Just got a 1994 Q45 w\issues

[enkeimx6]

Hey everyone,
Just got a Q45 and its got some issues . The largest one being when I got the car it ran o.k. however, below 2500-3500 R.P.M. it had no real power and if you pushed the gas down more than half way sometimes it would pop back through the intake. but once it got above 2500-3500 R.P.M. it would take off like a rocket and run great untill you got back below 2800 R.P.M.

Yesterday the issue got worse , now it idles horribly ,has no power no matter what R.P.M. you're at or how far you press the gas down.

I tried to use SEARCH but came up empty handed. I am just trying to get a rough Idea of where to start, I havent gotten a chance to fool with the car much ,I have changed the fuel filter thinking that maybe it was dirty but no change , maybe this weekend I can do some testing as far as injectors and etc. . Any suggestions of where to start looking would be greatly appreciated .

[goody90q45]

Is the check engine light coming on? If not it's probably a bad fuel pump or fuel pump control unit (FPCU).

How many miles on your Q? With the trunk open Is/was the fuel pump getting noisy, like a swrm of bees?

[Unnatural1]

If it's what I think it is...it could be anything!

Testing the injectors would be a great start. The fuel pumps in these cars have been known to cause lack of power issues when they begin to die. Dead knock sensors have been known to cause a lack of power as well. It's going to take some diagnosis to isolate the issue. But, it's a good bet there are multiple issues.

[Q45tech]

"The fuel pumps in these cars have been known to cause lack of power issues when they begin to die. "

How about every worn fuel pump in every brand of vehicle including trucks and lawnmowers cause the exact same problem set!

Not much unique or mistifying about a [1987-90] design compared to today's engines.............other than lack of plug wires or distributer/rotor button.....or push rods in today's cheapest engines.

[enkeimx6]

Alright, got home from work and had a little time to fool with the Q btw it has 173,000 miles on it . checked the injectors with an ohm meter and one of them is bad then i checked the fuel pressure and it was crap, 26 psi at idle and when I reved it up it went down to 20-22 . I pulled the plug on the cyl. that had the bad injector just to be sure that the injector was not leaking or hung open ,no evidence of excess fuel but had to check just to be sure . when i first started the car the fuel pump was quiet but after a few minutes of idleing in the driveway it started getting noisy , by the time I got done messing with the car the fuel pump was so loud that you could hear it when you were standing 5 feet from the car with all doors and trunk closed. I guess tomorrow I'm gonna take a trip to the parts store and get an injector ,fuel pump will have to wait untill next week but at least the car looks good sitting in the driveway. The only downside is that the birds and the pollen love the car and I just washed it a few days ago.so by next week it will look like a white polka-dotted /light green turd.

Thanks for the help guys

[Infinitiguy19]

Add a Fuel Pump Control Unit to that list as well. You can replace it with a know good one or re-solder it yourself if your good with electronics. There is also 3Q Jay here on NICO that does it for a price of which I am not sure it has changed or not.

And whats the condition of the body on your Q (Wax, Swirls, Scratches...)?

[enkeimx6]

I read one of the many writeups on re-soldering the fpcm and it does'nt look too dificult , i have exp. with a soldering iron and automotive electronics. As far as looks my Q is pretty decent , no dents , no scratches , but it does have some weathered paint on the roof . the car is maroon in color with a little bit of metal flake but thankfully not enough to make it ghetto fabulos. I'm planning on painting it after I get it to run correctly . It has 15" BBS Bugatti wheels on it but the chrome is starting to flake so they will be replaced , maybe with some larger wheels depending on how it looks . Interior on the car is black and nearly perfect the only flaw is on the drivers seat where one of the seams is starting to separate .

[Unnatural1]

Re-soldering a circuit board is not rocket science but you need a steady hand and don't over do it.

Sounds like a really nice Q. My drivers seat is pretty bad too and the paint has some defects from scratches to clear coat damage but it hasn't really faded. The previous owner didn't care for the paint like they did the mechanical items.

"How about every worn fuel pump in every brand of vehicle including trucks and lawnmowers cause the exact same problem set!

Not much unique or mistifying about a [1987-90] design compared to today's engines...."

You're right. My point however, is these cars have problems with fuel pumps and fuel pump modules. MANY other cars do not; even with 150,000+ miles on the odometer. I work on lots of other high mileage import cars (many with more than 200k miles) that have no issue what so ever with fuel pumps. If they do, the car simply doesn't start or dies while driving. In my experience, it's rare to have an electric pump that actually causes the noticeable acceleration problems seen with the Q. Usually, you'll find that a fuel filter is clogged, a bad fuel pressure regulator, etc... causing an issue like that.