CGCWO Posted February 20, 2021 Share Posted February 20, 2021 So I’ve got Little Blue (87 4x4 4.0 auto) to run. Having some issue though. Truck idles fair, but does stumble (drop) occasionally. It has a new CPS, MAP, IAC and TPS. Upgraded 746 injectors and new plugs. Plug wires and distributor look fairly new also. When running it has good power in reverse, in forward gears it does not seem to have much power but will move. I ventured around the block today. Started out moving pretty good, then about 1/2 mile in it stumbled and seemed to lose power. Engine was stumbling and had some backfiring, limped it around the block about 10-15 mph after a couple of stalls. Engine starts right up after a stall. What are y’all’s thoughts? Link to comment Share on other sites More sharing options...
JustEmptyEveryPocket Posted February 20, 2021 Share Posted February 20, 2021 Have you checked Fuel Pressure and Cylinder Compression numbers? That might be a good place to start looking at information. Link to comment Share on other sites More sharing options...
CGCWO Posted February 21, 2021 Author Share Posted February 21, 2021 3 hours ago, JustEmptyEveryPocket said: Have you checked Fuel Pressure and Cylinder Compression numbers? That might be a good place to start looking at information. Fuel system is all new except for rail and lines. New fuel pressure regulator, fuel line clip/connector, fuel pump and filter. I just repaired the splice for the fuel pump relay. Truck doesn’t smoke and has a fresh oil change. Link to comment Share on other sites More sharing options...
CGCWO Posted February 22, 2021 Author Share Posted February 22, 2021 So after a few more of @cruiser54s tips it seems I’ve got the idle better. She still wants to backfire and sputter if throttle is opened fast while parked, but that goes away after a moment or two and she revs fine to full throttle. Driving is a different story doesn’t want to accelerate at all under a load. Engine revs stay low and there is some sputtering and occasional backfire. I tried to recalibrate the new TPS from rock auto with no luck. Went back to the old TPS that came with the truck. It doesn’t want to calibrate either but it does at least show a reading. My base was 4.56 which means the out pit should be 3.78 all I can get out of the current TPS is 0.10. Ordered a Mopar TPS we shall see if that helps. IMG_3707.MOV Link to comment Share on other sites More sharing options...
BeatCJ Posted February 22, 2021 Share Posted February 22, 2021 I think you're on the right track, but what's the condition of your catalytic converter? Link to comment Share on other sites More sharing options...
MiNi Beast Posted February 23, 2021 Share Posted February 23, 2021 wrong/bad cps or out of alignment. check and replace as needed. Link to comment Share on other sites More sharing options...
CGCWO Posted February 23, 2021 Author Share Posted February 23, 2021 1 hour ago, BeatCJ said: I think you're on the right track, but what's the condition of your catalytic converter? I haven’t looked at the guts of the car but it’s there. I am sure it’s an old one but probably not OEM unless it’s been gutted. Exhaust is on the list of things to do. Current muffler is beat up to say the least (has dents in it). I have a new muffler and tail pipe ready to put on soon. Link to comment Share on other sites More sharing options...
CGCWO Posted February 23, 2021 Author Share Posted February 23, 2021 41 minutes ago, MiNi Beast said: wrong/bad cps or out of alignment. check and replace as needed. I recently replaced the CPS with one from rock auto. Also completed @cruiser54 Sensor ground fix #6 today. Link to comment Share on other sites More sharing options...
MiNi Beast Posted February 23, 2021 Share Posted February 23, 2021 2 hours ago, MiNi Beast said: wrong/bad cps or out of alignment. check and replace as needed. do it again. Link to comment Share on other sites More sharing options...
CGCWO Posted February 23, 2021 Author Share Posted February 23, 2021 10 minutes ago, MiNi Beast said: do it again. Ordered one from NAPA will see how that goes. Link to comment Share on other sites More sharing options...
MiNi Beast Posted February 23, 2021 Share Posted February 23, 2021 12 hours ago, CGCWO said: Ordered one from NAPA will see how that goes. did you check it first? deep pockets eh. Link to comment Share on other sites More sharing options...
CGCWO Posted February 23, 2021 Author Share Posted February 23, 2021 Not to deep, but deep enough. one thing I’ve learned is you can’t have enough spare parts for these trucks. Link to comment Share on other sites More sharing options...
JMO413 Posted February 23, 2021 Share Posted February 23, 2021 Have you checked fuel pressure with a gauge yet? New parts don't always mean good parts. Mine had very similar issues when I had low fuel pressure. Link to comment Share on other sites More sharing options...
JustEmptyEveryPocket Posted February 24, 2021 Share Posted February 24, 2021 2 hours ago, JMO413 said: Have you checked fuel pressure with a gauge yet? ^ This sounds like good advice.... Link to comment Share on other sites More sharing options...
cruiser54 Posted February 24, 2021 Share Posted February 24, 2021 which Tips have you completed? Check fuel pressure with a gauge. Link to comment Share on other sites More sharing options...
CGCWO Posted February 24, 2021 Author Share Posted February 24, 2021 2 hours ago, cruiser54 said: which Tips have you completed? Check fuel pressure with a gauge. Can’t remember all the specific numbers, but I’ve refreshed all the grounds. The splice for power to fuel pump relay, #6 just the other day and the idle got better. was just looking at the permeate fuel gauge install. Need to get the parts for that. I don’t have a fuel pressure gauge tester. I’ll be checking to see if I can rent one from a parts store. Link to comment Share on other sites More sharing options...
CGCWO Posted February 24, 2021 Author Share Posted February 24, 2021 Tested CPS and I getting no reading at all. (So much for new being good). Have a new one ordered through NAPA. Tested sensor grounds no problems found. Tried again to set TPS (my reference is 4.56 x .83 = 3.78 output) all I can get out of the TPS is 1.26. So I also have a genuine Mopar TPS ordered. While trouble shooting I decided to pull the plugs and see how they looked. These were put in after I got the truck and maybe have an hour of mostly idle run time on them. Front three looked like this: Cylinder # 4 looked like this: 5 and 6: Checked injector electrical connections and believe #4 was not making good contact. Reseated and idle seemed to smooth out. Checked all injector electrical connections and ensured they were seated good. Am I missing anything else? Link to comment Share on other sites More sharing options...
Ωhm Posted February 24, 2021 Share Posted February 24, 2021 18 minutes ago, CGCWO said: Tried again to set TPS (my reference is 4.56 x .83 = 3.78 output) all I can get out of the TPS is 1.26. Which connector are you taking your measurement off of? Link to comment Share on other sites More sharing options...
CGCWO Posted February 24, 2021 Author Share Posted February 24, 2021 The 4 plug square A and D 4.56, B and D 1.25. On the truck harness side. Good news is my backfire condition seems to have resolved. Thinking maybe that was some trash or bad/old gas. As I finally had to put some more new gas in today. Hope to get the REM from @NickInTimeFilmsin a day or so, received shipping info last night. Link to comment Share on other sites More sharing options...
CGCWO Posted February 24, 2021 Author Share Posted February 24, 2021 58 minutes ago, Ωhm said: Which connector are you taking your measurement off of? See above post forgot to quote you. Link to comment Share on other sites More sharing options...
Ωhm Posted February 24, 2021 Share Posted February 24, 2021 The most common way to adjust TPS is use C220 for engine related issues. I guess it could be done using C259. Anyways, follow @cruiser54 tip #8. http://cruiser54.com/?p=54 Link to comment Share on other sites More sharing options...
CGCWO Posted February 24, 2021 Author Share Posted February 24, 2021 Yes sir I’ve done both, waiting on deliver of the new tps and will start all over again. I at first you don’t succeed try and try again. Link to comment Share on other sites More sharing options...
cruiser54 Posted February 24, 2021 Share Posted February 24, 2021 Use only the flat 3 wire connector. Have you read my write-up on setting the tPS? Link to comment Share on other sites More sharing options...
JMO413 Posted February 25, 2021 Share Posted February 25, 2021 http://cruiser54.com/?p=54 This is cruisers write up on the TPS. 4.56 seems low to me maybe just me. It is a 5V reference. I would definitely check the ground. Where the 3 intersect into 1 would be my guess. I skipped resoldering it the first time I went through my wiring. Went back and did it and was pleasantly surprised at the difference at the sensor. http://cruiser54.com/?p=47 Here's the link to the wires I'm talking about. Link to comment Share on other sites More sharing options...
CGCWO Posted February 25, 2021 Author Share Posted February 25, 2021 I did both the three prong flat and the square as not only do I have the idle issues but also the auto trans shifting issues. I will go back over it tomorrow and post my results. 1 hour ago, cruiser54 said: Use only the flat 3 wire connector. Have you read my write-up on setting the tPS? I also have already tip #6, but I will go back and look at the connection again. 44 minutes ago, JMO413 said: http://cruiser54.com/?p=54 This is cruisers write up on the TPS. 4.56 seems low to me maybe just me. It is a 5V reference. I would definitely check the ground. Where the 3 intersect into 1 would be my guess. I skipped resoldering it the first time I went through my wiring. Went back and did it and was pleasantly surprised at the difference at the sensor. http://cruiser54.com/?p=47 Here's the link to the wires I'm talking about. On a happier note my electric fan works and comes on when the engine reaches temp. Still a long way to go, but moving forward. Get this sorted and then it’s on to brakes. Link to comment Share on other sites More sharing options...
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