'94 Q45t engine seizes 2 weeks after injector replacement

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task
Posts: 2
Joined: Tue Sep 13, 2022 9:12 pm
Car: 1994 Infiniti Q45t
1989 Honda Prelude SI 4WS
Location: Seattle

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Ayo,

I guess I got a Q45 project now?

quick back story - 2009ish moms took her '94 Q45t into shop for injector replacement. she drove it for 2 weeks after, seemingly fine. one morning however she describes, right after initial rev up maybe 1-2 sec, a loud clank and the car lunges forward and dies. tries to start it, no response. she ends up parking it on the side of the house and moves on. fast forward to couple months ago, car needs to be moved, so it comes to me.


reason for this post, to try and get peoples input on two things;
1. what do you think happened? & 2. what's the best way to get this car rollin' again?


1. - main reason I'm making this post tbh. I'm puzzled at how she could of driven for 2 weeks if something serious had fallen down into the intakes. maybe completely separate problem? wanna check timing chain. cams appear to be timed. I've currently got the intakes off, so I understand the lay out. if a bolt or something heavy had fallen in during the injector swap, that s*** woulda been sucked in almost immediately. I'd also assume I'd see it caught in a valve or cylinder/piston.
now I could see how an oily O-ring might take some time to migrate to the valves. I didn't see anything caught in the intake valves, can't see the exhaust yet. would an injector o-ring really cause catastrophic failure? since I've got the time, figure I try and solve the mystery. need to rent the proper gear pulley but then I should have the timing chain covers off. then work my way down to the cylinders. tryna do this with the engine in the car, hahaa.


2. - new engine from donor or swap? if I can find a cheap donor i'd assume just a replacement vh45de would be easiest? but those aren't supported much if at all anymore from what I've read. Vk45de maybe?


'preciate your time and any responses. have a dope day


fontana dan
Posts: 218
Joined: Tue Jun 21, 2022 11:10 pm
Car: 1997 Infiniti Q45
Location: Tennessee, USA

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If it were my car I would probably take the spark plugs out and borescope the cylinders looking for any signs of debris in there.
If no debris found, remove engine from car and disassemble, look for signs of oil starvation or broken timing chain.

task
Posts: 2
Joined: Tue Sep 13, 2022 9:12 pm
Car: 1994 Infiniti Q45t
1989 Honda Prelude SI 4WS
Location: Seattle

Post

@fontana dan, whatup man. Yeah I was gonna do that initially but once I figured I was gonna either be throwin' it out or tearin' it down it seemed pointless.
as far as oil starvation, I'll research oil starvation sign and see what I can find. engine hasn't ran in a decade so the rockers are dry but there's residue. dipstick shows proper levels.
can't see all of the timing chain yet. need to get the timing covers off, but what I can see is still tight.
thanks for the input dude!

User avatar
Q451990
Moderator
Posts: 11472
Joined: Tue Jul 23, 2002 8:21 am
Car: 1990 Q45 - 118K, 2022 Toyota 4 Runner, 2004 Frontier M/T - 108K, 2012 Xterra (Mom's), 2023 Rogue (Inlaws)
Location: Columbia, SC
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Maybe hydrolocked due to a failed lower o-ring on an injector? It's possible that it got pinched or partially cut during installation, but didn't fail catastrophically for a couple of weeks.

Ryantzer
Posts: 205
Joined: Sun Aug 11, 2013 5:37 pm
Car: 1990 Infiniti Q45
Location: Phoenix, AZ

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First things first, does the engine turn over by hand?

If it turns over by hand, will it crank with the starter?

If it cranks with the starter, does it start?

maxnix
Posts: 22628
Joined: Mon Jul 22, 2002 8:11 pm
Car: 1995 Infiniti Q45
1995 Infiniti Q45t
2000 Infiniti Q45

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Yeah, I had my injectors cleaned and replaced by a service and unknown to me had a bad O ring pinched in the rail. The servicer never checked the either rail after assembling it.


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