Ford 5.0 injectors(RENIX) hot start issue.

That works. That's what jeeps are all about. I wasn't raggin' on it, just the fact that an expensive paint job should be perfect.
 
88 Wagonman said:
That works. That's what jeeps are all about. I wasn't raggin' on it, just the fact that an expensive paint job should be perfect.
Click to expand...

The paint is perfect, there is however a few dings here and there that my dad put in it and I had those left for character. My dad bought this Jeep new and drove it until the day he died. Every mile is a memory on this XJ.
 
Still tinkering with this issue, I really do believe it is heat soak.

I can get it hot and try to start it and it will crank but not start for a while then it will slowly start catching until it will run on its own but very rough.

I then got it hot again (runs fine as long as you do not shut it down) and then shut it off, I stuck a fan on the top of the motor to cool the injectors and it fired right up.

Even though the Ford injectors are giving me great performance/mileage, I might just switch back to the Bosch replacements I had in there. I was hoping to be able to keep the Ford injectors due to the better spray pattern but it does not look like that will happen.

I plan on insulating the injectors from the heat and try again, if that doesn't work out then i give up. The Jeep is otherwise very dependable and gets decent mileage with the Bosch units.

Right now I have my second E-fan running almost all of the time to keep things cooler under the hood but that made little difference.
 
xjtrailrider said:
Ok, I did some tinkering tonight.

CPS ohm reading was 255 hot/cold/didn't matter, stayed nailed to 255

No crack(s) in the exhaust manifold

The injectors are not leaking, I have pressure on the rail (key off) when the issue is happening and it starts fine cold.

I really think its just too hot under the hood for the Ford injectors. I found that if I open the hood for only a minute it will start up easier but still run rough until the fuel cools injectors. Right now I have dual electric fans operated off of the stock temp sender in the radiator. I might change that and have one of the fans on with the ignition to keep things cooler under the hood.

Still looking for a solid answer.
Click to expand...

Read back through all of this and thinking maybe with the dual electrics (stock efans?) you may be getting heat soak.

You could consider adding a second fan switch into a later model thermostat housing and using a switch that comes on sooner rather than all the time.
 
joe_peters said:
Read back through all of this and thinking maybe with the dual electrics (stock efans?) you may be getting heat soak.

You could consider adding a second fan switch into a later model thermostat housing and using a switch that comes on sooner rather than all the time.
Click to expand...

The way I have it now is the stock E-fan is wired as usual and comes on as needed for the a/c or when it gets real hot. The second E-fan is a late model stock unit and comes on via a Hayden snap switch that is mounted through the rad fins. I have it wired direct to the battery so it can cool the engine even after shutdown. It turns on at around 195 but never really runs very long, maybe 20 sec max.

The engine stays warmer than it did but never gets over 205, it use to stay at 160-170 before I removed the mech. fan. I had trouble keeping it in the closed loop sometimes which I think is due to a new all metal 3-row rad and a perfectly working closed system. It was just too efficient.
 
xjtrailrider said:
The way I have it now is the stock E-fan is wired as usual and comes on as needed for the a/c or when it gets real hot. The second E-fan is a late model stock unit and comes on via a Hayden snap switch that is mounted through the rad fins. I have it wired direct to the battery so it can cool the engine even after shutdown. It turns on at around 195 but never really runs very long, maybe 20 sec max.

The engine stays warmer than it did but never gets over 205, it use to stay at 160-170 before I removed the mech. fan. I had trouble keeping it in the closed loop sometimes which I think is due to a new all metal 3-row rad and a perfectly working closed system. It was just too efficient.
Click to expand...

I have the same problem. I am now installing a timer to run the "E" fan for 3-4 minutes after shutdown, I hope this will remove enough heat to solve the problem.
 
Last edited:
xjtrailrider said:
The way I have it now is the stock E-fan is wired as usual and comes on as needed for the a/c or when it gets real hot. The second E-fan is a late model stock unit and comes on via a Hayden snap switch that is mounted through the rad fins. I have it wired direct to the battery so it can cool the engine even after shutdown. It turns on at around 195 but never really runs very long, maybe 20 sec max.

The engine stays warmer than it did but never gets over 205, it use to stay at 160-170 before I removed the mech. fan. I had trouble keeping it in the closed loop sometimes which I think is due to a new all metal 3-row rad and a perfectly working closed system. It was just too efficient.
Click to expand...

As the mechanical fan's clutch would engage when the air flow coming through the radiator and hitting the bi-metal spring was at 170 degrees, and the coolant would be 30 degrees hotter, I think you should try and adapt or change the threshold on the Hayden from the 195 to something lower. I have never liked the stock efan start temperatures--IMHO a little too late, like a "friend" that's "got your back" after you've already had the s*it kicked out of you.
 
joe_peters said:
As the mechanical fan's clutch would engage when the air flow coming through the radiator and hitting the bi-metal spring was at 170 degrees, and the coolant would be 30 degrees hotter, I think you should try and adapt or change the threshold on the Hayden from the 195 to something lower. I have never liked the stock efan start temperatures--IMHO a little too late, like a "friend" that's "got your back" after you've already had the s*it kicked out of you.
Click to expand...

I agree, I'm still working with this issue as well. The timer is a great idea.
 
Ok, its fixed. It is/was "hot soak" but not because of the injector swap but because of the E-fan swap. When I swapped over from the mechanical fan to the 96 XJ E-fan I had the new E-fan wired on a Hayden 195* snap switch and the aux E-fan on its factory controller. Neither fan was running enough to cool the engine bay but enough to keep the engine temps below 210.

Today I wired both E-fans off of an adjustable controller by Hayden and hooked the controller straight off the battery so even after shut down the fans will run and cool the engine bay. I have fans set to come on at 180* and they shut off around 170*, they are also wired so that they both come on with the AC compressor. I used (2) 40 amp relays to ensure they would be able to handle the fans

This fixed 99.9% of the heat soak issue. It will still idle a little rough until the fuel flow cools the injectors but then it smooths right out and runs like a champ!

As a side note to the injector swap, I'm getting killer mileage! i will post up results after a couple of tanks have gone through it.
 
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