4.0 how to identify the H.O. vs. non

[worlock]

just need alittle help and i did look old threads and I couldnt find anything I know after 92 are I beleave all are h.o. but once they are on the ground or more persicly transplanted to you tell????

 

[colby44]

the computer system, heads, and exaust manafold make it a HO, but idk how you can identify them...
btw im out in Sequim

 

[4LVLFWD]

???? grammar, just give it a shot

 

[Matthew Currie]

It may depend a little on what's still attached to the engine. A quick ID might be to look at the throttle body. If you can find an example of each to look at you'll see the difference, and probably find it easy to spot thereafter. Renix has the air tube attached to the throttle body with screws (three screws in a flange), while HO is clamped. I'm not sure whether it's a date or a Renix/HO difference, but early 4.0's had a heat shield on top of the manifold, where later ones do not, and that's another easy one to spot.

If you can get a closer look, Renix has an EGR valve, HO does not. Also Renix has a knock sensor on the driver's side of the block, where HO does not.

ed. to add, of course since some people have been known to transplant manifolds and the like, you cannot definitively tell at a glance unless you know it's not been done. But I'm pretty sure the threaded hole for the knock sensor would be fully diagnostic for pre-HO.

 

[worlock]

cool what i have is a 90 I bought and the kid said he put in a H.O. but it has a 3 bolt throttle body but I drive a 90 and thier is afew diffrentses in the two. U going to the drags on sat?

 

[worlock]

ya well grammar im not a typist and you get what im sayn

 

[colby44]

yeah maybe, not competing though only have a stock 89 thats my 900$ dd have you been out to alpine auto, they have some factory skids you might want to grab on a gold xj in the back right corner

 

[worlock]

I will have 2 check thouse out I will be running sat and sunday for the tuff truck white cherokee boggers 1990 top light bar

 

[1990JEEPXJ]

the easiest and quickest way, which was pointed out, is by the throttle body bolts. renix has 3, HO has 4.

 

[colby44]

right on, good luck.

 

[worlock]

I thought thet they where exchaingable intake and well all needed to do a straight swop and if thats the case then how do you know?

 

[4LVLFWD]

ya well grammar im not a typist and you get what im sayn

i wasnt tryin to be a dick about it. i really couldnt tell what you were tryin to say. as you can see mine isnt great but... you get the idea.

 

[worlock]

i will check for a knock sencer

 

[worlock]

all good mr. no prob.

 

[Hellbent]

look for the knock sensor, and/or coolant temp sensor in the driver's side of the block on a renix('90 and earlier). someone could have pulled the knock sensor, but likely would have left the coolant temp sensor there to plug the hole.

 

[worlock]

ok so a h.o. would it even have a place for a sencer? threded hole?

 

[5-90]

RENIX Giveaways:
- #2686 Cylinder Head (casting number found outside of valve cover rail, driver's side, above/between #3 & #4 exhaust cylinders.)
- Three-screw valve body.
- Drilled/tapped boss on the driver's side oil sump rail, about 1/3-way back, for the knock sensor.
- Manifolds still attached? Look for the EGR tube.
- No manifolds? Check the port floors in the head - for RENIX, they're all inline. For HO, the intake port floors are higher than the exhaust port floors.
- The fuel rail has the feed and return lines at opposite ends. OBD-I fuel rails have both lines at the same end (front?) and OBD-II uses a "returnless" system that even has the pressure regulator in the tank.

The only real difference on the engine block proper is the boss for the knock sensor. It is not a through hole, and the boss (unmachined) remained present through the 2006 production (I believe.)

RENIX is 1987-1990. HO/OBD-I (#7120 head) was 1991-1995. HO/OBD-II Gen I (#0630 head) ran 1996-1999, and HO/OBD-II Gen II (#0331 head) ran 1999-2006.

The four-digit casting numbers referred to are all in the same location - outside of the valve cover rail, driver's side of the head, midway back (above/between the #3 and #4 exhaust ports.)

Vehicle-side symptoms of having RENIX?
- NO PDC. There are four DIN relays behind the battery, at the front of the line is the starter motor relay (goldish colour, with a 3/8" screwpost for power disribution. There are fusible links coming off of the post, and there is a lead that comes from the battery + post.)
- NO PCM/SBEC/SMEC (big black dingus underhood with a 60-odd circuit plug.) The ECM for RENIX is under the IP, near your left knee. It has a cast aluminum case, and has the word "BENDIX" moulded into the topside.
- NO OBD diagnostic plug. The RENIX plugs are a pair of MOLEX plugs (2x3 and 5x3) with yellow rubber covers near the relays. OBD-I often had the plug underhood - but the ChryCo plug was a funky eight-pole affair - and OBD-II has it under the IP, within a foot of the centreline of the steering column.
- NO functioning CEL/MIL. RENIX is "pre-OBD," and does not "store" or "throw" codes. Fortunately, most RENIX diagnosis can be handled easily with a DMM, and most of the sensors are actually standard GM goodies (which are inexpensive. Since I work on a number of RENIX rigs, I just get the sensors in bulk from Marren Fuel Injection. Everything's GM except for the TPS and HEGO sensors.)

 

[worlock]

ok cool thats what I needed My head is a 7120 so its a first gen H.O. cool thats the engine that will be going into my xj in a few weeks thanks good info. to keep