: 11 10 15. Did disconnect the battery and connected it to a charger, causing 15?
KOER did not pull any codes... which seemed very odd..??

Have thought of looking into Pro-m & mirco/megasquirt computers. Our gut feeling it does not know how much air/fuel its getting then rich, computer issue. We also think the noise might be a bad rocker arm.

Plan on testing the MAF sensor (voltage & ohms) in near future | https://foxstang.com/complete-efi-sensors-fox-mustang-eec/

Please see the attached sound clip..

Any suggestions or recommendations would be helpful if anyone has had this in the past.
 

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John Dirks Jr

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Jun 28, 2013
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Sounds like valve train noise. Use a section of heater hose or other as stethoscope and try to narrow which valve cover its coming from. Pull the valve cover and start engine. Use hose as stethoscope and narrow down which rocker arm is making the noise. Check for worn parts, bent pushrod, proper adjustment (if applicable) and general valve train geometry.

For the rich condition. Make sure the O2 sensors are in place and all associated wiring is intact with good connections.
 
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jrichker

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Code 15 or 511 - No Keep Alive Memory power to PCM pin 1 or bad PCM (Memory Test Failure).

Revised 4-Jan-2019 to add removing any custom tuning chip for minimum configuration testing.

The voltage to the Keep Alive Memory (KAM) is missing (wiring problem) or the KAM is bad. The KAM holds all of the settings that the computer "learns" as it operates and all the stored error codes that are generated as a result of something malfunctioning while the engine is running. Use a voltmeter to check the voltage to the pin 1 on the computer - you should always have 12 volts. No constant 12 volts = bad wiring. If you do always have the 12 volts, then the KAM may be bad and the computer is faulty. Read on further to make this determination, since there are some exceptions.

Clearing the codes by pressing a button on the scan tool or disconnecting the test jumper used to start the code dump does not erase the “learned settings”. Disconnecting the computer from the wiring harness or disconnecting the battery (either power or ground cable) will erase the “learned settings” If the computer has to "relearn" all the optimum settings every time it powers up, the initial 15-30 minutes of operation may exhibit surges, poor low speed performance, and rough idle.

Note that some aftermarket chips will cause code 15 to set. Disconnect the battery and remove the chip, reconnect the battery and retest. If you have a custom burned chip using the data gathered from a dyno session, this may not be advisable since it may drastically alter the fuel/air and timing tables.
Disconnect the battery negative terminal for the next step.
Remove the passenger side kick panel and examine the computer. It is held in place by a diagonal plastic strap and 2 screws in the strap. The end of the computer opposite the wiring harness may have an accessory PC board with a big chip in a socket. That chip is a custom tune to accommodate the mods that affect fuel /air mixture, ignition timing and emissions equipment. If it is present, remove it and see if the engine runs any better. Remember that the car will need to be driven at highway speeds for at least 15-20 minutes in order for the computer to relearn the adaptive settings.

For stock engines or engines with minor modifications (OEM cylinder heads, stock 19 LB injectors, no NO2 or pressurized induction).
Before replacing the computer, remove the battery ground cable for about 20 minutes. This will clear all the codes and “learned settings”. Retest after several days of running. If the 15 code is gone, then don't worry about it. If it is still there, then you get to do some troubleshooting.

See the following website for some help from Tmoss (diagram designer) & Stang&2
Birds (website host) for help on 88-95 wiring http://www.veryuseful.com/mustang/tech/engine/

Diagram courtesy of Tmoss & Stang&2birds
88-91_5.0_EEC_Wiring_Diagram.gif


http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif

http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif

Disconnect the battery negative terminal for the next step.
Remove the passenger side kick panel and examine the computer. It is held in place by a diagonal plastic strap and 2 screws in the strap. The end of the computer opposite the wiring harness may have an accessory PC board with a big chip in a socket. That chip is a custom tune to accommodate the mods that affect fuel /air mixture, ignition timing and emissions equipment.

If it is present, remove it and see if the engine runs any better. Remember that the car will need to be driven at highway speeds for at least 15-20 minutes in order for the computer to relearn the adaptive settings.
 
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Mustang5L5

i'm familiar with penetration
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I bet there's a chip on the ECU which caused a code 15

Koer should at least generate a code 11. If you didn't get anything I would repeat. If there's anything seriously effecting how the car runs it would be generated here
 
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Romanoski2

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Jan 2, 2019
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Western Wisconsin
Figured out the fuel pressure regulator was bad. It was allowing fuel to be pushed into the upper intake, can check that off the list... Idles like a champ now.

Car still makes a squeaking/chirping noise. Switched the roller rocker arms to the other side and did not follow.

I have uploaded a YouTube video online. View: https://youtu.be/JXYpgpvvMbc


Appreciate all the information, everything is easier the more you do it. Thanks.
 

John Dirks Jr

there is enough sticking out to grab on to
Jun 28, 2013
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Maryland
Sounds like maybe a collapsed lifter. Does it randomly quite down a little then get louder again. If so that might be the lifter pumping up and taking up the slack. Then it bleeds down again allowing valve train slack which makes the tapping louder.
 
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jrichker

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It's stethoscope time...See your local auto parts store or Harbor freight for for one of these... Cost is $4-$11, Harbor Freight is the cheapest