Stumbling, stalling on way to work....help!!

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NYNick

NYNick

10 Year 15 Year
Joined
Jan 3, 2011
Threads
59
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506
Location
Old Saybrook, CT
Truck was giving me some early symptoms, but today it died on the highway. It started again and I limped it to work and to a gas station across the street. Running very rough, stumbling, stalled twice, almost didn't start the second time. Seems putting under load exasperates the problem...I'm lucky to have gotten it this far, but here I am....help? Things to look for?

Thanks

Nick
 
Moisture in the dist. cap, or bad cap and rotor. Fuel filter (if it has never been done before, like most).
 
Well, the mechanic said it was running on 4 cylnders...I tend not to beleive him, becuase he's an idiot. He's going to look at replacing the wires (good, new ones 3 years old), the cap and rotor (good, new one 3 years old) and take a look at the plugs. I doubt it's any of those things but he's got the car, sooo...
I just wish I had it in my garage so I could diagnose. It was running rough, and very slow uphills lately. Maybe he's right. Crap.

FYI the pump and filter are brandy new, also 3 years old. I wouldn't want to drop that tank again! I wanted to pull the codes, but he said he had it covered. If he doesn't, I will. I'm guessing TPS or timing. Maybe I'll just pull the codes when I go back to see him, after lunch.

Thanks for the replies!

Nick
 
Check the main air hose going from the air cleaner to the throttle body if it's split anywhere the 3FE won't run worth a damn.
 
You guys are not helping him in diagnosing the real issue. Tossing parts at the issue is a waste of time and money.

How does it idle? smooth? Well then there is no vacuum leak.
NY nick, if you have a fuel pressure gauge or can borrow one, go and buy a long fuel pressure line of the same inner diameter with a T and three clamps and then attach it near the inlet near carb and monitor the fuel pressure inside the truck when under a load. Do you see a real noticeable drop in pressure? Does this system have a fuel line return to tank? Please note pressure drop at one rpm and under load "50% throttle". Check that carb bolts are tight, inspect lines around carb. Inspect butterfly for ease of movement.

Second possibility is not enough current to pump "rare but happens" but you said it stalls, so not likely the issue.

The last option is week ignition, over heating ignition module. Does the truck start up right away after it stalls, or does it require some time to start, say cool down 10-20 min? that is indicative of a failing ignition.
 
I experienced similar plug issues a several years ago. I think it was a bad connection where the wires were not setting tight on the plug.

Keep us posted.
 
Ok, so after this happened last week the idiot monkey mechanic put plugs in...meanwhile, my old plugs looked just fine. However, the truck ran great and got me around. I put some Techron in it for giggles, and the truck was running great...did over 100 miles yesterday. Today was fine, until.....going up a hill, under load so to speak, it started again. I could feel it missing, and it got worse, I could'nt go past 1500 rpm's. Thank god I was close to home, and I limped it into the garage. Before shutting it off however, I put it in neutral and revved it...no probelm, no hestiation, purrrrfect.

So I pulled the codes. I suspected TPS, but got nothing. Normal operation, no codes.

As this has happened before, it seems like it happens when it's warm/hot out. I like the fuel pressure theory, but it's itermittant, and I never know when it'll happen. But, also, no carb on an FJ62. BTW, idles fine.

I'm off to the annual Porsche Parade tomorrow in Vermont, but need to keep after this issue when I get back. Thanks guys.

Nick
 
Sounds like it's either loosing fuel pressure or spark, under load.
Test fuel pressure with a Gage duck taped to WS while driving under load.
Test for spark with timing light on while driving under load.
 
Could it timing too?
 
@NYNick

Okay....

So even though I'm normally aspirated, I think there's a crossover.

I was experiencing the exact same thing. Only at the highest fuel
requirement...up a prolonged medium incline the 60 was cutting out
at 2500-2800RPM and couldn't get above a certain RPM once I lost it...
in hot conditions. ambient not engine temp.

Everywhere else...no problems at all.

So I started (cheapest to most expensive theory) with fuel filter.
wasn't that.

Was pretty sure it wasn't spark so I was looking at the secondary
vacuum diaphragm on the carb...ordered the rubber diaphragm and
the gasket for the housing...still inbound.

Here in SW Colorado, even the premium gas has ethanol in it...so
I had been purchasing special non-ethanolated gas (only available
at one station in town) but I had gotten lazy and just been putting
the highest octane gas I could get at a closer station.

On a lark, I topped the tank off with the non-ethanolated regular
(only an 86 octane rating) and put in a bottle of octane boost...

No cutting out up "the hill" and issue has not occurred again.

It may not be your problem (s***ty gas) but it's easy enough to check ;)
 
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I don't have a choke...or a carb. I did in fact put 2 bottles of Techron in before it happened again, along with some 93 premium. In checking my past notes I can't find any reference to replacing the cap and rotor when I went over the whoe car 3 years ago, or the plug wires, although they're NGK and look brandy new. I'll give everything a look tomorrow, and replace it all. It's cheap enough to do, I just can't imagine that's the problem tho...
 
I think your issue is an idiot monkey mechanic who is most likely younger than the 62 series.
 
3_puppies said:
I think your issue is an idiot monkey mechanic who is most likely younger than the 62 series.
Click to expand...
The IMM doesn't work on my truck...nobody does but me! It was just happenstance that I limped into that garage since I was having issues. I've known those guys for a long time, and I only let them do my NY Inspections.
 
UPDATE!

I decided to start with the easy stuff and work backwards from there. I ordered a new OEM coil (had aftermarket), new NGK wires (weren't that old) new OEM rotor and new OEM distributor cap. These cost a little over $100. When I went over the truck top to bottom 4 years ago I guess I decided not to replace those last two, as they were original to the truck, had 148,000 miles on them and were 28 years old!

I put some injector cleaner in the tank and ran it for a few days, then filled it with premium (ouch) and ran that tank.

All I can tell you is the truck is now running better than new! I'm guessing it was the rotor and cap as they looked a little uneven inside from wear, but so far so good. It's been great since July.

Fingers crossed it keeps running this well!

Nick
 
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