Multi-Faceted Q45 Problem

[senatorjames]

Ok, where to start. My '91 Q45 was running rough and wouldn't pass emission testing. This problem was cured by finding a disconnected vacuum hose leading to the EGR sensor. After that the car would run fine when started cold but upon restarting after about an hour, it would crank for quite a while bedfore catching, at which time it would run well until it warmed up to the midpoint on the temperature gauge. The car would then stall, restart after a short period of cranking and drive fine (with check engine light on ECU code for EGR) but could not be revved over 3000 RPM without shuddering. MAF was replaced and the problem stopped for awhile. The fuel pump started grinding and I replaced that along with the FPCM. Now The problem with the stalling and check engine light (EGR code) has increased. Today, I went to clean the Throttle body and found what I think may be one of the problems. I pulled off the throttle body to MAF intake hose and a puddle of gas poured out. What could be causing the flooding in the throttle body?

[Q451990]

Interesting... I would suspect injector issues. I wonder if the EGR was intentionally disconnected to cover up a problem? When you say "vacuum hose to EGR sensor" do you mean to the control solenoid? Also, since you have an EGR code, can I assume you have a California emissions Q? (doesn't really matter, just curious) You can confirm this by checking the under hood emissions label.

I would suspect that you're dealing with an injector issue, but for fuel to be in the throttle body? That's a new one on me. Do you know for sure that it was gas?

When I had an injector leak-down problem on my old Q, it manifested itself as you described... car started fine first thing in the morning (or after sitting 6-8 hours) but not after a hot soak for an hour or two. I didn't have the problems with the car shutting off but otherwise the hard start sounds familiar. I had remote start, so I could see black smoke from the tail pipe - which is a sure sign of flooding.

See if you can confirm this using an assistant to observe the exhaust...

Heath

[senatorjames]

Well, the new development is that I tried to start the car heard a huge backfire saw misty smoke coming out from under the hood, opened it ukp to find that my air filter was inn flames. So no doubt about gas rollon out of my throttle body all the way down past the MAF. I am so POed I have to replace the whole Air cleaner assembly including MAF, connecter hose and air box. Also kupon the prior hard start I would get quite a puff of white smoke from the exhaust.No it's not CA emission Q.

[Q451990]

Wow! Flaming air filter is not good! I think a plenum pull and injector check is your next step. There should be salvage yards or part-outs in progress that can help you on the air box/MAF front.

I would pull the fuel rails with the injectors intact, try pressurizing them and see what happens. I suspect you have a lower o-ring leaking... now is also a good time to ohm the injectors and look for defective units. AZ gas is hell on early Q injectors.

Heath

[goody90q45]

I just got finished with a similar problem about a month ago. A leaking injector lower o-ring flooded all 4 cylinders on the PS bank through to the air filter on the intake and the cats on the exhaust. Fuel was pouring out the cat with the engine running. I think I also came very close to a fire had I of not noticed the leak.

I was able to find the source of the leak by removing the spark plugs. Start by taking one out on each side. I think you will find one bank wet with fuel. When you remove all 4 plugs from the wet bank examine the tips and the one that is black (carbon buildup from unburnt fuel) is probably the culprit. If you're lucky it will be the PS bank because then it's a 50/50 chance the leaky o-ring will be on #2 or #8 FI which you can get to without removing the plenum. On the DS only #1 can be gotten to easily. I got lucky and my problem was a missing pintle cap on #8 FI that had allowed the o-ring to slip off. Good luck.

[senatorjames]

That sounds as reasonable as any explanation. Good advice. Thanks for your input, guys.

[Q451990]

Please let us know how things progress as you get to working on her...

Good luck!

Heath