1fzfe dies on acceleration

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Kfire01

10 Year
Joined
Dec 26, 2014
Threads
19
Messages
131
Location
Lubbock Texas
I just finished a rebuild of this motor, (93 FZJ80) and it runs smooth, but when you accelerate, it dies.You can start it and hold the throttle at 200-2500 rpms, and it runs smooth, but if you go to idle, and then try to accel, it drops dead.
Ive checked the AFM, ICV, TPS and Fuel Pump relay, per the FSM, and everything checks out. On the AFM, the first ohm reading (VS-E2 I believe) should be 200-600 ohms. Mine checks out at 199 ohms. Should I worry about that? Or chalk it up to meter variance? All the other tests on the AFM were in spec. I did pull the 2 screws to release the harness, before I found out that was a no no, but I soldered it back, and all readings are within spec per the FSM.
I have replaced the air intake hose and clamps, as well as a new throttle body gasket. I have checked all vacuum lines, which were replaced during the rebuild, and I cant see any that are disconnected.

I am going to pull the fuel pump and sock, and check that, but do you guys have any other suggestions?
My main harness seemed to be in pretty good shape, when I had it off, I check carefully around the EGR area, and no damage. It does have new plugs, wires, dizzy.

Any help would be appreciated.
 
This was a complete overhaul. I bored it out, rebuilt the head. I can get it to run at higher rpms. I tried put it on a timing light, but now I cant get it to idle long enough to time it. I checked for codes, but nothing shows up.
 
Let's start with cam timing. It runs real smooth at anything above idle. Would that be possible with the cams 180 out? Ignition timing, well, if I could get it to idle, I could get in time. I can get it close, but it idles I'm guessing about 300-400, then eventually dies. Since I can't get a CEL, I guessing its out or been disconnected. I think my next step will be to replace the CEL lamp and see if I'm getting any codes. Ive checked visually for vacuum leaks, grounds and connectors. Nothing that I can find.
 
Just yesterday I wrote about my mistake of removing those two screws. I posts pics of the internal damage I did with a gentle tug. Exactly when in this process did you
Kfire01 said:
I just finished a rebuild of this motor, (93 FZJ80) and it runs smooth, but when you accelerate, it dies.You can start it and hold the throttle at 200-2500 rpms, and it runs smooth, but if you go to idle, and then try to accel, it drops dead.
Ive checked the AFM, ICV, TPS and Fuel Pump relay, per the FSM, and everything checks out. On the AFM, the first ohm reading (VS-E2 I believe) should be 200-600 ohms. Mine checks out at 199 ohms. Should I worry about that? Or chalk it up to meter variance? All the other tests on the AFM were in spec. I did pull the 2 screws to release the harness, before I found out that was a no no, but I soldered it back, and all readings are within spec per the FSM.
I have replaced the air intake hose and clamps, as well as a new throttle body gasket. I have checked all vacuum lines, which were replaced during the rebuild, and I cant see any that are disconnected.

I am going to pull the fuel pump and sock, and check that, but do you guys have any other suggestions?
My main harness seemed to be in pretty good shape, when I had it off, I check carefully around the EGR area, and no damage. It does have new plugs, wires, dizzy.

Any help would be appreciated.
Click to expand...
Did you remove the screws from the AFM before or after the engine problem arose? I wrecked my AFM yesterday and could not see myself soldering the damage. Just so happened a guy 75 miles away is parting out a 94. It sounds to me like you are not getting the fuel when you put your foot down. The AFM could still be the culprit since you know that it "was" damaged.
 
It actually happened before I rebuilt the motor. After I repaired it, the motor ran, albeit rough, since it was in dire need of an overhaul. In the FSM, there are a few ohm readings to take on the AFM, all mine are in spec, except the first one, which comes in right below the low end of the resistance spec. It should be 200-600 ohms. Mine was 199. Just a few minutes ago I checked it again, and its even lower, I suspect the heat of the day may have something to do with that. I may have to bite the bullet and buy another AFM.
 
On a 1996 1FZ-FE there is a relay that throws full 12V to your fuel pump when needed. Otherwise, the power to the fuel pump goes through a resistor. If this relay isn't closing/working, you could starve for fuel pressure. The resistor is on the passenger fender, the relay is on the driver fender.

I'll ask a dumb question: Is there enough fuel in the tank? Wondering if it evaporated while it sat maybe...
 
lol, there are no dumb questions, as I am stumped. Yeah, its got plenty of fuel. I did check the fuel pump relay, but not the resistor. The relay checked out according to the FSM. Like I said, I think I am going to pull the dash cluster to make sure the CEL bulb is working. I wonder if the AFM is bad, will it throw a code?
 
Kfire01 said:
lol, there are no dumb questions, as I am stumped. Yeah, its got plenty of fuel. I did check the fuel pump relay, but not the resistor. The relay checked out according to the FSM. Like I said, I think I am going to pull the dash cluster to make sure the CEL bulb is working. I wonder if the AFM is bad, will it throw a code?
Click to expand...

No, it will not throw a code, necessarily. I know 2 people that had a damaged AFM and NEITHER had a code.
 
Search on here for fuel pump resistor, seems like this has been a problem recently for a lot of folks.
 
When I was a generator mech in the service I ran into a similar problem. The genset had no load it was fine but when I contacted the load it died. Turned out the fuel pump wasn't grounded good enough. I've never worked on my 80s pump yet so take it with a grain of salt...
 
Kfire01 said:
lol, there are no dumb questions, as I am stumped. Yeah, its got plenty of fuel. I did check the fuel pump relay, but not the resistor. The relay checked out according to the FSM. Like I said, I think I am going to pull the dash cluster to make sure the CEL bulb is working. I wonder if the AFM is bad, will it throw a code?
Click to expand...
My code was 24- IAT sensor which is integrated into the AFM.
 
Do you have a scangauge or ultragauge? Those will check and clear codes without the dash light. Check the dash light bulb when turning on the key to confirm operation. There is a sequence about if there isn't a light it can mean something else also. @toolsrus did you post this once?
 
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