1990 Q45 Frustration.....

[96Qowner]

would i still be able to move the car though

Read the stuff on Q45.org.

If it's chain guides, it's not gonna move under its own power until you open the engine and fix things, if it's not already toast from valve interference.

Sorry. The only way to know for sure is to remove the front cover and look at the guides - no other way to tell. The loud rattling and steam are the very bad signs you don't want to hear and see. Don't be optimistic.

[silkysmoothyjud]

Hydro lock from lower o-ring failure, perhaps? Dont try and turn it over for a while!! Check fuel pressure and let the gas seep past the flooded bank. Pull the rail and try and re seat your injectors while checking o-ring integrity. That would be good news in this situation...for real..
Modified by silkysmoothyjud at 7:15 PM 2/3/2009

[silkysmoothyjud]

Please check your starter and see if it is cracked on the outside. Does the starter sound louder when you try and start it? Hydro locking a Q will break your starter in two if you try and start it...better than killing your motor.

[sdkhalsa]

I have had two instances where a flooded Q will strip out the starter drive. This appeared to happen when there was back firing when trying to start it. For hydro-locking, I had good luck in hand cranking(ignition off !!!) the engine backward and then forward continuously until the engine moved freely. From there, with the fuel pump fuse removed, I would crank the engine with starter at short intervals until the fuel was burned out. This total intolerance to flooding convinced me that at the slightest sign of flooding to pull the fuse on the pump and blow out the excess fuel. In addition, I periodically take fuel pressure readings with clamps on the fuel lines to make sure that there was no leakage through the injectors(procedure in this forum).

[jimbyjimb]

It normally will run with an unplugged MAF. It goes on limp-home mode and will not rev past 2500 RPM. When any electrical component affecting timing or fuel delivery is malfunctioning to the point the computer catches it the computer will go to a default setting and only rev to 2500 rpm. A bad MAF connector will have intermittent issues as it is in fact a physical connection suffering from the whims of speed bumps, potholes, angle changes, etc... Though just because the MAF connector may be mad it may not send the computer to LIMP mode if two, one being ground, of the wires are still good. Look at the connections to your MAF and your CAS, clean them. Hold off on the di-electric until the problem is fixed because I have seen grease impair conductivity as it is a resistor and not a conductor. The MAF connection and wires to it on a G50 Q get old and weak, the wires will slip from the pins inside the connector. The problem may not be the connector but the wires inside of it. Examine it closely. Tug on each of the three wires slightly to see if the crimps have failed. My wire on my MAF fell right out with the slightest of tugs, so I purchased a new connector solving all of my problems AFTER I was stupid enough to throw a new CAS at it. Throwing parts never pays off.

[silkysmoothyjud]

used maf installed, no improvement!! My idle used to fluctuate a little when I wiggled the maf connector, now nothing......

My part guy included a connector with the maf. It has an external ground. I guess my next step will be to try the connector. I will have to cut and resplice, dont want to, but I am running out of options.....It is really sucking down the gas!Jesda, you are about to get mail!!

[silkysmoothyjud]

The used maf made it worse, switched out the connector and ran both maf, still misfire. Pulled fuel pump fuse, will let it sit overnight. I will get the fuel pressure checked. I have messed with the injectors, but the problem was there before I started fooling with them. Every time I mess with the injectors, the problem goes away completely, but reappears the next morning. Leaking o-rings, bad fuel pressure due to cold weather? My next attempt will be this weekend.

[Infinitiguy19]

I would check the fuel pressure at idle and at 4000 RPMs then leave the gauge in and do something for 10 min and see if there is still pressure, if the gauge reads ZERO then you have a leaking O-ring.

[silkysmoothyjud]

Thanks for the advice! I will T it up right past the fuel filter. I do not own a pressure gauge, but I will get one from autozone and take it from there....If that doesn't show a problem, any idea of what it could be? I have have injectors do this before, but once I replaced them, the prob went away and did not come back the next day.

If an o-ring was leaking, wouldnt the prob be constant? The misfire started out only being there when it was warm, a little miss, than a constant misfire. I played hide the injector already, pulled the plenum twice. Both times I swapped injectors it totally went away for the rest of the day, then it returned in the morning..

I went on vacation for a week, the prob started when I came back, and is getting worse. I only take the Q on a short commute 4 miles both ways to work...

[Infinitiguy19]

Autozone=no go.

They don't have one I tried them, then I went to harbor freight: http://www.harborfreight.com/c...92699

[silkysmoothyjud]

Would old fuel injector lines cause a pressure issue and subsequent misfire without gas leaking?

[Infinitiguy19]

Are you talking about the metal ones that run from the gas tank and the bottom of the car?

Or the rubber and aluminum ones in the engine bay?

There are fuel pressure dampeners to prevent such a thing from being a major issue. But a Fuel Pressure check will tell all and usually points to a bad fuel pump if pressure is insufficient.

34.5 PSI at idle.

43.3 PSI at WOT or 4000 RPMs+.

[maxnix]

I asked him about the MAF and he replied by saying it was not that it was the electrical.

I am not sure what that sentence means, but if he is saying there are no electrical components there, you need to pay for competent professional help!

When's the last time you changed your fuel filter, measured your fuel pressure?

[silkysmoothyjud]

the rubber ones that lead to the rails, mine are prolly original, 20k since fuel filter change. Never done a pressure check. Fuel pump isnt even a year old..

[maxnix]

Change your fuel filter soon, especially if there is ethanol in your fuel.

[silkysmoothyjud]

I went back under today and started pulling injector wires again and found that the miss did not change when I pulled #7. I swapped the injector..nothing changed. I pulled the coil cover and discovered # 7 was unplugged! I changed the plug and fired it back up. Misfire still there. Wash perhaps? I changed out injector #8 and the miss became less obvious. I will figure it out soon enough. I have a can of bg44k, but I do not want to spend it yet.

[Infinitiguy19]

No a can of Redline S1, BG44K used to be good. I have the MSDS I can email them or post them if you need further proof.

[silkysmoothyjud]

I am starting to think my injectors are spent. When I got the car, 1-4 failed one right after the other, now I think 5-8 are not far behind, but I don't want to spend the $$$ just to find out it did not fix it. Still waiting on my pressure gauge. I am only driving it to work and back, 4 miles round trip. Misfire gets worse the longer I drive it..

[Infinitiguy19]

Either there failing like your saying or just getting more and more clogged as you drive. When was the fuel filter last changed?

[silkysmoothyjud]

20k ago, maybe 30....it starts right up, so I am kinda dismissing a fuel pressure prob (it wouldnt start right away with a pinched ring)....about to spend the 44k, but that miss is solid, like the injector has kicked the bucket, but no cel? CEL was on for all of my other failures.I also hit the injectors with carb cleaner, and they worked fine, but after letting it sit overnight, the misfire came back

[Infinitiguy19]

CEL would only be on if you had a leaking injector.

Try this:

"I have a trick which shows if a rail flush will help: Use non biting pliers to close off fuel return rubber line in repeated but very short [ a second closed then wait 3 and repeat 10-15 times to raise rail pressure from 34psi to 60-70 psi to force trash thru the injector screens ----- fleck off carbon/deposits from injector tip..............does power balance ratios change? It should get temporarily better.

Usually helps without doing much fuel pump damage [pump has it's own blow off high pressure valve]. After all the pressure rises to 43.4 psi under acceleration."-Q45Tech".

Do with a the fuel press gauge installed obliviously.

[silkysmoothyjud]

is there a sensor that I could be jarring when I tip the plenum? I do not take it all the way off. I just remove the idle control three way hose in the rear from the plenum, {two connections) a couple hoses, runner bolts, EGR bolts. Easy squeezy. I can do it and put it all back together in an hour...

[Infinitiguy19]

I don't thinks so.

[silkysmoothyjud]

I will spend the bg44k, and then I will be looking into buying new injectors. D works remands, unless someone has a better idea...

[Infinitiguy19]

Well I have some injectors, But the important thing on your ens is to see what they OHM at when COLD and when HOT.

And again BG44k is not what it used to be Redline S1 now has what BG stopped putting in there formula.

[silkysmoothyjud]

I have already done that, even on my old failures...they ohm out to be around 15 hot or cold. Perhaps I am doing the test incorrectly?

[silkysmoothyjud]

not really into used injectors, been there too, they like to misfire when hot!! Thats why I am leaning toward replacement. I have already bought three brand new ones that did not fix the prob at around 500 bucks.....Not looking foward to another disappointment...playing find the bad injector sucks....

[Infinitiguy19]

Which OHMed at 15?

Yea D-works is good then.

[silkysmoothyjud]

freakin all of em, but when 1-4 was going, the all ohmed at around 12???

[Infinitiguy19]

Sound like a bad harness, but did you follow the picture on Q45.org when you did it?