Celica Gt 4 (gen 5)

[benje]

Hi, I'm new here and I'm really posting this on behalf of a friend who owns a 1990 Celica GT4.

Now my mate know very very little about cars, and brought this car because of its looks, however he doesnt know if its been modified or not, from what I can tell its had a dump valve, very big exhaust, lowered and new wheels, as for whether the boost has been wound up or not I couldnt say, or if he's got some sort of Hybrid on there.

Anyway when he's coming upto about 3000 - 4000 RPm, (when the Turbo is supposed to kick in) he tells me that it begins to stutter, theres no boost pressure and from what I can gather the revs are being limited as well, having only worked on my own car (Dont laugh a peugeot 306!!!!) I'm at a loss to know where to start looking.

One thing is for certain though, he doesnt look after it, thrapes it first thing in the morning, turns it off straight away after caning it, now I'm thinking has he knackered the turbo on this? It doesnt seem to be using oil?!?

Correct me if I'm wrong and I might be talking crap here, but if the Turbo is siezed and the ECU doesnt measure boost pressure, could it be over fuelling badly at the point of where the boost should be coming in?!? hence the crap running ?!?

Thanks for anyhelp

Ben

[Sirius]

Hi Ben

If your mate is driving the car like this I am reluctant to help out - he will cause himself or a future owner all manner of problems in the future.

However - It sounds like the car has reached whats called 'fuel-cut' where the ECU detects over boost. This condition requires a reset to remove, warm the car up then switch off and pull the 15 amp ECU fuse in the Fusebox and wait a couple minutes - put the fuse back in, take the car out for a GENTLE off boost for about 5 minutes then try to use some boost and see what happens.

Hopefully this will fix it, but his turbo will certainly not last long if he has hit fuelcut then chances are the boost pressure has been increased - increased boost + no warm up + no cool down = ££££ in a new turbo :(

[GT-Four NZ]

If boost is coming at 3000 to 4000 rpm it ain't standard. Did your mate buy it while it was doin this??? I get boost at 2000-2500 and the fact that your mates is coming soo late... sort of not sounding like he still has a the ceramic turbo under the hood. There should be TOYOTA CT-26 on the side of the compressor housing. I wouldn't worry bout the turbo tho cos turnign those things off after raping them is a sure fire way to arrive at a rebuild or replacement. If he's driving it like that I would hope he writes it off so no-one has the unfortunate experience of buying it in the future.

[benje]

Thanks for the replys guys.

I've told him hundreds of times about his driving and he wont listen. He managed to destroy a peugeot 306 Diesel in a short time, and then moving to this I honestly wasnt expecting it to last long!!! He's had it about 6 months and it was perfect before (Owned by another mate who knew about cars)

Anyway I'll have a look for him this afternoon, Is there anyway I can check the shaft play in his turbo, whats access like? I know you can check it on a Escort Cosworth easy enough, but what about a celica?!?

Cheers

Ben

[GT-Four NZ]

Not incredibly difficult, just remove the intake piping from the mouth of the turbo. the compressor wheel is just there. I cant remember if you need to remove air box to make it easier to get at but i think that jsut that short "s" section should be fine.

[benje]

Ok, bit of an update on this. Went out with him in the car. The Battery had died and had been taken off to be charged so I assume the ECU had been reset. Anyway car started after a bit and seemed to be running OK until it warmed up and the hesitation came back, it feels to me as though its ignition related as if it missis then goes OK again.

Only hesitating under med/heavy acceleration at certain revs, its holding back a bit

I've suggested he gets the HT leads and spark plugs replaced to see if that clears it up, is there anything else?

I can say its definatly not the turbo, all seems fine there (was only going on my mates word before )

[Sirius]

Plugs, HT Leads, Distrubutor cap and rotor arm.

If its an import be sure to run it on super unleaded as a minimum.