3S-GTE running strange

[Tayfun]

Hi

I have a strange problem with my MR2 Turbo. It all started last summer when in very warm weather and when engine was warm the car started hesitating and jerking between 2500 - 3000 RPM no matter in which gear it was. I couldn' find the fault. I bought new ignition coil, HT leads, spark plugs and cleaned the distributor cap and AFM, unfortunately the fault persisted. I used the car several times in this winter when the temperatures were freezing cold and it ran flawles, no hesitation or jerking. Only thing I noticed in winter was that the battery and catalytic converter dash lights camer intermittently came on and faded later on.

I took the car for a ride today and it started again with those problem in warm weather.

Car was running fine today till it warmed up, after 20 minutes drive it started hesitating at 3000 RPM, when it hit over 3000 RPM it ran fine again. After next 15 minutes it started jerking and after that running like a diesel engine till about 3000 RPM, as soon as it hit over 3000 RPM it ran fine again.

Note that it does that only when engine is warm and in warm weather.

I think it must be some faulty sensor that is causing this.

[markstevieandmads]

Open up the ecu and check the capacitors for leaking.

Also remove the foil and bracket and give the bracket a good clean where it connects to the bodywork as it earths through it.

[abovetherim]

It may be worth checking for error codes doing the paper clip check
http://www.mr2oc.co.uk/know-your-2.html ... bartid=162

It may also be prudent to check the functionality of the ecu coolant temp sensor. If this perm reads cool then engine will over fuel which will be most apparent at lower revs.

The problem of the dash lights is most likely the alt belt too slack/slipping or poor contacts in the plug for the alt or damaged corroded wires to/from the alt. It is worth noting that when laid up the alt can get a layer of corrosion on the inside that can seize it.

[Tayfun]

Hi

Small update.

Took the ECU out and opened it, all capacitors are fine, brackets are also clean no rust present. Also changed the ECU green water temperature sensor, installed a new one today.

No changes, car runs fine till it warmes up, than again it starts jerking, misfireing, strong fuel smell and backfires. Only thing now with new sensor is that the jerking is more evident but it feels like the car is choking and runs on 3 cylinders for few seconds and that again on 4 for a few seconds and then back on 3. If I hit the gas pedal strong it boost with slight hesitation but strong afterwards. I noticed now that when it starts jerking the battery and catalytic converter lights come up, when jerking stops they fade and than back on, this goes on and on because between jerking and normal running it's matter of seconds.

This is running me crazy.

[Tayfun]

Forgot to mention ECU doesn't show any error codes when i connect TE1 and E1 terminals.

[[email protected]]

When you take the oil cap off when idling does it stall?

[Tayfun]

Replaced the distributor cap today, went for a ride and after 40 minutes the same started again although its not that brutal jerking anymore but still present. I removed the oil cap today when the engine was hot, it doesn't stall, RPMs fall a little bit but still runs. Than again as soon as it started herking again it feels like it is misfireing and you can smell the unburnt fuel. Also while engine jerks the battery and catlytic converter lights come on, I am suspecting that the alternator may be causing all this?!

[abovetherim]

Alt could be on way out but first check your battery connections and also check the state of the coil pack

[Tayfun]

Coil pack is brand new. Need to check battery connections over the weekend.

[TheRoadWarrior]

Did you change the rotor arm when you put in a new distributor cap? I always found the 3SGTE especially fussy about ignition parts

[Tayfun]

Hi guys

Took some time in the morning to try and find the fault. And I did... 4th injector had a cracked connector so when the engine got hot the connector expanded from the heat and started wigling and caused misfire from bad connection, as soon as I pushed the connector down holding it firm engine stopped jerking. I welded the connector now with an iron heat gun, it now seats firm. I went on a 30 minutes ride to my mother in law. Till now no jerking or misfiring.

[rossonza]

Hi guys

Took some time in the morning to try and find the fault. And I did... 4th injector had a cracked connector so when the engine got hot the connector expanded from the heat and started wigling and caused misfire from bad connection, as soon as I pushed the connector down holding it firm engine stopped jerking. I welded the connector now with an iron heat gun, it now seats firm. I went on a 30 minutes ride to my mother in law. Till now no jerking or misfiring.

good effort mate, i bet that was aright pain to track down

[Tayfun]

Yes it was just a lucky coincidence. I have been hunting this problem for almost a year, fortunately it's sorted now.