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Discussion Starter · #1 ·
Mallory Unilite distributer with new cap, rotor, and module. Crane Hi-6 box, Crane coil, New MSD wires, new Autolite plugs.

Stack EFI from Momar, Haltech F-10 box. Aeromotive fuel pump and regulater.

Last Nov/Dec I removed the engine for a freshening up. New rings, bearings, gaskets. New camshaft.

Ran the engine about 5-6 hours in Dec, with 5-6 heat cycles. Got a good tune with my LM-1. Engine ran great; better than it ever has before. I parked the car in the garage in mid December, and it's been there ever since.


I started the engine once a couple of weeks ago. It sounded great, started right up, revved nicely. then I shut it down.

On Sunday, I started the engine, and backed it down my driveway. After I cleaned up in the garage a bit, I moved the car back in. Seemed to run just fine then.

Yesterday (Wednesday) the weather and roads are finally clearing out. Time for a drive. Started it up and let it warm up. Smooth as a kitten, sweet as strawberry pie.

Got out on the street, let out the clutch, and it died. Tried to drive down the street, and it just wouldn't run. Every time I gave it gas under a load, it would die. If I played with the throttle, it would rev up high and stay there. Then I could let out the clutch and drive it with the rpm's above 4,000.

In the garage, I can advance the throttle somewhat slowly, and it will go very smoothly to 5500 rpm's. Advance the throttle too quickly, and it dies at about 2,500.

AFR stays around 13 at idle. As I gradually advance the throttle, the AFR stays about the same, right around 13. If I davance the throttle quickly, the AFR goes to 15-16, and the engine dies.

With the engine off and ignition on, when I jiggled the wires that go into the distributer, and I would hear a relay click and the fuel pump would cycle. I had a spare, so I replaced the ignition module. The pump doesn't cycle anymore. But it didn't help the problem.

I checked the fuel pressure. Rock solid at 44psi. Just like it always has been.

Fuel problem? Ignition problem?

Fixed It!!!! See below (2/23/07) for full explanation

[ February 23, 2007, 10:21 PM: Message edited by: boB ]
 

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Don't know poo about stack systems.

I would put a timing light on and see what the timing is doing.

16:1 is lean but with no load the engine should be able to push through it. It sounds like the "accelerator pump" isn't working. Although if it is starting to miss and not burn fuel, it will show lean on the O2.

Depending on your cold enrichment cycle a lot of starting and idling may have just fouled the plugs. I'd pull a couple plugs and make sure they look ok.

Double check all of the wiring and connections of the bundle you were shaking.

Also look for something simple like a vacuum line that has come loose.
 

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when you rap the throdle does the fuel pressure drop? If it does you have a fuel filter issue. Ether the filter itself or the prefilter on the intank pump if you are using one.
 

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I think Gordon has it, sounds like an old time plugged fuel filter.

Chris.
 

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Discussion Starter · #5 ·
Originally posted by Gordon Levy:
when you rap the throdle does the fuel pressure drop? If it does you have a fuel filter issue. Ether the filter itself or the prefilter on the intank pump if you are using one.
Not all. Rock solid. I even increased the pressure to 49psi - no change. Still rock solid, still bogs with rapid throttle opening. So I put it back down to 44psi. Makes me think it's not a fuel problem.

I'll pull the plugs and see what they look like.
-----

I pulled out three of the plugs (1,2,3). They are a little black and sooty, but not bad for only having been run at idle. I'll put 8 new ones in on Sat and see what happens.

I checked over the wiring harness very carefully. Didn't see any frayed wires, nothing unusual. When I shook the harness before, odd things happened. But when I unplugged the distributer, that stopped happening. That's why I replaced the module.

[ February 08, 2007, 09:56 PM: Message edited by: boB ]
 

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Bob, can you run the engine with the Unitlite and bypass the Crane ignition box? Maybe the bad module cause some damage to the Crane box. Eric
 

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throttle position sensor or map sensor would be my guess....either the sensor itself or a screwed up wire. Can you datalog those sensors w/ your computer?
 

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sounds like bad gas . I had a lot of trouble with my Mallory dist ended up giving a burial at sea. Check tps voltage if stack injection has one sometimes they get a dead spot and possibly a mouse chewed a hole in the vac line to the map if it has one . I don't know much about stack injection but I do know a bunch about efi in general. Bob
 

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Bob,I would look at the ignition. Fuel pressure is good so doupt it is a fuel problem. Plugs black show you are getting too much fuel or not enough spark to fire the fuel. Can you ohm. out the coil and coil wire to be sure they are ok?
Have seen coil or coil wire go bad to the point they would cause the same symptoms you are having. It feels the same as if it's running out of fuel but really it's running out of spark.
 

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Discussion Starter · #11 ·
Thanx for the suggestions. It has fresh fuel, and good pressure. The computer program hasn't been changed. TPS and MAP seem to be reading right where they should be.

I'm also thinking ignition system. I have a sneaking suspicion it's the module in the distributer. I put in a used one I had in the basement. But I think that might also be bad.

I have to work a double shift today. But tomorrow I'l replace the plugs and check the entire ignition system. I have a spare ballast resister around here somewhere, so I can bypass the ignition box.
 

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Discussion Starter · #13 ·
Still stumped.

Replaced the plugs. All looked just a tad sooty. But three of them were actually wet and smelled of fuel.

Replaced the ignition module. Checked the coil. Bypassed the ignition box.

It starts fine. Idles fine. Slow to moderate throttle application and it revs easily to 4000+. Fast throttle application, and it stalls out and dies. Fuel pressure remains a rock steady 44psi.

When it cools down, I'm going to replace the cap, rotor, and wires. I'll pull the plugs and check them again, see if any are wet.

If that doesn't do it, I'll use a noid light and check all the injectors.

This is very frustrating. It ran great when I parked it in Dec. Hasn't been touched since, except to start it up in the garage once or twice. I havn't even hooked up the laptop for anything.
 

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Speaking of laptops, can you datalog the injection computer with your laptop?

If so, you might be able to narrow down the issue quickly.
 

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Did you have gas stabilizer in the tank? I had similar problems with my carbed engine after it sat for 2 months and new gas fixed it.

Bob
 

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My .02, dying under load would indicate an ignition problem.
In the old days, the first place you'd look was at the coil.
 

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Discussion Starter · #17 ·
Ronbo, I had the same thoughts. I'm almost 100% sure the fuel system is OK. I did some data logging, reprogrammed the computer, checked O2 sensor readings. The tank was only about 1/8-1/4 full when I parked it. I filled the tank Saturday with fresh premium fuel. I also added gas dryer. All that just didn't make any differance at all.

I pulled all the (fresh) plugs. They were all a little sooty. And some smelled of fuel.

I checked the primary and secondary curcuits of the Crane PS-91 coil. Perfect. Exactly the same as the new coil I have on the shelf.

I checked the resistance of all the MSD 8.8 wires, through the cap posts. All less than specs.

I pulled the distributer out, and I think I found the problem. The shaft is very difficult to turn by hand. and the mechanical advance mechanism doesn't turn at all. I have another distributor in the basement that had other problems. That one spins very easily, and the advance mechanism is easy to move by hand.

I think the shaft bearings are shot, and the advance plate is seized. This is the second Mallory Unilite to to fail in less than 6K miles on this motor. I'll be sending both of them back to the factory for a rebuild.

However, I won't be putting a Mallory back in there. I tried to find one of the new Cranes, with the externally adjustable advance curves. Jegs could maybe get me one in about 2-3 weeks. Summit doesn't carry them at all, because they have had too many probems with back orders.

I ordered a MSD plug and play from Summit; should be here by Friday.

[ February 15, 2007, 08:55 PM: Message edited by: boB ]
 

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boB,

I got my digital Crane and HI-6 from Summit. I bought the small cap model for my 302 block. I'm very happy but only have gokart miles so far. It is a sweet unit. Here is the 351 large cap listed though...
Crane Digital @ Summit

Eric
 

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Discussion Starter · #19 ·
Yeah, they list it. But the tech line says they don't stock it because of back order problems. Jegs said they could get me in in 2-3 weeks. Maybe.

I'm an American. I demand instant gratification
 

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Discussion Starter · #20 ·
I put in a second Mallory Unilite distributor. It spins freely, advance mechanism works good, has a new module, new gear. Timing set at 12*.

No Joy in Mudville. No change.

Maybe once things cool a bit, I'll go back to the fuel system.

Yesterday, I unplugged one of the injectors, and plugged in a noid light. It didn't light. That would indicate the injector is not firing. But if the injector isn't firing, how could the engine run? Doesn't make sense to me, either.

I'll shoot off an e-mail to Haltech and see what they say.
 
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