Fuel rail compatability info

[squeefoo]

Myself, and I know other '90 - '93 Q owners would like to know if the '94 - '95 fuel rails will fit the early Q's. Will they physically fit?...or would the 94 up injectors fit the 90 - 93 rails? (I don't think so)I'm sure the harness issues could be worked out via splicing.

Does anyone have both or tried it?... If so can you measure it or line it up?I may buy a set of 94 - 95 rails off BST and try, but looking for somewhere to start.

The real reason I'm asking is the bad injector problem constantly cropping up. I can get my plenum off in record time now because of this and it really pi$$e$ me off. You can only take it off so many times before the threads in the lower runner tubes get sloppy and strip...I know !!

This is the worst thing about this beautiful car and it would be really nice if it were finally resolved once and for all.

<steps off soapbox and bows>

[3rd Q]

Squee,Good question! I would love to know as well since I'm replacing my 30th and 31st injector tomorrow night! Replaced all 8 with oem about 18 months ago and now these are the 2nd and 3rd failures since then. The b*tch of it is, I just pulled the plenum about 3 weeks ago to replace another one and all the others at that time were within specs. Used to laugh about it, but the injector problem has gone beyond funny to painful .

It seems like the '94-'96 guys don't get to have all the fun pulling the plenum like we do . If anyone knows if the "94+ rails will work, please let us know!

Thanks,Paul

[DrewQ45]

Squee,Good question! I would love to know as well since I'm replacing my 30th and 31st injector tomorrow night! Replaced all 8 with oem about 18 months ago and now these are the 2nd and 3rd failures since then.

Wow, I'm sorry to hear that this is happening guys. I'm wondering if something else is amiss since I've never heard of injectors going bad so fast. At 192K I've never had to mess with a single injector on my 90. Sounds like something electrical may be frying them or bad gas? What makes you determine them to be bad, the resistance test? Sorry I'm not much help here but just curious about this issue.

....Drew...

[Q45tech]

Always the gross fluid that is sold as gasoline in many EPA containment areas.

The injectors can fit in old rails however the lower runner and head intake ports are not matched to injector flow shape at low air flows, so expect some idle cruise issues...........might be better or worse or just different.

Not sure the newer design is much better when alcohol and water are added to gasoline............as that area has had its rash of failures on brand new cars of every variety.

Short of creating your own gasoline you are at mercy of what's available.

[Q45denver]

I

Squee,Good question! I would love to know as well since I'm replacing my 30th and 31st injector tomorrow night! Replaced all 8 with oem about 18 months ago and now these are the 2nd and 3rd failures since then. The b*tch of it is, I just pulled the plenum about 3 weeks ago to replace another one and all the others at that time were within specs. Used to laugh about it, but the injector problem has gone beyond funny to painful .

It seems like the '94-'96 guys don't get to have all the fun pulling the plenum like we do . If anyone knows if the "94+ rails will work, please let us know!

Thanks,Paul

I think you're on the right track and I've been meaning to try the updated injectors as well. Both my 1995 Q's have never had any injector problems and the 1990 has them constantly. Curious that no one has tried this, I may check with the local Infiniti dealer later today. Won't drive the 1990 anymore without some gas drier in the tank. Nice to see Q45Tech back.

[3rd Q]

Always the gross fluid that is sold as gasoline in many EPA containment areas.

The injectors can fit in old rails however the lower runner and head intake ports are not matched to injector flow shape at low air flows, so expect some idle cruise issues...........might be better or worse or just different.

Not sure the newer design is much better when alcohol and water are added to gasoline............as that area has had its rash of failures on brand new cars of every variety.

Short of creating your own gasoline you are at mercy of what's available.

Dennis,Do you know if the harnesses are interchangeable or would splicing be necessary? Thanks,Paul

[Q45denver]

I'll answer for him since I own both. The connector ends appear to be the same but the connector plugs to the individual injectors are different so you would want to get both the harness and the new injectors.

I just did a search and came up with this link for a company that sells rebuilts with a lifetime warranty which might be a viable option.

http://store.yahoo.com/dpstore/322a1825.html

Also per this Chamber of Automotive Industries site only Nissan after 2004 were designed to run on 10% ethanol?

http://www.fcai.com.au/ethanol...mlber of Automotive Industries

[elwesso]

I see the worst case scenario being changing the lower intake runners out too...... Otherwise they should work...

Ive never replaced an injector on a Q45 (knocks on wood).. regular use of BG44k i think helps a little.

[Q451990]

I know the intake ports are different between the two engines, so I'm not sure the runners are cross-compatible.

Heath

[squeefoo]

1994 and up

'90 -'93

[96Qowner]

I'd blame the gas, too, and Wes's idea is probably the best, and cheaper with less hassle. Try using some BG44K.

Here's that old thread on automotive fuel for those that haven't read it:

zerothread?id=94900

All gas ain' the same. Shell and Chevron are the best.

[Raxephon]

All gas ain' the same. Shell and Chevron are the best.

Maybe where you live.

Best around here is Amoco Gold.

Shell & Chevron are pretty bad in my area.

[squeefoo]

Where 3rdQ lives it is impossible to get non-reformulated gas w/o a long round trip.

I can get it and it's all I use, seems to happen anyway, but I haven't replaced 32 of them yet either -only about 7 on 1 car !

It's the design and the gasohol, gasohol accelerates the winding failure. This has been covered exhaustively.

This is a thread intended for examining the possibility of adapting late fuel rails/injectors to early engines. Please stay on topic. Thank you.

[elwesso]

Squee... What Id do is try swapping like 2 or 3 that are easy to get at... If its going to effect anything you should notice it if that many cyls are running that way.

[jtesensky]

Hey Guys,From what I have to resource everything points to the injectors having a different fitment in the rail....

[elwesso]

Joe will the 94 fuel rail bolt to the 9093 lower runners?

[Q45tech]

How would anybody know for sure without trying this conversion?

Not something a dealer/tech wouldn't try except by accident....receiving wrong parts.

[Q45denver]

I'll let you know in a few days, Already ordered all the parts.

[Q45denver]

I matched up the the 94-95 fuel rail and injectors with the 90-93 lower runners and everything lines OK including the bolts holding on the rails. The insulator seals on the bottoms of the injectors between the runners and the rails is does not provide a good fit as the 94-95 requires about a 5/8" hole vs. the 90-93 insulators which have a 3/4" hole. I'll need to get some seals for a 94-95.

My main concern at this time is that the injector tip on the 90-93 extends down 3/8" further than the 94-95 nozzles--see picture of the two types of injectors below. This would lessen the effect of heat soak but might also effect the idle. I guess the car would run ok regardless-certainly better than it is now with two bad injectors.

1994 and up

'90 -'93

[elwesso]

seems like people may want to swap to the 94 lower runners... unfortunatley there arent as many blown 94 motors as there are 9093.....

someone should just try it and get it over with.... my guess is that it really wont make that much difference negatively, but one can only speculate until its done.

[Q45denver]

Shouldn't require the 94-95 lower runners for the conversion just the rubber insulators. I should have them installed within a month.

[squeefoo]

Shouldn't require the 94-95 lower runners for the conversion just the rubber insulators. I should have them installed within a month.

You are my hero! (flutters eyelids)