Strange Misfire Problem

[Idrees]

Hi guys,

I've lost hope in finding the fault with this so I'm trying my luck here. I have a TD04 Glanza running all the usual mods. I was driving along and felt a hesitation / misfire just as the car reaches full boost.

It did this continuously and it wouldn't pass around 5k rpm. Well it may have, but only with seriously trouble.

After looking around for some obvious signs and checking all vacuums I (well, me and Aamir) changed the spark plugs (gapped at 1mm), HT leads, Distributor cap and Rotor arm

This didn't help, so we moved on to replacing the Ignitor, Coil pack and Map sensor.

The igniter seemed to have helped. With this fitted, the car would rev all the way but had a flat spot at 5-6k rpm.

Next we changed the map sensor, TPS, injectors with new seals, fuel pressure regulator and the distributor itself. The cars now running worse than it originally was! It's hesitant and misfires even when idling.

Any used parts that have been fitted (such as igniter) have been replaced twice just to be sure.

I've disconnected all the vacuums connecting to the boost controller and BOV just to rule out any damaged pipes or connections. I've also fitted a new vacuum from the inlet manifold to the map sensor.

I unplugged the lambda sensor but that had no effect. the ignition timing has been set correctly. The ECU has stored no fault codes. Compression shows 170 across all 4 cylinders.

The next step is a water temp sensor and maybe a lambda sensor. I can't think of anything else!

Any thoughts may be handy!

[mikey4410]

When I had miss firing on mine it was at a very specific rev (2,100) and it was the coil pack was dead.

and at idle it would cut out all together and not start for good few seconds.

I would check all fuses if you havent already.

other than that u have covered alot of the bases mate

Edited July 29, 2014 by mikey4410

[Dean_mc88]

I had a similar issue and it was a knock sensor and knock sensor wire however not fully fixed it as I ran out of time, after changing my knock sensor it got better but still did it around 5k then I re wired the knock sensor worked for 10 mins then started again because I didn't earth the shielding. I have a full engine loom to replace my cut up loom see if this sorts it properly

[richardc9052]

I had this recently and quite a few others have started to have the same symptoms in my area. Turned out to be very bad fuel with shit that seemed to get passed the filter and clog the injectors. With your car idling you can touch the injector and feel if any feel weak.

Myself and 2 others have had to change filter and injectors bury the cars run sweet now

[Aamir]

I had this recently and quite a few others have started to have the same symptoms in my area. Turned out to be very bad fuel with shit that seemed to get passed the filter and clog the injectors. With your car idling you can touch the injector and feel if any feel weak.

Myself and 2 others have had to change filter and injectors bury the cars run sweet now

I've replaced both the Injectors and the fuel filter and it hasn't made it any better. If anything it's made the problem worse..

Edit: Also the car is mapped on V-Power and that's what we always use in it (don't use anything else but V-Power)

Aamir

Edited July 29, 2014 by Aamir

[Stu]

What earth cables do you have running to the engine? Still have the one on the drivers engine mount and the main earth from the battery to the chassis and gearbox bolt? It may pay to check your ignitor/coil are both well earthed to the body.

[Idrees]

Thank you a all for your responses.

All fuses have been checked and I've replaced some of the relays just to rule that out.

The knock sensor or the wire hasn't been inspected. If I've ever had one of these fail before it always throws up a fault code, but I'll change it anyway and I'll have a good look at the wire.

As above the cars always ran on V power and the fuel filter was changed in a major service around 2 weeks before this problem occurred. I will be replacing the fuel pump next.

Stu it has the original earth cables but I fitted a full earthing kit while diagnosing the problem. It didn't help whatsoever.

[mitsuruki]

Idrees can you let me know when you fixed it or so because im having the same prob ):

[daniel_g]

I had a very similar problem recently, changed and checked everything youve done, was a mix of lots of little running issues but the main thing was the ignition leads werent sitting securely on the dizzy cap and were working loose.

[mitsuruki]

heard some friends state to me that it possible its idle sensor .. or tps .. so im going to bring it to a mecanic that i know pretty well to check for me and let you know if it improves

[funny onion]

I've had this issue on my GT.

After trying new ignition system i had it dyno'd and it was the actualy AFR that was the issue. Lack of fuel under boost was causing it to hesitate and stutter/misfire really badly. knocked the fueling up slightly and fitted a better rrfpr (with gauge to assist adjustment). then tried it on the road and did that until it ran smoother, but had it mapped to cure it (and we all know how that ended... lol...)

[mikey4410]

Idrees what afrs u getting at idle, cruise and wot ?

[Frankieflowers]

I checked the voltage output of the TPS. It jumps out of scale when opening the throttle slowly. This should mean that it doesn’t work smoothly.

I tried to find a new one but I cannot find it. Could you help?

The new reference n. Of Denso 198500-3011 is 

Toyota

89452-22090

[Sam44]

Lukep might be able to help I think he found a issue with the tps on the auto to manual conversation, I believe he was 1 of the first to do the conversation. If you message him. 

Edited February 27, 2022 by Sam44

[Claymore]

15 hours ago, Frankieflowers said:

I checked the voltage output of the TPS. It jumps out of scale when opening the throttle slowly. This should mean that it doesn’t work smoothly.

I tried to find a new one but I cannot find it. Could you help?

The new reference n. Of Denso 198500-3011 is 

Toyota

89452-22090

FYI never inspected an actual 4efte TPS. This info is from ECU pinouts and forum posts and my experience with the EP91 4efe TPS.

As far as I know the Automatic 4efte uses a potentiometer (variable resistance) style throttle position sensor. But the ECU pinouts also mention an idle sensor (switch?). So it may have a switch to show closed throttle and variable resistance for throttle angle.

9 E2 = Sensor earth

10 VTA / PSW = Throttle angle (fte Auto) / Full throttle (switch, fte manual)

11 VCC = 5v power

12 IDL = Idle position (throttle closed)

How many contact pins does the sensor have? 

Does the ECU show any error codes?

How are you measuring the sensor? Which pins are you checking?

 -----------------------------------------------------------------------------------------------------

Starlet 4efe EP91 which I have checked with a multi meter=

18 VCC = 5v (power)

16 E2 = Sensor Earth (earth)

17 VTA = Throttle angle (signal)

I've checked the TPS on my EP91 4efe starlet and it shows variable resistance between pins (3) VTA and (1) VCC when the throttle is turned.

Hope this helps!

Edited February 28, 2022 by Claymore

[Frankieflowers]

12 hours ago, Claymore said:

FYI never inspected an actual 4efte TPS. This info is from ECU pinouts and forum posts and my experience with the EP91 4efe TPS.

As far as I know the Automatic 4efte uses a potentiometer (variable resistance) style throttle position sensor. But the ECU pinouts also mention an idle sensor (switch?). So it may have a switch to show closed throttle and variable resistance for throttle angle.

9 E2 = Sensor earth

10 VTA / PSW = Throttle angle (fte Auto) / Full throttle (switch, fte manual)

11 VCC = 5v power

12 IDL = Idle position (throttle closed)

How many contact pins does the sensor have? 

Does the ECU show any error codes?

How are you measuring the sensor? Which pins are you checking?

 -----------------------------------------------------------------------------------------------------

Starlet 4efe EP91 which I have checked with a multi meter=

18 VCC = 5v (power)

16 E2 = Sensor Earth (earth)

17 VTA = Throttle angle (signal)

I've checked the TPS on my EP91 4efe starlet and it shows variable resistance between pins (3) VTA and (1) VCC when the throttle is turned.

Hope this helps!

Thank you. Pin one and three are the feeder. The sensor has four pins. It jumps weirdly at a certain point of the throttle opening position that is what makes the acceleration weird between 2000 and 4000 RPM. 

[Claymore]

Found this on another forum....

From the diagram looks like the idle contact is a switch.

Test between E2-IDL with continuity setting (beeeeeeeep when at idle, open circuit off idle position)

Test between VTA-VC with resistance setting (resistance should change smoothly as the throttle is turned.)

That's how I would test it.

The EP82 4efte use 89452-14020 for 89-92

The EP82 / EP91 4efte use 89452-22090 for 92-99

[Frankieflowers]

8 hours ago, Claymore said:

Found this on another forum....

From the diagram looks like the idle contact is a switch.

Test between E2-IDL with continuity setting (beeeeeeeep when at idle, open circuit off idle position)

Test between VTA-VC with resistance setting (resistance should change smoothly as the throttle is turned.)

That's how I would test it.

The EP82 4efte use 89452-14020 for 89-92

The EP82 / EP91 4efte use 89452-22090 for 92-99

This is a useful information. Thank you very much  Today I set the timing from 7° back to 10° to see how it would react. The engine is running better in mid range and let’s say it’s back to normal behavior. I still have to run the test you suggested because it is obvious that it isn’t acting to its normal specifications. 

[Frankieflowers]

I bought from Japan a new TPS and a new rotator with NGK wires. I also bought a new distributor cap. I read it just in case so I have everything fresh. 

[Frankieflowers]

8 hours ago, Claymore said:

Found this on another forum....

From the diagram looks like the idle contact is a switch.

Test between E2-IDL with continuity setting (beeeeeeeep when at idle, open circuit off idle position)

Test between VTA-VC with resistance setting (resistance should change smoothly as the throttle is turned.)

That's how I would test it.

The EP82 4efte use 89452-14020 for 89-92

The EP82 / EP91 4efte use 89452-22090 for 92-99

I just spoke to my brother that the other day came by to test the TPS. We ran this test already and we discovered that with the opening of the throttle the tension was jumping in the mid range area and would then go back to lower levels of tension. This is a symptom of consumed graphite. This is why I bought a new one from Japan to see if it will solve the problem. 

[Frankieflowers]

How do I change the 4 pin RPS on the 4efte? Do I need to reset the ECU after? HOW? @Sam44 @Claymore

[Sam44]

Just disconnect the battery or pull the efi fuse for 10sec. 

[Claymore]

5 hours ago, Frankieflowers said:

How do I change the 4 pin RPS on the 4efte? Do I need to reset the ECU after? HOW? @Sam44 @Claymore

It's best practice to disconnect the battery before working on the electronics to prevent shorts / sparking problems.

There must also be a procedure for calibrating the new tps compared to throttle opening angle so the idle contact only connects at idle, as soon as the throttle is open a fraction the idle contact must open. Loosen screws, turn tps, check for continuity, feeler gauges etc..?

[Frankieflowers]

1 hour ago, Claymore said:

It's best practice to disconnect the battery before working on the electronics to prevent shorts / sparking problems.

There must also be a procedure for calibrating the new tps compared to throttle opening angle so the idle contact only connects at idle, as soon as the throttle is open a fraction the idle contact must open. Loosen screws, turn tps, check for continuity, feeler gauges etc..?

I will disconnect the battery and replace the TPS. I will try the voltage that must be between 3 and 7. I did not find any procedure besides making sure that the sensor is installed properly. I am still looking for a video to see if I can get it off without disassembling the throttle. 

[Frankieflowers]

Hey guys. I received the new distributor cap, rotor, NGK wires and dust cat seal from Japan. I already change the small gasket on the cam when we opened the engine. Although there is still a small leak in the distributor cap. I read around that it might be the bearing or the bearing ceiling gasket. It could be leaking around the shaft. we did take care of putting ceiling paste in the proper position to avoid it but it still leaks. This is why I also bought a new bearing. I haven’t found information about a distributor regeneration on this model. Do you guys have experience of putting one apart and replacing these parts for regeneration?

I also received the new TPS. I would like a piece of advice to change it. I understand the procedure about the position and electric check that has been done and I would like to know if the throttle has to be unbolted to do the job. 
 

if I am correct, the four pin TPS reads from 0 to 100 with its fader. There is no switch. The three pin TPS works differently but that is not my case. 

Edited March 19, 2022 by Frankieflowers