Engine quits

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Racer Chris
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Engine quits

Post by Racer Chris » Wed May 22, 2002 7:19 pm

Anybody seen this problem before? On a 2 liter with D-jet - after running for half an hour or so the engine quits. It won't start again for up to 15 minutes. Turns over fine. Cranks with no fire, then slowly sputters to life, while pumping the throttle. There is a bubbling noise which can be heard from the fuel filler and from the passenger footwell, even with the ignition off. The problem repeats itself after a short drive. I asked the owner if he could hear the fuel pump energize when the key is turned on, but he didn't notice. This happens in moderately cool weather.



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Bleyseng
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Engine quits

Post by Bleyseng » Wed May 22, 2002 7:42 pm

When was the last time the fuel filter was changed? could be plugged
Geoff

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76 914 2.0L

johnhora
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Engine quits

Post by johnhora » Wed May 22, 2002 9:48 pm

Chris..
You said it had no fire...no spark right..
Check the ignition switch. Had a customer D-Jet 1.7 do the same sort of thing. Run fine for a while then quit or not start after a short trip, few miles. Not hot weather. Would not start for anything....wait a while then try to start....fires right up....came up to be a bad ignition switch after lots of looking other places. Was crazy....just like thoes weber IDFs I was asking you about.

Regards,

John

HotRod
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Engine quits

Post by HotRod » Thu May 23, 2002 7:51 am

Chris,

Did you bleed the FI?

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Racer Chris
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Engine quits

Post by Racer Chris » Thu May 23, 2002 8:03 am

The customer says the fuel filter was changed last year.

I don't know if there is spark or not when this happens. While I had the car here it ran fine, except for the bad MPS, which I changed, hoping to cure this problem as well as the bucking. The bucking went away.

The next step is for the customer to drive to my shop, then to my house with me following. Hopefully it will act up so I can diagnose the problem as it happens.

I want to check the fuel pump relay, and the fuel pump. Also fuel pressure in the injector circuit. The bubbling noise he describes sounds like vapor lock, but the weather isn't hot. Maybe the pump is overheating due to internal friction.

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Dave_Darling
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Engine quits

Post by Dave_Darling » Thu May 23, 2002 9:10 am

That would be a new one on me--internal pump friction causing vapor lock? I think it would be more likely to simply kill the pump outright.

Back to basics is probably the only way to go about this one. Check for compression, spark, and fuel. If those are present, then it's the amount of fuel, or the timing of the spark (and possibly the fuel).

The problem being, you have to get it into the "failed" state before you can start checking...

--DD

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1974 VW-Porsche 914 2.0 (Type IV powered!)

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Racer Chris
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Engine quits

Post by Racer Chris » Thu May 23, 2002 11:13 am

The engine runs great except for this, and it doesn't happen until after 1/2 hour of driving. Then it happens repeatedly, with about 10-15 minutes required between starts. That's why it seems like a heat related thing. I was thinking of a bad bearing or something in the fuel pump, but I know, it's more likely to simply not run.

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HotRod
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Engine quits

Post by HotRod » Thu May 23, 2002 12:03 pm

Chris, I had the same thing happen a couple years ago, it was heat causing the Fuel pump to vapor lock. But this was on a race car and the fuel pump wasn't in the stock location...relocation of the fuel pump solved the problem...in my case anyway.

elocke
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Engine quits

Post by elocke » Thu May 23, 2002 2:20 pm

I had a rusty gas tank that was causing my engine to die intermittently. To diagnose, I T'd in a fuel pressure gauge, ran it out of the engine bay, and watched it through my rear-view...my way at the time to check fuel pressure related problems. Sure enough, the pressure would drop and it would start to die. I also ran wires from the fuel pump into the passenger compartment to a meter so I could see if it was getting juice. Maybe you could monitor for intermittent connections (voltage) in other places this way.

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Bleyseng
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Engine quits

Post by Bleyseng » Thu May 23, 2002 3:57 pm

Check for rusty tank as that can clog and unclog causeing crazy problems

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TwoLiter
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Engine quits

Post by TwoLiter » Thu May 23, 2002 5:24 pm

A similar problem on my 73-2.0L was traced to a worn follower on the points which caused the contacts to stay closed all the time. Bad dwell setting!

lilbstrd550

Engine quits

Post by lilbstrd550 » Fri May 24, 2002 2:27 pm

chris

on my 2L i would have the same problems w/ the engine quiting. after 3 mths trying to diagnose the problem the answer sort of "popped" up on it's own. turns out the black power lead from the ignition switch had cracked and severed at the point it leaves the firewall up into the rubber boot. it finally wore thru a ground wire in the loom, sizzling everything along the black wires path. the noticable engine power loss wasn't as concerning as the bright red glow from under the dash as the fuse box melted...

mind you i'm positive this is one of those freak once in a life time occurances Image

nathan

ray greenwood
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Engine quits

Post by ray greenwood » Fri May 24, 2002 7:20 pm

Chris, the bubbleing sound can be caused by several things. But usually it is from cavitation by the roller in the roller pump. When they get warm...parts expand. A worn roller pump is noisey. Vapor lock is not really possible at the pump...unless...and heres the trick....the fuel pressure regulator is bad. The fuel pressure reg is designed to not unload for about 15 minutes. It has some of the same function as the fuel accumulator on CIS. It keeps the line ubder pressure ...usually between 15-18 PSI...and slowly bleeds down so bubbles will not form in the fuel system when hot. Either/or a combination of worn rollers in the pump,and a bad fuel pressure reg will do this. All fuel pressure regs over 5-7 years old are suspect. They get rust flecks on the polished pressure plate above the spring, and leak down. A quick check, is to attach the guage to the fuel ring....run the car and turn off the ignition. The guage should not drop to zero in anything less than about 8 minutes. If so you need a new regulator. If you do not have one, a good fix...is to install another used reulator set for about 15-18 PSI right behind the one on the fire wall to back stop it at a lower pressure. It works well. The fuel pump itself...may also have high resistance to turning causing it to run hot. It should be smooth and quiet. When you bump the key, it should sound like its turning about 3500-4000 rpm. It should not sound slow and gravelly. Ray

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Racer Chris
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Engine quits

Post by Racer Chris » Fri May 24, 2002 11:04 pm

The owner drove to my shop this evening, then to my house, but the engine never quit. At the shop I listened to the pump energize when the key was turned - it sounded very quiet, almost inaudible (pshhhht). The engine was a little slow to start. Then at the house, after sitting, the pump sounded more normal when energized (Bvvvvvt). A thought I would put a gauge in the fuel line, but it turned out that I wasn't prepared to do this quickly. Based on the differing sound of the pump I am planning to swap it out with a much newer unit when I get a chance, soon. I will also weld up a tee fitting for a gauge to check out the regulator.

Thanks Ray and everybody,


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ray greenwood
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Engine quits

Post by ray greenwood » Sat May 25, 2002 9:00 am

Yep...You described the correct sound for a good running pump on start up. The lower gravelly sound is what a loose rattley pump (age) or a starving running dry pump makes. Also check for silt being drawn in at the inlet pipe. Sometimes it draws a pile around the tube while running....and slowly settles out after it sits overnight...giving a cleaner draw on start-up. My money is on a worn pump, or high resistance pump (electrically). Ray

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