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Discussion Starter · #1 ·
Hey all.

First off: I love this sight and I LOVE my trooper. Its great to see so many trooper enthusiasts. Just got a 90 trooper a couple of months ago. Ive been replacing parts since i got it trying to get it running right. Ive replaced plugs, wires, cap, rotor, vacuum lines, temp sensor, temp sender, fuel filter, air filter, and probably more, cant think of it now. Almost got it running perfect. The temp sensor gave me a lot better running when hot, i also unplugged the egr and I believe that helped as well. The problem? The other day I replaced the thermostat as the old one was stuck wide open. Ever since then my engine surges when coasting and stops after I come to a stop then it idles high. Also running a tad hot, just past the center on my gauge. Im all out of ideas and its driving me nuts! Everytime I fix something a new problem comes up. Any ideas would be greatly appreciated. I love this truck and want to keep it forever but right now I feel like Im doing more damage to it by running it with out it properly set up. it seems to run a little rough and lacking some power(air/fuel ratio). The temp sensor and deleting the cat helped tons. But now its acting funny. Someone please enlighten me :D Thanks in advance!!!!! 2.6 multi port 293000 miles :) seems strong! Love it!!!!
 

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You've got air in the coolant lines. The surging is caused by the temp sensor being covered and uncovered by coolant. It keeps sending back and forth signals to the ecm. Some aftermarket thermostats like to open close open close as well. Best is to PM jlemond on this site for an OEM Isuzu thermostat. Then install that with the little tickler valve on the top. This let's steam/air escape into the radiator. Open the heater to full hot and start it with the radiator cap off and let it warm up. Helps to point up hill some. This will help purge the air out.
 

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yeah.....pop the radiator cap, jack up the front end as high as you can get it and crank it up and let it run until the thermostat opens and the water is circulating. Be sure to top it back off.
 

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Discussion Starter · #4 ·
Sweet thanks! You guys are awesome! I thought that was the problem. I tried burping the system by parking it on a steep hill and letting it warm up with the cap off and I still cant seem to get the air out. I didnt know about the after market thermos opening and closing. Im also wondering if the water pump impeller has deteriorated because I dont see signs of good water flow. I feel no surge in the radiator hose, just gets hard with pressure. I also tried bleeding it out by taking the little nipple off the thermo housing while it was running and the water came out in spurts instead of a steady flow.??? Im thinking a bad pump wouldnt push hard enough to expel the air. Another funny thing is I unplugged the o2 sensor to see if it helped and im getting much smoother running and way more high end power. Thanks for the help guys! Your knowledge is like gold to me right now. Ive spent countless hours reading and working on this thing. Each time its getting a little better. Im starting to get even more excited! When it took off tonight after unplugging that 02 sensor I realized this thing has the power I thought it had in it. Just bad air fuel mixture. Im all ears to any advise you have. Thanks again! Be well...
 

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Discussion Starter · #5 ·
Still learning how to navigate this sight. Be patient with me guys. :?:
 

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yeah if burbing and an oem thermostat doesn't fix it then it migt be time to pull the water pump. Usually the bearings and seals go not the impeller. But who knows you might have a BS imported pump on there. Every seen the water pump out of a Taurus. Ford used a POS pump with a pot metal impeller. They start overheating so you pull the pump and there are no vanes on the impeller. Dissimilar metals and galvanic corrosion just disolves the pump in a short time.
 

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Discussion Starter · #7 ·
Cool. Thanks so much for the reply. Ill try the thermostat first since its way easier. At the parts store they had a standard one and a (supreme) one. While looking at them I think the supreme one ended up in the box. I wanted the standard. Should that one be oem? Or do I have to order it from a dealer?,
 

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Discussion Starter · #8 ·
By the way. Nice work on the trooper. I'm inspired!
 
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