Injectors & fan switch... I searched.

2000 XJ Sport - Stock with 206k miles.
Only visual upgrades currently.

New radiator, new fan clutch, new OEM t-stat, newer water pump, runs good gets 18.5 MPG.

Okay here it goes...

I obviously wanted to put a switch on my fan because of the sheer paranoia of buying a 2000 XJ and its lovely aluminum head thats feared. I am not new to Jeeps as this is my 4th one in 3 years. I buy them cheap, fix them, upgrade them & sell them. The last one was hard wired so I never dealt with it and the 2 prior never had any issue with overheating. I recently installed a new radiator, fan clutch, T-stat, and the water pump only has about 10k on it. I still want the fan hard wired because I enjoy piece of mind regardless how much it actually does.

I followed someones write-up where you tap into the grey PCM blue/pink wire and then ground it out with a switch on it. Some people have been able to get away with it on +97 vehicles and some have not. I am one that has not. Because I dont have a drill press I have yet to drill a hole where I planned on putting the switch. For now it is simply grounded out to the core support with the rest of my wiring. The fan obviously runs & it ran normal before so I am aware that this caused the MIL (P1491 - Radiator Fan Relay Circuit Fault ) which I would like to get rid of that but I love the simplicity of it and the fact I'm not good with wiring & shitt.

Also, I was curious if this was related (P0118 - Engine Coolant Temp Circuit High Input). This happened when I shut the Jeep off & turned it on 10 minutes later along with a cylinder 3 misfire. I am aware of the TSB regarding something similar to this so I let the engine cool, deleted the codes, & it never came back. That was until I did the fan hard wire. Is there any way this is related? I did not have any hard start rough start issues even after short periods of shut off after installing the new radiator, fan clutch, T-stat so I was just curious if it could be related. The Jeep does have that stupid uselsss aluminum shield / blanket but it didnt do much obviously.

Finally... Injectors. Everyone has stated that Ford 5.0 injectors or neon injectors are an upgrade because they go from a 1-hole system to a 4-hole system and there are even 6-hole systems. I know without computer XXXXk-with-idgery you cant get much in terms of performance but I simply want to improve how it idles, drives, & its MPG Everyone also states that 19 lb/hr injectors are an upgrade. All injectors I got of a website were tested at 43.5 and here it goes...

2000s have 49 psi fuel system & 22.5 lb/hr injectors. I read that 19lb/hr injectors are only good to around 1996. After that obviously the systems went to EV6 so the harness are different but on top of that the injector need regarding an upgrade is different. I have done a lot of research (at work haha) so I left the papers & numbers there so I will have to follow up in the morning. People say that 19lb/hr injectors arent a high enough flow rate for the 99+ vehicles. So I have conflicting information regarding the Neon Bosch 0280155702 injector being benificial or even a potential downgrade to our system because when you do the match it only brings them to 21.4 vs the 22.5 its got in it now. In my research I found that Volvo injectors also work, I am a Volvo nut so I went & pulled a set (they are only 1 P/N off from neons ) and are truely rated at 19 lb/hr vs. the neon ones that according to the P/N are 16.4 lb/hr... Are these an upgrade or can anyone give me an answer as to what ones are truly an upgrade?

I have found Ford injectors that people just give the part number XF2E-C4B (Five0Motorsports left out the "4") and according to this site

http://users.erols.com/srweiss/tableifc.htm

rate them at 19.42 lb/hr @ 43.5 psi. According to math this makes them 21.875 lb/hr @ 49 psi which is still shy of the magical 22.5 that 1999-2001 cherokees are already given... sooooo does anyone want to give me some info here regarding injectors? I have 18 (quantity not flow) Volvo injectors that are truely 19 lb/hr @ 43.5 psi injectors and I am just debating if its worth putting in because although people say "thats for older 4.0L" even other companies out there are simply selling 19.42 lb/hr injectors... which according to math still miss the mark

Thanks,

PoopJeep the IV'th

It should take you all of 30 minutes and $12 worth of new o-rings to swap them Volvo injectors in and then see for yourself if they work out(don't forget to disco power to reset pcm, so it can learn them). Worst case scenario is that your wot will be a tad lean(the pcm will adjust in closed loop). You could make a map adjuster and raise the voltage a little if so(you should have a wideband o2 to verify afrs though). I've had the ground control switch for the fan relay for a couple years but just recently added a 2nd relay to get rid of the P1491(look up fyrfytr's write-up for schematic) in my 96.

For the record- No 4.0 liter ever came with an aluminum head. The 2000-01 just has a shitty casting that cracks sometimes.

I'm not much help with the fan code, but that's very odd.

I have a relay/switch that simply sends power to the positive terminal on the efan when I want it. It still works like stock otherwise. No codes, ever. For 3+ years.

The point of asking if they would be beneficial, the same, or a hindrance was because I dont intend on putting them in the car and abusing it to find out if they are "wrong". It would be like being curious if your Jeep was water proof and I asked you to push it into a lake to find out.

I am aware that I could see this first hand data but I am not about to get a W/B just to see if I am running lean. I do not drive the Jeep hard enough to put a demand on the stock ones, I am simply interested in getting a better spray pattern to be more efficient hopefully resulting in some additional pep off the line & fuel mileage.

I am interested to hear what people with 1999-2001 Cherokees have done for an injector upgrade. People still say 19lb/hr ford injectors but again I have read that some people are sluggish after, some just dump fuel. I want to be on par with the stock ones just with a better pattern.

0-280-156-02822.8239.6172.443.53.022.8239.635.141.7EV1HighFord^ forgot what these are out of

0-280-155-78921.0220.7158.843.53.021220.732.338.4TopHighChrysler-^ look like the best bet so far?

0-280-155-71018.25191.813843.53.018.25191.828.133.3-HighFord 5.0 5.8 4.6 v8
^ these are the beloved 5.0 injectors... less than 19lb/hr but again they are tested at 43.9 so you have to find out what fuel pressure the vehicle they came out of was.

0-280-155-70316.75176126.643.53.016.7517625.830.6TopHighChrysler 4-2.4l, Dodge 4-2.0l^ these are the Neon injectors... Very low yet people adore them.

0-280-155-70219.0199.7143.643.53.019199.729.234.7-HighVolvo^ Personal favorite because I have 3 full sets of them & know Volvos in & out. Mathmatically these only bring me up to 21.4lb/hr but that still beats the 5.0 injectors & Neon Injectors.

F2E-C4B Black Tip19.42204.1146.843.53.019.42204.129.935.5EV6High2.5l, 3.0l, 3.8l^ these are what Five0Injectors recomends for 1999-2001 Cherokees that are stock but want 4hole injectors... welp they tooo are undersized?


I am not doing this out of spite I am just curious because I have never found a solid answer regarding what injectors will properly fuel the +99 XJ's

I will read up on the relay thing because as I said I just liked how simple it was to splice and ground even knowing the MEL are hit & miss

Sorry bout the whole head thing my mistake I was talking about Volvos & Jeeps when I was writing this and I got the two mixed up and never reviewed my post. I have the 0331 head with meh castings.

For where you wired a switch for the fan to the power... where did you tap into power source? I am not a fan of wiring let alone electricity so if you could tell me how you went about it I would appreciate it. I dont know if I want to be able to turn it on even without the car on or just have it wired so that it can only turn on when the key is in run position

This is how my fan is wired. I cut the blue wire in the fan pigtail; the wire from the fan is connected to pin 30, and the stock power wire is on the normally closed terminal. I ran a fused power lead from the battery, which is connected to the normally open terminal. I have a switch in the dash that draws power from a key-on circuit in the cabin fuse box, which controls the added relay. Switch off, it works just like stock. Switch on, the fan runs whenever the key is on.

The drawing kinda sucks, but this is a really straight forward modification.


The PCM does not monitor the fan, just the relay that controls that circuit, so altering the wiring at the fan motor does not trip the CEL.

For what it's worth, if you have 206K miles on the engine, you probably have one of the roughly 95 out of 100 heads that don't have a problem. They usually pop in the 20-80K range. I've only heard from a couple of people who had one go after 100K(..,and honestly, after 100K, it probably wasn't the head that was the issue at that point.)

PoopJeep said:

Finally... Injectors. Everyone has stated that Ford 5.0 injectors or neon injectors are an upgrade because they go from a 1-hole system to a 4-hole system and there are even 6-hole systems.

Click to expand...

I had a leaky injector so I replaced them with a set of Bosch/Ford injectors from Fiveomotorsports. They work fine but I did not see any significant change in mileage or drivability over the stock injectors.

PoopJeep said:

I am not doing this out of spite I am just curious because I have never found a solid answer regarding what injectors will properly fuel the +99 XJ's

Click to expand...

me either. i never seamed to get a solid answer where ever i looked most of the injector talk is for the older XJs

oh well I am putting Volvo Injectors in. Everyone says get these or these and I looked them up on their flow and even the newer ones are rated "too low" so seeing as the volvo injectors are rated higher than even what five0motorsports supplies while still falling short I am better off.

I have to get the bitchh inspected and I will do the swap after as I failed already because the only place I could go (goodyear) decided to fail me telling me I had contaminated brakes... they never took the drum hat off & the only thing I noticed was that my 206k mile axle was dirty & that the inspection plug was missing aka they assumed it magically went into my drums. They figured I would have them do the brakes. Basically I took brake cleaner to the drum hats, cleaned them new. put the plug in but now I have to go through a drive cycle yet I dont have a sticker to do so as they failed me because of "safety" what twats

Im 99.9999999% confident that the Volvo injectors will be the tits so if anyone is interested I have 4 full sets & access to... unlimited sets haha