HARD to start when cold

Looking for some input, want to get my hard start issue fixed before our weekend trip (yeah I know that gives me 4 days).

I’ve been dealing with a major rear main seal leak… started getting hard to start in the winter when it was cold. I did some research and replaced the crankshaft sensor. Started right up… now it’s hard to start again. After it sits for 3 hours it takes literally 2 minutes of cranking to catch. When it’s running it has no issues. Power is good, I can slam on the gas and it takes off, no lag. If it’s been running and I start it before the engine cools all the way down it fires right up. However, if it’s cool and I shut it off I’m dead in the water again.

What I’ve noticed:

  • no pressure check, but the rail has pressure even when it’s been off so I doubt it’s a fuel problem
  • check engine light flashes sporadically while cranking
  • loud clicking sound from bottom of relay panel (took out all relays and it still did it) - but it’s occasional not every time
  • rear main leak has been fixed (this week)
  • starter tests good - battery is strong

my suspicion is that either I have a short in my relay box / bad relay, or the crankshaft sensor is getting coated in oil and not registering the crank position. It’s getting fuel - I haven’t had the time to check for spark. Thought I had it fixed in the spring when I replaced the sensor, and know it’s doing the same symptoms again - I drove it for 2 months on a regular basis after I replaced the sensor with no problems.


Don’t turn it off

what brand CPS? I got one from napa and its on its way out again. Although i did get like 7k miles out of it :laughing:

From what Ive read the dealer is the best place to get said cps. I bought one from the zone and it was way too short.

could be the CPS again, also could be the fuel check valve.

not the check fuel valve - i’ve got pressure at the rail after it sits overnight.

Going to start going through this tonight:
jeepforum.com/forum/f12/91-h … ed-490788/

HA! I just realized WillyB is on the last page of that thread.

Got all the parts at lunch today (fuses, ignition switch, resistors) and will start diagnosing tonight.

finished the diagnosis - it’s the ECU. All else tested fine. Pulled the module and 2 of the capacitors have a little bubble in the silicone directly underneath - no other bubbles in the silicone casing. So I’m going with those being the culprit. time to get out the soldering gun and cross my fingers. Have to get it done before our trip.

[i][b]It sounds like when an engine used a high voltage coil and points. As small as the crack could possibly be, any moisture present would short it out, causing a problem like you are experiencing. It also caused a clicking noise each time the points closed which completed the low voltage electrical circuit to the coil. A crack in the distributor cap produced similar situation depending where the coil high voltage was shorting to.

Maybe??? :question: :question: :question: [/b][/i]

The first place I looked was the distributor cap. However last night I confirmed that I don’t have spark when trying to turn it over (used a timing light on the coil wire). Additionally my check engine light doesn’t come on when I key on the ignition, and blinks sporadically when cranking (my initial indication that the computer wasn’t powering on).

New capacitors are going in tonight. I’ll take photos and see if that fixes it. I’m very hopeful.

GAH! Found out at 8:30 that my soldering iron was dead.

Good thing Radio Shack is open until 9 :wink:

Took a while to work the capacitors into place… when taking it apart one was clearly blown out on the side and whatever was in it leaked out - was a small “melted” spot in the silicone.

Got it put back together and everything came on and fired up first (and second and third) time!

I think we’re back in business.

nice work Jon