Builds 1FZ-FE Rebuild full overhaul - picture heavy (3 Viewers)

[sbman]

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!

 

[COYS]

A set of new OEM injectors is almost $1200. Ouch.

No, it's not/not.

 

[sbman]

No, it's not/not.

That gets it down to around $1K., so that's a little bit better! Hopefully it's just a broken/loose connector.

 

[Green Hell Mustang]

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.

 

[chbrow10]

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?

 

[sbman]

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]

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]

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.

 

[geologic]

Very nice, highly educational thread, thank you!

 

[sbman]

A while back, I started getting a rough idle and an intermittent misfire on cylinder 5. I'm finally addressing it.

I determined it was either a bad injector or an issue with the wiring harness. I disabled the EGR system and that eliminated the misfire, but the rough idle persisted. I believe disabling the EGR system helped because it reduced heat in the area of the 5/6 injectors. I see no other changes (aside from CEL) from having the EGR system disabled. No change in mileage, performance or anything. I'll be doing a resistor mod on that next, I don't see any reason to hook it back up.

I'm in the middle of addressing the rough idle right now. I pulled the upper manifold and inspected the wiring harness near the EGR and it's in perfect condition, no melted wires or anything like that, no sign of excessive heat. I had insulated it during the rebuild and it seems to have held up well. I re-wrapped and re-insulated it, and I'm replacing all the injectors. I know people say injectors don't fail, but after 340K miles on them they do seem to be the culprit. My friend's 22R-E also had injector issues causing a rough idle, and his were also 300K+ miles, had been recently cleaned, but were still causing a rough idle. I'll posts more details of the injector replacement as I get it completed.

I found that if you remove the starter, you get plenty of clearance to easily remove the rear most bolt and two nuts that you need to remove to split the intake manifold. I've done it with the starter in place and it's MUCH more difficult. You need a 30"+ length socket extension and just slide under the truck and you can clearly see them and unbolt them from below. You can have the upper manifold removed in 30 minutes or so.

 

[sbman]

I'm driving the new injectors now and can say it has made a huge difference. It idles better, much smoother and consistent on RPM than it was before. It responds to A/C compressor on/off far better than it ever did before you can hardly tell when it switches on/off, it used to jump around on the RPM when the compressor turned on and off and often ran at different RPMs. It starts faster (less cranks) as well, I'm pretty sure some of the originals were leaking down rail pressure.

I used a non-stock Denso 12 hole (EV14) injector that flows the exact same cc/min as the original equipment which were 2 hole EV1. They require a custom adapter that changes them to a 'long' injector. They have the same electrical connector. These are a Denso 297500-0940 which was OEM on Nissan VQ35DE engines and they flow 305cc/min, the same as the OEM injector. I ordered them from a guy that makes the custom adapters and ships a set of injectors with the adapters, but I also ordered brand new injectors to use instead of the refurbs that he ships with. So far I'm very happy, it runs smoother than it ever has and the throttle response is improved (subjective). We'll see if it results in any kind of an MPG improvement, but I doubt it will. All of the missing and rough idle issues are completely gone.

I have no way to quantify how these injectors would compare to a new set of OEM injectors, I went from old 340K miles injectors (that had been cleaned and serviced 100K miles ago) to brand new injectors.

Are 12 holes better than 2? We may never know, but I wanted to see how a modern spray pattern injector would perform in an old 1FZ-FE.

 

[baldilocks]

Can you provide info for the seller of these injectors and adaptors? Thanks @sbman

 

[sbman]

He sells on eBay as a set only. I would have preferred to buy just the adapters but he sells them as a set and they are fairly cheap so I saved the reman injectors for spares and bought new injectors locally from an injector shop, only using the adapters.

Upgrade Flow Matched Fuel Injector Set 12-Hole Replacements for 23250-70080 | eBay

Replace your old and tired units with a superior injector design. 6 - Genuine Denso Flow Matched Fuel Injectors Per Order. Tightly flow matched units will ensure smooth idle. Flow test injectors and gather data.

www.ebay.com

 

[Wompom]

He sells on eBay as a set only. I would have preferred to buy just the adapters but he sells them as a set and they are fairly cheap so I saved the reman injectors for spares and bought new injectors locally from an injector shop, only using the adapters.

Upgrade Flow Matched Fuel Injector Set 12-Hole Replacements for 23250-70080 | eBay

Replace your old and tired units with a superior injector design. 6 - Genuine Denso Flow Matched Fuel Injectors Per Order. Tightly flow matched units will ensure smooth idle. Flow test injectors and gather data.

www.ebay.com

How are the new injectors going? I ordered a new set of OEM for my turbo'd 80 (that I also now need to pull for burnt valves). Debating trying the 12 vs 2 hole. curious what the performance difference would be if the atomization is different.

 

[BillyGoatMTB]

Didn't know upgrade injectors were available, thoughts sending them in for float testing cleaning and balancing was the way to go.

 

[sbman]

How are the new injectors going? I ordered a new set of OEM for my turbo'd 80 (that I also now need to pull for burnt valves). Debating trying the 12 vs 2 hole. curious what the performance difference would be if the atomization is different.

They are performing well. The differences are really subjective, I don't notice any measurable performance differences. It idles very smooth and the idle control seems better than it was before. Throttle response seems improved. MPG did not change at all. Long term fuel trims run 5-7%.

Didn't know upgrade injectors were available, thoughts sending them in for float testing cleaning and balancing was the way to go.

Cleaning and balancing is good, but after a certain age my injectors started dying, they are an electro mechanical device and had millions of operations on them, probably hundreds of millions operations. With 330K+ on the OEM originals (Cleaned/balanced at 220K), I was having issues with rough idles, intermittent severe misfires with loss of power and rough running (1-2 cylinders not firing at all). After determining the wiring harness was OK, the injectors were the only remaining culprit. New OEM would have worked fine but I thought I'd see what 12 hole injectors did for it. I knew for sure I wanted to replace all 6 since one or more were having an issue it didn't make sense to do one at a time.

Are they worth it? I don't see any advantage, but I also don't see any downside either. They seem to perform identically and MAY have a smoother idle. I've never had new OEM 2 hole injectors though so I can't say for sure.

 

[Outsane]

I am in the middle of a hg replacement and top of the guide broke.

Can the new plastic be slid into place without tearing down the whole motor?

From this picture it looks doable.

 

[Cruisers and Co]

I am in the middle of a hg replacement and top of the guide broke.

Can the new plastic be slid into place without tearing down the whole motor?

From this picture it looks doable.
View attachment 3538259

It's one part # (plastic and metal guide) so unless you decide to buy the guide, take it apart and not break it in the process it then I guess anything is doable but if the head is already off why not just do it the right way and replace the whole thing? It's my experience short cuts don't make good results. Just my 2¢

 

[Fj80oregon]

I do not think that’s doable that part is molded into the guide and would be destroyed by being removed.

 

[Fj80oregon]

If your savey enough you could possible remove and replace the guide with the cover in place. The bolts are only torqued to 15ftlbs and pretty shallow. The hard part would be getting the bolts started back in the block And if you dropped one may be a fight to get out.