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Renix/HO mashup questions (fuel pressure)


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Hey everybody! Hoping to shed the light on some issues that others may also be experiencing.

 

Here's the deal:

1987 MJ, Still has RENIX electrical system 

HO 4.0 Motor and head (2001)

HO intake manifold (95?, not the ramshorn style of 01)

Matching fuel rail to intake. Has a pressure regulator on the return line. Both supply and return lines are located at end furthest away from firewall.

 

I am looking for injectors that will work with this setup, but I am having trouble determining my necessary specs for the new injectors. Since I am buying new anyway, I would like to get 4 Hole injectors as well. It seems as if the renix injectors operate at a different psi than HO. Since I have Renix electronics, but a HO fuel rail, manifold, engine, I am not sure what injectors would work best.

 

 

 

 

 

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With a mishmash setup like that, and w/o knowing if any intake/exhaust port matching was done, you would have to get creative to do it right. I would go with a mid-range Bosch 4-holer injector, like the -703 "Neon" injectors. To dial them in you would need to get rid of your fixed pressure regulator and replace it with an adjustable like the Hesco unit, then monitor the resulting air/fuel ratio with an A/F meter. That's to do it right.

 

If you don't want to do it right, just throw some 4-holers in and see how it runs according to your butt dyno like most everyone does.

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2 minutes ago, DirtyComanche said:

Use the Volvo or Ford ones for the Renix, you're not picking up enough airflow to need more.

 

^^  If you don't want to do it right, just throw some 4-holers in and see how it runs according to your butt dyno like most everyone does.

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14 minutes ago, HOrnbrod said:

 

^^  If you don't want to do it right, just throw some 4-holers in and see how it runs according to your butt dyno like most everyone does.

 

I wasn't meaning that to imply that he shouldn't continue to tune it after, but all reading I've done suggests that the Neon injectors will outflow his requirements.  He will be a lot closer to the ballpark using the Volvo or Ford ones.  But maybe not.

 

I'm actually going to change my advice to "try it with whatever injectors you have and change them out accordingly."  If you legitimately have no working injectors on hand, then go get some junkyard or eBay ones.

 

(Are you actually planning to buy 'new' injectors?)

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11 minutes ago, cruiser54 said:

Renix ECU, right?

 

Start with something for stock Renix. Volvo 746s are a nice choice.

 

Thanks,

Yes, I still have the RENIX ECU. Its from a 89, which I now remember as being the most desired computer year for fuel ratio. At least thats what I think I remember reading. Its been a while out of the Jeep game, trying to remember all of the facts that got a little fuzzy haha. I also completed all of your Renix tips, Including recently eliminating the  C101 connector.

 

 I like the idea of a adjustable regulator, which I will look into now. I don't have a A/F meter, but I suppose that's something I could purchase If problems arise. I am wondering if the "Renix scan tool" that Nick sells would help me in someway with this mess as far as electronics to the fuel system go. I know 

 

As far as port matching goes, The intake and ebay header used matched my clearwater 3301 head perfectly. No I didn't professionally port match them, but a took care to sand the  inside of the intake manifold tubes. Also will be running a AEM dryflow filter and 1 inch throttlebody spacer (I realize its a very minimal if any aiflow gain, just figured I would mention it)

In case anyone in a similar situation is following along, here is one of cruisers links about the Volvo 746s for renix applications

http://cruiser54.com/?p=438

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7 hours ago, DirtyComanche said:

 

I wasn't meaning that to imply that he shouldn't continue to tune it after, but all reading I've done suggests that the Neon injectors will outflow his requirements.  He will be a lot closer to the ballpark using the Volvo or Ford ones.  But maybe not.

 

I'm actually going to change my advice to "try it with whatever injectors you have and change them out accordingly."  If you legitimately have no working injectors on hand, then go get some junkyard or eBay ones.

 

(Are you actually planning to buy 'new' injectors?)

I have a set of ebay remaanned injectors that I think are 3 hole. I ran these my Renix for 3 years. The truck never ran perfect, well consistently at least. I would rather not reuse these. I also have a bunch of other OEM jeep injectors from various years, and varying conditions. As a last resort I could clean them up and use them, But I would much rather purchase a remanufactured 4 hole set

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Also, I am looking to source new fuel lines as well. Does anyone know of a set of fuel lines that will fit the "quick connect" fittings of a HO XJ rail? I have used gastankman on ebay before for a different vehicle with great results, I contacted him but did not receive a response. I am going to contact him again, but in the meantime I was wondering if anyone else had any links to a fuel line set, without going AN

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2 hours ago, JeepComanche89 said:

I am wondering if the "Renix scan tool" that Nick sells would help me in someway with this mess as far as electronics to the fuel system go.

 

Yes, REM could help with A/F. It would just take driving time, adjustment, more driving time. O2 would determine Open/Closed Loop (14.7:1) while Fuel Trim (FT) would show Rich or Lean direction.

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33 minutes ago, JeepComanche89 said:

Also, I am looking to source new fuel lines as well. Does anyone know of a set of fuel lines that will fit the "quick connect" fittings of a HO XJ rail? I have used gastankman on ebay before for a different vehicle with great results, I contacted him but did not receive a response. I am going to contact him again, but in the meantime I was wondering if anyone else had any links to a fuel line set, without going AN

 

They are on both Ebay and Amazon for ~$70-$90 /ea.

 

28 minutes ago, Ωhm said:

Yes, REM could help with A/F. It would just take driving time, adjustment, more driving time. O2 would determine Open/Closed Loop (14.7:1) while Fuel Trim (FT) would show Rich or Lean direction.

 

Sure would be nice if a unit like this were available for the HOs.  :sad:

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1 hour ago, DirtyComanche said:

 

Got a link?

https://www.amazon.com/gp/product/B0002JMCQ4/ref=oh_aui_detailpage_o01_s01?ie=UTF8&psc=1

 

https://www.amazon.com/gp/product/B000E35WHO/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

 

https://shop.advanceautoparts.com/p/dorman-help-nylon-fuel-line-union-5-16-inch-nylon-lines-800-012/9110017-P?searchTerm=nylon+fuel+line

 

This is what I bought- quick connectors go to rail, steel union is going on tank side, with a peice of rubber line in between sending unit nipple and union. Either gonna use two more quick connects for the filter, or two more steel union-rubber line.  Havent done anything yet, but I will post some pics when I do. I used nylon line on another truck that I got from gastankman on ebay. Came out super nice, he sold a kit for the chevy, but not the comanche. The ends are pretty hard to push on. But I found a link a couple days ago that shows using a caulk gun and flaring block to put the barbed fittings into the nylon line:laugh:. You put the line in the flaring block, place the flaring block across the bottom of the gun, and press the fitting into the line like that. This is what I'm gonna try, but dorman also sells a tool which looks nice. 

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https://www.amazon.com/gp/product/B0002JMCQ4/ref=oh_aui_detailpage_o01_s01?ie=UTF8&psc=1

 

https://www.amazon.com/gp/product/B000E35WHO/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

 

https://shop.advanceautoparts.com/p/dorman-help-nylon-fuel-line-union-5-16-inch-nylon-lines-800-012/9110017-P?searchTerm=nylon+fuel+line

 

This is what I bought- quick connectors go to rail, steel union is going on tank side, with a peice of rubber line in between sending unit nipple and union. Either gonna use two more quick connects for the filter, or two more steel union-rubber line.  Havent done anything yet, but I will post some pics when I do. I used nylon line on another truck that I got from gastankman on ebay. Came out super nice, he sold a kit for the chevy, but not the comanche. The ends are pretty hard to push on. But I found a link a couple days ago that shows using a caulk gun and flaring block to put the barbed fittings into the nylon line. You put the line in the flaring block, place the flaring block across the bottom of the gun, and press the fitting into the line like that. This is what I'm gonna try, but dorman also sells a tool which looks nice. 

The Renix and HO systems use the exact same fuel pressure specs up until 96.

The GM 3/8" and 5/16" QD fuel fittings are a perfect fit for the Jeep fuel rails (both Renix and HO) just remove the Jeep plastic clips. The GM fitting are available and in stock at most parts stores.

As for Injectors ... Just because you swapped a few bits really isn't going to changes much given what you put in. Treat it like a Renix. The 95 intake is basicly the same intake as the Renix intake with only the fuel rail bosses and the throttle body patterns as the only real differences. There is the slight intake Port height difference as well if you want to get super picky.

There isn't going to be enough flow differences between stock heads to warrant more than a "butt dyno" tuning process anyway.

Volvo 746's are the gold standard for Renix. Ford 19lb/hr are also a decent match, as are the Neon 703's.

Other than the later (97 up) dual pattern Cam, internally there is nearly no difference from one 4.0 to the next. If you check your block you'll even find a 98 casting date (if not an earlier one). Bore, stroke, all the same. Really, other than a fuel management system change little was changed from 87-99 (to 01 in the XJ platform) ... A bit of extra ribbing here an there, a girdle added and an easily backdated change to the cam (the older cam's will still slide in and run in a newer motor).

When you take it down to the basics a 4.0 is a 4.0 ... Chrysler didn't have the courage to futz with it too much until 99 (only the WJ's and TJ's got those new block castings) and even then they kinda messed that up a bit up in a few spots.

 

I am currently running a set of stock 97 4.0L injectors as one of my 746's gummed up, not sure if it'll come back. The 97 injectors apparently flow close to stock Renix injectors on a 39psi rail and seem to match up fairly well so far. ST trims bounce from 70-85 and longterm is down to 118 ... So they appear to still flow more than a Renix needs. My 746's showed a ST of 86-90 and a LT of 124 on the same motor. Injectors are actually a fairly standardized item. But, my engine is a 97 with a 99 intake and an adapted HO throttle body. I've run various sensor mixes over the last year, currently running a GM 86-94 2.8L TPS (TH32), GM IAT (AC Delco 213-190), and a stock MAP sensor (Jeep used the same GM MAP sensor 87-95 on the 4.0). Even the later EV6 injectors will work with a connector swap (or an adapter).

 

Sent from my SM-G930W8 using Tapatalk

 

 

 

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Curious on what you did for an exhaust? Did you re-use the 01 two piece cast manifolds? Always looking for new ideas.
What did you do to adapt to the 95 intake? Plate adapter or adapt TPS the throttle body?



Sent from my SM-G930W8 using Tapatalk

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21 hours ago, Rockfrog said:

Curious on what you did for an exhaust? Did you re-use the 01 two piece cast manifolds? Always looking for new ideas.
What did you do to adapt to the 95 intake? Plate adapter or adapt TPS the throttle body?



Sent from my SM-G930W8 using Tapatalk
 

No I didnt  have the two piece manifold to mess with, so I bought a ebay SS header. Probably would of done that anyway. 95 Intake and ebay header matched the 0331 head, so no need for adapter to head. I'm using the HO throttle body, I plan on buying a hesco tps adapter rather than make one for a couple reasons

 

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23 hours ago, JeepComanche89 said:

https://www.amazon.com/gp/product/B0002JMCQ4/ref=oh_aui_detailpage_o01_s01?ie=UTF8&psc=1

 

https://www.amazon.com/gp/product/B000E35WHO/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

 

https://shop.advanceautoparts.com/p/dorman-help-nylon-fuel-line-union-5-16-inch-nylon-lines-800-012/9110017-P?searchTerm=nylon+fuel+line

 

This is what I bought- quick connectors go to rail, steel union is going on tank side, with a peice of rubber line in between sending unit nipple and union. Either gonna use two more quick connects for the filter, or two more steel union-rubber line.  Havent done anything yet, but I will post some pics when I do. I used nylon line on another truck that I got from gastankman on ebay. Came out super nice, he sold a kit for the chevy, but not the comanche. The ends are pretty hard to push on. But I found a link a couple days ago that shows using a caulk gun and flaring block to put the barbed fittings into the nylon line:laugh:. You put the line in the flaring block, place the flaring block across the bottom of the gun, and press the fitting into the line like that. This is what I'm gonna try, but dorman also sells a tool which looks nice. 

FYI:  I just realized today that the supply is 3/8 and the return is 5/16. looks like its going to work nicely though. Put one fitting on: Taped the line with electrical tape, put in flaring block which i put in the vise, and then took the fitting with center removed, started it then beat it in with mallet. actually went very nicely. 

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