Poor Running ST184 5S-FE

[Mk1_Oz]

Hi from a new posting member!

I have recently bought a 1990 Celica ST184 with a 5S-FE motor. It has been great for 6 months but the other day it nearly killed me when whilst pulling onto the freeway it started to misfire, surge and lose power resulting in a near miss with a truck :(

To solve the poor running I have tried to be methodical and so far have;

1. replaced the spark plugs (3 looked the same but one had dark carbon deposits on it)
2. replaced the fuel filter
3. replaced the oil filter and oil
4. replaced the air filter
5. checked the voltage outputs of the MAP sensor (all seems ok as far as I can tell)
6. checked the continuity of the throttle position sensor (all ok)
7. had the injectors cleaned and tested (all ok)
8. checked for vacuum leaks

Although the above has resulted in a smoother running car it is still not well. As it now stands it starts and idles nicely but has the following faults;

1. upon pressing the accelerator the engine noticeably knocks until the revs build
2. engine knocking can be heard (I think) under load
3. generally it then accelerated smooth although at 2800rpm something seems to switch and it comes a little more alive
4. down on power in all areas
5. makes a sound very similar to an exhaust leak as it drives (although I cannot find an exhaust leak!)

I am at a total loss now. I have not recently put fuel in so the knocking must surely be ignition driven? Low coil output? Ignition somehow suddenly jumped out?

Anybody had similar experiences and know the solution?

[johnn]

hi

had similar problems with 94 camry with 5sfe, tried everything like you. i had just filled petrol tank so as last resort drained it all put fresh fuel in and all problems disappeared. did try to make a claim against fuel company but they deny responsability. hope it helps only other thing i had problems with a corolla similar changed coil even though it didnt show up too bad with multi meter that fixed that.

[Mk1_Oz]

Thanks. Just bridged the E1 and TE1 terminals in the diagnostic port and the service light continually fast flashes. This has me a little confused UNLESS what I am seeing is actually a code 1 flash (single flash) repeated over and over? Probably got 3 flashes per second at a guess.

Comments??

[Mk1_Oz]

More playing in the shed.

I have now tested the EGR valve (the best I can accorsing to the service book). I sucked on the top vacuum line and it held the vacuum and with the car running that caused it to stall = good according to book.

I suck tested other vacuum lines (the ones to the charcoal cannister) and they all hold a vacuum.

The three vacuum lines on the trottle body all have vacuum/no vacuum at the correct times.

I put a timing light on it and at idle it shows sorta 10 degrees. Hard to tell really as the gauge has a mark for 0, a mark for 5, 2 marks for 10!!. Sits just on the first of the 10 marks which may or may not indicate it is a touch low. When the revs are bliped the advance shoots to high then settles back a little. Not sure if it should advance quite so quickly (I am of the old skool non-electronic ignition breed!!!!).

The distributor rotor has some cracks on the top just where the metal tang sicks out the front although appears to still have strength and integrity. The 4 pins in the cap are half worn through although I have not seen a new one so don't know if it started off like that or not. Will replace anyway I think.

Air gap on the distributor sensor is close to 0.008 (allowable is 0.008 - 0.016") so should be fine.

This knocking/pinging upon slight acceleration (even under no load) really has me beaten!!!!!!!!!!!!!!!!!!!!

HELPPPPPPPPPP

[trentmeyer23]

Compression Tested?

[Mk1_Oz]

Yes did that too. about 175-180psi on all cylinders.

[Mk1_Oz]

Either my thread has people stumped or there is not alot of traffic in here :(

I have now replaced the distributor cap and rotor to no avail. Did not replace the leads as they were $240/set. The ones I have look ok but I guess I cannot be totally sure. Not sure that bad leads would cause knocking?

The one thing I have yet to test (as I dont have the correct meter) is the fuel pressure. This could well cause low power although I am not sure it would be responsible for the knocking just off idle?

So so lost and in need of input.....

[trentmeyer23]

It really is hard to diagnose through a keyboard, a video of the fault and also codes could help.

[Mk1_Oz]

OK finally got it running sweet. I pulled apart alot of the EGR system. Cleaned the filter, manually operated the EGR valve to try to dislodge any carbon preventing it from opening/closing, put new ignition leads on it.......viola

I fail to believe that leads would cause knocking under acceleration so maybe I did something to the EGR system.

Thanks all.

[sebastiandivita]

Haha ! wow, after all that ! glad to know its running well again ! well done !

[farge]

OK finally got it running sweet. I pulled apart alot of the EGR system. Cleaned the filter, manually operated the EGR valve to try to dislodge any carbon preventing it from opening/closing, put new ignition leads on it.......viola

I fail to believe that leads would cause knocking under acceleration so maybe I did something to the EGR system.

Thanks all.

Hey,

Sorry to necropost, but your problem with pinging under any acceleration sounds very similar to what I'm seeing in my ST204 (also FS-FE engine).

I'm trying to follow the service manual instructions for the EGR system, but I've got a couple of questions for you (if you can remember):

1. What state was your EGR filter in? Mine's kinda crusty, far more than I expected. How did you clean yours?

2. Did you take the EGR valve off, or is there a way to work it (to remove carbon deposits) without doing so? If you took it off, did you have to get a new gasket?

Would appreciate any info you can give me!

Edited March 3, 2014 by farge

[LivingTheDream]

Hi mate, Ive just come across this post and reading it tells me that the guys original problem was not the EGR but the plug leads all along. The "pinging" noise he had was the misfire and only running on 3 cyl's. Unfortunately to say, he should've spent the money on new leads, not waste time on EGR's. I've never come across this problem in all my years.

[farge]

Does sound like that hey. Just wondering about the EGR because he mentioned that "coming alive" at around 2800 RPM, which is inside the rev range that the EGR is switching between a few of its different modes according to the service manual. My car's predictably rough, even jerky, at around that range but smooth at other engine speeds, so I thought maybe it was related. Doesn't look like he's still checking here though. Thanks for the reply!