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The mkiv Supra Owners Club

Need Help With The Supra Asap Please......


MattP
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Il try to be brief in my explanation bet basically my Full BPU 98 VVTI TT Supra has spat its dummy and I have spent all week trying to solve the cars issues but to no avail...

 

The issues are that...

 

1. I struggle to hit 0.20 boost

 

2. when started the car feels either like its going to stall or it is revving upto 1500rpm

 

 

I have stripped the car down and tried the following to resolve the issue.

 

1. replaced all spark plugs

 

2. swapped a boost pressure sensor for a Hodge had

 

3. replaced all vac pipes with silicone pipes

 

4.checked all sensors and components relating to boost I can think of

 

5.Fuel and Oil Filter changed

 

6. cleaned all coilpacks and connectors JM Imports have fitted new coil pack connectors on import last august.

 

 

Could a Fubard O2 sensor cause this?

 

 

Somebody give me a clue what it could be before I set the F****** thing on fire its making me suicidal

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all vac hoses fine..

 

Intercooler is fine and only 3 or so months old

 

all intercooler pipes are Whifbitz silicon smic replacements with Murray constant tension clamps and are all fine

 

Graham dont push me im on the edge.... The edge I tell you lol

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A fooked map sensor would see your revs all over the place and affect the boost. Do you get any black smoke when you rev it at all?

 

No mate I got another map sensor off hodge last week and its the same so that rules the sensor out..

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I just had issues turbo 2 wouldn't boost properly turns out my baffles had collapsed in my HKS super silent all that money for an exhaust I thought it would last a little longer than 5 years pulled baffles out problem fixed but it is slightly louder

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Matt, a couple of things, does it sound quite rough as well? you have covered most of the bases, I had a problem about 4 years ago that sounds similar and it turned out to be the exhaust gas control valve not the little switchie valve but the gert big one between the turbo exhausts and the exhaust, they are known for jamming, mine was stuck open, which gives you similar symptoms. with the engine off, see if you can reach down to grab the actuator arm and see if you can move it, this is not easy though, you may have to put some mole grips on it so you can give it some, even normal operation it takes some moving.

Just a suggestion if all else has failed, in the end I fitted another 2nd hand one, never happened again.

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What happens if you pull the crankcase ventilation valve out of the inlet cam cover and block the valve with your finger? Does it idle properly then?

 

We have spent the day replacing every sequential system hose with new braided rubber ones apart from the pressure tank which has 4mm silicon on which we will replace tomorrow when stripping the intake side down.

 

Notably when we started the car it idles high then comes down to around 4-500 revs and stinks of fuel it also sounds like it is missing like hell although yesterday we changed all the plugs and checked the coilpacks etc everything seems in order in there...

 

Moving on we took the car out for a spin it boosted this time upto 1bar but still doesnt feel right, as we pulled it back into the garage it was spluttering at idle of around 400-500rpm

and stunk of fuel and of course was missing still so we shut it off to scratch our heads a few minutes later we attempted to start the car it chugged into life and then cut out we tried once more same result.

 

Moving on again 5 minutes later I read this thread and saw your comment Chris so back out I went the car started straight away and idled at 1100rpm we tried doing as you asked but to no avail pulling the valve and covering it made little difference its still got a lumpy idle and stinks of fuel....

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theres 2 sensors, one for the gauge one for the ECU

 

i bust mine while doing my valve stem seals on my old supra, Idled like a pig and stunk of fuel, but still drove, allbeit slugishly

 

The sensors are on the waterneck

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You *MUST* have the two pin plug connected to the ecu water temp sensor at all times, it needs that signal. I believe you say it has a fuel cut eliminator / raiser (possibly Greddy or HKS?) Disconnected the red wire and connect the yellow and green together (effectively by passing it. A faulty FCD will cause those symptoms. Certainly a disconnected ecu water temp sensor will cause bad cold starting, but a stock ecu will fall back to a limp home mode if it sees the sensor as open. It is not very clever if it sees a weird MAP sensor voltage though, so a faulty FCD could certainly be the cause. Since you may have run it with the water sensor for the ECU disconnected it *SHOULD* now have a fault code stored for that. Has it? If I misunderstood and you didn't actually RUN it with it disconnected, warm it up, stop the engine, disconnect the two pin water temp sensor, and start it again. You should now have a fault code stored. If you try it from stone cold with that sensor disconnected it will be a pig to start. It will be a simple test for if the ecu and engine management light are working together correctly. Is there a solid vacuum source to the fuel pressure regulator valve? Pulling the pipe on and off should alter how the engine runs.

 

If you feel happy you could try measuring the voltage the MAP sensor signal wire is sending back to the ecu, firstly at the sensor, then at the ecu itself. Do it wrong and you just might fry the ecu though, although it should have protection against most mistakes.

I would bypass the FCD first though, if it has one and you have never tried that I feel confident it may well be your issue.

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You *MUST* have the two pin plug connected to the ecu water temp sensor at all times, it needs that signal. I believe you say it has a fuel cut eliminator / raiser (possibly Greddy or HKS?) Disconnected the red wire and connect the yellow and green together (effectively by passing it. A faulty FCD will cause those symptoms. Certainly a disconnected ecu water temp sensor will cause bad cold starting, but a stock ecu will fall back to a limp home mode if it sees the sensor as open. It is not very clever if it sees a weird MAP sensor voltage though, so a faulty FCD could certainly be the cause. Since you may have run it with the water sensor for the ECU disconnected it *SHOULD* now have a fault code stored for that. Has it? If I misunderstood and you didn't actually RUN it with it disconnected, warm it up, stop the engine, disconnect the two pin water temp sensor, and start it again. You should now have a fault code stored. If you try it from stone cold with that sensor disconnected it will be a pig to start. It will be a simple test for if the ecu and engine management light are working together correctly. Is there a solid vacuum source to the fuel pressure regulator valve? Pulling the pipe on and off should alter how the engine runs.

 

If you feel happy you could try measuring the voltage the MAP sensor signal wire is sending back to the ecu, firstly at the sensor, then at the ecu itself. Do it wrong and you just might fry the ecu though, although it should have protection against most mistakes.

I would bypass the FCD first though, if it has one and you have never tried that I feel confident it may well be your issue.

 

The car HAS NOT been run with any of the sensors unplugged Chris Im sorry I should have been more clear on that, I only had the sensors disconnected while the car was in bits.

 

Yes the car has a HKS FCD that JM-IMPORTS fitted I have never seen it or the ECU yet Il have a look at it tomorrow.

 

Il check the FPR line is that the one that goes past the injectors onto the upper inlet?

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Yes, it's fed from a tiny bore, filtered Sputnik think on the plenum. I feel kind of confident the FCD has died and bypassing it (cut red to it, insulate the red from whatever ecu wire they picked 12V + up from, and join the yellow and blue on the car side of the loom after cutting those). You are effectively isolating 12V + from the FCD, and joining the black with yellow tracer wires from the ecu and from the MAP sensor signal pin back together again, as stock. The FCD should be under the ECU plastic cover somewhere, hanging about on its leads. Won't be far from the ecu, they have shortish wires. Maybe tucked UNDER the ECU? Good luck!

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Just checked Chris 100% no fault codes

 

and pulled the fpr line off from the black device on the rail it moved the revs somewhat but the car was still missing.

 

the line had suction coming from the inlet sensor if thats normal...

 

I will have a look at the HKS device tomorrow Chris thanks for your help.

Edited by MattP (see edit history)
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