Cold start issue on 1997 TJ 4.0 (SOLVED!)

[BWS]

I have been having an issue with starting my 1997 Wrangler for a while. I can always get it to start, but when starting the first time of the day, I always have to follow the same routine.

The routine goes....
- turn key to initiate electrical and gauges; all lights come on, radio comes on, Check Engine light stays on, none of the gauges register (battery and gas gauge do not move), key off.
- turn key again, same thing with electrical, CEL, and gauges, key off.
- turn key a third time, all electrical and gauges operate properly, CEL goes off, Jeep starts.

If I attempt to start the Jeep on the first two steps, I never have any luck. If it is real cold in my garage (I'm in Northern Colorado), the Jeep will maybe start on that third key, but if not, always on the next attempt. During Spring/Summer, it will start on the third key on.

My assumption has been that the fuel pump/fuel pressure regulator needs to be changed as it seems that fuel is not getting to the engine as it should, and is also draining back into the tank. (I also have trouble starting the Jeep on inclines at all times; doesn't matter if it is hot or cold.) My 4x4 shop also believes that the fuel pump needs replacement as well, but they, and I, are confused by having to key the Jeep three times in order for gauges to actually register. That seems like an additional issue.

Has anyone seen this before, or have any experience with this issue? I am fine with dropping the tank and replacing the pump assembly, but am wondering if there is anything else I should be checking into prior to that.

Any help or insight is appreciated.

Thanks!

 

[Chris]

When you try to start it on the first and second try, does it turn over at all?

 

[BWS]

It turns over, but will never start.

 

[Chris]

It turns over, but will never start.

Oh, okay. I was thinking it sounded like an ignition switch that was possibly going bad (which it still may be part of the issue, especially given that the gauges and stuff don't come on until you turn the ignition on and off a few times).

However, I'm starting to think it is indeed the fuel pump. If you do end up replacing the fuel pump, be sure to get the Bosch unit as the others reportedly have issues. This is the one for your 1997: https://www.amazon.com/dp/B000BZJDK2/?tag=wranglerorg-20

Have you scanned the vehicle by chance to see if there are any stored error codes? That may be very telling if there are.

 

[BWS]

No error codes. I was having evap problems, but I solved those a few months ago. That's actually when this problem got more consistent. Thanks for the link on the fuel pump. I appreciate it.

 

[sinatranate]

I had this issue as well. Your pressure regulator is sitting on top of your fuel pump, which is located on top of (sitting inside of) your gas tank.

You will need to take out the screws at the front of the gas tank cradle (only), and let the hinge carry the assembly down. Best to do this with an (almost) empty fuel tank, as it will be extremely heavy and unwieldy otherwise. Careful of the rubber fuel line, which has very little slack from the factory, and will be brittle from exposure. There is a Y-fitting and a T-fitting for backwash, which splits the fuel line into delivery and a return back into the tank. You may break it, but don’t worry. They’re cheap(ish).

There is a ring at the top that screws down onto the threaded opening in the top of the gas tank, which is probably really stuck on there after years of driving. They make a special wrench, which I definitely recommend buying. You can order the entire assembly (if you want, and I recommend), but you can also get just the regulator. The regulator is held to the top of the pump with a spring clamp, and that will be dangerously hard to get off. It is next to plastic parts, and you can slip your screwdriver or pry-bar into one of these or your hand.

I also recommend taking pictures of the fuel lines before lowering the tank all the way and disassembling. That way you know how everything goes back together, with emphasis on the direction of the y-fitting in the return line.

If you decide to replace just the regulator, be careful replacing the spring clamp, again, as you may break something or hurt yourself. It is a very tight fit (for good reason). Any other questions, let me know.


Sent from my iPhone using Tapatalk

 

[BWS]

Thanks for the install tips, sinatranate. It's great to know the possible pitfalls on any Jeep repair. I'll just replace the entire assembly, rather than only the regulator. This will be a December project since trails close on Dec 1 around here. I'll put in a new gas tank skid at the same time. I appreciate the info.

 

[sinatranate]

I figured, having done nearly everything wrong the first time, myself (in the parking lot of an O’Reilly’s, no less!), I thought someone else might benefit from my experience. Let me know how it goes!


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[BWS]

I should have updated this thread as I tried different fixes. I replaced the fuel pump over a year ago with a Bosch unit. Didn’t fix anything. Everything I read still pointed to a fuel issue. My mechanic still thought the fuel pump was a problem, so after 5 months, I returned it to Amazon and installed another Bosch unit. I had to get that one locally at NAPA since I could not find any Bosch pumps online. Still no change with my starting issues. (At least I was able to get a new gas tank skid on this time. Not a total waste of time.).

In May, my distributor assembly was replaced, and when I got the Jeep back, it was starting up a lot easier. This remained through mid-August until the Colorado nights began getting cooler and my start issues crept back. As the weather got colder here, it took longer and longer for the ASD and fuel pump relays to respond.

With that confirmed cold temperature information, I searched the various forums a little differently and found many similar issues. I also found similar issues addressed in YouTube videos. In each instance where a resolution was posted, the pcm was the issue. So, I took a chance and contacted Flag Ship 1 in New York. They directed me to the correct pcm for my Jeep. I went ahead and ordered it. I figured, “what’s another $187!?!” It took a few days to program to my VIN. Then they sent it overnight USPS. It arrived today. Out of the package, it looked brand new! I wasn’t sure what to expect, but it does not look like it was ever used. It took 10 minutes to install. And....BAM! Jeep starts up like normal!

If you are having odd starting issues, or delayed starting issues, especially in cold weather, don’t overlook your pcm.

I hope this helps someone else out there.

 

[Jerry Bransford]

Wow that was a surprising fix but thanks for the update!!

 

[AndyG]

Man I'm telling you , on diagnosis, either your gut is dead on or it's keeping you on the wrong track .

I love this forum because it broadens our horizons.

 

[BWS]

Without these forums, I’d be lost. I vow to always post updates whenever I solve an issue. I can’t tell you how many posts I have found that lay out a plan of action, but never get updated with a resolution. So frustrating when going down various TJ rabbit holes.

 

[AndyG]

We can all hang together or hang separately.

 

[gonzvj]

I should have updated this thread as I tried different fixes. I replaced the fuel pump over a year ago with a Bosch unit. Didn’t fix anything. Everything I read still pointed to a fuel issue. My mechanic still thought the fuel pump was a problem, so after 5 months, I returned it to Amazon and installed another Bosch unit. I had to get that one locally at NAPA since I could not find any Bosch pumps online. Still no change with my starting issues. (At least I was able to get a new gas tank skid on this time. Not a total waste of time.).

In May, my distributor assembly was replaced, and when I got the Jeep back, it was starting up a lot easier. This remained through mid-August until the Colorado nights began getting cooler and my start issues crept back. As the weather got colder here, it took longer and longer for the ASD and fuel pump relays to respond.

With that confirmed cold temperature information, I searched the various forums a little differently and found many similar issues. I also found similar issues addressed in YouTube videos. In each instance where a resolution was posted, the pcm was the issue. So, I took a chance and contacted Flag Ship 1 in New York. They directed me to the correct pcm for my Jeep. I went ahead and ordered it. I figured, “what’s another $187!?!” It took a few days to program to my VIN. Then they sent it overnight USPS. It arrived today. Out of the package, it looked brand new! I wasn’t sure what to expect, but it does not look like it was ever used. It took 10 minutes to install. And....BAM! Jeep starts up like normal!

If you are having odd starting issues, or delayed starting issues, especially in cold weather, don’t overlook your pcm.

I hope this helps someone else out there.

I just ordered one!
I have the exact same issue.
I never thought It could be the PCM.
I already replace a lot of parts just like you.
Good thing is,.... I know I have a bunch of new parts.
Thanks!

 

[BWS]

I just ordered one!
I have the exact same issue.
I never thought It could be the PCM.
I already replace a lot of parts just like you.
Good thing is,.... I know I have a bunch of new parts.
Thanks!

Good luck gonzvj! Glad this has helped out. One way to really know that the PCM is the issue is to get your Jeep running and up to temperature. Then, remove the problematic PCM and put it in the freezer for about an hour. Put it back into your Jeep and try to start it. If it doesn't start, then you know the PCM is definitely the issue. But, it sounds like you have gotten to that conclusion the long way....like I did. I have had my replacement PCM for 27 months now and all is still working perfectly. I hope you have the same outcome. Stay warm down there in Texas!

 

[gonzvj]

Good luck gonzvj! Glad this has helped out. One way to really know that the PCM is the issue is to get your Jeep running and up to temperature. Then, remove the problematic PCM and put it in the freezer for about an hour. Put it back into your Jeep and try to start it. If it doesn't start, then you know the PCM is definitely the issue. But, it sounds like you have gotten to that conclusion the long way....like I did. I have had my replacement PCM for 27 months now and all is still working perfectly. I hope you have the same outcome. Stay warm down there in Texas!

Received the remanufatured PCM yesterday and it works perfect.
I wanted to confirm my suspicion that it was a bad capacitor, and I opened the bad PCM and that is what it was. Attached is a picture of the bad capacitor. I'll see if I can find one online to fix it, and have a spare PCM for the future.

Thank you for your help!!!!!

 

[BWS]

Received the remanufatured PCM yesterday and it works perfect.
I wanted to confirm my suspicion that it was a bad capacitor, and I opened the bad PCM and that is what it was. Attached is a picture of the bad capacitor. I'll see if I can find one online to fix it, and have a spare PCM for the future.

Thank you for your help!!!!!

View attachment 229478

Great news! Glad it worked out for you. I am sure my old PCM also has a bad capacitor. If you are able to repair yours, please post an update. I may try to do the same just to have a spare for the future.