Builds 1FZ-FE Rebuild full overhaul - picture heavy (1 Viewer)

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A minor update. The rebuilt engine is at 120K miles now, and aside from the valve issue I had it's been great.

I am experiencing an intermittent cylinder misfire on #5 that appears to be an injector or injector wiring failure. It will misfire 100% on cylinder 5 for a bit, then like a light switch not misfire at all until it switches back to misfiring. Either the wiring to that injector is having an issue or the coil is failing in it. The injectors are original and have 336K miles on them. Right now I'm looking at options. A set of new OEM injectors is almost $1200. Ouch. I hate to replace just one at a time though. I'll be investigating this weekend to see if it's just a wiring issue. Hopefully!
 

Green Hell Mustang

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A minor update. The rebuilt engine is at 120K miles now, and aside from the valve issue I had it's been great.

I am experiencing an intermittent cylinder misfire on #5 that appears to be an injector or injector wiring failure. It will misfire 100% on cylinder 5 for a bit, then like a light switch not misfire at all until it switches back to misfiring. Either the wiring to that injector is having an issue or the coil is failing in it. The injectors are original and have 336K miles on them. Right now I'm looking at options. A set of new OEM injectors is almost $1200. Ouch. I hate to replace just one at a time though. I'll be investigating this weekend to see if it's just a wiring issue. Hopefully!
If the engine harness is the same harness that came with the truck, it might be a good idea to check the injector wires. Also, check the condition of the harness at the firewall crossover, near the EGR where the thermal insulation is. That part can get crispy over time and mess with the injector signal.
 
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If the engine harness is the same harness that came with the truck, it might be a good idea to check the injector wires. Also, check the condition of the harness at the firewall crossover, near the EGR where the thermal insulation is. That part can get crispy over time and mess with the injector signal.
When I rebuilt the engine, I insulated the harness back there and it was in good shape at the time. Could still be an issue and when I get in there I'll look at it.

I know how hard it is to remove an injector, but to eliminate the wiring harness , can you swap the injectors with another cylinder and see if the misfire follows the injector?

I'm sure there's a better/easier way. If the manifold comes apart and one injector is out, they are all getting replaced.
 

1973Guppie

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A minor update. The rebuilt engine is at 120K miles now, and aside from the valve issue I had it's been great.

I am experiencing an intermittent cylinder misfire on #5 that appears to be an injector or injector wiring failure. It will misfire 100% on cylinder 5 for a bit, then like a light switch not misfire at all until it switches back to misfiring. Either the wiring to that injector is having an issue or the coil is failing in it. The injectors are original and have 336K miles on them. Right now I'm looking at options. A set of new OEM injectors is almost $1200. Ouch. I hate to replace just one at a time though. I'll be investigating this weekend to see if it's just a wiring issue. Hopefully!
they can almost always be cleaned professionally, and if found bad used ones are not too expensive.......
 

jbee

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I live in the big city, when I Google ‘injector service’ it’s typically diesel shops, you can still buy all the rubber grommets and caps and stuff from the Toyota dealer, I would have them cleaned and flow tested at a shop and put new rubber parts on them.

There are also reputable companies that will sell you a set of remanufactured Denso units on an exchange basis.

It seems like the turbo guys, specifically the supra crowd, changes out injectors quite a bit so there is an active market for them.

If your harness is bad you can still buy a brand new one. There’s some wrestling involved in replacing it, but it certainly eliminates all of the engine wiring issues.

The shop put some good insulation around the EGR portion of the harness when we put my new one in.
 

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