Hi, new member here looking for a solution to my 2.5 1998 jeep wrangler TJ.
The long version:
My jeep always stays outside but is hooked up to a Noco trickle charger to keep the battery in good shape. Up until about a year ago I had a rough idle problem with my jeep about 30sec after startup, which lasted for about half a minute to a minute, after which it seemed to fix itself each time. Occasionally my dashboard cluster also fell flat with no lights or gauges working apart from the airbag light (not sure anymore about the check engine light) but it always revived after pressing and releasing the brake pedal. This had been going on for at least 6months, perhaps a year, until a year ago it wouldn't start anymore, after which we replaced the battery. This did not fix it and being "scared" to start working on the electronics myself I had it towed to (pretty much) the only garage at a reasonable distance that deals with jeep in Belgium, but they weren't used to working on older models, which isn't ideal.
They suspected the computer (ECM?) was the culprit and had it checked and sent to the US to fix or change for a working one, not entirely sure what exactly happened but the one in it should be working properly. After they managed to get my Jeep to start again and claimed to have solved the rough idle I went to pick it up, only for it to not start, when they drove it outside shortly before that. Fast forward 2 weeks and the starting problem was "solved" (not sure how) but they couldn't fix the rough idle so I drove it back home and decided to work on it myself.
After spending hours on the internet and driving around with the rough idle at start for weeks I decided to change the upstream O2 sensor which my OBD2 also indicated something was wrong with (not sure about the exact code anymore), which fixed the rough idle and I don't have any problems anymore with my dashboard cluster dying while driving either. But this only lasted a couple of weeks after which my Tj started to have trouble starting again, until it finally gave out. It usually started at the second atempt, but now it only cranks, no matter how many times I try.
My jeep does not give me any error codes with the OBD2 reader or with the key trick to have the gauges checked and to display codes. After doing some more research I checked all the fuzes and the relays, which looked ok and were working, and then replaced the crankshaft position sensor, not sure if it's OEM as parts are not as easy to come by in Belgium or transport doubles the price if they even ship it to Belgium... Anyway, this did not fix it, even after resetting the computer by disconnecting the battery for a night. I then decided to change the Camshaft Position sensor, which was the other "easy" fix that I found to my problem, but this also did not fix it, even after resetting the computer again.
I have now also checked the coil, which is working and the sparkplugs are receiving power. So I thought there might be a problem with fuel, as my sparkplugs were looking kind of white when taking them out (see attachment). I do not have a fuel pressure tester to hook up to the schrader valve, so I just let the pressure off by pressing it in, and after turning the key and having the fuel pump prime the fuel lines it had pressure again, so the pump is working (although not sure if there is enough pressure). Finally I checked voltage at the injectors by putting a needle next to the wire in the connector (if you call it that) and after turning the key it received a short burst upto 10-12ish volt, and when cranking it also was around 11ish volts.
I am running out of options and ideas, so any help would be welcome to get my beloved Jeep running again.
Short version:
Belgium based 1998 Jeep Wrangler TJ 2.5 manual, hooked up to Noco trickle charger. Failed to start year ago, sent to garage, ECM should be good according to them (sent to US) altough I am not 100% sure, and they didn't fix rough idle after start but it did start again. Drove home, I replaced the upstream O2 sensor which fixed rough idle, but kept having trouble starting on first try, usually second try did it. Now it doesn't start at all, powerfull crank but no start. Battery changed, Crankshaft position sensor replaced (not sure if OEM), Camshaft position sensor replaced (not sure if OEM), there is spark, fuel pump works (not tested for enough pressure, don't have tools), injectors tested for voltage and they received 11ish volts for 1-2sec after turning key or when cranking engine. Out of options and ideas, please help
The long version:
My jeep always stays outside but is hooked up to a Noco trickle charger to keep the battery in good shape. Up until about a year ago I had a rough idle problem with my jeep about 30sec after startup, which lasted for about half a minute to a minute, after which it seemed to fix itself each time. Occasionally my dashboard cluster also fell flat with no lights or gauges working apart from the airbag light (not sure anymore about the check engine light) but it always revived after pressing and releasing the brake pedal. This had been going on for at least 6months, perhaps a year, until a year ago it wouldn't start anymore, after which we replaced the battery. This did not fix it and being "scared" to start working on the electronics myself I had it towed to (pretty much) the only garage at a reasonable distance that deals with jeep in Belgium, but they weren't used to working on older models, which isn't ideal.
They suspected the computer (ECM?) was the culprit and had it checked and sent to the US to fix or change for a working one, not entirely sure what exactly happened but the one in it should be working properly. After they managed to get my Jeep to start again and claimed to have solved the rough idle I went to pick it up, only for it to not start, when they drove it outside shortly before that. Fast forward 2 weeks and the starting problem was "solved" (not sure how) but they couldn't fix the rough idle so I drove it back home and decided to work on it myself.
After spending hours on the internet and driving around with the rough idle at start for weeks I decided to change the upstream O2 sensor which my OBD2 also indicated something was wrong with (not sure about the exact code anymore), which fixed the rough idle and I don't have any problems anymore with my dashboard cluster dying while driving either. But this only lasted a couple of weeks after which my Tj started to have trouble starting again, until it finally gave out. It usually started at the second atempt, but now it only cranks, no matter how many times I try.
My jeep does not give me any error codes with the OBD2 reader or with the key trick to have the gauges checked and to display codes. After doing some more research I checked all the fuzes and the relays, which looked ok and were working, and then replaced the crankshaft position sensor, not sure if it's OEM as parts are not as easy to come by in Belgium or transport doubles the price if they even ship it to Belgium... Anyway, this did not fix it, even after resetting the computer by disconnecting the battery for a night. I then decided to change the Camshaft Position sensor, which was the other "easy" fix that I found to my problem, but this also did not fix it, even after resetting the computer again.
I have now also checked the coil, which is working and the sparkplugs are receiving power. So I thought there might be a problem with fuel, as my sparkplugs were looking kind of white when taking them out (see attachment). I do not have a fuel pressure tester to hook up to the schrader valve, so I just let the pressure off by pressing it in, and after turning the key and having the fuel pump prime the fuel lines it had pressure again, so the pump is working (although not sure if there is enough pressure). Finally I checked voltage at the injectors by putting a needle next to the wire in the connector (if you call it that) and after turning the key it received a short burst upto 10-12ish volt, and when cranking it also was around 11ish volts.
I am running out of options and ideas, so any help would be welcome to get my beloved Jeep running again.
Short version:
Belgium based 1998 Jeep Wrangler TJ 2.5 manual, hooked up to Noco trickle charger. Failed to start year ago, sent to garage, ECM should be good according to them (sent to US) altough I am not 100% sure, and they didn't fix rough idle after start but it did start again. Drove home, I replaced the upstream O2 sensor which fixed rough idle, but kept having trouble starting on first try, usually second try did it. Now it doesn't start at all, powerfull crank but no start. Battery changed, Crankshaft position sensor replaced (not sure if OEM), Camshaft position sensor replaced (not sure if OEM), there is spark, fuel pump works (not tested for enough pressure, don't have tools), injectors tested for voltage and they received 11ish volts for 1-2sec after turning key or when cranking engine. Out of options and ideas, please help