New Used ECU issues! I think i hydrolocked my engine with fuel

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88sogreatv8

New Member
SO i have a 88 cressida with a 95 ls400 engine swapped I had to recently replace my Ecu with a used one , due to having a power output issues on my m-rel on the original ecu. now i have major issues after the computer swap!!!!
The first day i installed the new ecu it idled really low but overall it drove great good throttle response ect.
so i parked it in the garage and didn't drive it till the next day. the next day , i started the car and it idled perfectly ,so i let the engine warm up , but then i noticed the smell of raw fuel and it started to lightly smoke out of the tailpipe and reeked like fuel , i decided to drive it and see what was going on.

I noticed when driving it had good power and accelerated well, but when coming to a stop it ran rough and started smoking again and once again smelling like fuel. so i drove it back home and parked it . I hooked my scanner up to it later on and it had misfires on cyl 3,4,5,6,7,8 , and when i cranked it , it didnt fire and the engine shook violently, im guessing the fuel hydrolocked the engine so hopefully i didnt bend a rod in the process.

I believe that my computer is to blame for this, hopefully there is someone out there that can help with solving this issue.
 

blackdemon_tt

Member
Messages
38
Would you happen to upgrade the o2 sensor harness on your Cressida with the heated ones?? It may be that the ECU is detecting a rich fuel condition leaning out the engine and causing the misfires... I'm not completely sure on this though...

I get similar issues on my 93 SC400 with a heavy fuel smell out of the exhaust, but no smoke nor misfires, will stay on, and no fluctuation only the occasional hard start... may be an ECU capacitor issue, or leaking fuel injector.. I'm new to this so I may not have too much depth in this subject..
 

88sogreatv8

New Member
i dont have the rear 02 sensors wired , but the front ones appear to work fine. I Don't suspect o2s to blame . it didn't affect the drivability prior to the 1st computer. i replaced the old computer due to it losing m-rel power out. Im more concerned the engine hydrolocked when i was trying to start it and its bent a rod. i went ahead and got a new used computer ordered and returned the other one. both part numbers seemed to cross reference on https://www.toyodiy.com/parts/xref?s=89661-50230&mU=on. ( part numbers 89661-50231 / 89661-50230 )
 

gloverman

Well-Known Member
Messages
3,061
Location
Hamilton. New Zealand
Maybe so testing is in order. If I was really worried I would be measuring the TDC of each piston to confirm no bent rods. The Last number of a toyota part number is when a part is superseded so interchange fine.
 

gloverman

Well-Known Member
Messages
3,061
Location
Hamilton. New Zealand
Yes, I have seen maybe 5 ecus with stuffed injector drives causing injectors to stay on but its really easy to test for to confirm. Given the number of 1uz I work on this is an extremely small occurrance. One every 3 years. I have seen it a few times on other models but its very rare.
 

88sogreatv8

New Member
So update on engine issues. the new ecu didnt change much, i still idles right , but it still has smoke coming out that smells like fuel. i havnt tried driving it to see if this is just residual fuel or what . Injectors maybe? . #6 cylinder was flooded when i pulled all the plugs out. it was the only one , but all the plugs were damp . seems to run smoothly at idle
 

88sogreatv8

New Member
So i wanted to give an update on the engine flooding issue. I received a new used ecu and cleaned out all my cylinder of fuel. i cleaned the spark plugs and reinstalled them. I noticed that the #5 cylinder was full of fuel when i took out the plugs. All the plugs were black and wet with fuel tho. I am hoping that my #5 injector isn't sticking .

I have noticed that all my original issues seem to be gone with this new ecu. The car smokes a little bit when cold ( grayish white) , and smells like fuel , but after the idle drops and its fully warmed up no smoke, and it drives great full power . It is currently 30 degrees here and i dont drive the car in this weather normally , so im not sure if this is common with cold conditions. I am hoping that one of my injectors are not sticking .
 

ivan129

BlownZX
Messages
159
Location
Some where down under
Sounds like you have diagnosed this down to #5 cyl. so why not lift the fuel rails and get the injectors cleaned and flow checked. Don't forget to mark No. 5 injector so you can identify it.
 

88sogreatv8

New Member
Sounds like you have diagnosed this down to #5 cyl. so why not lift the fuel rails and get the injectors cleaned and flow checked. Don't forget to mark No. 5 injector so you can identify it.
i will probably do just that. im assuming the drivers were bad in the old computer , as it hydrolocked the engine but with the new engine it runs fine , i wonder if it was a combination of the two both stuck #5 and an ecu . maybe thats why the engine runs a little rich when cold
 

ivan129

BlownZX
Messages
159
Location
Some where down under
When you say it hydraulicked the engine assuming from fuel; surely the damaged cylinder or cylinders would have given you a clue to look for which injector or injector driver that caused the problem. That should rang alarm bells to repair before using the parts back on another engine. Hope you get it sorted.
 

88sogreatv8

New Member
When you say it hydraulicked the engine assuming from fuel; surely the damaged cylinder or cylinders would have given you a clue to look for which injector or injector driver that caused the problem. That should rang alarm bells to repair before using the parts back on another engine. Hope you get it sorted.
it seems to be fine now , i may have another issue with #5 , but atm its running great, with the 3rd replacement ecu. Only thing i notice is it has a light gray mist when cold , but after its warmed up its all good
 
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