Great Balls O' Fire!... out of the exhaust of my '93 Q45

[ScottJackson]

So I got Chopps Q45 to start today. It wouldn't rev over 4000rpm and wasn't running smoothly. But there wasn't any clattering noise or anything like that. After the dark smoke was gone from the exhaust, I let it idle down and it did idle, but there were 2 ft flames coming out of both exhaust tips. Not distinct fireballs, just solid, uninterupted flames. It looked awesome. I'll see if I can get a video of it and post it up soon. Anyway, does anyone know what could be causing this? Could it be grossly retarded ignition timing? Is it possible that the previous owner (N. Chopp) put in some diesel fuel by mistake and that's what's causing this issue? Any other ideas?

[maxnix]

Bet you are frying your cats.

[ScottJackson]

I agree. Once I saw there was fire coming out, I shut it off. If I were to start it again and record a clip it would just be for a second or two to show what it's doing. Thanks for mentioning it though.

[ScottJackson]

Well, I went ahead and pumped the 7 gallons of fuel out of the tank and put a fresh 2.5 gallons of gas in it. Still won't start. I pulled the front passenger side spark plug and it was wet and black. It looked used, but not excessively worn out as it was still at .040" gap. I'm going to check soon to see if that plug is firing when my dad turns the motor and I hold the tip of the plug against the plenum. If it's sparking strong, it'll be time to pull the driver side #1 plug and hook up the timing light to see if that's in the ballpark of where it needs to be. I've kinda been suspecting the CAS for a while now, but I'll go through the process of elimination. Oh yeah, I compression tested that one cylinder and it's at 160psi. Looks promising so far.

[ScottJackson]

ok, getting really weak spark to that one plug, but it is firing. There was one spark that seemed to be decently strong but the rest were just the faintest little arcs from tip to ground strap of the plug. Any ideas what might be causing this? The little square ignition box seems to be fine. I put it on my other q45 and it ran normal. Could it be the CAS or is it likely something else?

[3Q Jay]

might be obvious, but the spark won't happen unless the plug (threaded body/ground electrode) is grounded. after that, maybe see if it gets better with a new plug.

[elwesso]

are your injectors dumping fuel?

[ScottJackson]

Yes, I had the ground strap touching the upper plenum when I looked at the spark. I know it's not a real accurate way of measuring the spark power, but it's obvious to see a very weak spark vs. a strong one. Wes, I think the injectors may be dumping fuel. Is there anything in particular that causes them to do this? When I first turn the key on, I still get the light hissing noise like the fuel is bypassing the regulator. When I pinch off the return line, the hiss goes away completely, so I don' think it's the sound of the fuel going through the injectors and down into the cylinders. There's also no fuel coming out of the vacuum fitting on the pressure regulator. Is there anything obvious that would cause the weak spark? It's only started that one time. The other times it'll usually only do a small single "hit" or fire one pop right when I let off the key after cranking it over. Every now and then it'll do a small pop during cranking. To me this makes sense that the strongest spark would be when the starter isn't sucking juice from the battery. The battery is good and fully charged. The motor turns over fast and smooth. Would there be any spark at all if the ignition relay behind the ECU isn't working? That's about all I can think of it being other than maybe the CAS.

[ScottJackson]

checked the spark again just before dark and it seems to not be as weak as I'd thought. I would think that it should fire alright. Can the CAS get out of timing even if the housing doesn't slip? Hmm, I reckon tomorrow calls for pulling the #1 plug, doing a compression test, and checking ignition timing.

[goody90q45]

I've had the lower oring on a fuel injector give out on two occasions, sending fuel through the exhaust system and out the pipes. It hydrolocked the engine on the second occasion. Never had it ignite though.

At this point I think you're on track by pulling spark plugs. If you've lost an oring one plug or the entire bank of plugs will be wet with fuel. If you've already got the ornament covers off pull one from each bank (#1 and #2) for comparison. Good luck.

[ScottJackson]

#1 plug and #2 looked very similar; black, but not overly sooty. #1 compression was just under 170psi, #2 was 160psi. I don't think the cams have jumped time. I advanced the CAS and it popped just a slight bit more than usual. When I pulled the CAS and rotated it with the ignition key on, I could hear the injectors clicking. I don't think it's an O-ring on the injector leaking as it doesn't hydro lock at all (where it stops the starter or makes it pause a moment when cranking) and when I pinch off the return fuel line, the light hiss noise goes away from under the plenum so the injectors are stopping the fuel flow. I'll try to see about what the ignition advance is and post up the results.

[ScottJackson]

Update: Just got done pulling the plenum (fun fun as always). I pulled up both fuel rails with injectors intact as I suspected it may be a leaky injector or some O-rings. Well, when the fuel pump primes when the key is turned on, there's no leaks. When I crank the motor, all injectors squirt out blasts of fuel. So I think those are fine. I have compression (160-170psi). I have fuel being injected, and I'm getting spark (timing reads right near 15* BTDC when cranking the motor). So with those things, I'd think it should fire up and run at least decently. I checked the throttle position sensor and it checked out good. The temp sensor was a bit low on the ohm reading, but that should only make it run lean if anything. I've taken out the #1 and #2 spark plugs and they look alright and they fire when cranking the engine and I've got them in the coil with the ground strap touching the motor. They don't look to be in bad shape but the plugs certainly aren't new. I'm about tempted to just throw some new plugs in there and see if it fixes it. I can't imagine it would though. The motor has started twice for me and it runs VERY rich, puts out a bunch of grey/black smoke from the exhaust, won't rev over 4000rpm, and then the exhaust becomes flames shooting out the back when all that fuel ignites. I've taken the hoses off the fuel pressure regulator and damper and there's no fuel smell or wetness from them. All vacuum hoses look to be fine also. This is really confusing. I don't have a clue what could make it run so poorly (usually won't even start, throttle open or closed). Is it possible that the plugs are firing on the wrong crankshaft rotation? I see no way that the CAS could have become 180* off on its own and the 3 bolts that hold the CAS on didn't appear to have been touched lately. Any ideas? Anyone, anyone? Bueller, Bueller?

[Rex]

This is chopps old car, the one that had a wiring fiasco when trying to chaneg the MAF connector, right?

[ScottJackson]

Correct, it is Chopps old car. It does have a new maf connector and there's a spare MAF and computer in the car. I've tried completely unplugging the MAF and it still won't start. I unplugged the MAF on my running '92 Q and it started just fine, despite currently having two dead injectors. Chopp said it was running fine until one morning when he tried to start it and it just wouldn't start. Four shops (including one Nissan dealership) later, and still there was no clue what was wrong with it. So now I have it, and I will make it run. Failure is not an option! :-p

[elwesso]

Is the ECU from a 94 Q? IF so, its mine...

[ScottJackson]

The computer that's hooked up and laying on the floor has these numbers:

C7A18-B22 PCI 4426

[Q451990]

That's a 94 with TCS according to the JWT chart.

Heath

[ScottJackson]

Ok, so I need to get Wes back what is evidently rightfully his ECU. Too bad though because it doesn't seem to fire at all when hooked up the the ECU that's in the car. Oh well, I've got a spare in my parts q45. So I've been brain storming what the issue could be and the only scenario is that all injectors are putting in too much fuel. Soooo, since I don't have a fuel pressure gauge (gotta get one soon though), I pinched off the feed line with pliers and had my dad start the car. I then revved it up with the dark smoke coming out the exhaust and slowly pinched the feed line. The motor quickly revved right up to 7000rpm cleanly and sputtered out. I let up on the fuel line and it came back and missed with dark smoke again out the exhaust. Obviously getting too much fuel. So I figured my fuel pressure regulator wasn't bleeding off the fuel pressure as it should be. However, I disconnected the return line and tried to blow on the end of it and it's definately blocked, air tight. I would think it should be an open path back to the gas tank. I didn't have time to check it out further before I had to drive back up to school but I'll be back home next weekend and I'll try shooting some compressed air into the return line and see if I can open it up. I'll also hook up a line going to a gas can outside the car and let the return fuel go there to see if the car starts and runs cleanly with an open return line. Looks like it may be a great deal for $500. In hindsight, I didn't do a great job of following the KISS principle, but is a blocked return line a common issue? I looked under the car and it didn't look like any of the lines had be crushed.

[ScottJackson]

Well, if it quacks like a duck, it may be a duck... even if that duck was supposedly replaced with a good used one. It was the MAF. The MAF had been replaced with a supposedly good used one but after I checked the fuel pressure and found it fine, I decided to start swapping parts with my running Q45. First up was the MAF. The car started right up and runs great. So that's that. Of course hindsight would be to try that much earlier than I had, but I didn't because the MAF was changed by Chopp (previous owner) and it didn't fix the problem, so I decided that couldn't be the problem. As for the fuel return, I guess I didn't blow hard enough. I hooked up the air compressor to the line and it blew through it fine. Now just gotta fix the torn up part of the console and get the power steering working. The fluid is up and the speedo works but there's no power steering at any speed. The belt is good so it's likely that little pressure regulator valve that was sticking in my other Qs pump. Not a difficult fix.

[Jesda]

AWESOME! Another great deal. Another Q brought back to life.

[ScottJackson]

I knew you were interested in it for a bit there, but I had to call dibs on it. Now it's just time to see if any of my friends has a boroscope to check and see if it has the good chain guides.

[Jesda]

I think one reason I never bought it was because he didn't post any pictures. How is it cosmetically? Is the AC working?

[Q45tech]

If you can use a bore scope to see if guide are plastic you are better than I am.

[maxnix]

If you can use a bore scope to see if guide are plastic you are better than I am.

It's timing chain cover time!

[ScottJackson]

Crap. I will still give it a try, but I've done the job before so I guess I can do it again. Hmpf! As for the A/C, it supposedly worked fine before the MAF issue but I didn't test it out. Most of the weekend was spent getting a commercial freezer with my dad. I wasn't told the power steering was dead (although I guess it's possible that it went bad while parked, somehow), so I'm not too hopeful the A/C is good. Cosmetically it is good. Very minimal rust since it spent most of its life in California and then a stint in Colorado. Needs a few interior things and the brake pedal pulses a bit, but that type of stuff is to be expected.