02 head gaskets and injectors low power

[mamu]

We bought this 02 1 ton new and she blew the gaskets at about 60k last year. So we put new grade c gaskets with arp studs. Cleaned all cups and put a new set of injectors ( from fuel injection shop that we use for work). Put everything back together and it runs like a sowing machine.

BUT........ This rig is gutless. We run a ppe on it on level 4. Stock trans. Air dog 150 set @ 8.5-9psi. Ppe boost valve. Fuel mileage is still about 12 like it's always been. Fuel rail pressure reads good. Shows about 22-24 psi boost. No smoke unless you really really load it then it might haze a little.

Any ideas where to go first? I'm out of ideas.

 

[Bonestock]

You say fuel psi is really good. How much is really good? You should be around 23000 psi wot on lb7 / lly truck cp3 regulator. If you are commanding 23000 and only able to make 15000 then there is your low power. If you have any way of running a log file like efi live v2 or autocal we can help. Also get a psi tester and pressure your system up to make sure you have no boost leaks. Your turbo can still make 24 psi of boost with a nasty leak.

 

[mamu]

yea the fuel pressure is around 22-23k psi. ill try to get my v2 in it tonight and record some data. we sent the radiator and charge air cooler out to be flowed and tested. everything checked out good but ill check it again. in theory....if i was loosing boost wouldn't it smoke pretty healthy due to more fuel in the air/fuel ratio?

 

[Dmax87]

No codes what so ever? Where are you getting your boost numbers from? Definetly log it and go from there. Hard to diagnose something that sounds like everything is in check.

 

[blk smoke lb7]

Do you have a boost gauge hooked up? What kind of psi is it producing?

 

[mamu]

no boost gauge rite now. i tried to plumb one in from the shop but couldn't find the correct fittings. used my snap-on souls and watched fuel and boost while driving.

fuel
desired 159 mpa
actual 163 mpa

and boost measured 73.8 inhg which i converted to psi and it came out to 36.24 psi.
taking out the 14.4 psi for atmospheric pressure that leaves me at about 21-22 psi of boost.

this was just truck with compressor and welder on bed no trailer. it runs better like this but still not great. when you put a 32' gooseneck behind it empty it kills the power.

1 code logged: p0380 glow plug/heater

 

[mamu]

truck sits like this.

2002 gmc 3500hd ext cab (cab chassis) with skirted bed.
welder and air compressor on bed.
305/70/16 nitro terra grappler on rock star wheels.
ppe on level 3 (i believe) ppe boost valve.
air dog 150
airaid intake straight 4'' exhaust
hg and studs.
new injectors.

truck ran great before we put head gaskets and injectors in it. I'm just looking for some help identifying if my injectors are not that high of quality or if one is bad.


another note!!! in the winter the truck has a hard time starting. we have built the filter base twice just to be sure. most of the time it will crank, bust, die. then you have to kill yourself pumping the bulb/battery charger/cranking even when its plugged up. but the bulb gets hard in say 3-5 pumps every time.

 

[Bonestock]

Leaking air on the low psi side or high psi side. You can crank up the psi @ idle to try and help you find the air / fuel leak.

 

[mamu]

like crank up fuel pressure using the scanner? or air by plugging one side and putting pressure to the other boost tube to check tubes and cac?

 

[mamumtsllc]

What should the return fuel flow rate from each head be?


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[Bonestock]

like crank up fuel pressure using the scanner? or air by plugging one side and putting pressure to the other boost tube to check tubes and cac?

Yes you can use efi or scanner to turn up fuel rail psi @ idle to help find a fuel leak. Also if you are searching for a boost leak if you remove the boost tube coming off the turbo and put a bung fitting with 3/8 air fitting you can hook up an air line and regulator and send 40-50psi thru your intercooler and boost-charge pipes into the engine to try and find a boost leak. This is a must for a poor running truck. Often over looked.

 

[Brent@LDS]

What should the return fuel flow rate from each head be?

12 ml per bank.

 

[durallymax]

Being that the injectors came from "a shop" I would be suspect of those, unless that shop was just a dealer for the GM or Bosch remans. Hard starting and low power along with poor fuel economy are good signs of a bad one.

Ramp the fuel pressure to 160MPa at idle to see if it can hit it. If not, try 2,000. It should hit 160 at idle easily if the CP3 is in good shape and there are no bad injectors.

Then run the return rate test. If you do not know how to do this, search around here a bit or just ask. The return rate test will tell you if you have any injectors with high return rates, a leaking FPRV, or it can help determine a bad CP3 (if max rail pressure cannot be hit at idle and nothing else is leaking).

 

[mamumtsllc]

So I've been scanning the truck with a snap on solos and only checking engine codes. Hooked up efi tonight since I was pulling the race car to the track. Logged some data and checked codes. Found p0100 mass air flow sensor circuit and p0400 EGR system performance both being thrown by the trans.........since when can this happen? This rig don't even have EGR. Cleared codes and it runs better. Still a little laggy in overdrive when you approach a incline. But I'll post some logs tomorrow.


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[mamu]

So I've been scanning the truck with a snap on solos and only checking engine codes. Hooked up efi tonight since I was pulling the race car to the track. Logged some data and checked codes. Found p0100 mass air flow sensor circuit and p0400 EGR system performance both being thrown by the trans.........since when can this happen? This rig don't even have EGR. Cleared codes and it runs better. Still a little laggy in overdrive when you approach a incline. But I'll post some logs tomorrow.


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here are 3 logs and idling/in gear with the injector balance rates. I had to put them in a folder to be able to attach them. I guess I haven't figured out how to attach just a log file. truck runs better until you hit overdrive. then it falls on its face. even empty. I plan to check for boost leaks Monday.

 

[av8or]

So what ever happened with this? In 2010 I changed my HGs to what merchant automotive sells(I think Grade C),Changed all glow plugs (Bosh), new bus bars to connect them and I get a P0380 code now. Mileage is not bad 17- 20 MPG, but it is not the same truck as before the HG got replaced?