Lq4 lasted 3 days
Lq4 lasted 3 days I was finishing up my d1sc procharger build on my car and my lq4 has already let go while doing some datalogging. Not even any wide open throttle pulls. I crunk it up today and it has a lot of blow-by at idle. Oil pressure also fluctuates from 40ish to low 30's. Hooked it up to HP Tuners to verify correct pressure but it is not reading at all. It only says -15psi and doesnt move up or down. Like its not reading at all. Pull the plugs on the driver side and the number 7 plug was coated in oil and black. All the other plugs look fine. Worst case scenario, i'll be needing to buy or rebuild the short block. So who is the recommended go to shop for a good short block? I'm thinking of just buying a good 370ci short block to get it back going.
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On The Tree
Joined: Jun 2015
Posts: 182
Likes: 3
From: Portland OR
A complete diagnosis is in order or you may shortly need a second shortblock to replace the second ruined shortblock if the cause is not addressed.
Unless you can prove it was an ignition problem I would flow test the injectors and have a very knowledgeable person look over your tune.
Unless you can prove it was an ignition problem I would flow test the injectors and have a very knowledgeable person look over your tune.
Injectors are new from FIC. Baseline tuning was done by Pat G. all the fuel components are new. Oil pressure is over 40 on the car gauge, but dropped after it warmed up. Dropped to like 30. Hp Tuners will not read the oil pressure though for some odd reason. Now i have so much blow-by coming from the dipstick, valve cover, and valley cover. I'm going to remove the driver head today, if the piston is damaged, i'll be ordering a new short block from thompson. I bought this lq4 as a long block from a salvage yard years ago. First set up it had 243's and cam. Now i just added small bore ls3 heads, and d1sc procharger. Would rebuild this motor myself but after 2 years of not driving it and having the pleasure of feeling "boost" for the first time for a few days, I rather avoid the downtime lol. I actually made ONE WOT pull for about 4 seconds. 12 degrees of timing and slightly rich for now.
Well I just removed the head. The head isnt beat up, few small barely noticeable spots. But yes the ringland is broken at #7.
Last edited by Ws6Dnero; Oct 18, 2015 at 10:01 PM.
not sure. couldnt get a good view. i just held my phone over the cylinder to get this pic. when i lower the car back down, ill take a look. Debating on if i should take the time pulling this motor and building or just buying a short block already built from TMS. after 2 years of the car sitting and building it, i dont think i have the patience to build a motor. I bought this lq4 from a salvage yard years ago. When i removed the heads and pan it had .10 over pistons and fresh cross hatching so it was rebuilt at some point and time.
