91 turbo cutting out under boost - Toyota Nation Forum : Toyota Car and Truck Forums

mr2-55 · 03-03-2005, 09:55 AM

I just bought a 91 turbo 2.0L with 120k miles. It is stock except for the cat back pipe and the K&N filter. It runs fine except for when its on boost under load. I can hear the turbo spool up and watch the boost gauge start up, I hear what sounds like detonation, and then the engine cuts out. It seems that the knock sensor is hearing the detonation and cutting back the timing. This happens consistently whether taking off in first gear or trying to accelerate out of a corner. No check engine light and it does it whether the temp is hot or cold.

I have tried setting the timing to 10 and 8 degrees with no improvement.

I have tried premium fuel from bp, exxon, shell, and am on my fourth tank of injector cleaner (lucas and redline)

I have changed the o2 sensor, fuel filter, plugs, distributor cap, and rotor button.

It does not seem to be the variable induction system problem because it happens way before 4200 RPM (although I have not checked the system)

The next things I am going to try are sending the fuel injectors off for cleaning and balancing, and replacing the timing belt. I really don’t think it’s the belt, it runs too well when not under boost to have a cam a tooth off.

Could it be a bad turbo pressure sensor which is advancing the timing too far? Something else in the turbo circuit? ECM problem?

Is this common? I saw this mentioned in other threads but nothing really seemed to help my situation.

What do you guys think? Any suggestions?

carcatz · 03-03-2005, 06:11 PM

I am having a similar problem, I've had my timming belt changed and new, cap, rotor, wires, plugs, I was thinking it mght of started happening when I put my k+n on. it might be taking in hot air from the engine compartment, I've taken it to the dealer and they said that there were no codes it might be from the K+N. I really don't know.

***MRQtwinturbo*** · 03-04-2005, 06:00 AM

do u have an aftermarket boost gauge??...how much boost are u hitting??.....maybe you're hitting fuel cut.....

mr2-55 · 03-04-2005, 12:24 PM

The Filter is easy enough to try. I'll check it out.

I have plug wires on order, Other threads say that is usually the problem. I also bought Bosch plugs, someone recommended not using Bosh so I am going to try NGK's.

I dont have an after market boost guage, it hapens just as the boost starts up so I dont think its getting to the point where it should be cutting fuel.

There are other threads where they talk about knocking causing the computer to cut the timing back which really sounds like my problem. They said the fix is usually to replace plugs (NGK only), wires (OEM only), and cap. They also talk about aftermarket BOV's. Mine is stock so unless its bad it should be OK.

carcatz · 03-04-2005, 03:42 PM

nom aftermarket guage yet, what would cause that, to much boost? and how did it get turned upon a factory mr2 with no mods but a K+N.

Piddy · 03-04-2005, 04:03 PM

You can 'turn it up' with a fuel cut defencer..... or you can eliminate it by plugging the hose leading the the pressure sensor. I have a couple diy fcd's for sale if you want one.

Piddy · 03-04-2005, 04:16 PM

BTW:... if you are hitting fuel cut... you will get a check engine light..... and it will come up when you pull the codes.

carcatz · 03-04-2005, 06:57 PM

thats the problem I'm not getting a light, nor the codes it happens at high rpm boost?

***MR2Jedi*** · 03-04-2005, 08:01 PM

since everything else has been tried/addressed..cuz I am surely no expert, but is it possible that the intercooler is dirty with blowby and not suffiently giving the higher boost adaquet cooling causing knock and then retarding the timing? Just a thought. I cleaned mine out when i bought my '91(125kmiles) just to make sure everything was hunky dory.

carcatz · 03-04-2005, 08:13 PM

how would I go about cleaning the intercooler?

***MR2Jedi*** · 03-04-2005, 08:47 PM

just remove it and fill it with any of the engine degreasers-purple power,mean green, etc. shake it around and let it soak some. then just rinse it out best you can. then get as dry as you can before reinstalling it. a little water inside won't hurt. I took a blow dryer and and put it up to one of the pipes and dried it out that way.of course spray the outside fins too. there was a considerable amount of blowby in mine. I didn't have the problem you are talking about. it was more of a preventitive thing.but certainly doesn't hurt to have a clean intercooler..hope it helps

carcatz · 03-05-2005, 05:26 AM

well if it has to be removed I guess I will upgrade it because its not an easy part to replace.
thanks
do you think when it got serviced they did not reconnect the knock sensor?
would that cause this or would it cause the dash light to come on?

***MR2Jedi*** · 03-05-2005, 10:50 AM

I think if thet didn't re-install your knock sensor, it would knock severly every time you stepped on the gas. wouldn't hurt to do a visual check though.. as far as CEL, I don't know..ishcolebo, the Doc or MRQ might answer that one for u.

mr2-55 · 03-08-2005, 10:25 PM

My OEM plug wires arrived today. I installed them and went for a drive. Wow what a diffrence! The car runs great. Plug wires was JekylandHyde's suggestion on another thread. Up until today I replaced everything but the wires. I am going to buy the NGK plugs tomorrow.

BTW I tried putting the stock filter (and taking the K&N out) but it did not help.

carcatz · 03-09-2005, 07:14 AM

Yeah it must be something else. I haven't had time to play with my car this winter to cold and snowy, nothing great about living on cape cod this winter!