Renix issue?

[Ecomike]

I know folks have permanently bypassed the ballast resistor, does this affect the longevity of the pump at all or does it just quiet it down. Didn't know if I should bypass or replace.

The bypass resistor quites it down. At start up the FP gets full battery voltage, which drops during cranking to about 10 volts. Once the engine is running the system voltage goes to about 14 volts, and the ballast resistor drops that back to a lower voltage, similar to the starting voltage. It is OK to bypass it until you get a replacement. Some have done it permanently, I don't recommend doing it permanently.

 

[jujuscisyn]

Thanks, the resistor has 1.1 ohms stamped on it but mine ohms out at 1.5 ohms wouldn't have thought that it would have made that much difference but according to the jeep it does. Thanks for the heads up on the cam position sensor I was checking voltage wrong I do have 5+volts on there.

 

[jujuscisyn]

Actually, now that I think of it, it may not make that much difference if the pump or something else is going bad. The increase in voltage by bypassing it may bring it the pressure back up to almost suitable levels. Sound bout right?

 

[Ecomike]

Actually, now that I think of it, it may not make that much difference if the pump or something else is going bad. The increase in voltage by bypassing it may bring it the pressure back up to almost suitable levels. Sound bout right?

Your meter could be off by .5 ohms, what does it read when you short the meter leads? If it reads .4 ohms, subtract that from the 1.5, and you get 1.1 ohms.

The resistor may be failing under load, about to burn out. Retest it hot, after running it a few minutes if you can to see if the resistance doesn't jump.

 

[jujuscisyn]

Wow, 15psi on the rail ain't gonna cut it. Took the vacuum line off of the fpr and got no change. Jumped the resistor and got 17 surging to 19 still not enough. Maybe the line between the sending unit and pump at best at worst new pump. Probably replace it anyway. Can't say that its my whole problem but its a good jumping off point. I'll get back to you guys. Thanks a million.

 

[Ecomike]

Wow, 15psi on the rail ain't gonna cut it. Took the vacuum line off of the fpr and got no change. Jumped the resistor and got 17 surging to 19 still not enough. Maybe the line between the sending unit and pump at best at worst new pump. Probably replace it anyway. Can't say that its my whole problem but its a good jumping off point. I'll get back to you guys. Thanks a million.

Is the FPR new or old? I think you can test the FPR and pump by clamping the return hose some while it is pumping. Could be a restriction in the fuel line, bad fuel filter (external),bad FPR or bad pump.

 

[jujuscisyn]

I'm going through that stuff now. I have no idea the history of the FPR was there when I got it. I borrowed the neighbors pressure gauge and he's one of those guys that doesn't take a leak without getting paid. So I checked and got it back to him right quick. In doing so, I forgot to pinch the return line but when I got back I started the heep and pinched the return line with no change in idle( still stumbling). pressure should have skyrocketed if I remember correctly and cleared up the stumble. Checking fuel lines now, filter has about 2000 miles on it but i'm gonna check anyway.

 

[jujuscisyn]

Siphoned 15 gallons of gas out of my tank(yuch). Pulled the pump, the outlet hose between the pump and the sending unit was barely on. the hose was actually bent at a approximately a 30 degree angle on the outlet nipple. It hadn't come off but had slipped down far enough to allow it to bend. I put it back on, tightened the clamp and I'm in the process of putting it back in to make sure I didn't do it while taking it out. Hopefully, I didn't bang the float around so much that the fuel gauge is off. Keep your fingers crossed.

 

[jujuscisyn]

Oh, the lines and filter were clear.

 

[1990JEEPXJ]

ok so i thought i had the stuttering/bucking problem on OD fixed but i was wrong. it sputtered and died on me about 1/4 mile from home, luckily i was able to coast it to where i park it. it didnt start when i parked it. it started bucking about only 2 miles from home and just got real bad as i got closer. i dont know what it could be. everything i do fixes it for a few days but then goes away. its as if im only putting band-aids over the real problem.

 

[Ecomike]

Cap and rotor?

 

[1990JEEPXJ]

thats on the list. probably doing that tomorrow along with the vacuum line from the MAP to the throttle body.

 

[Portuga_XJ]

thats some good info in here!

Im having similar problems on my 96 xj, gonna try some of the stuff ive read here to see if the popping/backfiring goes away.

 

[jujuscisyn]

I tightened that output hose on the pump and haven't had a stumble yet. Still crossing my fingers. Noticed that after a shutdown and key in run engine off the pump only runs for a second or maybe less. Turn the key back off then back on it doesn't run at all so it sounds like its holding pressure. Before, I'd have to cycle the pump three maybe four times before the pump wouldn't run. I recommend anyone suffering these problems at least check the output hose between the pump and the sending unit. Like I said not sure if it fixed my problem but it hasn't done it sense so I'm waiting for more symptoms to diagnose. Hopefully I got it and best of luck to everyone struggling with this. I'll definately keep tabs.

 

[1990JEEPXJ]

hmmm. is that output hose just on the outside of the tank? i might have to check that. so i got me jeep towed home last night at 2am after an 18 hour shift. cranked fine but no start. im going to check the coil tomorrow and change the cap and rotor. is there a way to check the ignition switch or ignition control module?

 

[Ecomike]

hmmm. is that output hose just on the outside of the tank? i might have to check that. so i got me jeep towed home last night at 2am after an 18 hour shift. cranked fine but no start. im going to check the coil tomorrow and change the cap and rotor. is there a way to check the ignition switch or ignition control module?

Output hose is the fuel tank.

Check for spark first. If no spark, it is probably a bad CPS, Crank Shaft Position sensor. Pain to get to, it is on top of transmission bell housing, under the firewall, behind the engine. Lots of write ups here on how to test it and how to change it.

If you have spark, try cranking with gas peddle floor, that will unflood it if it is flooded.

 

[Ecomike]

Typo correction: Output hose is in the fuel tank.

 

[1990JEEPXJ]

ah. the CPS is new and was the first thing i replaced to try and remedy this problem. i will read up on testing it after i check for spark. i just put in a new cap and rotor. nothing, still no start. fuel comes out of the Schroeder valve if i push the needle so it has at least some fuel getting to it. so i will test spark and CPS and go from there.

 

[1990JEEPXJ]

ok checked CPS resistance, within spec. each time i tested the ohms they were slightly different but were all within the 125-175 spec. checked for spark, nearly nothing. would a bad cam position sensor cause this or simply a bad coil? what about the ignition control module?

 

[1990JEEPXJ]

update: had the ICM and coil tested at AZ. ICM was good, coil bad. replaced the coil and it started right up and ran great. idled better. well see if it lasts or was another bandaid like the other fixes.