jroypdx Posted October 12, 2019 Share Posted October 12, 2019 Yesterday I bought a Comanche. Have a few questions. It's an 87 Sport Truck, 2.5L 4speed, 2wd. Questions: With that engine and trans combo, is it 3.55 geared? Can EGR be deleted without any check engine lights? Same questions for the hot air tube off of the exhaust mani? Thanks in advance. Link to comment Share on other sites More sharing options...
eaglescout526 Posted October 12, 2019 Share Posted October 12, 2019 Renix has no check engine lights. So you can do that if you want. Take a look at the Differentials pumpkin and look at the part number tag that is bolted to it. It should have the ratio. Or jack it up and count how many times the drive shaft spins to complete one full rotation of the tires. Chances are it could be 4.10 gear. Or 4.56 but that was on autos. Link to comment Share on other sites More sharing options...
jroypdx Posted October 12, 2019 Author Share Posted October 12, 2019 1 minute ago, eaglescout526 said: Renix has no check engine lights. So you can do that if you want. Take a look at the Differentials pumpkin and look at the part number tag that is bolted to it. It should have the ratio. Or jack it up and count how many times the drive shaft spins to complete one full rotation of the tires. Chances are it could be 4.10 gear. Or 4.56 but that was on autos. I did some googling and found it should be 3.55, but yeah at some point I'll get under it and check. Link to comment Share on other sites More sharing options...
Warren Mohler Posted October 12, 2019 Share Posted October 12, 2019 eaglescout is correct if it had CEL it would illuminate at key on then go off Renix systems do not store codes if I remember correctly they would display codes but only if fault occurred with proper scan tool hooked up. for EGR deletion you will not see much difference in performance EGR adds a small amount of inert gas to help cool upper cyl. temperatures with it unhooked you may experience detonation or ping. hot air tube is there to aid in cold engine drivability. If working properly these can be a benefit 20 minutes ago, jroypdx said: Yesterday I bought a Comanche. Have a few questions. It's an 87 Sport Truck, 2.5L 4speed, 2wd. Questions: With that engine and trans combo, is it 3.55 geared? Can EGR be deleted without any check engine lights? Same questions for the hot air tube off of the exhaust mani? Thanks in advance. Link to comment Share on other sites More sharing options...
eaglescout526 Posted October 12, 2019 Share Posted October 12, 2019 If you do delete the EGR and tube hang on to them. Someone might want them as Renix 2.5L stuff is getting harder to find amongst the 4.0’s. Link to comment Share on other sites More sharing options...
jroypdx Posted October 12, 2019 Author Share Posted October 12, 2019 eaglescout is correct if it had CEL it would illuminate at key on then go off Renix systems do not store codes if I remember correctly they would display codes but only if fault occurred with proper scan tool hooked up. for EGR deletion you will not see much difference in performance EGR adds a small amount of inert gas to help cool upper cyl. temperatures with it unhooked you may experience detonation or ping. hot air tube is there to aid in cold engine drivability. If working properly these can be a benefit If you do delete the EGR and tube hang on to them. Someone might want them as Renix 2.5L stuff is getting harder to find amongst the 4.0’s. Interesting. In most other platforms I delete those things and it is all benefit. In reality the 2.5 is very temporary anyways so maybe I'll leave it alone. I've owned tons of 4.0 HO stuff, but never a 2.5 and never a Renix.I found a Renix cluster with a tach, are those a straight swap or is there additional wiring work to get the new gauges functional?Sent from my GM1915 using Tapatalk Link to comment Share on other sites More sharing options...
eaglescout526 Posted October 12, 2019 Share Posted October 12, 2019 4 minutes ago, jroypdx said: found a Renix cluster with a tach, are those a straight swap or is there additional wiring work to get the new gauges functional? Depends on the year. All 84-90 are plug and play. But the speedo plugs are different for 84-early 87 model years and 87 late-90. Link to comment Share on other sites More sharing options...
jroypdx Posted October 12, 2019 Author Share Posted October 12, 2019 Depends on the year. All 84-90 are plug and play. But the speedo plugs are different for 84-early 87 model years and 87 late-90. My truck is an 87 but not sure on the mfg date the info is worn away on the sticker. Any way to tell other than that?Also is this cruise control aftermarket. The box and the way it's scotch locked into the tach wire tells me yes, but the control inside looks stock.Sent from my GM1915 using Tapatalk Link to comment Share on other sites More sharing options...
eaglescout526 Posted October 12, 2019 Share Posted October 12, 2019 Few things. Post your VIN in the registry and I will decode it for you. Second. The speedo cable plug is what you need to worry about for the different year clusters. It’s not hard to look up from under the dash and see clip or plug type cable Three if you have cruise there should be a yellow box under the dash. That control looks like a YJ style or another GM style stalk. And your speedo cable will have a rev counter or speed controller in between the two cables to split it. Link to comment Share on other sites More sharing options...
jroypdx Posted October 12, 2019 Author Share Posted October 12, 2019 Few things. Post your VIN in the registry and I will decode it for you. Second. The speedo cable plug is what you need to worry about for the different year clusters. It’s not hard to look up from under the dash and see clip or plug type cable Three if you have cruise there should be a yellow box under the dash. That control looks like a YJ style or another GM style stalk. And your speedo cable will have a rev counter or speed controller in between the two cables to split it. Gotcha, I'll probably just remove the cruise stuff if it's aftermarket. I don't care about having it. I'll post the VIN now.Sent from my GM1915 using Tapatalk Link to comment Share on other sites More sharing options...
eaglescout526 Posted October 12, 2019 Share Posted October 12, 2019 Don’t get rid of it if it is factory. The yellow box will say AMC on it Link to comment Share on other sites More sharing options...
jroypdx Posted October 12, 2019 Author Share Posted October 12, 2019 Don’t get rid of it if it is factory. The yellow box will say AMC on it Do you know what area under the dash I might be looking to check? I suspect this isn't the factory one. I'd be surprised to see the factory use a scotch lock for rpm signal.Sent from my GM1915 using Tapatalk Link to comment Share on other sites More sharing options...
eaglescout526 Posted October 12, 2019 Share Posted October 12, 2019 The cruise control box will be right under the steering column. It’s a small yellow box. If you lay on your back and look up under the dash you would see it. As for that RPM thing, I have no idea. Looks foreign to me. Link to comment Share on other sites More sharing options...
jroypdx Posted October 12, 2019 Author Share Posted October 12, 2019 The cruise control box will be right under the steering column. It’s a small yellow box. If you lay on your back and look up under the dash you would see it. As for that RPM thing, I have no idea. Looks foreign to me. Yep no yellow box, must be aftermarket. There's a bunch of not-oem wiring under there too. Gonna have to sort that out.Sent from my GM1915 using Tapatalk Link to comment Share on other sites More sharing options...
eaglescout526 Posted October 12, 2019 Share Posted October 12, 2019 Tons of fun. Link to comment Share on other sites More sharing options...
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