7.4 vortec fuel issue

[Travon]

How much did they charge for the diagnostic? And hey, I'm glad we didn't steer you wrong, though I don't envy you having to test into the intake again.

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Charged $120 to diagnose. Between time and money I can see why most people opt to buy new, but even new or newer have issues.

 

[someotherguy]

Not sure if their fancy tool would have shown any different than simply clamping off the rubber portion of the return line as I've done in the past. I've got a thick, folded piece of flexible plastic I keep in my toolbox for this purpose; vise grips tightened down with the plastic to protect the rubber and just have it on there momentarily to deadhead the pump and see what pressure it can make. Caveman-style but it generally will show you a bad regulator.

Will be interested to see the end result from the dealer; I'd be surprised if that Standard brand regulator was bad out of the box. Anybody can have defects but I felt like they were a pretty trustworthy brand and I've used their parts in the past - including FPR's for Vortec 7.4's.

Richard

 

[Travon]

Not sure if their fancy tool would have shown any different than simply clamping off the rubber portion of the return line as I've done in the past. I've got a thick, folded piece of flexible plastic I keep in my toolbox for this purpose; vise grips tightened down with the plastic to protect the rubber and just have it on there momentarily to deadhead the pump and see what pressure it can make. Caveman-style but it generally will show you a bad regulator.

Will be interested to see the end result from the dealer; I'd be surprised if that Standard brand regulator was bad out of the box. Anybody can have defects but I felt like they were a pretty trustworthy brand and I've used their parts in the past - including FPR's for Vortec 7.4's.

Richard

True. Caveman or not I'm sure would've produced the same results. I would be surprised as well. When searching for a
reliable one I believe it was a recommendation on another thread you gave that prompt my
purchased.

 

[Travon]

ok guys! Well the dealership wasn't able to find anything wrong, so they say.
The only thing they did do that wasn't done was the compression test. Numbers
are..
1-105 2-110
3-105 4-110
5-110 6-100
7-115 8-120

Any thoughts?

 

[RawbDidIt]

ok guys! Well the dealership wasn't able to find anything wrong, so they say.
The only thing they did do that wasn't done was the compression test. Numbers
are..
1-105 2-110
3-105 4-110
5-110 6-100
7-115 8-120

Any thoughts?

You've put in a new reg, and no difference?

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[Schurkey]

ok guys! Well the dealership wasn't able to find anything wrong, so they say.
The only thing they did do that wasn't done was the compression test. Numbers
are..
1-105 2-110
3-105 4-110
5-110 6-100
7-115 8-120

Any thoughts?

Around here, that would be very low. I'd expect a "lazy", low-powered, gas-sucking engine.

In Denver, maybe that's not so bad. The way I remember it, GM spec is 100 psi or more; and within 20% of each other--but I haven't looked that up in a long time 'cause MY specs are much less lenient.

Compression pressure is affected by altitude, cranking speed, cam duration, and about two dozen other factors--INCLUDING defective or inaccurate compression tester gauges.

Since "they" did the compression test, you won't have access to the gauge to verify the accuracy. The easy way to do that is to plug them into a source of compressed air; and see if the compression tester gauge agrees with the gauge on the air compressor regulator. Most compression testers have a quick-coupler that's compatible with Milton "M"-style (Industrial Interchange) compressed air couplers.

Next step might be to perform a cylinder leakdown test.

 

[Travon]

You've put in a new reg, and no difference?

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Yes! Installed a Ac delco one. Psi went up 1lb.
Not really enough improve to justify the work.

 

[Travon]

Around here, that would be very low. I'd expect a "lazy", low-powered, gas-sucking engine.

In Denver, maybe that's not so bad. The way I remember it, GM spec is 100 psi or more; and within 20% of each other--but I haven't looked that up in a long time 'cause MY specs are much less lenient.

Compression pressure is affected by altitude, cranking speed, cam duration, and about two dozen other factors--INCLUDING defective or inaccurate compression tester gauges.

Since "they" did the compression test, you won't have access to the gauge to verify the accuracy. The easy way to do that is to plug them into a source of compressed air; and see if the compression tester gauge agrees with the gauge on the air compressor regulator. Most compression testers have a quick-coupler that's compatible with Milton "M"-style (Industrial Interchange) compressed air couplers.

Next step might be to perform a cylinder leakdown test.

I thought about location as well. I'm in Maryland, don't know if that'll make much
difference. Might do the leak down next
when time permits..