Dream Car - But now a big problem. Please help.

[PhysicZ32]

OK, so a few weeks back I purchased a 1990 2+2 300ZX with a TT engine. The car had seemed to be running perfect other than a few things that I thought could be easily fixed. I notice a little idle issue - car would shake just a little when idling. Then sometimes it felt like I was loosing power here and there, nothing drastic but noticeable. Since the car wouldn't pass emissions because it had the Catalytic converters removed, so I when into a local shop to get some estimates, while I was there I had them do a compression test. Two cylinders have low compression. He didnt give me the numbers just that I had two cylinders that would having issues. I was told that this is most likely because of damaged values, or possibly something wrong with the piston rings. I am having a full all out diagnostic this thursday - $300. Since I get they have to remove the top of the engine to see for sure what the problem is. If its the valves its looking like a $3000 fix. If its the rings he said I would probably be better off replacing the engine. I don't know a lot about engines and everything so any advice would be greatly appreciated. I was also told that one of my turbos is leaking. A couple people told me that this could be causing most of the issues. But could that in any possible way cause low compression on two cylinders? I got a good deal on the car and the body/transmission/clutch all seem to be in excellent condition. I think the reason I got it for so cheap was because the guy knew something major was wrong. Anyways would it be better just to replace the entire engine? I have looked on line and looks like I could get the one I want for a little over $2200. Installation of it would be close to $2000. What are your guys experience with replacing valves? I was told that if the timing belt was messed up for awhile this could be what caused the damaged values.

I have wanted this car my whole life, I knew it was going to have some issues but not like this. I would have to take out a loan to fix the valves, so I was thinking since its only around $2000 more for the whole engine that I should just do that. If I go that route where would you guys suggest I get it from? I more or less would be happy with the same engine type I have now. After I get this major issue fixed I want to completely restore everything else. I love this car! I could sale it right now and get more than what I paid but I really want to keep this one because besides this its great, All new interior/Brand new Clutch/Excellent Exterior and rims and tires. I am so lost on what to do, I have never had a car that had issues like this. I am not very mechanically inclined. Sorry for the long post, just wanted to provide as much info I could so I could get some help. Thank you SOOOO mcuh!!

[Ace2cool]

I'd take that money and put it into the engine you already have.

Also, you're throwing money away paying that much for a full diagnostic, if your only worry is the low compression. I have a much easier way to isolate if it's pistons or valves. If you can replace spark plugs, you can do a compression test.

Isolate which cylinders have low compression, then put a tablespoon of motor oil in the spark plug tube. If the compression goes up, it's the rings. If not, most likely culprit is valves.

Do that first, and save yourself some money. May be more cost effective to rebuild what you already have.

[BlackWidowZ]

+1 on rebuilding what you have and doing diagnostics yourself. For the price they are asking lol you could get your own consult pretty much.

[PhysicZ32]

I will give that compresion test idea a try. If it does turn out to be the rings would you guys suggest just replacing the engine? I have seen several for sale for $1200 - $2000 that have between 40,000 and 60,000, I guess the have some weird law in Japan. I found a shop that wil install the motor for $1200. The reason I am just considering the swaping out the engine is that I have been told by several mechanics that if the time belt get messed up and the person just keeps driving it can damage more than just the valves. Im flippin sick over this, I absolutly love this car it actually runs excellent most of the time. For some reason every once in a while it just feels like the motor is having a hell of a hard time. Also maybe this symptom will give you guys an idea of what the actual problem may be. If I am constantly accelerating the car has no issue. That is when I am accelerating fairly quickly. The problem seems to only happen when I am maintaining a constant speen ie, just barely touching the gas pedel.

If I do end up deciding to replace the motor have any of you had any experiance purchacing one off eBay? There seem to be some pretty damm good deals, some even come with the transmission. My car has about 140,000 original miles and about 20,000 on the motor that is in it now. I've taken it to a few places to see if I am getting the same diagnosis from differant mechanics. They have all told me that who ever replaced the motor did a half assed job. Just by looking at the engine you can see things like electrical tape around the tops of the spark plug connectors. The engine itself is very clean and the pipes are in great shape. Just the little things that add up like missing screws here and there make me think it may have been done by someone with not much knowlege of installing an engine

[t.mcginley.jr]

Don't have time to read your whole post right now, but I got my 90 NA for $1600 so don't let prices scare you too bad. And $3000 for valves?! And don't buy the stuff off ebay, they are Japanese Domestic Market (JDM) engines that have been shipped from Japan. They are usually hit or miss, with mostly misses. Meaning that they usually come with problems already, like poor compression. You are better off either picking up a good used USDM engine from someone or having yours rebuild. If you just want it running then find a good used engine and have a shop drop it in.

[nissanfreak12]

Take it somewhere else. Period. If you cannot do the test yourself, take it to a shop that regularly works on Z, and that knows how. These cars can be finicky. If the mechanics says the timing belt was messed up for a while it could damage the valves, run. Don't go back. Let us know what you find out.

[schwar74]

Either you misunderstood the mechanic, or he's full of crap. You can't "keep driving the car" with a broken timing belt. The motor won't run. If it breaks, it can/will ruin the motor, and then its dead, but its all at once.

Get a second opinion.

Scott

[PhysicZ32]

So I ended up taking my 90 2+2 TT to a performance shop, they did the compression test and said there is nothing even close to a problem. He did say that I was having a piston misfire and that it was most likely electrical. I spoke to him about ten last night and he said he already had it running much smoother. Kinda make me wonder if that other place just f*** up, or were straight up trying to f*** me out of several grand. So Now it looks like I will have my issue taken care of within a day or two, and only for a couple hundred. I noticed that my Z has an upgraded ECU, it has 370 circled. So two more questions, I heard you can flash the ECU your self, or have someone like these performance guys do it and it can make a major difference it several aspects, Any thoughts? Even Possible? I ended up learning that my Z has about $6000-$7000 in upgrades, Engine, Clutch, ECU, Intercoolers, But They showed me I am still using the Stock air intake, I've been reading about Pop Chargers? Would that be the next logical step in stepping my Z's horses up? Or is there something you thing I could better spend around $1000? Interiors almost perfect, very very little body damage. I hooked it up with quite the system already, Ended up getting two Ten inch Audiobahn 1000Watt Woofers and upgraded the previous 6 1/12 and what ever the hell size that was supposed to be in the back. 1000 watt RMS JL Audio amp powering it all. So, Pop Chargers? ECU Flashing? I do think I am going to take about $300 or so and replace every electrical cable I can see that even looks a little suspicious. Found complete replacements online for $280-$350 depending on how good of shape the electrical crap is. eBay seems to have just about the same s*** as everyone else, but a little cheaper, Anyone have any bad experiences through eBay, concerning Z32 parts? As for the pop charger which one do I want? I also think I should replace all my fuel ijectors with the after market ones, this shop said they could do it for pretty cheap, also would upgrading PIVOT Turbo Timer do anything? Also, Im sure this shop will have it figured out, but could the Mass flow air sensor cause the engine to run to rich or too lean??? Guess , I went off there a little, just excited that its not messed up valves or piston rings. More than a couple questions, thanks guys!!!!

[PhysicZ32]

Will someone please tell me what type of fuel injectors I need to buy. My mechanic said that the last owner who upgraded my z32 1990 2+2 to a stage 4 turbo and put an upgraded chip in, however he did not upgrade the fuel injectors. I not positive what year my engine is and how to know which ones I need. Can someone tell me real quick? I dont want to mess up and order the wrong thing. He ended up getting it running flipping awesome for now though. He said I need to replace the injectors ASAP, he said that he more or less had to shock the crap out of two of them to get them to spray. How do I determine what fuel injectors I need? My ECU says "Z1 ECU UpgradeTT/5Speed/370/91Octane/Single, then it has info on the spark plugs, which one that I am supposed to use. But nothing about the fuel injectors unless the 370 that is circles signifies that I need a 370cc Fuel injector, Please help!

[schwar74]

The 370 does mean you need 370 cc injectors in order for you to use the same ECU. However, if you're looking to upgrade to more power, you could put larger injectors in, but you'd need a new EPROM chip for your ECU. You should be able to just buy a new chip and drop it in the ECU. I think they're around $150. From what I've read, the injector size should approximate the horsepower your looking for. If you're wanting more horsepower than stock, then you need bigger injectors. Also, if the injectors you have are the old style, then they should be upgraded to the new style. This takes an adaptor kit for the fuel rail, new injectors, and new plugs that get soldered on the original wiring harness. The old style plugs are square and have a wire retaining clip. The retainer on the new style injector plug is integrated into the plastic.

Scott