symptoms - alot of trouble or maybe just one cause?

[Valmon]

I have a 1993 Q45, 147,000 miles. Previously, the only problem I had was humming in the back seat, which I discovered from this forum was the fuel pump and/or modulator. I purchased both from Pops and intended to get them replaced, when the humming stopped. The check engine light used to stay on constantly - now it comes and goes, more often then not is off, though. However, during take off (1st gear I guess) it sounds like there is backfiring under the hood and it barely accelerates. Once it is over 30, though, she moves nicely.

I'm sorry for using you as a sounding board, but I am in the middle of a divorce, don't have alot of money and no male friends who know anything about cars!

If you have some ideas, please share:) At least I knew enough to come here!

Many Thanks!

Linda

[elwesso]

Welcome to NICO Linda!!!

I am going to move this post to the online mechanic once I see you've replied....

At any rate, if you heard a humming you need to replace the fuel pump regardless. Generally i dont recommend buying used ones as theyll just go out again!!!

I think the first thing you need to do is see why the CEL is coming on... IF you have a set of tools (a 10mm wrench and a screwdriver) you can take the ECU out and check the diagnostic codes... and then we can see whats going on, thats probably the first step...

[maxnix]

Well, if you need a diversion from your current situation, reading on this site can provide hours of it.

I suggest starting with Tangaloras excellent post about fuel pump replacement in the Infiniti Online Mechanic Forum.

The I would read about timing chain guides in the Articles Forum before even starting the car again. Especially if you go "Huh?"

Welcome to our group. Search first (a tutorial in itself), then ask if you can't find the answer. 99.5% of the time answer is in a previous post.

[Valmon]

Ok, I'll arrange to have the parts replaced. POPs (from NICO) assured me they were good.

Do you think this is what is also causing the backfiring? I want to be able to lead the mechanic to the problem, not have him replacing every part in the car, if you know what I mean.

I think I need to buy a Q45 repair book so I can understand where these items are, LOL

Thanks!!!

Linda

[elwesso]

Ive never heard of a Q backfiring, unless of course (which could be VERY possible) your chain guides broke!!!!

Does the car "backfire" at idle, revving in neutral, or when? It could be there is an exhaust leak or something, ive never heard of a Q45 motor backfiring through the intake that ran normally...

[Q451990]

Mine backfired when the guides went

I think mine slipped two teeth... Wasn't there another post about this recently from someone else?

Heath

[Q451990]

Linda,

I just thought of something... what's the production date of your 93 Q? The later the better - as the change-over to the updated guides started sometime in that model year run. Nothing definate - but at least there's a chance that you're not driving a time bomb.

[Q45tech]

I want to be able to lead the mechanic to the problem, not have him replacing every part in the car, if you know what I mean.

Two things scare me: First that you use the term mechanic and second that you are not using a certified expert TECHNICAN on your car who works on these models weekly if not daily.

Most Q are destroyed [made worse] by uneducated owners and uneducated MECHANICS.

Certified Infiniti Technicans rarely hurt or destroy cars.

Two things to always demand of the shop that works on your car:THAT THEY HAVE A FSM for your year and modelTHAT THEY HAVE A CONSULT DIGNOSTIC COMPUTER with the appropriate plug in software for your options.