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Precision Auto Injectors for my 01. (install)

srmitchell

NAXJA Forum User
Hey Naxja. I recently started looking at getting a set of new injectors, and i was too lazy to track down a jy set.

I have 4.56's, so the torque is great, but who doesn't love extra power?

I bought a set of Precision Auto Injectors, for my 2001 xj, 4.0L. They are flow matched, cleaned, and reconditioned.

They have 4 holes, bosh models. I got them on sale, and they only took 3 days from florida. Customer service was great, and the packaging was awesome.
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So on to the install.
-Disconnect your battery. (Please, you're working with fuel.)
-Remove the throttle linkage, ccv hoses, and anything else in the way.
-You need to remove the little clips on the injectors, and bleed the fuel rail. (Valve at the front of the rail)
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This part was simple, but the hardest was removing the connectors. All of my ev2 electrical connectors were old, and brittle. 2 of the clips broke, so be careful. Having them sit in the sun under the hood vents must not help.

Make sure you number the connectors! (The blue tape in the photos.)

The fuel rail has 4 bolts, and it lifts out. Fuel will spill, and it hard to remove from the manifold, so be careful.

Once that was out, I made sure to remove all old orings, and clean all of the fuel ports.

The new injectors were packaged in oil, so they were easy to slip back in. I replaced the clips, and did the reverse of removal.
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Done! I had to cycle my key back and forth to prime the fuel, it wouldn't start at first. I also reset the PCM and replaced the spark plugs to get the full benefit.

So far, Ive noticed more power, smoother idle, and better overall engine sound. No comments on mileage, I wont know until the pcm relearns my driving habits. I was getting about 18 freeway, so we'll see.

-Columbus.
 
Sounds like a nice setup. How much did they run you and where did you get them?
 
Precisionautoinjectors.com.

Its best to email him, and he will get ou what you need.

I only paid 109 shipped to CA.
 
I have an '01 as well and might give these a shot...

I know it may be a bit too soon to tell, but definitely let us know if you notice any difference in their resistance to vapor lock (if you have a fan timer or hood vents, this very well may not be possible). The heat soak issue is killing me and I have yet to install a fan timer.
 
So far, it runs really well, but it won't start everytime!

Before, I could hold the key for half a second and it would fire right up.

Now I have to let it crank much longer, and sometimes I have to give it more gas or try a second time. In fact, last night i went to crank it, and it spun, started, and died... but it shook like a diesel shutting down.

Not happy about that.
 
Have you run any MMO, seafoam or FI cleaner at all? I have installed the orange top ford injectors, and it starts quicker and everytime. Mileage improved, and idle is better, not sure there is much power gain tho. I know you said they were all cleaned and such, but running some cleaner thru the tank should help. Maybe your fuel filter needs to be replaced?
 
I just recieved my set in the mail today. I have a stupid question. I ordered mine for a 98 XJ 4.0, but the ones I have are what looks like brown tops and they are single hole. Did I order the wrong ones? I know my connectors are different than the 01 connector, but don't they make a 4 hole injector to fit a 98? Sorry bout the hijack.:gee:
 
19 lbs per hr, or what ever. They flow the same as stock. The difference is the holes.


you sure about that 19lbs? The flow changed through the years.

Model Year Part Number Color Fuel Pressure Static Flow
1987-1990 53003956 Black 39psi 18.6lb/hr
1991-1993 33007127 Brown 39psi 21.0lb/hr
1994-1995 53030343 Tan 39psi 21.0lb/hr
1996-1999 53030778 Grey 49psi 23.2lb/hr
1999-2006 04854181 Blue Tip 49psi 22.5lb/hr
 
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