1988 3Fe power weak (1 Viewer)

[MostlyNuts]

Took the 62 up HWY 88 and made it 1/2 to Soda Springs, CA (~2500’) before we had to turn back due to lack of power and it began to sputter under load. I suspect a few things.

• Possible bad TPS still (connector needs replacing)
• MAF still not working correctly (doubting because its fine in other circumstances)
• Kick-down cable not set correctly
• Injectors need replacing

Any of this make sense to you or you have any other ideas I should check? I plan to mess with the CD cable later tonight when I have some time.
It’s like a carb that has mixture off bad vac leak. Runs fine at sea level, albeit the CD cable needs adjustment.
Thanks all,
MN

 

[Roonie]

my experience with something similar on my 62 was fixed by doing a combination of things but ultimately I think it was by buying new injectors. I also replaced the computer and the tps sensor. I replaced the air intake rubber as they had vacuum leaks. And made sure all my spark plug caps were sitting tight and working. A combination or all the above or one of the above worked and fixed it for me. I was having a misfire in one of the cylinders and losing power at highway speed only.

 

[diesellibrarian]

Is it throwing any codes?

I would start with a full tune-up (valve lash, timing, compression test, plugs, air cleaner, fuel filter, etc.) so that you can rule out those fundamental factors.

If the problem persists, dig deeper looking at possible vacuum leaks, fuel pressure issues, and injectors. It's also not to difficult to test the various sensors and VSVs that the ECU relies on to manage the engine, but you'll need a copy of the FSM to get the correct specs for testing.

 

[60Works]

You might try changing the fuel pressure regulator and/or the fuel pulsation dampener. They're inexpensive but kinda hard to get to. My 62 would idle just fine and start to accelerate then fall on its face at 1,200 rpm. It acted like it was starved for fuel and tended to overheat (possibly from running lean). If I gradually increased speed and got the tach up to 3,200 rpm it would shake it off and pull normally again.

Changing the regulator and dampener at the same time fixed it so I don't know which one was the culprit.

 

[KxvilleFj62]

Had this same thing happen to my 88, 62. Just as @Roonie mentioned, it was a mix of multiple fixes/replacements that returned mine to a properly functioning machine.

New injectors
Kickdown cable - mine broke
Adjusted TPS and timing

 

[MostlyNuts]

ok, it's got a new TPS, fuel dampener, fuel regulator, fuel filter, fuel system flush, MAF sensor. I cleaned the injectors myself so highly suspecting those. Curious though that it runs fine around town, even if you step on it but then struggles at 2500'.
I'll try some more of what you guys mention. My first step though is to readjust that darn kickdown cable. It could be as simple as that (fingers crossed) but I'll let ya know after i try it.
Thanks all!

 

[Bleu62]

Did that work?

 

[Bleu62]

You might try changing the fuel pressure regulator and/or the fuel pulsation dampener. They're inexpensive but kinda hard to get to. My 62 would idle just fine and start to accelerate then fall on its face at 1,200 rpm. It acted like it was starved for fuel and tended to overheat (possibly from running lean). If I gradually increased speed and got the tach up to 3,200 rpm it would shake it off and pull normally again.

Changing the regulator and dampener at the same time fixed it so I don't know which one was the culprit.

Mine is doing exactly this. I've bled the fuel from the pressure regulator and it clears up for a one trip then starts again the next time I start the car.

 

[MostlyNuts]

Sorry for the delay. I had to step away for a bit. ;o)
Still working it. What I did last was removed and bench tested the throttle body. It was very difficult to dial in so I replaced with another I got from @orange45 that I was able to calibrate. I fixed the hesitation issue strangely. With my questioning the injector I cleaned myself I decided to just get rebuilt good ones. Again, @orange45 helped me get known new good ones and they are all installed. Fuel pressure looks good, compression good on all cyl, TPS measures good...It runs really rough now. Actually died on me on a test dive down the street. started right up after.

So, I did not give up but rather- due to time and sanity sake- it's in the shop and we'll hopefully have it properly diagnosed by those with al the right tools. I have a lot but am not specifically set up as an auto shop in my garage.

Will update ya'll once we have a good answer.
Cheers!

 

[TheElegantFox]

My journey to get power back on mine was extensive. Rear diff rebuild, new water temp sensor, adjust kick down cable back to FSM spec + lubricant, new TPS, new O2 sensors, new OEM exhaust from cat back, new vacuum lines.

Each of these made an impact on mine, next on my list is likely a spark plug refresh since I haven’t done that under my care yet but the truck is driving a lot better than day one when I picked it up from the PO.