86 intermittently losing power

D

Denise Burchette

True Classic
I've been having a problem with this 86 that has been so intermittent I didn't have enough info to share but it seems to be getting a little more consistent. It doesn't matter if it's hot or cold or if it was just started, stop and go traffic or highway driving, but occasionally, when I am accelerating or keeping a constant speed, it feels like the engine stops pulling. The rpms stay the same, even as I push down on the accelerator. Sometimes it will clear itself and sometimes I'm too impatient so I downshift and floor the sucker. It usually responds and has never cut off. I don't feel it's an ignition problem since my rpms stay constant. Would a weak fuel pump be intermittent or maybe a clogged fuel filter? Thanks in advance for any help.
 
Hey Denise...

Hope you and yours are well otherwise...

Do download and read the FI Troubleshooting Guide in WIKI here...

For the QUICK possibiliies... I would check pump pressure and then also pull and have the injectors tested and cleaned PROFESSIONALLY.

But those are only GUESSES... Hope this helps...
 
YES

My experience with worn fuel pumps has always been intermittent failure. Sometimes on the highway, sometimes at idle. It could also be water in the gas.

If you don't see any idiot lights going on like the no-charge light, or the low-fuel light, or just random sparks shooting out of the dashboard (kidding), then it's probably the pump.

And since the failure is intermittent and random, it will be hard to check, because it's usually working.

Personally, I'd change it anyway just to avoid being stranded. Do the filter too. They don't last forever, and like a cam belt or radiator hose, it will strand you instantly if it breaks.
 
Thanks for the response guys. It stands to reason the fuel pump would need to be replaced. This is my third X19 and third fuel pump. At least it's an easy fix.
 
Well Denise... you can prove it with DOLLARS or...

... with a pressure guage... whichever is cheaper/easier for you.

There are other things involved like Eddie said... the fuel pump regulator, the fuel filter and possibly other FI gadgets I know nothing about... and even a VACUUM control line. That is why I suggested reading the FI T.S. Guide...

I betcha that live-in race-car guy ya live with could probably ascertain the issue before ya get too greasy...

HA!
 
other possibles...

The contact of the sweeper to the circuit board could be worn out. One fix is to bend the sweeper in a zig-zag fashion to make it touch in a different arc. Another possibility is the connector is loose or has corrosion.

And, you could have a crack in the main air hose between the AFM and the throttle body. I'd remove it and carefully check for cracks, and check other hoses for air leaks. A large vacuum leak could act like this.
 
A new fuel filter if you haven't already replaced it and some Seafoam in the intake (spray through a manifold vacuum line like the brake booster). The stuff really cleans out the injection system.
 
Hello Denise,

Really sounds like a fuel delivery problem..
Start at the tank, tank pick up and move down the system from there.

Keep us posted,

Bernice

Denise Burchette said:
I've been having a problem with this 86 that has been so intermittent I didn't have enough info to share but it seems to be getting a little more consistent. It doesn't matter if it's hot or cold or if it was just started, stop and go traffic or highway driving, but occasionally, when I am accelerating or keeping a constant speed, it feels like the engine stops pulling. The rpms stay the same, even as I push down on the accelerator. Sometimes it will clear itself and sometimes I'm too impatient so I downshift and floor the sucker. It usually responds and has never cut off. I don't feel it's an ignition problem since my rpms stay constant. Would a weak fuel pump be intermittent or maybe a clogged fuel filter? Thanks in advance for any help.
Click to expand...
 
budgetzagato said:
And, you could have a crack in the main air hose between the AFM and the throttle body. I'd remove it and carefully check for cracks, and check other hoses for air leaks. A large vacuum leak could act like this.
Click to expand...

Just recently I had a WHOLE bunch of issues with my fuel system centered around the injectors. However when I put the system back together I also found even though the car showed RPM it was just a dog. I looked at the air snorket between the AFM and the intake manifold and found a bunch of cracks. Soon after the car started to "whistle" when excellerating. I filled the cracks with an epoxy (just cant find a reasonably priced replacement) and the dogness was gone and the car pulled well.

I would take a look, get into the engine bay and listen real good while revving the engine.
 
Great advice

I'll go ahead and replace the fuel filter and install a pressure gauge. What pressure should I be looking for? I'll check for cracks in the hoses and vacuum leaks. I have a friend from CA coming for Freakout and this is the car he's driving for a couple weeks so I hope it's a simple problem. I still got a set if IDFs on the kitchen table needing rebuilt for the FFO....too little time.
 
My problem was the fuel filter, but ended up replacing the fuel pump and adding an inline filter just before it, both as precaution. But start with the fuel filter.
 
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