How well built are these motors? I ask 'cause this one car I'm debating on buying (90% sure I am) has a misfire.
And apparently has been running like that for a couple of years.
The guy that was the "mechanic" replaced an injector that was easy to get to in the front.
They replaced a coil...
But he said he thinks it's one that's under the intake and they weren't about to do all of that.

I've owned one before... a 1990 and it had misfires but I've replaced injectors... no problems.

My thing is I know certain Nissan motors can't run with an injector that's stuck closed or the rings will get damaged.

Is the vh45 like that... preferably 89-92?

Thanks in advance

to NICO!

As long as it's not flooding, I'd think it would be OK, if you're getting the full story. The big weakness besides injector failures, is the timing chain guides. Otherwise, these engines are rock solid if they haven't been neglected.

Thank you.
I used to own one... and man she was a beauty.
I used to be a member here as well... but yea kinda long story (nothing bad on here lol).

Yea he said he tried to do a compression test but the hose was leaking.
The owner did say he was being honest and not sell a lemon.
AND it looks like they were just throwing parts...
Cause maf was replaced... the "distributor" ... powersteering hose...
The car rides good.
And the engine is quiet.
So yea she gonna need some work but knowing the fact the motor can handle the fact it ran x amount of years with no fuel in a particular cylinder and she'll be fine once I replace injectors gives me great confidence lol

It might be great, but....
The guides are an issue unless you have documentation that they have been retrofitted with the metal backed.
And, as Heath said...how do you know it's a 'no fuel' cylinder vs. a 'dumping fuel' cylinder? The outcomes are night and day different.
Maybe you want to sample/analyse the oil prior to purchase?

3q Jay if it was dumping fuel I'd smell it.
Even at times see smoke. Also the connectors are known to be brittle as well.
So ima order the connectors as well.
And the 300zx tt injectors too...

I'm not trying to talk you out of buying a 1st gen Q45, but you need to be aware that parts support has been dicontinued by Infiniti. Most generic parts are available, but model specific parts are getting hard to source. If you can't find it used online, then the only other option is japanese used parts vendors. These are 25-30 year cars. Unfortunately, they aren't Mercedes or Bentleys, where there a niche market supporting them. I plan on hanging on to mine as long I can, but I know it'll be some part I can't find that forces me to get rid of the car. Part probably costs less than $100, when available.

If it's a easy fix- buy it and drive it till the wheels fall off. My 95 Q45 has been a solid running car, that had issues when I bought it. Turns out it needed a Fuel Pump Control Unit. I found one, and then repaired the original as a spare. You might want to check to see if it a bad FPCU

Cbird805 you didn't talk me out of it.
Lol. I already know what I'm up against. I've owned one before and she was a great car.
I've had quite a few people tell me though about this misfire issue.
So that was a positive.
I plan on replacing the knock sensors as well... anything else since I'm going to have the intake up and off ?

91q45t wrote: ↑

Mon Aug 10, 2020 6:39 am

And the 300zx tt injectors too...

Why would you change injectors to a different flow volume/rate if you are not also remapping your ECU to match?
I do support switching from the VH45DE Mk I injectors to the Mk II. Since you are planning to build yourself an injector harness anyway, just be sure to get the Mk II connectors (thumb snap, vs. the spring wire clip). You'll also need to change your rails. as for doing the knox, good idea. that harness is also no longer available, but you can build one. be sure to use genuine 30P00 knox, that have the JECS and the Hamburger logo. scan the bar code on the bag/box to be sure it codes to the genuine part number---very easy to print fake Nissan Japan parts labels that look the part, but are not. Lotsa counterfeit knox out there.
And then of course hoses while you have the plenum off.
I'd also reseal the valve covers and do new NGK 2x plats.

Hmm good question. So ... how would I go about tuning? Like with a apexi safc?

I feel fairly qualified to answer this question As you read other members response they’re all pretty accurate. As for durability the VH45 is rock solid If yours is like mine 90-93 the timing chain guides must be replaced If they let go your engine could be junk. I’ve been in the slow process of rebuilding mine due to the guides failing. Parts are extremely hard to find. You need to have extreme patience as it’s a slow process. You’ll need time to search for parts and you’ll need to spend much more money than the car is worth. That being said if you’re still interested you’ll have to for the love of the car. If you don’t have maintenance records hit me up I can give you advice. As for the rough idle it could be injector/injectors but those aren’t easy to get to. The entire upper plenum has to be removed to get them. Don’t replace one replace them all. I did this while changing my chains and guides. What makes me Leary is either the mechanic that had it was not very good or he’s not telling you the truth. You need to find a good Japanese import technician that is willing to work on one of these. Getting an engine from Japan is expensive plus you’ll need to reprogram the ECU and that’s a lot of work also.

91q45t wrote: ↑

Tue Nov 17, 2020 12:12 pm

Hmm good question. So ... how would I go about tuning? Like with a apexi safc?

Why would you want to go to the extra effort and cost of installing injectors that aren't correct for the engine, then running a piggyback computer as a bandaid to make it run right? Are you planning on significant power upgrades in the future that will exceed the maximum duty cycle of the stock injectors?

Yea

You can get the ECU re-mapped and tuned with Nistune, but I think it requires the older ECU with the 8 bit chipset. If you google Nistune it should pop up. That's about the only aftermarket tuning for VH45, if you plan on higher flow injectors.

Well I regret to inform you that the motor is no good...
I ordered the injectors but they sent the wrong ones. Luckily the 2 that were bad I was able to pick up locally, rebuilt.

The 3rd one had a bad connector. The car seem to ran fine... had decent take off etc.
Sooo... her fate was met when I went up against a 1st gen jeep srt in mexico.
She did good.
Then came my buddy lexus ls430 she was doing good 1/2 way... then at 120 that's all she had ... in fact she slowed down.
I pulled over immediately and while the rpms were dropping unseen the oil light flicker. And that's when I knew I f*** up.
There was coolant kinda splattered as well.
We let her cool off and once she ran... she was knocking.

I took her to a shop and they said what I did had nothing to do with the motor being blown. He claims the previous owner covered it so well I wouldn't had known till something like this happened.

One of my friends were saying the fact the motor was revving alot the oil wasn't making its way back down fast enough causing starvation and next time to add 8 qts

NO happy to hear this sad news but not sure i understand the particulars..