[jacobnbr1]

[jacobnbr1]

What is the name and model of that alarm? (That alarm isn’t doing a better job than the factory system does) I posted a diagram above.

[jacobnbr1]

No I already checked for remote mounted driver, that car don’t have that system.

Yes you are reading it right pnk/blk and blk.

Look at that diagram and look at all the voltage stops along the way and where ever there is a component there is a potential for a voltage drop starting at the fuse box feed to the fuse.

It only requires battery source voltage from the output of the fuse so if you confirm the 6.65 volts at the pump, change over to the ground wire side and run the test lead from battery positive to the fuel pump ground and if it reads 12.4 (or whatever source voltage is) then the ground is perfect but the problem is in the positive side circuit of the vehicle harness.

You can move on from there and test the voltage drop at the output of the inertia switch, relay, fuse and if you have 6.65 there, then the problem is in between that component and the pump connector.

Let me know if you don’t understand and I will break it down for you.

I mean lets make an example…

The battery for the available source for what it is of say 12.5 with the fuel pump energized (fuel pump prime, key on engine off) so we leave the battery with 12.5 and go to fuse f16 utilizing a protection of 20 amps(and still having 12.5) following that wire to the fuel pump relay and exiting (still having 12.5) then on to the s138 splice(still having 12.5) then passing through the crash safety feature inertia switch exiting with (6.65) and continuing to the pump connector (with only 6.65). In this example the inertia switch is causing the voltage drop because we should transfer the full 12.5 to the pump with the pump energized(fuel pump prime, key on engine off) but can’t because say the windshield leaks water into the cabin and down the A piller into the switch causing corrosion and a bad connection. (true story on an f series truck)

[jacobnbr1]

Here is an update on this topic.

Friday after the ‘Guess’ and after the fuel pump (400.00) was installed the vehicle still had 17lbs of fuel pressure and would hardly run so I once again pointed to the 26 step diagnostic flow sheet and walked away.

Tuesday the tech just really hasn’t a clue where to go with this thing and dreaded the thought of the flow sheet, takes another suggestion from a buddy that works in another shop and decides to replace the remote mount fuel pump driver (cost 105.00) to no avail the truck still runs like poop. The tech then stated he thought the converters were clogged. (Holy cow dude, Based on what evidence?)

Today I came in and told him to do nothing but watch me perform the diagnostic flow sheet armed with nothing more than the factory flow sheet and on step 3 I had already confirmed the health of the other components that he thought were bad and on step 5 I found the evidence I was looking for, and that evidence was that the injection rail pressure sensor reads 65 psi when the mechanical gauge reads 17psi and the flow sheet says if the reading from the sensor is inconsistent with mechanical pressure to replace the fuel rail pressure sensor (87.00).

Bingo!!! Truck came alive and pressure came up to spec.

Problem solved and I had less than two hours troubleshoot to repair.
The pcm thought the fuel pump was delivering 65psi of pressure and reduced the flow output to retract the pressure but in actual it was reducing the pressure where the engine would starve for fuel.

Glad it is fixed but this dude seriously needs to get with the program and do his due diligence!

[jacobnbr1]

6.65? Was the battery dead or weak? Let me see something… Nope! This car does not have an external pump driver and should be battery voltage of whatever the battery storage is minus the load itself.

You should have battery voltage meaning if you check the battery and it has 12.4 your pump voltage should be the same or close to it. 1/2 a volt less is the start of a problem somewhere.
Make sure you run a test lead directly from the battery to the tester (make sure the lead is good as well) so if you are checking the pos side of the pump circuit then you need to run your lead from the negative side of the battery post thus checking the pos voltage and so on for the ground side.

Note: take a reading from the battery alone with the pump energized and note that voltage reading as it is, and when you check the pump circuit it should be close to the battery voltage.

I do this test all the time without doing the voltage drop thing but I have the trained eye to determine if a voltage drop should be performed.

I have commonly seen after market alarms with immobilizer systems cause this very issue as they normally interrupt the fuel pump circuit and now the immobilizer alarm box now becomes part of the circuit.(They suck)

[jacobnbr1]

Check the neck of the radiator for a broken tab or distorted flange. Make sure the engine isn’t overheating and full of coolant. (if ok see below)

You need to perform a block test to confirm you are not getting combustion gasses into the coolant chamber via a head gasket, cracked head etc.

Those gasses will cause additional pressure causing the pressure to exceed the limits of the cap.

You can get a block test kit at NAPA for about 20.00 usd and follow the instructions on the box it is real easy to do just don’t let any antifreeze mix with the test fluid as it will not complete the test.

[jacobnbr1]

+1 the cams could line up but you still need to confirm the crank is lined at top dead center at the same time the cams are. Recheck the plug wires are in the correct distributor cap holes and not advanced one hole forward or backwards

[jacobnbr1]

I will post an update when this case study is over.

All I can say at this point is the guess was wrong and the problem is very much still alive.

There has been chaos in the shop and and the appointment schedule is way off track due to this event.

[jacobnbr1]

+1 the cams could line up but you still need to confirm the crank is lined at top dead center at the same time the cams are. Recheck the plug wires are in the correct distributor cap holes and not advanced one hole forward or backwards

[jacobnbr1]

First, remove the instrument cluster and locate the Red wire in the Blue connector. With the lights on back-probe and ground the Red wire, the dash light should light up bright. If the dash lights work, verify that the Red/Black wire in the same connector has battery voltage, with the lights on, and that the Black wire has a good ground. If all tests are OK, it is the function of the CPU in the cluster to vary the ground on the Red wire so the dash light would operate.
Find out if an aftermarket stereo has been installed. The CPU might have gotten damaged during installation.

[jacobnbr1]

You need to perform a voltage drop test on the circuits as follows:

Fuel System Troubleshooting and Electrical ChecksThe ProblemFuel system repairs are often performed without proper diagnosis, leading to unneeded parts and the inconvenience of doing a complex repair that does not fix the vehicle problem.
The SolutionBasic fuel system troubleshooting and diagnosis can be accomplished with a digital voltmeter and some knowledge of vehicle electrical systems. This bulletin provides some guidelines for system electrical tests.
System Components to Check FirstIf the vehicle will not start, check the following:

[jacobnbr1]

Hey Dude, Can you oblige us with the engine size, year,make and model for what you are working on?

[jacobnbr1]

1. Jump the 2-cavity connector in the right kick panel area and see if the “S” light will flash any codes. The wire colors in the connector are Orange/Red (ORN/RED) and Green/White (GRN/WHT).

2. If there are no codes, unplug a transmission solenoid and see if it will set a code. If it does not, try removing the battery cable and resetting the memory of the Transmission Control Module (TCM).

3. Next, check the powers and ground to the TCM, and if those are OK, open the covers on the control unit and look for a burnt circuit board. If the circuit board is burnt, verify the resistance of the TCM solenoids.
Check the key switch and brake switch input. See if the park nuetral input to the control unit is good. Energize the wire that controls the shift lock solenoid to make sure it will operate.

[jacobnbr1]

The lash is most definitely adjustable and you shouldn’t need shims (see below for the how to)
INSPECTION

HINT: Inspect and adjust the valve clearance when the engine is cold.

1. DISCONNECT PS RESERVOIR
2. REMOVE CYLINDER HEAD COVER

• [li]Disconnect these cables and hoses:

[/li]

• [ul]
  [li]Accelerator cable from throttle body
• Accelerator cable from clamp on intake manifold
• Accelerator cable from clamp on generator bracket
• A/T throttle control cable from throttle body
• Positive Crankcase Ventilation (PCV) hose from air cleaner hose
• PCV hose from intake manifold

[/li][/ul]

• [li]Disconnect the high-tension cords from the spark plugs.
• Remove the 2 bolts, and disconnect the accelerator cable bracket from the intake manifold.

[/li]

• [li]Disconnect the engine wire protector from the 2 mounting bolts of the No.2 timing belt cover in the sequence shown.

[/li]

• [li]Remove the 4 nuts, grommets, cylinder head cover and gasket.

[/li]

HINT: Arrange the grommets in the correct order, so that they can be reinstalled into their original positions. This minimizes any possibility of oil leakage due to reuse of the grommets in different positions.

1. SET NO.1 CYLINDER TO TDC/COMPRESSION

[ul]

[jacobnbr1]

I would tear down and re-check the mechanical timing belt to confirm it is in time cause to me it sounds like your off a tooth.
You can actually have a good timing signal with a light but still be out a tooth somewhere.

[Author]

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