Electrical Gremlins in 97 TJ driving me Nuts - No Start!!
Good Morning Folks,
I am reaching out for advice as to how to get my 97 TJ to start - I have been religiously searching, reading and following advise posted on either this forum and others trying to get it to start, but with no luck. I'm hoping you all can point me in the right direction.
The backstory - this will be longwinded, but I want to put everything that occured down, as it may or may not have played a role:
The Jeep is a 97 TJ with a 4.0L - It looks to me like the 4.0 is out of a 96 Wrangler, or at least some accessories are anyways (more about that later).
Tranny is a 32RH
4 weeks ago I had put her on its side (passenger) - due to choosing a stupid line:facepalm:.....anyways, we righted her but not before all my atf bled out. A quick trip back to town sorted that out and got it running. At the time I also bought a can of break clean and hammered anything that had atf on it to get that gunk off. It started without issue and I ran around the rest of the day. The following day I noticed that my oil pressure gauge was reading very high - 60-65 at idle and any amount of throttle pegged the gauge at 80. Being cautious, I put it on the trailer and headed home - after reading the posts on these forums I am guessing that it's a sending unit issue as that was coated in atf, however after cleaning with contact cleaner, it would do the same.
2 weeks later, I changed the front axle shafts fo CrMo ones (a bit more trail induced carnage from the previous weekend ;)), and flushed and changed motor oil and coolant. Oil pressure gauge was still reading wonky but I figured its the sending unit rather than something physically wrong with the lube system. We went wheeling the next day to a place about 2 hours out - rather than trailer it I drove there as it was close. Ran like a top, wheeled like a top all day. On the way back home on the interstate, the girl abruptly died - felt similiar to when a fuel pump dies - not much notice just a little grumble then nothing. It would crank, and I did see fuel at the fuel rail (I did not measure pressure, but it came out "good"). I pulled one spark plug and check for spark. I did have spark, however I'm not sure what the difference is between good and bad spark - I could see it and it jumped the gap.
I trailered it the house and started the process:
Tried to check for codes - the on, off x3 method did not throw codes, bought a scanner but OBD port not sending signal
I disassembled the fusebox in the engine compartment and thourghly cleaned all parts with contact cleaner - let dry and reassemble
Checked all fuses for continuity (cab and engine fuse box)- all good
Opened, Cleaned and checked (continuity, resistance) all relays in engine fuse box - all good
Checked TPS, MAP, CrankPS for function - MAP and TPS looked to be good from voltage and resistance tests, CPS had frayed wired at pigtail that were taped
OBD port functioning again - code was P0123 - TPS issues.
Replaced TPS with Autozone one - found out this TPS was out of a 96 Wranger instead of a 97 - round pin needed instead of flat one given (2 trips for that realization:facepalm:)
Replaced CPS with OEM one - paper disc was already glued on end of sensor.
Erased codes - no start:nonono:
I hit it with Starting fluid to see if its possibly a fuel issue or something I overlooked....
Now that one got me thinking - Starting fluid should have got it going if there was ANY type of spark, the fact that I got nothing made me take a hard long look at the ignition.
Camshaft position sensor - distributor is a lucas 53006150, which from what I found comes from out of a 91-93 YJ:confused:, and from what I see there is not a removable CPS in it - it has the pigtail, but it goes to a sensor thats sitting under the rotor and connected to the shaft. I cleaned the hell out of it with contact cleaner and reassembled. On top of that I have another trip to Dodge to return the disc shaped one I have (guess if I bought the CPS or disassembled the distributor first....) .
At this point, I don't know which direction to go -
Did I do one of my checks wrong?
Do I have a bad Coil/Distributor/plugs? To replace that sensor in that year of distributor (91-93), do I need to replace the entire distributor? What is a good way to check this?
Oil sensor still on order and I have not changed it yet - could it prevent start if damaged/not functioning?
I highly doubt that there is an issue with the PCM as I can read codes, and I was getting a 5v signal going to every sensor I checked.
Verify no spark by pulling a plug wire put another plug in it ground the plug base to the block. Then crank the engine for around five seconds. If no spark then the next thing would be to check the cap and rotor also ensure all the connections are hooked up. See if your getting power to your coil and distributor. Sounds almost like a coil though but a cps could also cause the issue.
Thanks gents, i will try both - i did confirm that I have spark, i just didnt do it yet over all 6 plugs.
As to the TPS, i am thinking the same, as well as taking another long look at the MAP, as its the only sensor I have left relatively alone minus a voltage /resistance check.
I'll get this bitch sorted yet....
Ok so we got it going - I was able to get my hands on a Pro-Grade scanner and we were able to monitor all sensors realtime - after changing the oil sending unit, all were functioning normally, but no start.
We really started to scratch our heads and took another look at the coil/distributor - we pulled each wire and checked for spark - again there was a spark, but very little (the spark would jump when within 1/8" of ground). Our mechanic on call (the guy we got the scanner from) mentioned that a good coil should throw spark as far as an inch or 2 - not too sure if I buy that but what we had was nowheres near there. Seeing as we damned near changed everything anyways, we decided to do a plug/coil/distributor swap.
Did the distributor first - no start
The cap had a hairline crack, so we thought it may have played a role - changed it and the coil.
Be damned if the girl didn't start up instantly!
I sure got a great lesson on how to troubleshoot connections and sensors, regardless if it was needed this round or not - invest in a good multimeter!
There is such a thing as good and bad spark - with a good coil, it should throw over quite a distance (maybe as much as an inch??)
And just a lesson that I already learned, but this reinforced - buy OEM sensors, don't f about with cheapo sensors if your intention is to work your jeep hard cause it just make room for one more variable that you need to take into account.
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