No more Bosch fuel pumps produced. What is the next best?

Roadrash74 said:
Try putting a hair dryer on the ignition switch and let it warm up, then see if it starts right up...wouldn't hurt.

Copy. I look forward to hearing the fix.
Click to expand...
Tried the hair dryer on the swith with no luck.
Replaced the Coolant Temperature Sensor nothing.

I noticed inside the quiet garage and fuel pressure on the fuel gauge, that when turned the key to the on position(13 seconds on the video) the gauges won't move and the pump keeps priming for 13 seconds until you heard the purge solenoid click, then right after you heard a gushing of gas inside the engine(26 seconds on video). At the same time the gauges move to normal.
Looks like the PCM don't send the signal right away.
Other times the pump primes for 2 seconds and stops.
Videos with my phone are to large to attach.
Here is a link
https://photos.app.goo.gl/wKNCLhSU7goA3RSd7
 
This is another video from the inside.
Turned the key to the on position, the gas gauge is all the way down and the battery is at about 11V. All lights are on, fuel pump prime for several seconds, in the mean time all of the lights came off except the service engine light, then stop priming the gas gauge goes up, the battery goes to around 13V, and the service engine light comes off.
Tried a few times after and prime for 2 seconds and gauges worked.
https://photos.app.goo.gl/7SBAeSHN8NkabMnv9
 
I was finally able to watch the videos you posted. There looks to be an electrical issue somewhere, a bad ground or connection. Your battery sounds strong and the starter circuit sounds good once the relay is actuated. You may need to try several electrical items (lights, radio, blower, etc) and see what works and doesn't work when your gauges aren't reading. Once you get a list of as many things as you can find, dive into the schematic and see what everything has in common. If you list all the symptoms on here, every gauge, every light, every little thing that's doesn't seem to be getting full power, then I can also look on Tuesday when I get back to a computer that I can see on...me cell phone is too small for looking at schematics.
 
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Roadrash74 said:
I was finally able to watch the videos you posted. There looks to be an electrical issue somewhere, a bad ground or connection. Your battery sounds strong and the starter circuit sounds good once the relay is actuated. You may need to try several electrical items (lights, radio, blower, etc) and see what works and doesn't work when your gauges aren't reading. Once you get a list of as many things as you can find, dive into the schematic and see what everything has in common. If you list all the symptoms on here, every gauge, every light, every little thing that's doesn't seem to be getting full power, then I can also look on Tuesday when I get back to a computer that I can see on...me cell phone is too small for looking at schematics.
Click to expand...
I will definitely do that.

Today, I hade to run an errant inside the garage turn the key to the on position and waited until the gauges came up and check engine light off,(took 16 seconds) but started at the first time. On my way back after the jeep sitting on the 21° weather for 2 hours, I did the same turn the key to the on position and waited for the gauges to come up and the check engine light to come off and it took about 32 seconds, but started at the first time.

I will check all the electrical and the schematics today.

Thank you all!!

PD. I am sorry this tread deviate from the original fuel pump to this (Electrical Problem) I really thought my problem was a fuel pump issue.
 
Last edited:
gonzvj said:
PD. I am sorry this tread deviate from the original fuel pump to this (Electrical Problem) I really thought my problem was a fuel pump issue.
Click to expand...
No worries. I'm following closely because I have a very similar long start issue. I hope you get to the bottom of this!
 
I did check a grounds with the help of schematics I found online, and nothing.
Then decided to warm the PCM with a heat gun, and gauges and everything worked, the problem is only when the PCM is cold.
So I decided to keep looking on the forums and found this tread that has the exact same issue.

https://wranglertjforum.com/threads/cold-start-issue-1997-4-0l-manual-solved.7618/
I will order a PCM tonight from here

https://www.fs1inc.com/engine-compu...010411aa-05014152aa-4-0l-ecu-ecm-pcm-oem.html
$206.00 free shipping.

I will tell you if that fixes my issue.

Again,
THANK YOU ALL!!!
 
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SecondChanceTJ said:
No worries. I'm following closely because I have a very similar long start issue. I hope you get to the bottom of this!
Click to expand...
Confirmed, it was a bad PCM.
I just installed the one I ordered and fixed the the proem. I opened the old PCM just to see, and I found a bad capacitor. I'll see if I can replace that capacitor and have a spare PCM.

THANKS A LOT!!!!!
Everyone that helped out.

20210226_165018.jpg
 
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gonzvj said:
Confirmed, it was a bad PCM.
I just installed the one I ordered and fixed the the proem. I opened the old PCM just to see, and I found a bad capacitor. I'll see if I can replace that capacitor and have a spare PCM.

THANKS A LOT!!!!!
Everyone that helped out.

View attachment 229479
Click to expand...
Nice find, electrolytic caps tend to eventually do that. I'd probably replace the others too.
 
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