LQ4 Swap Rough running - The 1947 - Present Chevrolet & GMC Truck Message Board Network

billrobbobjo · 06-19-2018, 10:48 PM

I have put a LQ4 6.0 out of an express van into my truck, 1957 chevy. I currently have it running and the motor is bone stock from how GM sold it. I have 2 O2 sensors w/ cherry bombs off the stock exhaust manifolds. I have deleted a few wires out of the harness, stuff that that LT1swap.com said i didnt needed. Long story short the motor will run but once I w/ a load on it, it struggles. I can rev it up to about 3500 rpm. I have check the fuel pressure which I unhook the vacuum and get 55-58 pounds when i hook it back up I have 48 PSI. When i rev it the vacuum pulls the dial around, which seems to work normal. I have swapped the Plugs and wires, I have been messing with the fuel pump and lines these are 3/8 inch. Currently I have the pump in the tank with it free floating. I checked most some injectors w/ a Noid light. All of it seems to work pretty well. When the motor starts to act up it struggles to run it seems to only run on 2 or 4 of the cylinders (slow running/ exhaust feels different when it fires. If it pulls out of the struggle it runs normal again. I havent ever really had the motor moving in this truck before. First week w/ it running. Any tips or advice?

**Captainfab** · 06-20-2018, 12:03 AM

Does the PCM have the stock tune or have you had it modified to fit your needs and deleted connections? FYI, you might get more responses if you have a mod move this to the LSx swap section.

billrobbobjo · 06-20-2018, 08:21 AM

It is a stock tune minus the VATS.

Super73 · 06-29-2018, 05:39 PM

Does it have everything stock? IE manifolds, intake, intake tube, maf, filter box etc?

If not, there is a good chance the ECU is confused and not controlling fuel/timing correctly for the combo

06-19-2018, 10:48 PM	#1
billrobbobjo Registered User Join Date: Nov 2013 Location: St. Cloud/ Alexandria MN Posts: 101	LQ4 Swap Rough running I have put a LQ4 6.0 out of an express van into my truck, 1957 chevy. I currently have it running and the motor is bone stock from how GM sold it. I have 2 O2 sensors w/ cherry bombs off the stock exhaust manifolds. I have deleted a few wires out of the harness, stuff that that LT1swap.com said i didnt needed. Long story short the motor will run but once I w/ a load on it, it struggles. I can rev it up to about 3500 rpm. I have check the fuel pressure which I unhook the vacuum and get 55-58 pounds when i hook it back up I have 48 PSI. When i rev it the vacuum pulls the dial around, which seems to work normal. I have swapped the Plugs and wires, I have been messing with the fuel pump and lines these are 3/8 inch. Currently I have the pump in the tank with it free floating. I checked most some injectors w/ a Noid light. All of it seems to work pretty well. When the motor starts to act up it struggles to run it seems to only run on 2 or 4 of the cylinders (slow running/ exhaust feels different when it fires. If it pulls out of the struggle it runs normal again. I havent ever really had the motor moving in this truck before. First week w/ it running. Any tips or advice? __________________ 1957 Short Box http://67-72chevytrucks.com/vboard/s...d.php?t=671001 1969 GMC 3/4

06-20-2018, 12:03 AM	#2
Captainfab 60-66 Nut Join Date: Mar 2007 Location: Coeur d'Alene, Idaho Posts: 23,252	Re: LQ4 Swap Rough running Does the PCM have the stock tune or have you had it modified to fit your needs and deleted connections? FYI, you might get more responses if you have a mod move this to the LSx swap section. __________________ Power Steering Box Adapter Plates For Sale HERE Power Brake Booster Adapter Brackets For Sale '63-'66 HERE and '67-'72 HERE and '60-'62 HERE and "60-'62 with clutch HERE Rear Disc Brake Brackets For Sale. Impala SS calipers HERE Camaro Calipers HERE D52 Calipers HERE 6 Lug HERE Hydroboost Mounting Plates HERE

06-20-2018, 08:21 AM	#3
billrobbobjo Registered User Join Date: Nov 2013 Location: St. Cloud/ Alexandria MN Posts: 101	Re: LQ4 Swap Rough running It is a stock tune minus the VATS. __________________ 1957 Short Box http://67-72chevytrucks.com/vboard/s...d.php?t=671001 1969 GMC 3/4

06-29-2018, 05:39 PM	#4
Super73 Registered User Join Date: Nov 2007 Location: Bay Area, Ca Posts: 2,841	Re: LQ4 Swap Rough running Does it have everything stock? IE manifolds, intake, intake tube, maf, filter box etc? If not, there is a good chance the ECU is confused and not controlling fuel/timing correctly for the combo __________________ ------Motor---------------Bottle 60'---1.53---------------1.41 1/8---6.58 @ 105.92----5.87 @ 118.41 1/4---10.38 @ 126.97----9.24 @ 142.49



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