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Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go hereXJ (84-01)
All OEM related XJ specific tech. Examples, no start, general maintenance or anything that's stock.
2000 XJ Sport - it runs beautifully and starts instantly - up until 2 weeks ago. Overnight it developed an issue where it would not stay running when started. It was the day after I took the old side trim off with a rubber wheel, but I think that’s more coincidental than vibrations triggering something. With some trial I discovered it runs normal when warmed up, and starts the first time when warm.
Did some research here and the apparent culprit is the electrical signal sent to the fuel pump when cold. A poster said turning the key off an on 3 or 4 times solves the problem, and I found that to be true. I’ve also noticed it’s become more difficult to pull the key out after turning it off.
My question is this: is it likely to be an ignition switch issue or just the sending unit on the fuel pump? Or is there another potential cause that I’m unaware of?
Please share if you’ve run across this and how it was eventually solved?
2000 XJ Sport - it runs beautifully and starts instantly - up until 2 weeks ago. Overnight it developed an issue where it would not stay running when started. It was the day after I took the old side trim off with a rubber wheel, but I think that’s more coincidental than vibrations triggering something. With some trial I discovered it runs normal when warmed up, and starts the first time when warm.
Did some research here and the apparent culprit is the electrical signal sent to the fuel pump when cold. A poster said turning the key off an on 3 or 4 times solves the problem, and I found that to be true. I’ve also noticed it’s become more difficult to pull the key out after turning it off.
My question is this: is it likely to be an ignition switch issue or just the sending unit on the fuel pump? Or is there another potential cause that I’m unaware of?
Please share if you’ve run across this and how it was eventually solved?
Thank you!
The pulling the key out issue is almost certainly it's own issue with either the key cylinder or the ignition switch. If you take very good care to get the key in the exact position, I bet it will come right out. You can try a little bit of lock lubricant (graphite - preferably one that sprays so it will get deep in there) it may help.
Considering that once you're up and running, it's running fine, I doubt there is an issue with the fuel pump power along the wiring.
Do you hear the fuel pump prime EACH time that you turn the key to ON (during the On-Off dance) --- or at least every FIRST time you switch it to ON?
I had an issue where I had to do the On-Off key thing with my 95 and had long crank-no-start, but I noticed that I wasn't hearing the pump prime. IF I DID hear it prime, the Jeep started right up. The colder it was, the harder (or more tries) before it started. I researched the issue and found that another guy had the same issue and needed to replace his PCM to solve it. In my case I actually was replacing my PCM anyway (the O.P. had the wrong part number and I'd found a good deal on the correct part number) and I swapped out the PCM and the fuel pump relay and I now start up right away every time regardless of weather.
However, bear in mind that the fuel pressure regulator is DIFFERENT on a 95 than a 2000 --- AND --- The PCM type is completely different.
It may be worthwhile to replace your relay since it's cheap and clean up the connection while you're at it.
If you (as I suspect is the case) have the prime occur audibly every first time you switch it to ON, then you likely have a pressure regulator problem (or leaky fuel injectors) which will mean dropping the fuel tank and replacing the fuel pump assembly.
If you pop the hood and can smell gas, or your exhaust has a gasoline smell on first startup of the day, then you might have leaky injectors.
Either way, the pressure is being lost in the system and the multiple On-Off process helps to restore pressure in the lines. I'd check for a gas smell first and if there isn't any obvious smell, put a fuel pressure test gauge on it and do a fuel pressure and leakdown test as outlined in the FSM. If you need the FSM, I believe Cruiser's page has a link for 2000 - http://cruiser54.com/?page_id=365
2000 XJ Sport - it runs beautifully and starts instantly - up until 2 weeks ago. Overnight it developed an issue where it would not stay running when started. It was the day after I took the old side trim off with a rubber wheel, but I think that’s more coincidental than vibrations triggering something. With some trial I discovered it runs normal when warmed up, and starts the first time when warm.
Did some research here and the apparent culprit is the electrical signal sent to the fuel pump when cold. A poster said turning the key off an on 3 or 4 times solves the problem, and I found that to be true. I’ve also noticed it’s become more difficult to pull the key out after turning it off.
My question is this: is it likely to be an ignition switch issue or just the sending unit on the fuel pump? Or is there another potential cause that I’m unaware of?
Please share if you’ve run across this and how it was eventually solved?
Thank you!
I do not have much experience diagnosing ignition switch problems, but the issue seems like it could be fuel related. I've seen lots of people on here using the 3-4 key turn method when their fuel pump starts failing because it primes the pump up. The fact that the issue isn't present when the jeep is warm, leads me back to a fuel related issue. Rent yourself a fuel pressure tester kit from your local auto parts store (free with a deposit) and see whats happening when ignition is switched on and when the engine is running. Fuel pressure for an 00 XJ should be 49psi +- 5 at idle.
Thank you guys. I didn’t detect any gas odor. I didn’t hear a prime sound the first key turn but did the 2nd and third key turn. Started right up. It’s probably the original fuel pump (it has 111K on it), so that’s probably an eventual replacement. I can certainly live with this for a bit.
Test the fuel pump relay and the connector to the pump to ensure that both are working correctly. Also, the relay itself by simply swapping it with another one.
Post the voltages that you read at which wires and in what conditions.
Before installing a new pump ground, pull the driver's side panel in the trunk and clean up the ground there - it's often overlooked but will cause all kinds of weird electrical gremlin-ing if it's corroded.
Cleaning up that ground wire as suggested by PatH is a must do.
Swapping the relay for the Fuel Pump and the Auto Shut Down are cheap to do. Do them both with new relays. Relays can become intermittent when failing.
Do a fuel pressure test at earliest opportunity. Pumps output can become weak prior to full failure.
I don’t have the equipment or expertise to do some of the testing, but that doesn’t deter me. At least some of this I can do myself!
So question about the fuel pump related relays: there are 2- Fuel Pump Relay and Automatic Shut Down Relay-? In this diagram they appear identical, and I can only find one parts item for this. Does the same part work for both relays?
Side note- I had a one-off strange warm start issue stopping by the grocery store after driving a friend to the airport. It started and sputtered, misfired and pressing the gas pedal had zero effect on anything. After an anxious minute it fixed itself and ran beautifully again. It was a WTF.
Said a moderator had to approve it? Was a pic of a diagram of the power distribution relays and wanting to know if the fuel pump and automatic shut down relays were actually the same part?
(there were no naked people in the power distribution diagram that I’m aware of..... just saying)
I’ve removed and cleaned the IAC, not the culprit. My approach now is to replace the fuel pump relay next, then pull the rear side panel and check the ground I’ve been told of. Last resort I suppose is replace the fuel pump assembly which I cannot do myself.
Ordered a relay from Parts Geek and it’s not the correct one. They said 2000 Jeep Cherokee fuel pump relay is a square one, and in reality it’s rectangular about half the size. The only corresponding part I can find so far is for a Grand Cherokee. Are they likely to be the same?
Are there other more reliable sources for such a thing without going to a dealer?
And... NO I didn’t pull the plastic cover off and check before I ordered �� My bad. At least it was just $10 delivered.
02-22-2019, 05:04 PM
Cold start issue
