What's the worst damage a blown fuel pump can do
09-12-2012, 01:08 AM
#1
2nd Gear
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What's the worst damage a blown fuel pump can do
What's the worst damage a blown fuel pump can do?
I have 90k km 2005 987 2.7L
It lost power & went into limp home mode on the weekend & then stalled once the revs were low enough as I approached a junction.
I had towed to a well known & respected Indy who said it was a blown fuel pump.
Fuel pump replaced and the car still wont start.
They now say that I need to replace all my plugs as they've been destroyed & that fuel flooded the whole shebang causing the failures.
What I want to know is at worse, what will a blown fuel pump do the engine?
How will it effect the heads? What sequence of events from the pump failure to head damage occurred?
I'm not hugely mechanically minded but to my mind, wouldn't the fuel filter catch the debris if the pump grenaded itself? Wouldn't the techs have spotted the fact that the heads were iffy whilst diagnosing the problems in the first place?
I've gone from a $500 replacement fuel pump to a potential head rebuild & not too happy.
Your thoughts & opinions requested!
.
I have 90k km 2005 987 2.7L
It lost power & went into limp home mode on the weekend & then stalled once the revs were low enough as I approached a junction.
I had towed to a well known & respected Indy who said it was a blown fuel pump.
Fuel pump replaced and the car still wont start.
They now say that I need to replace all my plugs as they've been destroyed & that fuel flooded the whole shebang causing the failures.
What I want to know is at worse, what will a blown fuel pump do the engine?
How will it effect the heads? What sequence of events from the pump failure to head damage occurred?
I'm not hugely mechanically minded but to my mind, wouldn't the fuel filter catch the debris if the pump grenaded itself? Wouldn't the techs have spotted the fact that the heads were iffy whilst diagnosing the problems in the first place?
I've gone from a $500 replacement fuel pump to a potential head rebuild & not too happy.
Your thoughts & opinions requested!
.
09-12-2012, 12:04 PM
#2
Drifting
Worst that could happen is your car runs lean at high RPM, and detonates, putting holes in your pistons. It shouldn't have flooded anything (that would be an injector problem, or a lack of ignition), but running lean can burn the electrodes off of your spark plugs. It won't hurt to pull the plugs and see what they look like.
09-12-2012, 05:30 PM
#3
Race Director
What's the worst damage a blown fuel pump can do?
I have 90k km 2005 987 2.7L
It lost power & went into limp home mode on the weekend & then stalled once the revs were low enough as I approached a junction.
I had towed to a well known & respected Indy who said it was a blown fuel pump.
Fuel pump replaced and the car still wont start.
They now say that I need to replace all my plugs as they've been destroyed & that fuel flooded the whole shebang causing the failures.
What I want to know is at worse, what will a blown fuel pump do the engine?
How will it effect the heads? What sequence of events from the pump failure to head damage occurred?
I'm not hugely mechanically minded but to my mind, wouldn't the fuel filter catch the debris if the pump grenaded itself? Wouldn't the techs have spotted the fact that the heads were iffy whilst diagnosing the problems in the first place?
I've gone from a $500 replacement fuel pump to a potential head rebuild & not too happy.
Your thoughts & opinions requested!
.
I have 90k km 2005 987 2.7L
It lost power & went into limp home mode on the weekend & then stalled once the revs were low enough as I approached a junction.
I had towed to a well known & respected Indy who said it was a blown fuel pump.
Fuel pump replaced and the car still wont start.
They now say that I need to replace all my plugs as they've been destroyed & that fuel flooded the whole shebang causing the failures.
What I want to know is at worse, what will a blown fuel pump do the engine?
How will it effect the heads? What sequence of events from the pump failure to head damage occurred?
I'm not hugely mechanically minded but to my mind, wouldn't the fuel filter catch the debris if the pump grenaded itself? Wouldn't the techs have spotted the fact that the heads were iffy whilst diagnosing the problems in the first place?
I've gone from a $500 replacement fuel pump to a potential head rebuild & not too happy.
Your thoughts & opinions requested!
.
If the plugs are due to be changed you can certainly have them changed/replaced. Be sure you get the old plugs for pics and post here for comment.
But I also think you might want to consider having this work done at another shop.
While a failing fuel pump can deliver less fuel and fuel pressure than the DME (engine controller) expects for this less than ideal fuel supply to do any damage to the engine is while possible is very rare. I think were this to be the case with your car you'd be the first case I have come across.
Limp mode can arise from excessive engine coolant temp, bad MAF, something amiss with the E-Gas, a Tip acting up to name a few.
Are any warning lights on? Is the CEL on? Was it on? What were the error codes read?
Added: I reread your post, and I have to add that if the pump actually came apart -- I've never heard of this happening (they just stop running) it can have put debris in the fuel lines.
Assuming the fuel filter was before the pump -- as is the case with my 02 Boxster -- this debris could block fuel flow through the lines assuming the pump was still able to deliver any fuel at all, which is unlikely as the pump is in pieces.
IIRC the fuel injector is "protected" by small fine mesh screen that traps any small particles that could make it past the fuel filter and plug up the fuel injector holes or cause wear/damage to the fuel injector pintle.
Was there any debris coming from the fuel pump lines? Did the tech who replaced the fuel pump see any pump debris in the tank or even inside the fuel pump enclosure? The pump -- at least in the case of my 02 Boxster is a beer can sized housing of heavy alum. that sits in a larger plastic box and which pulls gas through a fine plastic mesh (the "fuel filter"). While there can be trash caught in the mesh, outside of the mesh, inside there should be nothing.
If the fuel filter is located after the pump this of course should have caught any trash a "blown" fuel pump generated.
Sincerely,
Macster.
09-15-2012, 02:54 PM
#4
2nd Gear
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Thanks for your replies.
From the time the engine lst power to it cutting out, there were no CEL's at all.
I now know a little bit more about what's going but still don't know the exact cause of the failure.
Firstly, the shop admitted the fuel pump was misdiagnosed.
Second, compression tests showed low compression on the left bank of cylinders.
Third, hand turning the engine, they could feel it tighten & catch, then loosen u again during the rotation.
Fourth, the cam timing is out.
This sounds to them like a bent or stuck open valve, causing the engine to flood with fuel.
They're almost certain that it's not an IMS failure, but still want to drop out the engine the case to investigate. Sounds reasonable I guess, but now I'd rather use another shop, who has better M96 knowledge, to get a second opinion.
What do you guys think?
.
From the time the engine lst power to it cutting out, there were no CEL's at all.
I now know a little bit more about what's going but still don't know the exact cause of the failure.
Firstly, the shop admitted the fuel pump was misdiagnosed.
Second, compression tests showed low compression on the left bank of cylinders.
Third, hand turning the engine, they could feel it tighten & catch, then loosen u again during the rotation.
Fourth, the cam timing is out.
This sounds to them like a bent or stuck open valve, causing the engine to flood with fuel.
They're almost certain that it's not an IMS failure, but still want to drop out the engine the case to investigate. Sounds reasonable I guess, but now I'd rather use another shop, who has better M96 knowledge, to get a second opinion.
What do you guys think?
.
09-16-2012, 03:18 AM
#5
Race Director
Thanks for your replies.
From the time the engine lst power to it cutting out, there were no CEL's at all.
I now know a little bit more about what's going but still don't know the exact cause of the failure.
Firstly, the shop admitted the fuel pump was misdiagnosed.
Second, compression tests showed low compression on the left bank of cylinders.
Third, hand turning the engine, they could feel it tighten & catch, then loosen u again during the rotation.
Fourth, the cam timing is out.
This sounds to them like a bent or stuck open valve, causing the engine to flood with fuel.
They're almost certain that it's not an IMS failure, but still want to drop out the engine the case to investigate. Sounds reasonable I guess, but now I'd rather use another shop, who has better M96 knowledge, to get a second opinion.
What do you guys think?
.
From the time the engine lst power to it cutting out, there were no CEL's at all.
I now know a little bit more about what's going but still don't know the exact cause of the failure.
Firstly, the shop admitted the fuel pump was misdiagnosed.
Second, compression tests showed low compression on the left bank of cylinders.
Third, hand turning the engine, they could feel it tighten & catch, then loosen u again during the rotation.
Fourth, the cam timing is out.
This sounds to them like a bent or stuck open valve, causing the engine to flood with fuel.
They're almost certain that it's not an IMS failure, but still want to drop out the engine the case to investigate. Sounds reasonable I guess, but now I'd rather use another shop, who has better M96 knowledge, to get a second opinion.
What do you guys think?
.
Anytime there's apparent interference when turning over an engine that's serious.
Cam timing out is a smoking gun, to state the obvious. A cam chain tensioner has lost its tension, or a cam chain guide/rail has come apart and allowed too much chain slack and a cam chain has jumped a tooth or two. FWIW I do not think a cam chain has failed. If the cams weren't spinning you'd not be able to turn the engine over.
Anyhow there is some interference with the valves and pistons. It is not bad -- it could be worse -- in that the interference appears to have been just enough to bend some valves. Had it been much worse one or more valve heads would have come apart and then the engine would have suffered fatal damage.
If I'm right then the less the engine is turned over save by hand the better. At some point the valves that are contacting a piston can come apart and then the engine will no longer turn over. If this condition is ignored the forces generated by the valve on top of the piston solidly contacting the head can crack heads, blocks, bend/break rods, crank.
With the potential for serious extremely serious engine trouble getting another opinion is good. A problem is often the seriousness of what is wrong s not something that can be determined from outside the engine.
In your case the engine probably needs to be partially torn down and the problem id'd and an appraisal of the engine's basic suitability to fix made.
It may be the engine is just not a good rebuild candidate.
The engine almost certainly has to come ouf the car.
A complication is if the engine is removed at some shop that is the shop that probably ought to do the work.
You can't be having one shop remove/tear down the engine, then haul the pieces over to another shop for its analysis.
So, you probably ought to figure out to which shop you are going to entrust any repairs, engine replacement -- if it comes to that -- going forward and get the car there and let things move forward.
Sincerely,
Macster.
