Dammerung Posted October 17, 2020 Share Posted October 17, 2020 So, it’s been a while since I’ve posted. My Comanche’s just come off a month long break due to coolant tank hoses and the tank itself being busted. Now that she’s back on the road, a few new issues have come up. The truck will now sometimes stall when on an incline or in reverse (Today was the first day I’ve driven it and it has done it twice, once while I pulled into my driveway and once when I reversed down it). It also stumbles and bucks under acceleration sometimes, though it isn’t consistent. One thing to note is that I don’t believe my idle air control valve is working properly, as I’ve pulled the plug on it multiple times with no changes to my idle. Could this be the reason behind this? Any help would be appreciated. 1988 4.0 Liter w/ AW4 Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
MiNi Beast Posted October 17, 2020 Share Posted October 17, 2020 no change then no worky. no biggie. I'm leaning towards cps. does it stumble under load mostly? Link to comment Share on other sites More sharing options...
fiatslug87 Posted October 17, 2020 Share Posted October 17, 2020 Also check your EGR system. Link to comment Share on other sites More sharing options...
Dammerung Posted October 17, 2020 Author Share Posted October 17, 2020 no change then no worky. no biggie. I'm leaning towards cps. does it stumble under load mostly? Yes, and in reverse gear. When it’s in reverse the engine RPMs pulse a lot.Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
Dammerung Posted October 17, 2020 Author Share Posted October 17, 2020 Also check your EGR system.I’ve checked that as well. According to the NickInTimeDesign engine monitor that I’ve got, I have an open EGR solenoid code.Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
SVPete Posted October 18, 2020 Share Posted October 18, 2020 Try removing the vacuum line elbow from the EGR solenoid and plugging it with golf tee. That's next to the fuel pump ballast resistor in the photo. Drive for a couple of days. If the stalling, etc. goes away, next thing to look at is the EGR transducer. Link to comment Share on other sites More sharing options...
Dammerung Posted October 19, 2020 Author Share Posted October 19, 2020 Try removing the vacuum line elbow from the EGR solenoid and plugging it with golf tee. That's next to the fuel pump ballast resistor in the photo. Drive for a couple of days. If the stalling, etc. goes away, next thing to look at is the EGR transducer.Thanks! I’ll try it and get back to youSent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
Dammerung Posted October 21, 2020 Author Share Posted October 21, 2020 Okay, so I blocked off that elbow on the egr, but it still stumbles. That stumbling nearly got me into an accident yesterday when I tried to accelerate on a left turn. What else can I try? Could it be my IAC? I see no change when I unplug it, but I’ve replaced the IAC twice, so I’m not entirely sure. Is there a fuse or relay for the IAC or a grounding issue with it or something? Way back when I got my truck, it did not run right, as it would sometimes die and not even start, but jogging and replacing all the relays by the diagnostic ports managed to fix it. Could it be a problem there? Because I know the fuel pump uses a relay there.Also, on start up it struggles a bit and then hits 2000 RPMs. I don’t think this is normal and I think it may be related to the other issues.Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
MiNi Beast Posted October 21, 2020 Share Posted October 21, 2020 did you check the cps? Link to comment Share on other sites More sharing options...
Dammerung Posted October 21, 2020 Author Share Posted October 21, 2020 did you check the cps? Is there a way to diagnose it or do I just replace it?Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
MiNi Beast Posted October 22, 2020 Share Posted October 22, 2020 give it a jiggle if stumbles replace or tighten back down. Link to comment Share on other sites More sharing options...
MiNi Beast Posted October 22, 2020 Share Posted October 22, 2020 ohm test be about 5. volts i reckon Link to comment Share on other sites More sharing options...
fiatslug87 Posted October 22, 2020 Share Posted October 22, 2020 1 hour ago, MiNi Beast said: ohm test be about 5. volts i reckon Ohms is for resistance not voltage Link to comment Share on other sites More sharing options...
Dammerung Posted October 22, 2020 Author Share Posted October 22, 2020 ohm test be about 5. volts i reckon Looked it up on cruiser’s site, (thank god a man like him is around) and it supposed to be .50 volts. Mine reads .248 volts so I guess I got a CPS to replace. Any brand recommendations?Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
MiNi Beast Posted October 22, 2020 Share Posted October 22, 2020 the 60 dollar one Link to comment Share on other sites More sharing options...
MiNi Beast Posted October 22, 2020 Share Posted October 22, 2020 common issues with jeeps and cps. i now after this last summer stranded in the woods cause of a cps. bushed fixed and carry a brand new one. will swap when needed. Link to comment Share on other sites More sharing options...
MiNi Beast Posted October 22, 2020 Share Posted October 22, 2020 30 minutes ago, fiatslug87 said: Ohms is for resistance not voltage oh yeah thats it. idk never have figured out how to use a meter reader. Link to comment Share on other sites More sharing options...
Dammerung Posted October 23, 2020 Author Share Posted October 23, 2020 Replaced the CPS, but it’s still no good. It’s reading .28 now, so I guess I gotta take it off and drill it out.Also, another symptom I noticed is when I blip the throttle hard, when it comes back down, it hits around 200 RPM. Is this a potential symptom from the CPS?When I look at the monitor data, it says an open egr solenoid code on the data list with a sorted code for a lean loop fault. How would I deal with the lean loop? Link to comment Share on other sites More sharing options...
MiNi Beast Posted October 24, 2020 Share Posted October 24, 2020 how is your cps connector? sometimes they're issues with the plug itself and the fix was a direct connection per say. but the reading your getting seems to say your not getting enough juice to it, so hows your grounds and connections overall? Link to comment Share on other sites More sharing options...
MiNi Beast Posted October 24, 2020 Share Posted October 24, 2020 well the cps controls fuel as well and perhaps part of issue. o2 sensor good yet? air fuel and exhaust to run. seal the system to run effectively. Link to comment Share on other sites More sharing options...
Dammerung Posted October 24, 2020 Author Share Posted October 24, 2020 how is your cps connector? sometimes they're issues with the plug itself and the fix was a direct connection per say. but the reading your getting seems to say your not getting enough juice to it, so hows your grounds and connections overall? They way I’ve done it is unplug the CPS and stick the connector with probes. That’s how I get my reading, so I don’t have any external power from the truck itselfSent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
MiNi Beast Posted October 24, 2020 Share Posted October 24, 2020 so getting 2,5 at the plug or the cps itself? http://cruiser54.com/?p=50 Link to comment Share on other sites More sharing options...
Dammerung Posted October 24, 2020 Author Share Posted October 24, 2020 so getting 2,5 at the plug or the cps itself? http://cruiser54.com/?p=50At connector A in his diagram, which has the male end connector on the CPS, is where I stuck the probes in after I unplugged it from the harness.Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
Dammerung Posted October 24, 2020 Author Share Posted October 24, 2020 At connector A in his diagram, which has the male end connector on the CPS, is where I stuck the probes in after I unplugged it from the harness.Sent from my iPhone using TapatalkI just brought up my CPS to drill out the hole to 3/8 like cruiser says to. While I was under there I noticed 2 things: one, there’s a steel cable underneath that isn’t connected to anything, like it may be cut. It’s in a bundle wrapped in some brass foil. Also, I checked my oxygen sensor for the hell of it and found that the three wires in the connector have some white crap in it, both on the male and female side. Am I right I’m assuming this is some corrosion? (I’m a youngster so I haven’t seen much in the way of auto work and connectors yet). Would I have to go about replacing that?Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
MiNi Beast Posted October 24, 2020 Share Posted October 24, 2020 yeah o2 sensor prolly no good and should be replaced helps run better. cable for shift kick down or cable for emergency/parking brake..? Link to comment Share on other sites More sharing options...
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