Hey there everyone! I am new to the LQ1 community, but I am picking up pretty quickly! I have learned a LOT from the posts on this forum, so kudos to everyone who submits their 2 cents and invaluable information.
I have several issues going on with my '94 Z34, and pretty much I am looking for opinions on where to start. I bought the car about 3 months ago, not knowing anything about it, just knowing that it was a Chevy, and I wanted an American car becuase I was tired of having to track down expensive parts from dealerships for imports. I thought an older Chevy would be fun to work on - as was my previous 3 1967 Chevelles. ** Scratch to the head ** Not even remotely as fun to work on! lol
Performance: To begin, the car has 138,000, unknown to when last timing belt was changed. Idle is slightly high in Park, drops about 200 RPM with a distinct *thud* when engaged into any drive gear. Once in gear and a forward motion begins, it feels as if the car has about 112 to 120 HP (I gauge that by the known HP of my previous import car - the Z did not have any get up and go). The supposed 7 - 8 second 0-60 time is in reality about 35 -40 seconds for me. Once up to about 50-55, the shimmy and shakes, but not always. If I have about 25% throttle at the foot, the shimmy and shakes are very noticeable. If I have 75-100% throttle at the foot at those speeds, the shimmy's downgrade a bit. At 50% throttle, i.e. going up slight hill while maintaining speed, the shimmy shakes aggressively re-appear. If I take my foot off the gas, let RPM drop to 1200 or so, put foot back on gas, throttle climbs back to 2000 or so, almost immediately, and i get a break from the shimmy's for a few seconds.
Problems I have found: Timing belt... I took the covers off, found the ends of the teeth are separating from the belt itself. I can bend the tooth down and away, maybe a good 1/8 - 1/4 inwards, towards the centerline of the belt. I don't think that is good. ** Might be throwing my timing off, want to replace it ASAP **
Fuel Filter - took it off, turned it upside down, brown dirty fuel dripped out. Obvious that it was in dire need to be replaced. Did it.
Plugs - pulled front 3 out, all 3 were different plugs - NGK, Bosch, and Autolite. Mistakenly replaced with 6 Bosch plugs... I know I have read many places on here to get them out of there. I plan on it. Also, replaced the wires with a set from Autozone - I am going to stick with the Taylors that I have read about on here. Also had quite a bit of oil on a few of the old plugs. Excessive oil on at least one. Think that is worn valve guides?
Smoke - Right above the front exhaust manifold, I have oil burning off. I understand the heads need to come off to access the O-Ring on the Oil Pump Drive, but haven't done that. It doesn't seem to be leaking out of there - currently I have the LIM and UIM off, to troubleshoot the oil leak. Does the Oil Pump Drive thingy move during engine operation? It freely spins, and lifts up to the little bracket that holds it down. Can I use a gasket sealant and just seal around the little disc top?
Intake - Troubleshooting steps involved spending my day taking off my manifolds. I found two cracks in the upper intake plenum - guessing that added to my poor performance. I also found 3 vacuum hoses, with the 90* elbows cracking. The hose at the rear underside of the plenum, goes over to the brake booster (possibly) very spongey. Looking at the heads with both intakes off, the coolant passages are almost closed off due to chunky crystalized crap. I scraped some off, and noticed that there are deposits all throughout the cooling system - every hose I took off had crap in it. The inside of the plenum, even tho its cracked and needs replaced, was completely covered in a lot of carbon buildup, looking into the heads i see almost no clean metal - cabon buildup on everything! Valves, walls, everything just looks all built up and gunked up.
Body and interior - was owned by an older lady, so a few slightly visible scratches, but very good paint, good pinstriping, good glass, beautiful interior with slight color degradation due to sunlight - all in all looks really really good. Good enough that I think it is with the hours and dollars to get it running to as near perfect as I can.
So, after that essay - does anyone have any words of encouragement for me? lol
Thanks!
I have several issues going on with my '94 Z34, and pretty much I am looking for opinions on where to start. I bought the car about 3 months ago, not knowing anything about it, just knowing that it was a Chevy, and I wanted an American car becuase I was tired of having to track down expensive parts from dealerships for imports. I thought an older Chevy would be fun to work on - as was my previous 3 1967 Chevelles. ** Scratch to the head ** Not even remotely as fun to work on! lol
Performance: To begin, the car has 138,000, unknown to when last timing belt was changed. Idle is slightly high in Park, drops about 200 RPM with a distinct *thud* when engaged into any drive gear. Once in gear and a forward motion begins, it feels as if the car has about 112 to 120 HP (I gauge that by the known HP of my previous import car - the Z did not have any get up and go). The supposed 7 - 8 second 0-60 time is in reality about 35 -40 seconds for me. Once up to about 50-55, the shimmy and shakes, but not always. If I have about 25% throttle at the foot, the shimmy and shakes are very noticeable. If I have 75-100% throttle at the foot at those speeds, the shimmy's downgrade a bit. At 50% throttle, i.e. going up slight hill while maintaining speed, the shimmy shakes aggressively re-appear. If I take my foot off the gas, let RPM drop to 1200 or so, put foot back on gas, throttle climbs back to 2000 or so, almost immediately, and i get a break from the shimmy's for a few seconds.
Problems I have found: Timing belt... I took the covers off, found the ends of the teeth are separating from the belt itself. I can bend the tooth down and away, maybe a good 1/8 - 1/4 inwards, towards the centerline of the belt. I don't think that is good. ** Might be throwing my timing off, want to replace it ASAP **
Fuel Filter - took it off, turned it upside down, brown dirty fuel dripped out. Obvious that it was in dire need to be replaced. Did it.
Plugs - pulled front 3 out, all 3 were different plugs - NGK, Bosch, and Autolite. Mistakenly replaced with 6 Bosch plugs... I know I have read many places on here to get them out of there. I plan on it. Also, replaced the wires with a set from Autozone - I am going to stick with the Taylors that I have read about on here. Also had quite a bit of oil on a few of the old plugs. Excessive oil on at least one. Think that is worn valve guides?
Smoke - Right above the front exhaust manifold, I have oil burning off. I understand the heads need to come off to access the O-Ring on the Oil Pump Drive, but haven't done that. It doesn't seem to be leaking out of there - currently I have the LIM and UIM off, to troubleshoot the oil leak. Does the Oil Pump Drive thingy move during engine operation? It freely spins, and lifts up to the little bracket that holds it down. Can I use a gasket sealant and just seal around the little disc top?
Intake - Troubleshooting steps involved spending my day taking off my manifolds. I found two cracks in the upper intake plenum - guessing that added to my poor performance. I also found 3 vacuum hoses, with the 90* elbows cracking. The hose at the rear underside of the plenum, goes over to the brake booster (possibly) very spongey. Looking at the heads with both intakes off, the coolant passages are almost closed off due to chunky crystalized crap. I scraped some off, and noticed that there are deposits all throughout the cooling system - every hose I took off had crap in it. The inside of the plenum, even tho its cracked and needs replaced, was completely covered in a lot of carbon buildup, looking into the heads i see almost no clean metal - cabon buildup on everything! Valves, walls, everything just looks all built up and gunked up.
Body and interior - was owned by an older lady, so a few slightly visible scratches, but very good paint, good pinstriping, good glass, beautiful interior with slight color degradation due to sunlight - all in all looks really really good. Good enough that I think it is with the hours and dollars to get it running to as near perfect as I can.
So, after that essay - does anyone have any words of encouragement for me? lol
Thanks!
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