2001 challenger 1800 efi240 does not rev 25mph too speed

[Chia48]

Hi, thanx in advanced!
Just bought boat. Starts fine ides good. Will rev on hose not under load! Previous owners marina mechanic installed new plugs new coils new fuel pumps .fuel filter compression is between 139 and 142 in all cylinders ..
I purchased In line spark testers all 6 cylinders on hose are firing even when I rev engine .. any ideas where to start? Thanx again mike

 

[Tim75]

Hi, thanx in advanced!
Just bought boat. Starts fine ides good. Will rev on hose not under load! Previous owners marina mechanic installed new plugs new coils new fuel pumps .fuel filter compression is between 139 and 142 in all cylinders ..
I purchased In line spark testers all 6 cylinders on hose are firing even when I rev engine .. any ideas where to start? Thanx again mike

What is your fuel pressure? Should be 36psi. Have your injectors ever been serviced? 21 years old. A lot of non-use and ethanol gas. You may have one or more stuck closed. This means that one or more cylinders are not getting any oil. How much time on those new spark plugs? Do some look new and others brown or black? Clean ones point to injectors not working. No combustion.

 

[Chia48]

Hi thanx for the reply. Yes fuel pressure is 36psi. Plugs were just installed I bought boat this way 4 days ago. I did compression test my set today all at 140
Check all wires with in line spark tester today.
When I pulled top plugs on left and right sides .. they seemed dry. So I loosened plug wires. Started boat and pulled each wire off. Engine ideal did not change.
I’m guessing injectors are bad!!
Does anyone know where to buy a set? Thanx

 

[ripcuda]

The injectors can be professionally inspected/cleaned/tuned... which might save them if they are not dead dead. I had mine done at Bucato FIS (brucatofis.com). Only 1 of my 6 couldn't be saved.

 

[Chia48]

Thanx for the info

 

[Tim75]

Thanx for the info

Mercury dealers- local or online, can order them. About $800 per set of 6.

After you get them removed, service shops charge about $25-$30 each, for clean and calibration (matching flow rates).

Most big cities have a fuel injector service shop.

 

[Chia48]

Ok so I’m at a loss… friend has same boat same year .. took the completed fuel injector housing rail Amd Injectors off his running boat Installed it on mine.. same issue 2 top cylinders are dead.. both have 140 psi compression .. pull spark plugs left bolt on started engine .. has awesome spark from plug.
Anyone have any ideas?

 

[ripcuda]

Have you ohm-tested the trigger? 3 trigger-coils on the trigger... each trigger-coil triggers a pair of CDMs (coil packs). On my engine, I had good spark at idle... but under load and as I throttled up... I lost spark to #1 and #4 cylinders (both share same trigger-coil). You might have multi-trigger-coil failures.

 

[Chia48]

Have you ohm-tested the trigger? 3 trigger-coils on the trigger... each trigger-coil triggers a pair of CDMs (coil packs). On my engine, I had good spark at idle... but under load and as I throttled up... I lost spark to #1 and #4 cylinders (both share same trigger-coil). You might have multi-trigger-coil failures.

I’ve done in line spark testers Amd spark is good through throttle range

 

[Chia48]

I think it’s a fuel issue?

 

[Chia48]

I think it’s a fuel issue?

Does the stator or trigger plate control injectors?

 

[Tim75]

Ok so I’m at a loss… friend has same boat same year .. took the completed fuel injector housing rail Amd Injectors off his running boat Installed it on mine.. same issue 2 top cylinders are dead.. both have 140 psi compression .. pull spark plugs left bolt on started engine .. has awesome spark from plug.
Anyone have any ideas?

You have a very good friend that would take apart a good engine for you.

Any spark plug that is clean, is not having combustion and heat. Either no spark or no fuel.
Check the fuel inj. harness. Starboard, down low, thumb size, 4 wires. Clean connections. All ground wires clean. Also each coil has a ground. Any carbon tracking around coils?
Time to swap coils. Known good to bad locations.
The tps can fail and cause a “flooded” condition at idle.
At the air intake- make sure all 4 throttle plates are completely opening.
Check all the bleed system hoses. The small black ones. They are prone to crack and break at the fitting causing vacuum leak. Replace with Tygon hose.

 

[Chia48]

You have a very good friend that would take apart a good engine for you.

Any spark plug that is clean, is not having combustion and heat. Either no spark or no fuel.
Check the fuel inj. harness. Starboard, down low, thumb size, 4 wires. Clean connections. All ground wires clean. Also each coil has a ground. Any carbon tracking around coils?
Time to swap coils. Known good to bad locations.
The tps can fail and cause a “flooded” condition at idle.
At the air intake- make sure all 4 throttle plates are completely opening.
Check all the bleed system hoses. The small black ones. They are prone to crack and break at the fitting causing vacuum leak. Replace with Tygon hose.

All plugs and coils are new. Have inline spark tester showing great spark at all throttle openings
I installed complete fuel injector housing woth all sensors from running boat , just installed new trigger plate today .. cylinders 1 and 2 are not getting fuel ..

 

[Chia48]

All plugs and coils are new. Have inline spark tester showing great spark at all throttle openings
I installed complete fuel injector housing woth all sensors from running boat , just installed new trigger plate today .. cylinders 1 and 2 are not getting fuel ..

All fuel pumps are new as well as filters .. have 36 psi

 

[Tim75]

All fuel pumps are new as well as filters .. have 36 psi

Both manifolds show the same issue. What do they both have in common?
Wiring and control of the injectors. Start at the ecu wiring. Check the inj wiring harness. Unplug and check resistance from common to each other pin. Specs are in the service book. But they should be close to the same. You are checking for any open circuit.

 

[Chia48]

Ok so I tested injector harness .. ohm reader set to 200 scale
Positive on pin 2 from meter and co extend negative to other terminals.
I’m reading 2.2 on each terminal.. book days remove induction manifold And inspect.. what am I looking for?? Thanx again

 

[Tim75]

Ok so I tested injector harness .. ohm reader set to 200 scale
Positive on pin 2 from meter and co extend negative to other terminals.
I’m reading 2.2 on each terminal.. book days remove induction manifold And inspect.. what am I looking for?? Thanx again

Looking for bad connections in ind. man. to each inj.

Possible you have a bad ECU, but unlikely. Check for clean connections in the connector from the ECU (starboard, forward, in a silver bracket). Recheck ohms while gently moving the wires.