So this is a continuation of my last post concerning replacing an ECU. I have two cylinders on the right bank that are constantly firing and causing raw gas to come out of the tailpipe. The engine was just replaced. I also got all new injectors via VH Performance. Before the engine was replaced this was a current problem I had when I acquired the car. Does this sound like an ECU problem?

Might be blown injector drivers in the ECU, but a wiring issue is much more likely since they're both in the same bank. Was there any harness-swapping or modification done as part of the replacement?

The original engine had this problem when I bought the car last year I’ve done no modifications and don’t believe the last owner did either. I’m not sure about the harness if it was swapped from the old engine or if the one used is from the replacement engine. I’ll find out and report back.

With the same problem between engines, it's a decent bet the harness was the issue all along. Check the signal wires on the two flooding cylinders for a short to ground

Thank you. I will and I'll let you know what happens

Did your new injectors come with new o-rings and pintle caps? Did you upgrade from Mk I to Mk II injectors? I know you are working with and therefore somewhat at the mercy of your mechanic, PLEASE--emphasise that this engine is susceptible to hyrdolock (yeah, I suppose all are....but hydrolock has killed multiple VH45DEs). Might also consider doing a leakdown test of the fuel pressure (bad injector seat/leaky o-ring). if the harness checks out ok.

Yes the technician and I are aware of hydrolock so being very cautious. I'm not sure about the style of the injectors but due to the fact this happened in the previous engine with the old injectors I would think it's more of a wiring, harness or ECU issue But I'm open to all help and suggestions and I pass them all down Ethel mechanic

The usual injector flooding cause is a pinched or bad lower o-rings. Ideally, you'd do all of the diagnostics in the factory service manual, checking wire continuity etc. In your case, where you're paying for the work it might be cheaper to try another ECU like this one on ebay for $32 shipped or best offer. It's the correct part number for a 91 with non active suspension without traction control.

https://www.ebay.com/itm/363025945175?e ... Sw0~de7OZP

What sensors (if any) were moved from the old engine to the new one?

Wow thank you for all your help. You’re awesome. I was waiting for the tech to get me the ECU part number so I could search it. For $32 I’ll just buy that one on eBay I’ve been reading the service manual all afternoon to see what I could find. I’ll have him check all the wiring like you suggest then try the replacement ECU. Thanks again truly appreciate your help.

Q451990 wrote: ↑

Sun May 23, 2021 3:31 pm

What sensors (if any) were moved from the old engine to the new one?

Since it had exactly the same issue before the swap, things like injector o's aren't likely unless the old rail was swapped over wholesale without service or inspection. In general, the problem has to be something preserved from the original engine.

I agree

Follow up. It was a bad ECU causing the two injectors to constantly fire and dump raw fuel into the cylinders which was why I had raw gas pouring out of the tailpipe. He also feels that was the ultimate demise for the motor by gas dumping into the cylinder and causing it to eventually hydro lock. New ECU installed and engine running and no fuel coming out of the tailpipe.

Thanks for letting us know, and I'm glad you got it fixed!

Glad you are up and running properly. First "blown" ECU I've heard of on these cars, but shows sometimes things way down on the fault tree can't be ruled out minus the troubleshooting data.
Is driving the G50 now as you remember from 30 years ago?

3Q Jay wrote: ↑

Thu Jun 03, 2021 8:01 am

Glad you are up and running properly. First "blown" ECU I've heard of on these cars, but shows sometimes things way down on the fault tree can't be ruled out minus the troubleshooting data.

Yep. The exception that proves the rule, but glad you got it fixed!

Again thank you everyone for your help. I wish I knew this problem up front. Would have saved me ten months and $7500. The car still needs a few little things but it’s a fun hobby to work on over the summer. And no, driving it now isn’t exactly what I remembered from thirty years ago but it’s all good. I rescued a Q45/G50 that otherwise would have gone to a scrap years.

I think for the few of us out there that are committed to maintaining (and enjoying) our G50s that we are caretakers of what may be eventually appreciated by future generations.....

Infinitiace1992 wrote: ↑

Thu Jun 03, 2021 11:46 am

And no, driving it now isn’t exactly what I remembered from thirty years ago but it’s all good. I rescued a Q45/G50 that otherwise would have gone to a scrap years.

Did you own a Q back when they were new, or just got a chance to drive one? I remember my first time driving one. It was a used 90 or 91 in charcoal, maybe 3 or 4 years old. Something was sketchy about it because it was priced cheap, and the guy selling it only had it for a few weeks - but I just remember it being so smooth and a beast at the same time. I ended up getting a 91 Maxima instead, but after an unfortunate incident with a ditch and fence beside the interstate killed it - I got my first 90 Q45 about a year later in 1996. Depreciation wasn't kind to these cars, but that made them a good enough value for me to have one as a senior in college.

After college my first job was selling Infiniti’s in the early 90’s. I was in love with the car then and my passion showed as I sold more Q’s than anyone in our region and was lucky enough to have one as a company car. My first was a 93 and had them until 96. So when I found this car a year ago it was a nostalgic thing I just had to have it. It’s taken me 11 months and an insane amount of money to restore it but honestly the car inside and out now looks as good as new.

Infinitiace1992 wrote: ↑

Fri Jun 04, 2021 5:31 am

It’s taken me 11 months and an insane amount of money to restore it but honestly the car inside and out now looks as good as new.

sweet.....but....

A Q company car. That's a hell of a perk! I agree, we need pictures.

I agree. Tried to upload pics but the file image is to big it says.