overheating (Kinda long)

[Dingo509]

ok installed the map adjuster, and removed the vacuum line going to the fuel pressure regulator, yes i capped the vacuum port. i also found the stock injectors and swapped them back in. i then set the map adjuster to 5.3 volts with the fuel pressure at 40 psi (autometer procomp mechanical guage). trying to get it to run rich. i didn't change anything it still gets just as hot just as fast.

so 2 more ideas. what should the fuel pressure be without the regulator hooked up?
and (long shot) but if i understand the map sensor adjuster correctly it only works in open loop operation correct? If the computer operates in closed loop operation then the adjuster does basically nothing. so could you use the same basic concept (and maybe parts) the build and o2 sensor adjuster? i think the o2 sensor only gets 1 volt instead of 5 but if you could change parts a little you should, in theory, be able to adjust the o2 sensor voltage so it will lean or richen the mixture in closed loop mode.

I think.

Dingo

 

[JungleXJ]

You could hook up one of those aquarium air valve adjusters that you get from pet shops. That way you can adjust the vacumn, costs next to nothing.

 

[rsalemi]

You can adjust the fuel pressure to 46 lbs or so and/or set the MAP to 5.8V to get more fuel in there. My 4.0 with K&N and Borla made the most HP (189 at rear wheels) with 48# pressure on the stock injectors. In tuning - you need to make big steps to see results - then back down to refine it.

 

[CRASH]

Just for comparison. I have a Renix based 4.6 stroker, very open intake, header, 2.5" mandrel bent exhaust. I use 24 pound injectors, and it runs dead smack at 14.7 to 1 on the highway. The adjustable MAP does nothing for you under light throttle, it only works under WOT, when the computer is ignoring the o2 sensor. In fact, I pulled my adjustable MAP out because A) it failed under off-road conditions and B) I had it set up at 5.0 volts, same as factory. Under WOT, at 5.0 volts, I run 13.2 to 1.

All readings are with a 5 wire Bosch wide-band O2 sensor and digital guage.

As a note, it takes more than you might think to get the engine to drop into WOT mode. At least 2 seconds of foot-to-the-floor on a steep grade and it will finally drop down to 13.2 or so.

I don't think running lean is your problem. I had the EXACT SAME condition as you, and I fixed it with a new 2 core Modine radiator (there is no such thing as a three core Modine, contrary to info in this thread).

Edit: See this thread : http://www.naxja.org/forum/showthread.php?t=43966

CRASH

 

[rockwerks]

Just a few thoughts here I dont think his problem is a lean one I think it is a gearing, auto trans problem

what gearing are you running and what tire size, or is it all stock?

I ran 33's and 3:54 gears and had the same problem, not a hill friendly setup the trans was overheating due to the tire gear ratio problem, I fixed it by removing the tranny cooler lines from the radiator and putting in a seperate trans oil cooler and fan with adjustable thermostat that came on at 180* never had any more problems

also dont forget you can put on the heater and the temp goes down not too comfortable for the summer but it does stop the overheating

 

[Dingo509]

<< You can adjust the fuel pressure to 46 lbs or so and/or set the MAP to 5.8V to get more fuel in there >>

Can the fuel pressure be adjuster somehow without buying an adjustable fuel pressure regulator?


<< I don't think running lean is your problem. I had the EXACT SAME condition as you, and I fixed it with a new 2 core Modine radiator (there is no such thing as a three core Modine, contrary to info in this thread). >>

In the original post i listed all the cooling mods, i have run 2 radiators (stock 91 HD and now a GDI 3-core) no change at all. I have had the GDI pulled apart and cleaned like 3 times so far too.


<< what gearing are you running and what tire size, or is it all stock? >>

33x12.50 Superswamper SSR's on 15x10 Trailready Beadlocks.
D44 front, full float D60 rear, with 4.56 gears. 4 wheel disc and ARB's

The tires/gears/axles/brakes etc. where on before the overheating started i did however change the Wheels. they where some cheap lightweight aluminum 15x10's the trailreadys have steel centers.


<< also dont forget you can put on the heater and the temp goes down not too comfortable for the summer but it does stop the overheating >>

Actually I did run with the heater on in 100 deg temps on the freeway and it didn't help much i could go about 40 miles starting with a cold engine before it would boil over.

Last night i tryed setting the map adjuster to 6.0 volts and the check engine light came on; code 14 map sensor voltage. how high can you run it without it throwing a code?

I hope i don't sound like an ass answering all these questions so short. I really appreciate all the ideas and i know with everyones help we can get this XJ to run cool again. (well at least as cool as you can an XJ)

Did anyone catch the post on possible making a 02 sensor adjuster?

Thank you and keep the ideas coming.

Dingo

 

[CRASH]

The GDI's have notoriously poor build quality, sometimes 30% of the tubes are occluded. Cleaning it does nothing ot help this problem. My GDI ran fine on the trail, but overheated on any long climbs. The Modine fixed the problem.

Is it overheating only at WOT or under cruise conditions? Your computer may not be dropping into WOT mode for a variety of reasons, making it run hot when you are in the throttle for extended periods.

You can enrich your mixture in various ways. If you bump your fuel pressure, it will fatten evything up across the board. But remember, your O2 sensor is fighting these efforts when the enigine is in closed loop mode. It wants you to run 14.7 to 1, so it will do all it can to fend off the extra fuel, within it's mapping. Once you exceed its mapping parameters, it will throw a code. The only time the enrichment efforts help are when you are in open loop mode, at start-up and under WOT.

In your specific case, you don not have nearly enough mods to be out of the OEM mapping parameters, so don't sweat it. If anything, you are having a malfunction of one component or another, not allowing the computer to drop into open loop mode.

What are your trans temps like?

CRASH

<< You can adjust the fuel pressure to 46 lbs or so and/or set the MAP to 5.8V to get more fuel in there >>

Can the fuel pressure be adjuster somehow without buying an adjustable fuel pressure regulator?


<< I don't think running lean is your problem. I had the EXACT SAME condition as you, and I fixed it with a new 2 core Modine radiator (there is no such thing as a three core Modine, contrary to info in this thread). >>

In the original post i listed all the cooling mods, i have run 2 radiators (stock 91 HD and now a GDI 3-core) no change at all. I have had the GDI pulled apart and cleaned like 3 times so far too.


<< what gearing are you running and what tire size, or is it all stock? >>

33x12.50 Superswamper SSR's on 15x10 Trailready Beadlocks.
D44 front, full float D60 rear, with 4.56 gears. 4 wheel disc and ARB's

The tires/gears/axles/brakes etc. where on before the overheating started i did however change the Wheels. they where some cheap lightweight aluminum 15x10's the trailreadys have steel centers.


<< also dont forget you can put on the heater and the temp goes down not too comfortable for the summer but it does stop the overheating >>

Actually I did run with the heater on in 100 deg temps on the freeway and it didn't help much i could go about 40 miles starting with a cold engine before it would boil over.

Last night i tryed setting the map adjuster to 6.0 volts and the check engine light came on; code 14 map sensor voltage. how high can you run it without it throwing a code?

I hope i don't sound like an ass answering all these questions so short. I really appreciate all the ideas and i know with everyones help we can get this XJ to run cool again. (well at least as cool as you can an XJ)

Did anyone catch the post on possible making a 02 sensor adjuster?

Thank you and keep the ideas coming.

Dingo

 

[Dingo509]

trans temp, well i installed the sending unit in the wrong spot its after the radiator but before the aux. cooler. it stays cool at first but after about 30 mins. it mimicks the engine temp with a delay its never gotten above 200 though.

Where is the best place to put the sending unit besides the pan. out going or return line?

Dingo

 

[CRASH]

trans temp, well i installed the sending unit in the wrong spot its after the radiator but before the aux. cooler. it stays cool at first but after about 30 mins. it mimicks the engine temp with a delay its never gotten above 200 though.

Where is the best place to put the sending unit besides the pan. out going or return line?

Dingo

Do you have the trans running through the OEM radiator fittings? If so, pull it out and just run it through the aux.

CRASH

 

[Gojeep]

You cannot build an adjustable O2 sensor. The reason is that is does not run a reference voltage like a Map does is it makes it's own voltage according to the conditions of the fuel mix. We are only talking around 1 volt.

 

[rsalemi]

you can increase fuel pressure by making your own adj regulator. Get a 1/4X20 long nut (sold to join 2 pieces of threaded rod together) and epoxy it over the vacumn tube - then cut a piece of 1/16 rod - I used welding rod -to fit under a 1/4X20 bolt. You need VERY little adjustment to raise the pressure - 1 flat raised mine 1 lb. - If you want to run the stock vacumn you also need to epoxy a vacumn port back on the reg. as you have blocked the original.

 

[Dingo509]

i like the idea of that adjustable regulator. looks like a trip to the hardware store is in order. What pressure should i run it at to start with?

Dingo

 

[Roll-over]

really dumb question... you said it overheats on the trail... going uphill or level terrain?

 

[Dingo509]

Re: overheating (Kinda long) update

update
fuel pressure at about 50 Gauge bounces between 40 and 60 and map sensor at 6.00V Its running rich now, i can smell it and it hardly idles but guess what
NO CHANGE!!
Im hoping to make the NW run this year but as it stands i can't drive across town with our recond hi's almost 70

Anyway any other ideas?
Dingo

 

[CRASH]

Re: overheating (Kinda long) update

update
fuel pressure at about 50 Gauge bounces between 40 and 60 and map sensor at 6.00V Its running rich now, i can smell it and it hardly idles but guess what
NO CHANGE!!
Im hoping to make the NW run this year but as it stands i can't drive across town with our recond hi's almost 70

Anyway any other ideas?
Dingo

Shocking.

In your specific case, you do not have nearly enough mods to be out of the OEM mapping parameters, so don't sweat it.

 

[C85D4x4]

i dont get whats going on with some of ur xjs?
i never have a heating problem in my 93
the temp gage never gos more than half way

maybe its b/c i live in ohio

 

[Dingo509]

Re: overheating (Kinda long) update

Shocking.

I agree Crash but at this point im out of ideas, so what do you recomend? I'll try just about anything.

Dingo
Now enrolling in voodoo and witchcraft classes

 

[CRASH]

Before i get yelled at for this let me give you a history:

91 XJ 4dr. 233K 4.0 aw4 with a/c
In order of install per item
2 Radiators a stock 2 core and currently a gdi 3 core
3 water pumps 1 mopar, 1 cheap rebuilt, currently new aftermarket
6 thermostats mopar, 4 aftermarket 2@180, 2@ 195, currently mopar
2 heater valves, both mopar
2 t-stat housings both mopar, currently hand ported
all hoses have replaced at least twice

Fan setup went from stock electric and mechanical to dual electric (1 stock 1 flex-a-lite 110) to dual flex-a-lite 110

Other mods 99+ intake swap, 60mm throttle body, donaldson airbox rated at 350 cfm, 98 5.2L durango injectors

I have pulled the head and it checked and machined flat (.007 max is .006)
I can drive it just fine if the temperature is below 60 otherwise it overheats
Mainly on the freeway, i can sit idle in traffic at over 100 ambient and it runs below 200 all day. it also overheats very fast when pulling steep grades, at any speed or ambient temperature.

Ive been fighting this for 3 yrs. now and basically can't drive it in the summer.
Any ideas?

Dingo

Have you checked your cat? Is the power OK? Clogged cats can really heat up a motor.

Is there a spring in the lower radiator hose? IF there isn't one there, the hose can collapse from hydrostatic pressure under high fluid passage.

I hate to say it, but can you get your hands on a different radiator? Preferably a virgin one? Modine would be best,.....

 

[Ed A. Stevens]

Check the catalytic converter first. Drive it to heat it up to where you have the problem. Uncork the exhaust before the cat (if possible) and test drive it hot (noisy, but effective) and report back if the top end power and overheating goes away? A restricted cat will cause all the problems you report.

Is the new aftermarket water pump the correct (reverse) rotation?

Is the volume of water bypassing the radiator through the heater valve excessive (do you have a flow restrictor in the valve or heater core bypass hose)?

Is the air dam and shroud under the radiator support in place?

 

[Dingo509]

Have you checked your cat? Is the power OK? Clogged cats can really heat up a motor.

Is there a spring in the lower radiator hose? IF there isn't one there, the hose can collapse from hydrostatic pressure under high fluid passage.

I hate to say it, but can you get your hands on a different radiator? Preferably a virgin one? Modine would be best,.....

The cat's hogged out nothing but a resonator now.
The Lower hose is a new mopar one with the spring
I talked to radiator shop today where i got my gdi about swapping me for a modine since the gdi didn't fix anything since the begining, i have to talk the owner (Who's is very willing to help) mon.