Misfire and sputtering during acceleration

[Cruiser535]

I have 93 Land Cruiser..and recently started having issues during acceleration on highways. Between 2k-3k rpm..the engine sputter slightly ...when I let go of the gas sputtering stopped. I took it to the dealer..and they cleaned the injectors, throttle body, changed the spark wires, fuel filter, and plugs ($$$$$). The problem still persist. Engine compression, coolant pressure, fuel pump pressure all checked out ok. Dealer is now talking about replacing the injectors. Before I go any further and burn more $$$. Any thoughts on what might be wrong with my cruiser? Everything with the rig is good, smooth idle, no leaking of fluid etc...except this hesitation/sputtering on highway. I suspect bad fuel...so I poured a couple of bottles of iso-HEET. The issue is still there. Any advice is appreciated. Thanks!

 

[gtfour43]

Hows your intake hose?

 

[Cruiser535]

Intake hose looks good. no crack or anything.

 

[landtank]

engine harness

 

[theside00]

TPS sensor?

 

[95ToyCruiser]

engine harness

I second that, check the harness above the egr valve, it tends to go bad there..

I also have an extra motor if you need any parts, I have the harness too, pm me if you need anything...

Good luck,

Shane

 

[084runnerltd]

I second that, check the harness above the egr valve, it tends to go bad there..

I also have an extra motor if you need any parts, I have the harness too, pm me if you need anything...

Good luck,

Shane

Also check wiring harness in glove box....the wires rub on the side of box and will expose the wire causing said problems.

 

[Cruiser535]

Ok. Over the weekend I put a new set of NGK spark plugs and brand new coil pack. The issue goes away for about 2 days and return to sputtering again during highway acceleration. Now I am coming to believe it’s the injectors. How challenging is it to replace the injectors on 1FZFE? Dealer is asking $1500 (parts and labor). Is there a guide on mud? …how does rebuilt injectors from GB compare to OEM injectors? GB rebuilt injectors are about $50 on eBay and OEM are like $150. Thanks.

 

[george_tlc]

http://www.george4wd.taskled.com/injectors.html

CHECK THE HARNESS too !!!

If the dealer actually removed/cleaned the injectors then they should have also been flow tested at that time. Ask them what was done to 'clean' them...

cheers,
george.

 

[Cruiser535]

Thanks George. I am going to work on the injectors tomorrow. To depressurize ...you mentioned removing the relay and run the engine til it stop. There are 2 EFI fuses in the panel ...big round one and small one. Can I just remove the small one? I am still trying to figure out how to remove the big one (round) ..don't want to damage the plastic clip.

 

[george_tlc]

You can also just let the vehicle sit for a while - it will lose pressure on its own. There will be fuel in the rail so it will leak out unless you depressurized the system.

The relay (at least of 97 OBD2 models) is just inside the driver's side fender - below where the abs stuff is. Easy to unplug and then run the engine.

Crack open the fuel cap and leave it loose (or off) during the injector job - that stops the pressure building in the tank and then pushing fuel out the opened fuel rail, especially in warm weather.

cheers,
george.

 

[Cruiser535]

Ok. I found the bad injector. #6. Seriously corroded by drips of coolant leak from the heater hose above. What's a good cleaner to clean it? Should I use dielectric grease when I put it back. Thanks for all the info on the disassembly...it saved me all the guess work!

 

[Polar Bear]

Go with an electronics contact cleaner-leaves no residue. Use an appropriately sized fuzzy pipe cleaner to rod out the worst of it and then finish it off with some more contact cleaner.

Not so sure about the grease when you're dealing with narrow tolerance low voltage signal. I could be wrong however...

 

[george_tlc]

I'd personally look at buying a new harness end injector pigtail and cutting off the corroded one and splicing in the new one. Not worth doing a half arse job on electrics unless you want to turn your 80 into a rover product...

What's the injector side look like - I'd consider a new injector if that is a mess as well, keep the original as a spare if it is functional.

Where's the coolant leak coming from - bad hoses, clamps or a heater valve that is about to give way. Read threads on this forum - the heater valve deteriorates over time and the plastic pipe ends will give way catastrophically, has happened to many including myself.

cheers,
george.

 

[Cruiser535]

Thanks for all the tips guys. My LC runs so smooth now. I replaced all injectors and seals with rebuild injectors, replaced injector #6 connector housing, wrap heat shield to the harness, and replaced the heater control valve to fix the leak as well. ..putting misfire to a graceful closure

 

[george_tlc]

Excellent! Glad you did the job(s) properly. Now you can enjoy your vehicle.

cheers,
george.

 

[dmatter4]

How much did this cost you in dollars and in time?