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Please help me! Erratic-won't run after ECU change

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Old 09-22-14, 05:33 AM   #1
power54
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Exclamation Please help me! Erratic-won't run after ECU change

I have a 1993 Lexus ls400 with 180,000 miles on it, which I got from a junk yard. When I first got it would hesitate when i suddenly press on the gas and sometime it would surge forward after hesitating. Sometimes the car would rock back and forth when going uphill when gas pedal is press too hard

After looking on online forum I came to the conclusion that replacing the ecu caps would solve the problem. When I messed up the ecu I got a refurbish one off eBay.

Now my vehicle won't start. It will crank, but won't start and sometimes it will start and then dies immediately. I looked online again and came to the conclusion that it was the fuel pump, and fuel filter that was the culprit, i changed both and still it won't start.
I really like the car and I don't want to junk it, any advice on what could be the problem?

Jobs I have done so far:
I changed sparks plugs with original denso plugs
I have changed the oil and filter
I have changed the tps
I have changed PVC valve and coolant temp sensor
I have changed fuel pump and filter
I changed sparks plug wires too.
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Last edited by RA40; 09-22-14 at 08:51 AM.. Reason: descriptive title
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Old 09-22-14, 07:11 AM   #2
sha4000
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First off did you check the car for codes? If your check engine light is on that would be the best place to start. I would not keep throwing parts at it.
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Old 09-22-14, 07:21 AM   #3
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and double check the ECU you bought online... The reason they pulled the ECU from a car could be because they scrapped it BECAUSE OF the ECU.
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Old 09-22-14, 08:50 AM   #4
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For future post titles please be descriptive when titling the subject header other than "Please help".
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Old 09-23-14, 05:29 PM   #5
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Instrument panel does not work. I t comes on and off, but net stays on long enough for me to pull codes. I have odb2 scanner and it does not work for pre 1996 vehicles.
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Old 09-23-14, 05:30 PM   #6
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Sure thing will be mindfull next time about being more descriptive in posting.
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Old 09-23-14, 06:51 PM   #7
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Quote:
Originally Posted by power54 View Post
After looking on online forum I came to the conclusion that replacing the ecu caps would solve the problem. When I messed up the ecu I got a refurbish one off eBay.
the dangers of that thread and recommending people attempt that job on their own..if I were u I would send ur ecm to jim walker...he just did mine,my car is back together and running fine. u might as well start with knowing ur ecm is not the issue at this point.
u can email him here:
thelexpert@gmail.com
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Old 09-23-14, 07:36 PM   #8
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Quote:
Originally Posted by python View Post
I would send ur ecm to jim walker...he just did mine,my car is back together and running fine. u might as well start with knowing ur ecm is not the issue at this point.
u can email him here:
thelexpert@gmail.com
Sweet! good to know! thanks!
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Old 10-09-14, 07:19 PM   #9
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Problem fixed!!!
As it turns out it was the ECU i purchased for it was faulty, i sent it back to the seller i bought it from, and they sent me another one (free of charge of course), and it started right up!
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Old 10-10-14, 11:37 AM   #10
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Glad to hear that, and thanks for following up.

BTW - it's very easy to read codes on the pre-OBD2 cars. Search and you'll find details, but basically you put a paperclip jumper across terminals under the driver's side dash, then count flashes on the instrument panel when you turn the car on to get the codes. Similarly, HVAC has a very simple built-in diagnostics procedure - hold in two buttons (Auto and recirculate, I think) while turning the car on, then read the display codes off the HVAC LCD panel.
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