Roush 427R engine issue. Troubleshooting..
 

Hi guys,

I just got a car with a new Roush 427r 550hp engine and am having a problem. The car was delivered yesterday and ran AMAZING for the first few hours but then started shutting off under acceleration and had to have it towed. Here is exactly what it did. It would start normally but as soon as you gave it any major gas, it would TOTALLY shut off. It would then be difficult to start for a few minutes then would start and you could drive it for a few 100 yards and it would shut down again. Did this 5 or 6 times trying to get home and eventually it would not start anymore. Thought I burned the starter or killed the battery. Here comes the weird part. Towed the car to the dealer and when they drove it this morning, It ran PERFECT. even dyno tuned it to try to duplicate the problem and were unsuccessful. They did tell me the car is making 450hp at the rear wheels which they said is strong for the 427r engine. Any Suggestions?? Really do not want to get stuck again!!! Could it be the carb? I know I read somewhere that there were issues with the holley setup roush is using. Was thinking of ordering a pro system carb but not sure if that has anything to do with this. Other thought I had was the fuel pump but it has the mechanical pump so the dealer told me that was not going to be it. What else could it be? Anything that would be heat sensitive as it appears the problem happens after the car has been run for awhile...

Thanks for any input...

Ross

don't go buying parts until you identify the problem. its fuel or electrical. start with fuel filter and pump and go from there

It has to be the fuel pump or supply line. You are running out of gas!!! I would check to make sure the fuel filter is installed with the flow in the right direction. Pull your dipstick, is it overfilled? If so does it smell like gasoline, alot of times when a mechanical pump fails it will leak into the crankcase. Yes brand new components fail. It is possilbe the pump is loosing its prime, line kinked, hose kinked, something in the tank blocking the pick up (unlikely since it not directly on the bottom). Next time it stalls out, poor a little gas in the carb and see if it fires, if it does you have a fuel problem not an engine problem. Be very carefull you do not catch the car on fire and stand back from carb when starting!!

It is possilbe if you are using the ford duraspark ignition it could be bad even an MSD, like I said next time it stalls and it will, poor a little gas in the carb if it fires it is fuel if not it is ignition. When it shutdown does it stumble and sputter = fuel, cuts off hard = ignition

450 RWHP equates out to about 520ish Flywheel, as for your problem wht ignition system do you have? Is it mounted in the engine bay or inside the passenger compartment? The underhood temps will effect the system as well as vibration.

If an electronic component is opening up do to heat this would explain why it ran after cooling off at the dealership and fine on the dyno. They dyno'd with hood up and a fan on it right?

I know the dealer checked the filters and pump. As far as the ignition system, I am not sure which one it has as the car is still with the dealer. The engine is a brand new 427R. Any idea as to why it would only have 520 HP at the flywheel? Roush sells it as a dyno proven 550hp. After I get this issue resolved, whats the easiest way to pick up some HP? Anything I can do without voiding the warranty??

Oh, and I was not there when they dynoed it so I have no clue if the hood was off. It only makes sense to me that it has to be some kind of heat issue...

What kind of car is it?

It is a sales pitch they phrase it as up to or something like that.

It depends on the Engine I have the 427SR/TW and it dyno'd on the engine stand at 507 hp and 520tq. They sent me the traditional 550hp ID plate. When I inquired why it differed from the dyno sheet I was told the plates are all the same cookie cutter ones. They don't differ, I asked for one with the right numbers and they accomodated me.

A rule of thumb is a manual tranny is 15% drive train loss so if yo have 450RWHP if you had 530 x .85= 450.5

Doubt you can do anything and not jeapordize the warranty, I know some have put different carb on (larger) for more HP or a different intake.

Another way is to inject it.

What Roush engine number is this? Right on the valve cover there might be a 427R - XXX. The XXX is the engine number. What number is it?

I would sugguest you start with the easiest and cheapest things first. Battery connections, Chassis ground at battery, Power and ground connections at ignition box. If all these items are good, check the charging system. (Contact me if you need info how to do it) Then I would have the battery load tested (free at auto parts shop) and lastly the Ignition Switch.
So many problems like this are loose wiring, or a bad battery or cable.

Sounds like vapor lock. Maybe a fuel line is too close to something hot...

Eric

Not sure on the engine #. The car is in the shop. It is somewherein the mid 700s. Vapor lock sounds like it could be it.. Whats the fix? Different fuel pump??

Depending on where you live, the transition from winter fuel to summer fuel is just starting. Vapor lock would come with a winter fuel when it is warm out or if your fuel is getting overheated in the engine compartment. You don't want to go through this every winter, so if it is vapor lock, you might look for a cooler way to route the fuel line. Is there a heat shield missing? modern day fuel injected engines don't suffer from vapor lock issues.

I live in Miami. Last night was in the 50s so not sure if that's the issue. Whole thing is strange. It has to be either fuel or a short somewhere.

I test drove a 427R that stalled out after about 1 mile. Turns out the mechanical choke was closed. The engine had no choke cable to open or close from the cockpit. A long shot I'll admit

I don't understand. They advertise this engine as 550 hp and it doesn't really have that? It is 5-10% less?

I don't know, but if I paid "X" amount of dollars for a 550 hp engine, it better have VERY close to 550 hp or I would be asking for a few bucks back.

The choke thing sounds pretty good. That happened to me. The screw for the manual choke cable came loose and the choke had closed.

New engine , in the shop . obviously a bug as car/engine not yet sorted out.

Maybe the cause is not Roush but something else, however , you pay big bucks for their engines and they have warranty,,,,,,,,,has anyone called ROUSH ? Bill

Roush makes three versions of the 427, the 427R - 550hp, 427SR - 520hp and, 427 S = 500hp. The difference is in the cams and intakes. You do not want the 550hp 427R sure you get the hP at 5800 rpm's, do you drive around town at 5800 rpms? no you want the SR which is what you have because it gives you low end torque, that is what you feel not horspower. Dyno numbers can also swing 25% based on temp, air density, dyno machine etc

As far as the name plate mine came with the exact dyno numbers, engine number and even installer name.

less than 1% on this forum can manage 400hp, you guys crack me up, I want 600 hp etc, heck get a nascar engine they are 800 hp at 8000 rpms, you would have to drop the clutch everytime you left a light to prevent it from stalling.

I agree with Blas ...start simple then eliminate. I had a similar issue in two seperate circumstances. First was a loose battery cable (if you car has a cutoff switch check those connections too). The second was a failed coil wire...it looked fine until i pulled the terminial...and it was completely off the wire.