'93-1FZ Hesitation (1 Viewer)

[IheartmyTLC]

Hi all, Can someone please help me. My '93 80 (1FZ) hesitates during take off. The check engine light will kick on but the vehicle never dies. I checked the DELC1 and from that I determined that the problem was with Volume Air Flow meter. I have checked the OHMs of the VAF and Intake Air Temp meter IAT and they both seem to be with in specified ranges. I'll be checking it later after the vehicle has been running to see if it still is with in range. I have done a fuel system cleaning and now I am running full synthetic oil. Anyone have this problem? I have yet to test the O2 sensors but what I have read is that the ECU only uses the O2 for fuel economy and it's condition won't impact performance outside of fuel consuption.

Any thoughts?

 

[tucker74]

Have you checked the intake hose - it commonly cracks w/ age between the flow meter and intake...letting air in that causes the engine to die (particularly at idle).

Tucker

 

[Scamper]

I would check the hose as Tucker suggested first--I suspect that's your culprit. Check it really well as it likes to crack on the bottom between the flexes and is hard to see. You'll need to remove it to give it a good check.

If that does not produce a solution, (or even if it does...), you might want to clean the MAF since they can accumulate dirt/grime and make them malfunction. They can really get grimy if you use one of those aftermarket oil-impregnated filter elements. Just use some carb cleaner on it, then dry it out (gently) with compressed air. Don't touch it with anything!

 

[quicktodoze]

I have yet to test the O2 sensors but what I have read is that the ECU only uses the O2 for fuel economy and it's condition won't impact performance outside of fuel consuption.

Not true. I've had the misfortune of a bad 02 sensor before and it felt like I was running an old Briggs & Stratton under the hood. Does this happen after the engine has warmed or does it happen when it's cold too? You said that the engine never dies, which isn't completely like my experience - I couldn't keep it running when I let off the gas - but don't count out the sensor, especially if this happens only after it's had a chance to warm up.

Nic

 

[IheartmyTLC]

I will check this tonight and let you know. Though idle has always seemed solid... it's in mid take off that it starts to act up. None the less, that maybe it. I will let you know my finds.

Thank you, Thank you, Thank you

 

[IheartmyTLC]

Hi quick,
It does only happen after the vehicle warms up. Usually after 30 minutes of driving... it won't happen in a 20 minute drive.. Testing the O2's this weekend then.

 

[landtank]

Watch out for the wiring harness that passes near the EGR valve. When the engine torques it will act up. Usually in drive. When it acts up try reverse and see if it is better.

 

[quicktodoze]

Glad I could help.

 

[ppc]

No MAF on a 93 it has the VAF that was already tested. Sounds like the problems I'm having with the fuel pump. After 30 minutes it gets hot. How much fuel do you have in the tank?

 

[IheartmyTLC]

Hi PPC. I've seen it happen on full and empty. I pretty much the fuel run the full cycle (lazy on refueling). Currently the tank is creeping up on empty. Because this happens at take off I know it's either fuel or air or the proper mixture, so I'd be interested in hearing more. Another thing that hit me in mid thought of your porst..... I am running ethenol. Not unleaded, I'm thinking it's worth a try to change to Unleaded even though it costs me more. Thanks

 

[ppc]

My thoughts are if you run low on fuel the pump is not longer submerged in fuel to cool it and its performance is degraded. The Land Cruiser uses a dual voltage setup on the fuel pump. The ECM controls the fuel pump relay that either runs 12V through a resistor providing a lower voltage or direct to the pump. What you need to do is attach a volt meter to the "data link connector" pin one or terminal FP and monitor the behavior related to the voltage supplied to the fuel pump. An old tired pump can't provide the pressure required when operating in the lower voltage. When the ECM switches the relay and pump gets full voltage the engine gets a shot of adrenaline.