5.0gi PEFS stalls and deceleration

Galvez83

Petty Officer 1st Class
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Oct 31, 2019
Messages
242
Guys maybe someone can point in the right direction. The issue i am having is stalling and deseleration on a new 5.7 that replaced my old 5.0gi. Evrything else is the same cept the engine. The engine has new evrything, if you name it is new. Engine shakes at idle to the point of moving the serpentine belt off the raw water pump tracks. I had several "mechanics" over and everyone wants to toss parts at it. I need some guidance as to what to look at and maybe track down the issue. Today i replaced the spark plug and wires ....again and no change. Did another compression check all cylinders above 145 to 160. Here is a list of the new parts for your enjoyment.

Distributor with cap and rotor
Spark plugs and wires
Ignition coil
Risers and manifolds
TPS
IAC Valve (2x, one from amazon then a mechanic stated that i might be bad so i ordered one from ACDelco and still no change. When i unplug the sensor the engine has no audible or physical change)
Temp sensor
Knock sensor
Oil pressure sender
Fuel pump (10 low, 30 high, both tested constant no drop)
Fuel filter
Oil Filter
Power steering pump
Circulation pump
TBI rebuilt kit
ECM recalibrated for 5.7

Fuel injectors where sent out to be cleaned and flow tested and are working fine. I am sure i am forgetting misc parts but you get the jist of it. Any ideas what could be causing the issue?
 

QBhoy

Fleet Admiral
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Mar 10, 2016
Messages
8,286
Does it always run rough at idle ? Just also wondering about the ecu compatibility from 5.0 to 5.7. See you mention it was recalibrated. I wasn’t aware that could be done or possible. Could be wrong though. How’s the engine alignment and mounts ?
 

Galvez83

Petty Officer 1st Class
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Oct 31, 2019
Messages
242
Idle seems to be running ok after several attempts at starting. When it starts by giving it throttle engine shakes or vibrates. Engine was aligned and drive installed by a shop because of previous misalignment upon engine intall. Once engine starts you very slowly throttle past 2000 rpms it "tends" (and i say that loosely) to stay at that given rpm. Anything below 1500 engine will decelerate and sometimes shut off. All of this on muffs. Engine has still not been broken in due to not wanting to take it out and really mess it up.
 
Last edited:

Galvez83

Petty Officer 1st Class
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Oct 31, 2019
Messages
242
I got someone to look at it and hook up a computer. Even IF it gets resolved i see a carburator in my future. Several people have sugested this due to poor reliability of TBI. Any thoughts?
 

alldodge

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Mar 8, 2009
Messages
40,583
What I hear
The 5.0 ran fine with no issues, replaced with 5.7 and not it doesn't

TBI and pressure stays at 30 psi
Shake at idle, wants to stall, needs to get above 2K rpm to smooth out some

Incorrect firing order, timing
EST dizzy, base base timing mode used to set timing?

Injectors not supplying correct amount of fuel (said they were cleaned and flowed). Who and how were the injectors tested?

Which plugs are installed?
VP 3851857, Champion RS12YC, AC MR43LTS
 

Galvez83

Petty Officer 1st Class
Joined
Oct 31, 2019
Messages
242
What I hear
The 5.0 ran fine with no issues, replaced with 5.7 and not it doesn't

TBI and pressure stays at 30 psi
Shake at idle, wants to stall, needs to get above 2K rpm to smooth out some

Incorrect firing order, timing
EST dizzy, base base timing mode used to set timing?

Injectors not supplying correct amount of fuel (said they were cleaned and flowed). Who and how were the injectors tested?

Which plugs are installed?
VP 3851857, Champion RS12YC, AC MR43LTS
The boat was bought with the 5.0 locked solid, i got a cheap deal out of it. Timing was set from what i saw by non base. Then i came along after a back and forth with who did it and did the timing as per volvo. Paper clip jumping at dtc with a timing light and got 8 btdc, engine still rough. I took the injectors to a local place that does that and they cleaned and flow tested them, supposedly. Plugs are mr43lts gap at 45.
 

alldodge

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Mar 8, 2009
Messages
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Everything can be checked, timing, firing order, etc except injectors. If everything checks the only thing left is injectors.

Injectors can provide more or less then needed fuel. Unless the tester knows how much should be released per time period then all they can say is they started here and ended here after cleaning
 

Galvez83

Petty Officer 1st Class
Joined
Oct 31, 2019
Messages
242
Everything can be checked, timing, firing order, etc except injectors. If everything checks the only thing left is injectors.

Injectors can provide more or less then needed fuel. Unless the tester knows how much should be released per time period then all they can say is they started here and ended here after cleaning
To be honest this had been a real pain in the ***. Really considering the swap to carb.
 

alldodge

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Engine shakes at idle to the point of moving the serpentine belt off the raw water pump

Lets go back to the motor. Was the motor bought as a complete "new/reman" long block or something else?

I'd like to see the motor shaking, or at least some still pics?

Use a straight edge on crank pulley and see if it aligns with the others. No matter how it shakes it should not loose the belt. The motor shakes as a unit
 

Galvez83

Petty Officer 1st Class
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Oct 31, 2019
Messages
242
Yes motor was bought reman long block. I will return with updates as i have an appt to drop the boat off today to have ECM scanned and/or to swap to carb. I will have the mechanic go from top to bottom with a fine tooth comb. If its something simple with the TBI such as timing or a sensor or other small detail TBI will stay. Will report back with findings. I will also ask the mechanic to inspect valves, pushrods and any internal to determine if it is being caused by something internally.
 

Galvez83

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Oct 31, 2019
Messages
242
Here is a close up of the first time the engine was fired up. The video does not do it justice as now after being installed it is more prevalent. I dropped the boat off at the mechanic today and after a brief view by the mechanic i stated that there is also a noise upon start up after being off for a day or so. Not present after repeated start ups. We started the boat so he could see. The mechanic said he heard the noise from underneath. Of course he would have to look deeper but the noise upon start up after being off, "coming from underneath the engine" and the wobble at the harmonic balancer sent the devil up my spine. Now im hearing things like, rod knock, thrust bearing, and bad crankshaft.

The power of Christ compells me!!!
 

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Galvez83

Petty Officer 1st Class
Joined
Oct 31, 2019
Messages
242
Update, crank is bent
 

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