I have no throttle response, engine will not turn over 2000 RPM, fuel smell, crackling cats. Sudden onset on a 2 mile trip, crawled home. Had MAF cleaned by tech, with no effect. MAF, EGO sensors, and TPS appear to be in range according to him. Found no help in search. Thoughts?

 

bad ignition coil?

 

Hmm, so far that has not been explored. What triggers the so called "limp mode"? I should mention that no codes were recovered in two sessions. Would a bad coil cause an erratic tachometer? (one more symptom)

 

if the tach is reading erratic, id say its ignition related.

 

What triggers Limp In Mode is a list of things. Bad 02 sensors,misfiring of the plugs,arching threw the spark plus wires to the motor,bad coils, anything related to emissions which include vacuum sensors. There a couple other items I forgot to mention ,but type A codes and type B codes set the computer in Limp In Mode. Type C codes are body codes and other systems that should not affect the running of the vehicle. For example a error with the A/C circuit. I am not so sure with the coil issue cause my friend had a coil go out on his SC400 and it didn't make the tach go crazy. Does the tach get stuck and you have to hit it to move(common issue). Very strange that there isn't any check engine light. Is there something mechanical that could be a possible issue? Weird thing I will ask around my work to see what a possible solution is.

 

Tach appears to be normal at idle, albeit very low idle. Applying throttle wil take it bumpilly (yeah bumpilly) to 2K, whereupon the needle will drop and bounce, out of synch with apparent engine RPM. Don't recall mentioning it, but no ck eng light is correct. Scanner used was Snap-On OBDS I believe.

 

To bad you don't live near me cause I have 2 extra coils I am not using at the moment. If you know anyone that you could possibly score it from I would see if you could change those out and see if it is the problem. Thinking about it seems to be leading to that.

 

I'm having the same issues with my 95 sc400. Did you ever find a solution OP?

 

yep having the same problem starts fine then idle at 2-300 rpm and limp mode
on a 92 sc400 I pulled the iacv and checked it it was cleaned so I put it back together I also check for burnt resistors in the ecu it looked fine nest I just pulled the lower intake man and the throttle body to clean them
I will get new o2 sensors for sure

 

btw no codes either I crosed the dig plug and nothing!!

 

Hey,

I just went through this. Cats were red hot and the car has zero power whatsoever. Raw gas smell. This is an ignition coil that is not firing. Its usually driver side, but test both. Super easy fix. Got once off ebay for 17 bucks and car is running like a champ now. I hope this helps.

 

well I be sure to check that first I see the sc 400 got 4 o2 sensors worth about 200$ USD to replace all(if you don't have a soldering gun and cant be bothered to do it yourself from universal 4 wire sensors)
so yeah ill be borrowing some sort of matching coil and test them out first dude tks a lot btw
oh do you remember the part # that you got it off ebay ?

Cheers Bryan